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  • 1.
    Bagheri, Maryam
    et al.
    Ilam University of Medical Science, Iran .
    Rezakhani, Arjang
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Nyström, Sofie
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Roghani, Mehrdad
    Shahed University, Iran .
    Hammarström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Mohseni, Simin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Amyloid Beta1-40-Induced Astrogliosis and the Effect of Genistein Treatment in Rat: A Three-Dimensional Confocal Morphometric and Proteomic Study2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 10Article in journal (Refereed)
    Abstract [en]

    Astrocytes are highly involved in regulation and homeostasis of the extracellular environment in the healthy brain. In pathological conditions, these cells play a major role in the inflammatory response seen in CNS tissues, which is called reactive astrogliosis and includes hypertrophy and proliferation of astrocytes. Here, we performed 3D confocal microscopy to evaluate the morphological response of reactive astrocytes positive for glial fibrillary acidic protein (GFAP) in rats, to the presence of Aβ1–40 in the rat brain before and after treatment with genistein. In 50 astrocytes per animal, we measured the volume and surface area for the nucleus, cell body, the entire cell, the tissue covered by single astrocytes and quantified the number and length of branches, the density of the astrocytes and the intensity of GFAP immunoreactivity. Injecting Aβ1–40 into the brain of rats caused astrogliosis indicated by increased values for all measured parameters. Mass spectrometric analysis of hippocampal tissue in Aβ1–40-injected brain showed decreased amounts of tubulins, enolases and myelin basic protein, and increased amounts of dihydropyrimidinase-related protein 2. In Aβ1–40-injected rats pretreated with genistein, GFAP intensity was decreased to the sham-operated group level, and Aβ1–40-induced astrogliosis was significantly ameliorated.

  • 2.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Umeå University, Umeå, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Fowler, Christopher J.
    Umeå University, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Linn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Effects of Two Different Specific Neck Exercise Interventions on Palmitoylethanolamide and Stearoylethanolamide Concentrations in the Interstitium of the Trapezius Muscle in Women with Chronic Neck Shoulder Pain2014In: Pain medicine (Malden, Mass.), ISSN 1526-2375, E-ISSN 1526-4637, Vol. 15, no 8, p. 1379-1389Article in journal (Refereed)
    Abstract [en]

    Purpose. Chronic neck/shoulder pain (CNSP) is one of the most common pain conditions. The understanding of mechanisms, including the peripheral balance between nociceptive and antinociceptive processes, is incomplete. N-acylethanolamines (NAEs) are a class of endogenous compounds that regulate inflammation and pain. The aim of this study was to investigate the levels of two NAEs: the peroxisome proliferator-activated receptor type-a ligand palmitoylethanolamide (PEA) and stearoylethanolamide (SEA) in the muscle interstitium of the trapezius muscle in women with CNSP randomized to two different neck specific training programs and in a healthy pain-free control group (CON). Materials and Methods. Fifty-seven women with CNSP were randomized to strength + stretch or stretch alone exercise programs. Twenty-nine subjects underwent microdialysis procedure before and after 4-6 months of exercise. Twenty-four CON subjects underwent microdialysis procedure before and after 4-6 months without any intervention in between. Microdialysate samples were collected from the trapezius muscle and analyzed by mass spectrometry for PEA and SEA levels. Results. PEA and SEA levels were significantly higher in CNSP patients compared with CON. PEA was significantly higher in CNSP than in CON after both training programs. SEA was significantly higher in CNSP than in CON after stretch alone but not after strength + stretch training. A significant positive correlation was found between changes in pain intensity and in SEA levels in the strength + stretch group, but not in the stretch alone group. Conclusion. Our results indicate that exercise interventions differentially affect the levels of the bioactive lipids PEA and SEA in the interstitium of the trapezius muscle in women with CNSP.

  • 3.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Linn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Fowler, Christopher J.
    Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    High Levels of N-Palmitoylethanolamide and N-Stearoylethanolamide in Microdialysate Samples from Myalgic Trapezius Muscle in Women2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 11Article in journal (Refereed)
    Abstract [en]

    Background: N-acylethanolamines (NAEs) are endogenous compounds that regulate inflammation and pain. These include the cannabinoid ligand anandamide (AEA) and the peroxisome proliferator-activated receptor-a ligand palmitoylethanolamide (PEA). Little is known as to the levels of NAEs in pain states in human, particularly in the skeletal muscle. The aim of this study was to investigate the levels of these lipid mediators in muscle dialysate from women with chronic neck-/shoulder pain compared to healthy controls. Methods: Eleven women with chronic neck-/shoulder pain and eleven healthy women participated in this study. All participants went through microdialysis procedures in the trapezius muscle. Muscle dialysate samples were collected during four hours and analysed by nano liquid chromatography tandem mass spectrometry (nLC-MS/MS). Results: We were able to detect AEA, PEA, N-stearoylethanolamine (SEA) and 2-arachidonoylglycerol (2-AG) in a single chromatographic run. Of the NAEs studied, PEA and SEA were clearly detectable in the muscle microdialysate samples. The muscle dialysate levels of PEA and SEA were significantly higher in myalgic subjects compared to healthy controls. Conclusion: This study demonstrates that microdialysis in combination with mass spectrometry can be used for analysing NAEs in human muscle tissue regularly over time. Furthermore the significant group differences in the concentration of PEA and SEA in this study might fill an important gap in our knowledge of mechanisms in chronic myalgia in humans. In the long run this expanded understanding of nociceptive and anitinociceptive processes in the muscle may provide a base for ameliorating treatment and rehabilitation of pain.

