Hyperpolarization moves S4 sensors inward to open MVP, a methanococcal voltage-gated potassium channel.
MVP, a Methanococcus jannaschii voltage-gated potassium channel, was cloned and shown to operate in eukaryotic and prokaryotic cells. Like pacemaker channels, MVP opens on hyperpolarization using S4 voltage sensors like those in classical channels activated by depolarization. The MVP S4 span resembles classical sensors in sequence, charge, topology and movement, traveling inward on hyperpolarization and outward on depolarization (via canaliculi in the protein that bring the extracellular and internal solutions into proximity across a short barrier). Thus, MVP opens with sensors inward indicating a reversal of S4 position and pore state compared to classical channels. Homologous channels in mammals and plants are expected to function similarly.
Sesti
Federico
F
Department of Pediatrics, Yale University School of Medicine, Boyer Center for Molecular Medicine, 295 Congress Avenue, New Haven, Connecticut 06536, USA.
Rajan
Sindhu
S
Gonzalez-Colaso
Rosana
R
Nikolaeva
Natalia
N
Goldstein
Steve A N
SA
D000595:Amino Acid Sequence / Q000235:genetics; D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence / Q000235:genetics; D003001:Cloning, Molecular; D003545:Cysteine / Q000378:metabolism; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D004926:Escherichia coli / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D019143:Evolution, Molecular; D008564:Membrane Potentials / Q000502:physiology; D008698:Mesylates / Q000494:pharmacology; D017017:Methanococcus / Q000378:metabolism; D008969:Molecular Sequence Data; D011188:Potassium / Q000378:metabolism / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D011387:Prokaryotic Cells / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
D018076:DNA, Complementary; D008698:Mesylates; D024642:Potassium Channels, Voltage-Gated; C109154:(2-(trimethylammonium)ethyl)methanethiosulfonate; D003545:Cysteine; D011188:Potassium