title: Removal of the outermost arginine in IVS4 segment of the Ca(V)3.1 channel affects amplitude but not voltage dependence of gating current.
abstract: Positively charged amino acids in S4 segments of voltage-dependent Ca(V)3.1 channel form putative voltage sensor. Previously we have shown that exchange of uppermost positively charged arginine in IVS4 segment for cysteine (mutation R1717C) affected deactivation and inactivation, but not activation of macroscopic current. Now we compared gating currents from both channels. Maximal amplitude of charge movement in R1717C channel decreased but voltage-dependent characteristics of charge movement were not significantly altered. We concluded that mutation of R1717C affects the coupling between S4 activation and pore opening, but not the S4 activation itself.
authors.affiliation: Institute of Molecular Physiology and Genetics, Centre of Excellence for Cardiovascular Research, Slovak Academy of Sciences, Bratislava, Slovakia.
authors.forename: Mária
authors.initials: M
authors.lastname: Karmažínová
authors.forename: Lubica
authors.initials: L
authors.lastname: Lacinová
mesh_terms: D001120:Arginine; D020746:Calcium Channels, L-Type / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004553:Electric Conductivity; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D009154:Mutation
chemical_list: D020746:Calcium Channels, L-Type; D001120:Arginine