  • 4.
    Hadrévi, Jenny
    et al.
    Umeå University, Sweden.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Carlsson, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Linköping University, Faculty of Medicine and Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Hellström, Fredrik
    University of Gävle, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Myosin light chain and calcium regulating protein differences in chronic musculoskeletal neck and shoulder pain2016In: Journal of Integrated OMICS, ISSN 2182-0287, Vol. 6, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Proteomic screening analysis has detected myosin light chain (MLC) as a protein implied to be involved in chronic musculoskeletal neck and shoulder pain. Several analyses of MLC proteins have stated a difference in phosphorylation being the determining factor for protein activation hence altered contrability of the muscle in i.e. senescence. In continuation of a previous publication, this study is an attempt to analyze the different MLC isoforms by mass spectrometry and immune-analyses in myalgic and healthy trapezius muscle. In the present study no differences in phosphorylation level between the corresponding individual proteins were detected using LC-MSMS and immunoblotting; instead we assigned different isoforms of regulatory MLCs. To further elucidate the contrability: calcium (Ca2+) regulatory proteins, sarco(endo)plasmic reticulum Ca2+ ATPase 1 (SERCA-1) and calsequestrine (CSQ) were analyzed by western blot. The analysis revealed a significantly increased abundance of SERCA-1 protein in the myalgic muscle and a significantly increased abundance of CSQ in healthy muscle. Myalgic muscle contraction patterns have in previous studies shown to differ from healthy muscle which may be connected to the Ca2+ availability in the muscle. Here we present the proteomic characterization of differences in Ca2+ regulating proteins and particularly regulatory MLCs in trapezius muscle of women with chronic musculoskeletal neck and shoulder pain.

  • 5.
    Herbstova, Miroslava
    et al.
    Washington State University, USA Academic Science Czech Republic, Czech Republic University of S Bohemia, Czech Republic .
    Tietz, Stefanie
    Washington State University, USA .
    Kinzel, Christopher
    Washington State University, USA .
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Kirchhoff, Helmut
    Washington State University, USA .
    Architectural switch in plant photosynthetic membranes induced by light stress2012In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 109, no 49, p. 20130-20135Article in journal (Refereed)
    Abstract [en]

    Unavoidable side reactions of photosynthetic energy conversion can damage the water-splitting photosystem II (PSII) holocomplex embedded in the thylakoid membrane system inside chloroplasts. Plant survival is crucially dependent on an efficient molecular repair of damaged PSII realized by a multistep repair cycle. The PSII repair cycle requires a brisk lateral protein traffic between stacked grana thylakoids and unstacked stroma lamellae that is challenged by the tight stacking and low protein mobility in grana. We demonstrated that high light stress induced two main structural changes that work synergistically to improve the accessibility between damaged PSII in grana and its repair machinery in stroma lamellae: lateral shrinkage of grana diameter and increased protein mobility in grana thylakoids. It follows that high light stress triggers an architectural switch of the thylakoid network that is advantageous for swift protein repair. Studies of the thylakoid kinase mutant stn8 and the double mutant stn7/8 demonstrate the central role of protein phosphorylation for the structural alterations. These findings are based on the elaboration of mathematical tools for analyzing confocal laser-scanning microscopic images to study changes in the sophisticated thylakoid architecture in intact protoplasts.

  • 6.
    Ingelsson, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Fristedt, Rikard
    Biophysics of Photosynthesis Physics and Astronomy Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Phosphorylation stoichiometry determination in plant photosynthetic membranes.2015In: Plant Phosphoproteomics: Methods and Protocols / [ed] Waltraud X. Schulze, New York: Springer-Verlag New York, 2015, p. 121-134Chapter in book (Refereed)
    Abstract [en]

    This chapter describes different strategies for the study of phosphorylation dynamics and stoichiometry in photosynthetic membranes. Detailed procedures for the detection, large-scale identification, and quantification of phosphorylated proteins optimized for plant thylakoid proteins are given.

  • 7.
    Kargul, Joanna
    et al.
    Wolfson Laboratories, Division of Molecular Biosciences, Imperial College London, UK .
    Turkina, Maria V
    Linköping University, Department of Clinical and Experimental Medicine, Cellbiology. Linköping University, Faculty of Health Sciences.
    Nield, Jon
    Wolfson Laboratories, Division of Molecular Biosciences, Imperial College London, UK .
    Benson, Sam
    Wolfson Laboratories, Division of Molecular Biosciences, Imperial College London, UK .
    Vener, Alexander V
    Linköping University, Department of Clinical and Experimental Medicine, Cellbiology. Linköping University, Faculty of Health Sciences.
    Barber, James
    Wolfson Laboratories, Division of Molecular Biosciences, Imperial College London, UK .
    Light-harvesting complex II protein CP29 binds to photosystem I of Chlamydomonas reinhardtii under State 2 conditions2005In: The FEBS journal, ISSN 1742-464X, Vol. 272, no 18, p. 4797-4806Article in journal (Refereed)
    Abstract [en]

    The State 1 to State 2 transition in the photosynthetic membranes of plants and green algae involves the functional coupling of phosphorylated light-harvesting complexes of photosystem II (LHCII) to photosystem I (PSI). We present evidence suggesting that in Chlamydomonas reinhardtii this coupling may be aided by a hyper-phosphorylated form of the LHCII-like CP29 protein (Lhcbm4). MS analysis of CP29 showed that Thr6, Thr16 and Thr32, and Ser102 are phosphorylated in State 2, whereas in State 1-exposed cells only phosphorylation of Thr6 and Thr32 could be detected. The LHCI–PSI supercomplex isolated from the alga in State 2 was found to contain strongly associated CP29 in phosphorylated form. Electron microscopy suggests that the binding site for this highly phosphorylated CP29 is close to the PsaH protein. It is therefore postulated that redox-dependent multiple phosphorylation of CP29 in green algae is an integral part of the State transition process in which the structural changes of CP29, induced by reversible phosphorylation, determine the affinity of LHCII for either of the two photosystems.

