Modulation of cloned neuronal calcium channels through membrane-delimited pathway.
Modulation of voltage-gated Ca2+ channels by the receptor coupled GTP-binding proteins (G-proteins) is essential for controlling secretion and muscle contraction. We have expressed cloned Ca2+ channels in dysgenic myotubes to study G-protein modulation through the membrane-delimited pathway. The results obtained by the expression of alpha 1B channels and mutant channels of alpha 1B suggest that the two effects observed in G-protein modulated N-type channels (depression of current and slowing of activation) are through two independent mechanisms. In addition, neither the region linking repeat II and III nor carboxy-terminal region, which were demonstrated in L-type channels to determine some of their specific functions, are directly involved in G-protein modulation. The results obtained by the expression of the alpha 1A channel suggest that this channel is modulated through a novel membrane-delimited pathway that may not involve G-protein activation.
Zhou
J
J
Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536-0812.
Zong
S
S
Tanabe
T
T
D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology*; D002642:Chick Embryo; D017931:DNA Primers / Q000737:chemistry; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D011994:Recombinant Proteins
D015220:Calcium Channels; D017931:DNA Primers; D011994:Recombinant Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins; D002118:Calcium