Structure, function, and modification of the voltage sensor in voltage-gated ion channels
2008 (English)In: Cell Biochemistry and Biophysics, ISSN 1085-9195, E-ISSN 1559-0283, Vol. 52, no 3, 149-174 p.Article in journal (Refereed) Published
Voltage-gated ion channels are crucial for both neuronal and cardiac excitability. Decades of research have begun to unravel the intriguing machinery behind voltage sensitivity. Although the details regarding the arrangement and movement in the voltage-sensing domain are still debated, consensus is slowly emerging. There are three competing conceptual models: the helical-screw, the transporter, and the paddle model. In this review we explore the structure of the activated voltage-sensing domain based on the recent X-ray structure of a chimera between Kv1.2 and Kv2.1. We also present a model for the closed state. From this we conclude that upon depolarization the voltage sensor S4 moves ~13 Å outwards and rotates ~180º, thus consistent with the helical-screw model. S4 also moves relative to S3b which is not consistent with the paddle model. One interesting feature of the voltage sensor is that it partially faces the lipid bilayer and therefore can interact both with the membrane itself and with physiological and pharmacological molecules reaching the channel from the membrane. This type of channel modulation is discussed together with other mechanisms for how voltage-sensitivity is modified. Small effects on voltage-sensitivity can have profound effects on excitability. Therefore, medical drugs designed to alter the voltage dependence offer an interesting way to regulate excitability.
Place, publisher, year, edition, pages
Humana Press Inc , 2008. Vol. 52, no 3, 149-174 p.
Kv channel, voltage sensor domain, modulation, gating, excitability, S4
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-15628DOI: 10.1007/s12013-008-9032-5OAI: oai:DiVA.org:liu-15628DiVA: diva2:126810
The original publication is available at www.springerlink.com: Sara I. Börjesson and Fredrik Elinder, Structure, function, and modification of the voltage sensor in voltage-gated ion channels, 2008, Cell Biochemistry and Biophysics, (52), 149-174.http://dx.doi.org/10.1007/s12013-008-9032-5. Copyright: Humana Press Inc., www.springerlink.com2008-11-212008-11-212014-08-11Bibliographically approved