  • 8.
    Karlsson, Helen
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre. Östergötlands Läns Landsting.
    Sundberg, Sofie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Levels, J H M
    Acad Med Centre, Amsterdam, Netherlands .
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Daniel, G
    National Centre for Science Research Demokritos.
    Chroni, A
    National Centre for Science Research Demokritos.
    Kuivenhoven, J A
    Acad Med Centre, Amsterdam, Netherlands .
    Hovingh, G K
    Acad Med Centre, Amsterdam, Netherlands.
    Holleboom, A G
    Acad Med Centre, Amsterdam, Netherlands.
    Lindahl, Mats
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    MUTANT apo A-I (L178P) IDENTIFIED IN HDL FROM HETEROZYGOTES OF A FAMILY WITH ENDOTHELIAL DYSFUNCTION AND INCREASED ARTERIAL WALL THICKNESS in ATHEROSCLEROSIS SUPPLEMENTS, vol 11, issue 2, pp 67-672010In: ATHEROSCLEROSIS SUPPLEMENTS, Elsevier Science B.V., Amsterdam. , 2010, Vol. 11, no 2, p. 67-67Conference paper (Refereed)
    Abstract [en]

    n/a

  • 9.
    Karlsson, Thommie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Yakymenko, Olena
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Vikström, Elena
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    The Pseudomonas aeruginosa N-Acylhomoserine Lactone Quorum Sensing Molecules Target IQGAP1 and Modulate Epithelial Cell Migration2012In: PLOS PATHOGENS, ISSN 1553-7374, Vol. 8, no 10Article in journal (Refereed)
    Abstract [en]

    Quorum sensing (QS) signaling allows bacteria to control gene expression once a critical population density is achieved. The Gram-negative human pathogen Pseudomonas aeruginosa uses N-acylhomoserine lactones (AHL) as QS signals, which coordinate the production of virulence factors and biofilms. These bacterial signals can also modulate human cell behavior. Little is known about the mechanisms of the action of AHL on their eukaryotic targets. Here, we found that N-3-oxododecanoyl- L-homoserine lactone 3O-C-12-HSL modulates human intestinal epithelial Caco-2 cell migration in a dose- and time-dependent manner. Using new 3O-C-12-HSL biotin and fluorescently-tagged probes for LC-MS/MS and confocal imaging, respectively, we demonstrated for the first time that 3O-C-12-HSL interacts and co-localizes with the IQ-motif-containing GTPase-activating protein IQGAP1 in Caco-2 cells. The interaction between IQGAP1 and 3O-C-12-HSL was further confirmed by pull-down assay using a GST-tagged protein with subsequent Western blot of IQGAP1 and by identifying 3O-C-12-HSL with a sensor bioassay. Moreover, 3O-C-12-HSL induced changes in the phosphorylation status of Rac1 and Cdc42 and the localization of IQGAP1 as evidenced by confocal and STED microscopy and Western blots. Our findings suggest that the IQGAP1 is a novel partner for P. aeruginosa 3O-C-12-HSL and likely the integrator of Rac1 and Cdc42- dependent altered cell migration. We propose that the targeting of IQGAP1 by 3O-C-12-HSL can trigger essential changes in the cytoskeleton network and be an essential component in bacterial - human cell communication.

  • 10.
    Lemeille, Sylvain
    et al.
    University of Geneva.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Vener, Alexander
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Rochaix, Jean-David
    University of Geneva.
    Stt7-dependent Phosphorylation during State Transitions in the Green Alga Chlamydomonas reinhardtii2010In: Molecular & Cellular Proteomics, ISSN 1535-9476, E-ISSN 1535-9484, Vol. 9, no 6, p. 1281-1295Article in journal (Refereed)
    Abstract [en]

    Photosynthetic organisms are able to adapt to changes in light conditions by balancing the light excitation energy between the light-harvesting systems of photosystem (PS) II and photosystem I to optimize the photosynthetic yield. A key component in this process, called state transitions, is the chloroplast protein kinase Stt7/STN7, which senses the redox state of the plastoquinone pool. Upon preferential excitation of photosystem II, this kinase is activated through the cytochrome b(6)f complex and required for the phosphorylation of the light-harvesting system of photosystem II, a portion of which migrates to photosystem I (state 2). Preferential excitation of photosystem I leads to the inactivation of the kinase and to dephosphorylation of light-harvesting complex (LHC) II and its return to photosystem II (state 1). Here we compared the thylakoid phosphoproteome of the wild-type strain and the stt7 mutant of Chlamydomonas under state 1 and state 2 conditions. This analysis revealed that under state 2 conditions several Stt7-dependent phosphorylations of specific Thr residues occur in Lhcbm1/Lhcbm10, Lhcbm4/Lhcbm6/Lhcbm8/Lhcbm9, Lhcbm3, Lhcbm5, and CP29 located at the interface between PSII and its light-harvesting system. Among the two phosphorylation sites detected specifically in CP29 under state 2, one is Stt7-dependent. This phosphorylation may play a crucial role in the dissociation of CP29 from PSII and/or in its association to PSI where it serves as a docking site for LHCII in state 2. Moreover, Stt7 was required for the phosphorylation of the thylakoid protein kinase Stl1 under state 2 conditions, suggesting the existence of a thylakoid protein kinase cascade. Stt7 itself is phosphorylated at Ser(533) in state 2, but analysis of mutants with a S533A/D change indicated that this phosphorylation is not required for state transitions. Moreover, we also identified phosphorylation sites that are redox (state 2)-dependent but independent of Stt7 and additional phosphorylation sites that are redox-independent.

