Small vertical movement of a K+ channel voltage sensor measured with luminescence energy transfer

Voltage-gated ion channels open and close in response to voltage changes across electrically excitable cell membranes 1 . Voltage-gated potassium (Kv) channels are homotetramers with each subunit constructed from six transmembrane segments, S1–S6 (ref. 2 ). The voltage-sensing domain (segments S1–S4...

Celý popis

Uloženo v:

Podrobná bibliografie
Vydáno v:	Nature (London) Ročník 436; číslo 7052; s. 848 - 851
Hlavní autoři:	Posson, David J., Ge, Pinghua, Miller, Christopher, Bezanilla, Francisco, Selvin, Paul R.
Médium:	Journal Article
Jazyk:	angličtina
Vydáno:	London Nature Publishing Group UK 11.08.2005 Nature Publishing Nature Publishing Group
Témata:	Animals Biological and medical sciences Cell membranes. Ionic channels. Membrane pores Cell structures and functions Charged particles Electric fields Energy Transfer Fundamental and applied biological sciences. Psychology Humanities and Social Sciences Ion Channel Gating Ion exchange letter Luminescence Luminescent Measurements Molecular and cellular biology Movement multidisciplinary Oocytes - metabolism Potassium Potassium - metabolism Potassium Channels - chemistry Potassium Channels - genetics Potassium Channels - metabolism Potassium Channels, Voltage-Gated - chemistry Potassium Channels, Voltage-Gated - genetics Potassium Channels, Voltage-Gated - metabolism Science Science (multidisciplinary) Shaker Superfamily of Potassium Channels Toxins Xenopus laevis Human Luminescence Lipids Ionic channel Excitable membrane Subunit Protein Toxin Electric field Arginine Models Membrane channel Potassium
ISSN:	0028-0836, 1476-4687, 1476-4687
On-line přístup:	Získat plný text
Tagy:	Přidat tag Žádné tagy, Buďte první, kdo vytvoří štítek k tomuto záznamu!

Popis
Shrnutí:	Voltage-gated ion channels open and close in response to voltage changes across electrically excitable cell membranes 1 . Voltage-gated potassium (Kv) channels are homotetramers with each subunit constructed from six transmembrane segments, S1–S6 (ref. 2 ). The voltage-sensing domain (segments S1–S4) contains charged arginine residues on S4 that move across the membrane electric field 2 , 3 , modulating channel open probability. Understanding the physical movements of this voltage sensor is of fundamental importance and is the subject of controversy. Recently, the crystal structure of the KvAP 4 channel motivated an unconventional ‘paddle model’ of S4 charge movement, indicating that the segments S3b and S4 might move as a unit through the lipid bilayer with a large (15–20-Å) transmembrane displacement 5 . Here we show that the voltage-sensor segments do not undergo significant transmembrane translation. We tested the movement of these segments in functional Shaker K + channels by using luminescence resonance energy transfer to measure distances between the voltage sensors and a pore-bound scorpion toxin. Our results are consistent with a 2-Å vertical displacement of S4, not the large excursion predicted by the paddle model. This small movement supports an alternative model in which the protein shapes the electric field profile, focusing it across a narrow region of S4 (ref. 6 ).
Bibliografie:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 ObjectType-Article-2 ObjectType-Feature-1 content type line 23
ISSN:	0028-0836 1476-4687 1476-4687
DOI:	10.1038/nature03819