Requirement of negative residues, Asp 95 and Asp 105, in S2 on membrane integration of a voltage-dependent K+ channel, KAT1.
Voltage-dependent K+ channels consist of a voltage-sensing region and a pore-forming region. Here we have identified the negative residues of the second transmembrane segment in the plant voltage-dependent K+ channel, KAT1, which involves the function of voltage sensing. Point mutations at D95 and D105 but not D89 and D116 failed to complement the K+ uptake deficient properties of the mutant yeast. In vitro translation and translocation experiments showed that the membrane integration of the third and fourth segments involving voltage sensor were impaired by the replacement of D95 or D105 by serine. These data show that both the residues play a crucial role in the membrane topogenesis of the voltage sensor in KAT1.
Sato
Yoko
Y
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Hosoo
Yoshihiro
Y
Sakaguchi
Masao
M
Uozumi
Nobuyuki
N
D000595:Amino Acid Sequence; D001224:Aspartic Acid; D002462:Cell Membrane / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010940:Plant Proteins; D017354:Point Mutation; D015221:Potassium Channels / Q000737:chemistry* / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D021381:Protein Transport; D016415:Sequence Alignment
D010940:Plant Proteins; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated; D001224:Aspartic Acid