  • 11.
    Ljunggren, Stefan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences.
    Levels, Johannes H M
    Department of Vascular Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
    Turkina, Maria V
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Sundberg, Sofie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Bochem, Andrea E
    Department of Vascular Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
    Hovingh, Kees
    Department of Vascular Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
    Holleboom, Adriaan G
    Department of Vascular Medicine, Academic Medical Centre, Amsterdam, The Netherlands.
    Lindahl, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences.
    Kuivenhoven, Jan Albert
    University of Groningen, Groningen, The Netherlands.
    Karlsson, Helen
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    ApoA-I mutations, L202P and K131del, in HDL from heterozygotes with low HDL-C2014In: PROTEOMICS - Clinical Applications, ISSN 1862-8346, E-ISSN 1862-8354, Vol. 8, no 3-4, p. 241-250Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Mutations in apolipoprotein A-I (apoA-I) may affect plasma high-density lipoprotein (HDL) cholesterol levels and the risk for cardiovascular disease but little is known about the presence and effects of circulating apoA-I variants. This study investigates whether the apoA-I mutations, apoA-I(L202P) and apoA-I(K131del) , are present on plasma HDL particles derived from heterozygote carriers and whether this is associated to changes in HDL protein composition.

    EXPERIMENTAL DESIGN: Plasma HDL of heterozygotes for either apoA-I(L202P) or apoA-I(K131del) and family controls was isolated using ultracentrifugation. HDL proteins were separated by 2DE and analyzed by MS.

    RESULTS: ApoA-I peptides containing apoA-I(L202P) or apoA-I(K131del) were identified in HDL from heterozygotes. The apoA-I(L202P) mutant peptide was less abundant than wild-type peptide while the apoA-I(K131del) mutant peptide was more abundant than wild-type peptide in the heterozygotes. Two-dimensional gel electrophoresis analyses indicated that, compared to controls, HDL in apoA-I(L202P) carriers contained less apoE and more zinc-α-2-glycoprotein while HDL from the apoA-I(K131del) heterozygotes contained more alpha-1-antitrypsin and transthyretin.

    CONCLUSIONS AND CLINICAL RELEVANCE: Both apoA-I(L202P) and apoA-I(K131del) were identified in HDL. In heterozygotes, these mutations have markedly differential effects on the concentration of wild-type apoA-I in the circulation, as well as the HDL proteome, both of which might affect the clinical phenotype encountered in the heterozygous carriers.

  • 12.
    Ramezani, Amir
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Eng, Lars
    The Institute for Protein Environmental Affinity Surveys (PEAS Institute).
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Divison of Neurobiology. Linköping University, Faculty of Medicine and Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Nayeri, Fariba
    The Institute for Protein Environmental Affinity Surveys (PEAS Institute).
    A Sputum Screening Test to Rule Out Pneumonia at an Early Stage With High Negative Predictive Value2018In: Point of Care, ISSN 1533-029X, Vol. 17, no 4, p. 101-108Article in journal (Refereed)
    Abstract [en]

    Background Pneumonia is a serious and widespread cause of morbidity and mortality. At an early stage, the symptoms are similar to other respiratory disorders, and there is no single criterion standard for diagnosis. Antibiotics are used too often as a precaution.

    Objectives The objective of this study was to perform an assessment and clinical evaluation of a rapid sputum screening test (index test) to rule out pneumonia.

    Methods Leftover sputum samples (467) collected at the Department of Microbiology from November 2016 to March 2017 were blindly analyzed within 72 hours with the index test. The clinical accuracy of the test was estimated for pneumonia by comparison with the established diagnosis by independent physicians (International Classification of Diseases, 10th Revision). Hepatocyte growth factor and calprotectin were measured on random samples (80), and layman volunteers (40) were asked to perform the test on artificial samples.

    Results Two of 73 cases of pneumonia (community-acquired and nosocomial) showed negative results by the sputum strip test (97% sensitivity and 94% negative predictive value). The test results were highly correlated to hepatocyte growth factor and calprotectin concentrations in samples (R 2 = 67% respective 39%). Importantly, all of the volunteers were able to estimate the correct positive and negative results.

    Conclusions The novel rapid sputum test represents a feasible tool for screening and ruling out the overwhelming majority of nonsevere respiratory infections at primary care settings, at home or when properly equipped laboratories are not available.

  • 13.
    Rohini Rajan, Meenu
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Fagerholm, Siri
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Jonsson, Cecilia
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Kjölhede, Preben
    Linköping University, Department of Clinical and Experimental Medicine, Obstetrics and gynecology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Phosphorylation of IRS1 at Serine 307 in Response to Insulin in Human Adipocytes Is Not Likely to be Catalyzed by p70 Ribosomal S6 Kinase2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 4Article in journal (Refereed)
    Abstract [en]

