Oligomerization of the voltage-gated proton channel.
The voltage-gated proton channel exists as a dimer, although each protomer has a separate conduction pathway, and when forced to exist as a monomer, most major functions are retained. However, the proton channel protomers appear to interact during gating. Proton channel dimerization is thought to result mainly from coiled-coil interaction of the intracellular C-termini. Several types of evidence are discussed that suggest that the dimer conformation may not be static, but is dynamic and can sample different orientations. Zn(2+) appears to link the protomers in an orientation from which the channel(s) cannot open. A tandem WT-WT dimer exhibits signs of cooperative gating, indicating that despite the abnormal linkage, the correct orientation for opening can occur. We propose that C-terminal interaction functions mainly to tether the protomers together. Comparison of the properties of monomeric and dimeric proton channels speaks against the hypothesis that enhanced gating reflects monomer-dimer interconversion.
Musset
Boris
B
Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL, USA.
Smith
Susan M E
SM
Rajan
Sindhu
S
Cherny
Vladimir V
VV
Morgan
Deri
D
DeCoursey
Thomas E
TE
D001491:Basophils / Q000378:metabolism; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008564:Membrane Potentials; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D021122:Protein Subunits; D011522:Protons; D013329:Structure-Activity Relationship; D015032:Zinc / Q000378:metabolism
C510235:HVCN1 protein, human; D007473:Ion Channels; D021122:Protein Subunits; D011522:Protons; D015032:Zinc