Functionality of the voltage-gated proton channel truncated in S4
2010 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 107, no 5, 2313-2318 p.Article in journal (Refereed) Published
The voltage sensor domain (VSD) is the key module for voltage sensing in voltage-gated ion channels and voltage-sensing phosphatases. Structurally, both the VSD and the recently discovered voltage-gated proton channels (Hv channels) voltage sensor only protein (VSOP) and Hv1 contain four transmembrane segments. The fourth transmembrane segment (S4) of Hv channels contains three periodically aligned arginines (R1, R2, R3). It remains unknown where protons permeate or how voltage sensing is coupled to ion permeation in Hv channels. Here we report that Hv channels truncated just downstream of R2 in the S4 segment retain most channel properties. Two assays, site-directed cysteine-scanning using accessibility of maleimide-reagent as detected by Western blotting and insertion into dog pancreas microsomes, both showed that S4 inserts into the membrane, even if it is truncated between the R2 and R3 positions. These findings provide important clues to the molecular mechanism underlying voltage sensing and proton permeation in Hv channels.
Place, publisher, year, edition, pages
2010. Vol. 107, no 5, 2313-2318 p.
ion conduction, membrane topology, membrane insertion, voltage sensor
IdentifiersURN: urn:nbn:se:su:diva-50516DOI: 10.1073/pnas.0911868107ISI: 000274296300091OAI: oai:DiVA.org:su-50516DiVA: diva2:381648
authorCount :72010-12-282010-12-282010-12-28Bibliographically approved