    The insulin receptor substrate-1 (IRS1) is phosphorylated on serine 307 (human sequence, corresponding to murine serine 302) in response to insulin as part of a feedback loop that controls IRS1 phosphorylation on tyrosine residues by the insulin receptor. This in turn directly affects downstream signaling and is in human adipocytes implicated in the pathogenesis of insulin resistance and type 2 diabetes. The phosphorylation is inhibited by rapamycin, a specific inhibitor of mammalian target of rapamycin (mTOR) in complex with raptor (mTORC1). The mTORC1-downstream p70 ribosomal protein S6 kinase (S6K1), which is activated by insulin, can phosphorylate IRS1 at serine 307 in vitro and is considered the physiological protein kinase. Because the IRS1 serine 307-kinase catalyzes a critical step in the control of insulin signaling and constitutes a potential target for treatment of insulin resistance, it is important to know whether S6K1 is the physiological serine 307-kinase or not. We report that, by several criteria, S6K1 does not phosphorylate IRS1 at serine 307 in response to insulin in intact human primary adipocytes: (i) The time-courses for phosphorylation of S6K1 and its phosphorylation of S6 are not compatible with the phosphorylation of IRS1 at serine 307; (ii) A dominant-negative construct of S6K1 inhibits the phosphorylation of S6, without effect on the phosphorylation of IRS1 at serine 307; (iii) The specific inhibitor of S6K1 PF-4708671 inhibits the phosphorylation of S6, without effect on phosphorylation of IRS1 at serine 307. mTOR-immunoprecipitates from insulin-stimulated adipocytes contains an unidentified protein kinase specific for phosphorylation of IRS1 at serine 307, but it is not mTOR or S6K1.

  • 14.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Functional proteomics of protein phosphorylation in algal photosynthetic membranes2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Plants, green algae and cyanobacteria perform photosynthetic conversion of sunlight into chemical energy in the permanently changing natural environment. For successful survival and growth photosynthetic organisms have developed complex sensing and signaling acclimation mechanisms. The environmentally dependent protein phosphorylation in photosynthetic membranes is implied in the adaptive responses; however, the molecular mechanisms of this regulation are still largely unknown. We used a mass spectrometry-based approach to achieve a comprehensive mapping of the in vivo protein phosphorylation sites within photosynthetic membranes from the green alga Chlamydomonas reinhardtii subjected to distinct environmental conditions known to affect the photosynthetic machinery.

    The state transitions process regulating the energy distribution between two photosystems, involves the temporal functional coupling of phosphorylated light-harvesting complexes II (LHCII) to photosystem I (PSI). During state transitions several of the thylakoid proteins undergo redox-controlled phosphorylation-dephosphorylation cycles. This work provided evidences suggesting that redox-dependent phosphorylation-induced structural changes of the minor LHCII antenna protein CP29 determine the affinity of LHCII for either of the two photosystems. In state 1 the doubly phosphorylated CP29 acts as a linker between the photosystem II (PSII) core and the trimeric LHCII whereas in state 2 this quadruply phosphorylated CP29 would migrate to PSI on the PsaH side and provide the docking of LHCII trimers to the PSI complex. Moreover, this study revealed that exposure of Chlamydomonas cells to high light stress caused hyperphosphorylation of CP29 at seven distinct residues and suggested that high light-induced hyperphosphorylation of CP29 may uncouple this protein together with LHCII from both photosystems to minimize the damaging effects of excess light.

    Reversible phosphorylation of the PSII reaction center proteins was shown to be essential for the maintenance of active PSII under high light stress. Particularly dephosphorylation of the light-damaged D1 protein, a central functional subunit of the PSII reaction center, is required for its degradation and replacement. We found in the alga the reversible D1 protein phosphorylation, which until our work, has been considered as plant-specific.

    We also discovered specific induction of thylakoid protein phosphorylation during adaptation of alga to limiting environmental CO2. One of the phosphorylated proteins has five phosphorylation sites at both serine and treonine residues. The discovered specific low-CO2- and redox-dependent protein phosphorylation may be an early adaptive and signalling response of the green alga to limitation in inorganic carbon.

    This work provides the first comprehensive insight into the network of environmentally regulated protein phosphorylation in algal photosynthetic membranes.

    List of papers
    1. CO2 limitation induces specific redox-dependent protein phosphorylation in Chlamydomonas reinhardtii
    Open this publication in new window or tab >>CO2 limitation induces specific redox-dependent protein phosphorylation in Chlamydomonas reinhardtii
    Show others...
    2006 (English)In: Proteomics, ISSN 1615-9853, Vol. 6, no 9, p. 2693-2704Article in journal (Refereed) Published
    Abstract [en]

    Acclimation of the green alga Chlamydomonas reinhardtii to limiting environmental CO2 induced specific protein phosphorylation at the surface of photosynthetic thylakoid membranes. Four phosphopeptides were identified and sequenced by nanospray quadrupole TOF MS from the cells acclimating to limiting CO2. One phosphopeptide originated from a protein that has not been annotated. We found that this unknown expressed protein (UEP) was encoded in the genome of C. reinhardtii. Three other phosphorylated peptides belonged to Lci5 protein encoded by the low-CO2-inducible gene 5 (lci5). The phosphorylation sites were mapped in the tandem repeats of Lci5 ensuring phosphorylation of four serine and three threonine residues in the protein. Immunoblotting with Lci5-specific antibodies revealed that Lci5 was localized in chloroplast and confined to the stromal side of the thylakoid membranes. Phosphorylation of Lci5 and UEP occurred strictly at limiting CO2; it required reduction of electron carriers in the thylakoid membrane, but was not induced by light. Both proteins were phosphorylated in the low-CO2-exposed algal mutant deficient in the light-activated protein kinase Stt7. Phosphorylation of previously unknown basic proteins UEP and Lci5 by specific redox-dependent protein kinase(s) in the photosynthetic membranes reveals the early response of green algae to limitation in the environmental inorganic carbon.

