title: The cytoplasmic coiled-coil mediates cooperative gating temperature sensitivity in the             voltage-gated H(+) channel Hv1.
abstract: Hv1/VSOP is a dimeric voltage-gated                     H(+) channel in which the gating of one subunit is reportedly                 coupled to that of the other subunit within the dimer. The molecular basis for dimer                 formation and intersubunit coupling, however, remains unknown. Here we show that the                 carboxy terminus ends downstream of the S4 voltage-sensor helix twist in a dimer                 coiled-coil architecture, which mediates cooperative gating. We also show that the                 temperature-dependent activation of H(+) current through Hv1/VSOP is regulated by thermostability of the coiled-coil domain,                 and that this regulation is altered by mutation of the linker between S4 and the                 coiled-coil. Cooperative gating within the dimer is also dependent on the linker                 structure, which circular dichroism spectrum analysis suggests is                 α-helical. Our results indicate that the cytoplasmic coiled-coil strands                 form continuous α-helices with S4 and mediate cooperative gating to adjust                 the range of temperatures over which Hv1/VSOP                 operates.
authors.affiliation: Laboratory of Integrative Physiology, Department of Physiology, Graduate School and Faculty of Medicine, Osaka University, Yamadaoka 2-2, Suita, Osaka 565-0871, Japan. fujiwara@phys2.med.osaka-u.ac.jp
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Kohei
authors.initials: K
authors.lastname: Takeshita
authors.forename: Megumi
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Okochi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakagawa
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okamura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D018360:Crystallography, X-Ray; D003593:Cytoplasm / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011522:Protons; D016415:Sequence Alignment; D013696:Temperature
chemical_list: C540876:Hv1 proton channel, mouse; D007473:Ion Channels; D011522:Protons