    Keywords
    Amino acid sequencing, Chlamydomonas reinhardtii, CO2 limitation, Mass spectrometry, Protein phosphorylation
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-12927 (URN)10.1002/pmic.200500461 (DOI)
    Available from: 2008-02-06 Created: 2008-02-06 Last updated: 2009-06-05
    2. The transit peptide of CP29 thylakoid protein in Chlamydomonas reinhardtii is not removed but undergoes acetylation and phosphorylation
    Open this publication in new window or tab >>The transit peptide of CP29 thylakoid protein in Chlamydomonas reinhardtii is not removed but undergoes acetylation and phosphorylation
    2004 (English)In: FEBS letters, ISSN 0014-5793, Vol. 564, no 1-2, p. 104-108Article in journal (Refereed) Published
    Abstract [en]

    The surface-exposed peptides were cleaved by trypsin from the photosynthetic thylakoid membranes isolated from the green alga Chlamydomonas reinhardtii. Two phosphorylated peptides, enriched from the peptide mixture and sequenced by nanospray quadrupole time-of-flight mass spectrometry, revealed overlapping sequences corresponding to the N-terminus of a nuclear-encoded chlorophyll a/b-binding protein CP29. In contrast to all known nuclear-encoded thylakoid proteins, the transit peptide in the mature algal CP29 was not removed but processed by methionine excision, N-terminal acetylation and phosphorylation on threonine 6. The importance of this phosphorylation site is proposed as the reason of the unique transit peptide retention.

    Keywords
    Transit peptide, Thylakoid membrane, CP29, Protein phosphorylation, Mass spectrometry, Chlamydomonas reinhardtii
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-12928 (URN)10.1016/S0014-5793(04)00323-0 (DOI)
    Available from: 2008-02-06 Created: 2008-02-06 Last updated: 2009-06-05
    3. Light-harvesting complex II protein CP29 binds to photosystem I of Chlamydomonas reinhardtii under State 2 conditions
    Open this publication in new window or tab >>Light-harvesting complex II protein CP29 binds to photosystem I of Chlamydomonas reinhardtii under State 2 conditions
    Show others...
    2005 (English)In: The FEBS journal, ISSN 1742-464X, Vol. 272, no 18, p. 4797-4806Article in journal (Refereed) Published
    Abstract [en]

    The State 1 to State 2 transition in the photosynthetic membranes of plants and green algae involves the functional coupling of phosphorylated light-harvesting complexes of photosystem II (LHCII) to photosystem I (PSI). We present evidence suggesting that in Chlamydomonas reinhardtii this coupling may be aided by a hyper-phosphorylated form of the LHCII-like CP29 protein (Lhcbm4). MS analysis of CP29 showed that Thr6, Thr16 and Thr32, and Ser102 are phosphorylated in State 2, whereas in State 1-exposed cells only phosphorylation of Thr6 and Thr32 could be detected. The LHCI–PSI supercomplex isolated from the alga in State 2 was found to contain strongly associated CP29 in phosphorylated form. Electron microscopy suggests that the binding site for this highly phosphorylated CP29 is close to the PsaH protein. It is therefore postulated that redox-dependent multiple phosphorylation of CP29 in green algae is an integral part of the State transition process in which the structural changes of CP29, induced by reversible phosphorylation, determine the affinity of LHCII for either of the two photosystems.

    Keywords
    Chlamydomonas, CP29, photosynthesis, protein phosphorylation, State transitions
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-12929 (URN)10.1111/j.1742-4658.2005.04894.x (DOI)
    Available from: 2008-02-06 Created: 2008-02-06
    4. Environmentally modulated phosphoproteome of photosynthetic membranes in the green alga Chlamydomonas reinhardtii
    Open this publication in new window or tab >>Environmentally modulated phosphoproteome of photosynthetic membranes in the green alga Chlamydomonas reinhardtii
    Show others...
    2006 (English)In: Molecular & cellular proteomics, ISSN 1535-9476, Vol. 5, no 8, p. 1412-1425Article in journal (Refereed) Published
    Abstract [en]

    Mapping of in vivo protein phosphorylation sites in photosynthetic membranes of the green alga Chlamydomonas reinhardtii revealed that the major environmentally dependent changes in phosphorylation are clustered at the interface between the photosystem II (PSII) core and its light-harvesting antennae (LHCII). The photosynthetic membranes that were isolated form the algal cells exposed to four distinct environmental conditions affecting photosynthesis: (i) dark aerobic, corresponding to photosynthetic State 1; (ii) dark under nitrogen atmosphere, corresponding to photosynthetic State 2; (iii) moderate light; and (iv) high light. The surface-exposed phosphorylated peptides were cleaved from the membrane by trypsin, methyl-esterified, enriched by immobilized metal affinity chromatography, and sequenced by nanospray-quadrupole time-of-flight mass spectrometry. A total of 19 in vivo phosphorylation sites were mapped in the proteins corresponding to 15 genes in C. reinhardtii. Amino-terminal acetylation of seven proteins was concomitantly determined. Sequenced amino termini of six mature LHCII proteins differed from the predicted ones. The State 1-to-State 2 transition induced phosphorylation of the PSII core components D2 and PsbR and quadruple phosphorylation of a minor LHCII antennae subunit, CP29, as well as phosphorylation of constituents of a major LHCII complex, Lhcbm1 and Lhcbm10. Exposure of the algal cells to either moderate or high light caused additional phosphorylation of the D1 and CP43 proteins of the PSII core. The high light treatment led to specific hyperphosphorylation of CP29 at seven distinct residues, phosphorylation of another minor LHCII constituent, CP26, at a single threonine, and double phosphorylation of additional subunits of a major LHCII complex including Lhcbm4, Lhcbm6, Lhcbm9, and Lhcbm11. Environmentally induced protein phosphorylation at the interface of PSII core and the associated antenna proteins, particularly multiple differential phosphorylations of CP29 linker protein, suggests the mechanisms for control of photosynthetic state transitions and for LHCII uncoupling from PSII under high light stress to allow thermal energy dissipation.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-12930 (URN)10.1074/mcp.M600066-MCP200 (DOI)
    Available from: 2008-02-06 Created: 2008-02-06 Last updated: 2009-06-05
  • 15.
    Turkina, Maria
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Klang, Hanna
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Vener, Alexander
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Differential Phosphorylation of Ribosomal Proteins in Arabidopsis thaliana Plants during Day and Night2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 12Article in journal (Refereed)
    Abstract [en]

    Protein synthesis in plants is characterized by increase in the translation rates for numerous proteins and central metabolic enzymes during the day phase of the photoperiod. The detailed molecular mechanisms of this diurnal regulation are unknown, while eukaryotic protein translation is mainly controlled at the level of ribosomal initiation complexes, which also involves multiple events of protein phosphorylation. We characterized the extent of protein phosphorylation in cytosolic ribosomes isolated from leaves of the model plant Arabidopsis thaliana harvested during day or night. Proteomic analyses of preparations corresponding to both phases of the photoperiod detected phosphorylation at eight serine residues in the C-termini of six ribosomal proteins: S2-3, S6-1, S6-2, P0-2, P1 and L29-1. This included previously unknown phosphorylation of the 40S ribosomal protein S6 at Ser-231. Relative quantification of the phosphorylated peptides using stable isotope labeling and mass spectrometry revealed a 2.2 times increase in the day/night phosphorylation ratio at this site. Phosphorylation of the S6-1 and S6-2 variants of the same protein at Ser-240 increased by the factors of 4.2 and 1.8, respectively. The 1.6 increase in phosphorylation during the day was also found at Ser-58 of the 60S ribosomal protein L29-1. It is suggested that differential phosphorylation of the ribosomal proteins S6-1, S6-2 and L29-1 may contribute to modulation of the diurnal protein synthesis in plants.

  • 16.
    Turkina, Maria
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Olofsson, Annelie
    Umeå University, Sweden.
    Magnusson, Karl-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Arnqvist, Anna
    Umeå University, Sweden.
    Vikström, Elena
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Helicobacter pylori vesicles carrying CagA localize in the vicinity of cell-cell contacts and induce histone H1 binding to ATP in epithelial cells2015In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 362, no 11, p. fnv076-Article in journal (Refereed)
    Abstract [en]

    Helicobacter pylori produces outer membrane vesicles (OMV), delivering bacterial substances including the oncogenic cytotoxin-associated CagA protein to their surroundings. We investigated the effects of H. pylori OMV carrying CagA (OMV-CagA) on cell junctions and ATP-binding proteome of epithelial monolayers, using proteomics, mass spectrometry and imaging. OMV-CagA localized in close vicinity of ZO-1 tight junction protein and induced histone H1 binding to ATP. We suggest the expression of novel events in the interactions between H. pylori OMV and epithelia, which may have an influence on host gene transcription and lead to different outcomes of an infection and development of cancer.

  • 17.
    Turkina, Maria V
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Blanco-Rivero, Amaya
    Department of Plant Physiology, Umeå University, Umeå, Sweden.
    Vainonen, Julia P
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Vener, Alexander V
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Villarejo, Arsenio
    Department of Plant Physiology, Umeå University, Umeå, Sweden.
    CO2 limitation induces specific redox-dependent protein phosphorylation in Chlamydomonas reinhardtii2006In: Proteomics, ISSN 1615-9853, Vol. 6, no 9, p. 2693-2704Article in journal (Refereed)
    Abstract [en]

    Acclimation of the green alga Chlamydomonas reinhardtii to limiting environmental CO2 induced specific protein phosphorylation at the surface of photosynthetic thylakoid membranes. Four phosphopeptides were identified and sequenced by nanospray quadrupole TOF MS from the cells acclimating to limiting CO2. One phosphopeptide originated from a protein that has not been annotated. We found that this unknown expressed protein (UEP) was encoded in the genome of C. reinhardtii. Three other phosphorylated peptides belonged to Lci5 protein encoded by the low-CO2-inducible gene 5 (lci5). The phosphorylation sites were mapped in the tandem repeats of Lci5 ensuring phosphorylation of four serine and three threonine residues in the protein. Immunoblotting with Lci5-specific antibodies revealed that Lci5 was localized in chloroplast and confined to the stromal side of the thylakoid membranes. Phosphorylation of Lci5 and UEP occurred strictly at limiting CO2; it required reduction of electron carriers in the thylakoid membrane, but was not induced by light. Both proteins were phosphorylated in the low-CO2-exposed algal mutant deficient in the light-activated protein kinase Stt7. Phosphorylation of previously unknown basic proteins UEP and Lci5 by specific redox-dependent protein kinase(s) in the photosynthetic membranes reveals the early response of green algae to limitation in the environmental inorganic carbon.

  • 18.
    Turkina, Maria V
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Kargul, Joanna
    Wolfson Laboratories, Division of Molecular Biosciences, Faculty of Life Sciences, Imperial College London.
    Blanco-Rivero, Amaya
    Department of Plant Physiology, Umeå University, Umeå, Sweden.
    Villarejo, Arsenio
    Department of Plant Physiology, Umeå University, Umeå, Sweden.
    Barber, James
    Wolfson Laboratories, Division of Molecular Biosciences, Faculty of Life Sciences, Imperial College London.
    Vener, Alexander V
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Environmentally modulated phosphoproteome of photosynthetic membranes in the green alga Chlamydomonas reinhardtii2006In: Molecular & cellular proteomics, ISSN 1535-9476, Vol. 5, no 8, p. 1412-1425Article in journal (Refereed)
    Abstract [en]

    Mapping of in vivo protein phosphorylation sites in photosynthetic membranes of the green alga Chlamydomonas reinhardtii revealed that the major environmentally dependent changes in phosphorylation are clustered at the interface between the photosystem II (PSII) core and its light-harvesting antennae (LHCII). The photosynthetic membranes that were isolated form the algal cells exposed to four distinct environmental conditions affecting photosynthesis: (i) dark aerobic, corresponding to photosynthetic State 1; (ii) dark under nitrogen atmosphere, corresponding to photosynthetic State 2; (iii) moderate light; and (iv) high light. The surface-exposed phosphorylated peptides were cleaved from the membrane by trypsin, methyl-esterified, enriched by immobilized metal affinity chromatography, and sequenced by nanospray-quadrupole time-of-flight mass spectrometry. A total of 19 in vivo phosphorylation sites were mapped in the proteins corresponding to 15 genes in C. reinhardtii. Amino-terminal acetylation of seven proteins was concomitantly determined. Sequenced amino termini of six mature LHCII proteins differed from the predicted ones. The State 1-to-State 2 transition induced phosphorylation of the PSII core components D2 and PsbR and quadruple phosphorylation of a minor LHCII antennae subunit, CP29, as well as phosphorylation of constituents of a major LHCII complex, Lhcbm1 and Lhcbm10. Exposure of the algal cells to either moderate or high light caused additional phosphorylation of the D1 and CP43 proteins of the PSII core. The high light treatment led to specific hyperphosphorylation of CP29 at seven distinct residues, phosphorylation of another minor LHCII constituent, CP26, at a single threonine, and double phosphorylation of additional subunits of a major LHCII complex including Lhcbm4, Lhcbm6, Lhcbm9, and Lhcbm11. Environmentally induced protein phosphorylation at the interface of PSII core and the associated antenna proteins, particularly multiple differential phosphorylations of CP29 linker protein, suggests the mechanisms for control of photosynthetic state transitions and for LHCII uncoupling from PSII under high light stress to allow thermal energy dissipation.

  • 19.
    Turkina, Maria V
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Vener, Alexander V
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Identification of phosphorylated proteins.2007In: Methods in Molecular Biology, ISSN 1064-3745, E-ISSN 1940-6029, Vol. 355, p. 305-316Article in journal (Refereed)
    Abstract [en]

    Reversible protein phosphorylation is crucially involved in all aspects of plant cell physiology. The highly challenging task of revealing and characterizing the dynamic protein phosphorylation networks in plants has only recently begun to become feasible, owing to application of dedicated proteomics and mass spectrometry techniques. The experimental methodology that identified most of the presently known proteins phosphorylated in vivo is based on protein cleavage with trypsin, following chromatographic enrichment of phosphorylated peptides and mass spectrometric fragmentation and sequencing of these phosphopeptides. This procedure is most efficient when it is limited to the tryptic digestion of proteins in distinct isolated fractions or compartments of plant cells. Immobilized metal affinity chromatography (IMAC) is most useful for phosphopeptide enrichment after methylation of the peptides in the complex protein digests. The following tandem mass spectrometry of the isolated phosphopeptides results in both identification of phosphorylated proteins and mapping of the in vivo phosphorylation sites. The relative quantitation of the extent of phosphorylation at individual protein modification sites may be accomplished by either stable isotope labeling technique or dedicated liquid chromatography-mass spectrometry measurements.

  • 20.
    Turkina, Maria V
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Villarejo, Arsenio
    Umeå Plant Science Center, Department of Plant Physiology, University of Umeå, Umeå, Sweden.
    Vener, Alexander V.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    The transit peptide of CP29 thylakoid protein in Chlamydomonas reinhardtii is not removed but undergoes acetylation and phosphorylation2004In: FEBS letters, ISSN 0014-5793, Vol. 564, no 1-2, p. 104-108Article in journal (Refereed)
    Abstract [en]

    The surface-exposed peptides were cleaved by trypsin from the photosynthetic thylakoid membranes isolated from the green alga Chlamydomonas reinhardtii. Two phosphorylated peptides, enriched from the peptide mixture and sequenced by nanospray quadrupole time-of-flight mass spectrometry, revealed overlapping sequences corresponding to the N-terminus of a nuclear-encoded chlorophyll a/b-binding protein CP29. In contrast to all known nuclear-encoded thylakoid proteins, the transit peptide in the mature algal CP29 was not removed but processed by methionine excision, N-terminal acetylation and phosphorylation on threonine 6. The importance of this phosphorylation site is proposed as the reason of the unique transit peptide retention.

  • 21.
    Vainonen, Julia P
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Aboulaich, Nabila
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Turkina, Maria V
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Strålfors, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Vener, Alexander V
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    N-terminal processing and modifications of caveolin-1 in caveolae from human adipocytes2004In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 320, no 2, p. 480-486Article in journal (Refereed)
    Abstract [en]

    Caveolin, the principal structural protein of caveolae membrane domains, has a cytosol-exposed N-terminal part that was cleaved off by trypsin treatment of caveolae vesicles isolated from primary human adipocytes. Sequencing of the released tryptic peptides by nanospray quadrupole time-of-flight mass spectrometry revealed that both caveolin-1alpha and caveolin-1beta were processed by excision of the starting methionines. The N-terminus of the mature caveolin-1alpha was acetylated, while caveolin-1beta was found in acetylated as well as in non-acetylated forms. Fractional phosphorylation of serine-36 in the mature caveolin-1alpha and of the homologous serine-5 in caveolin-1beta was identified. This is the first experimental evidence for in vivo phosphorylation of caveolin-1 at the consensus site for phosphorylation by protein kinase C. The phosphorylation was found in both the acetylated and non-acetylated variants of caveolin-1beta. This variability in modifications is consistent with critical involvement of the N-terminal domain of caveolin in the regulation of caveolae.

1 - 21 of 21
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