Interaction of GTP‐binding protein Gq with photoactivated rhodopsin in the photoreceptor membranes of crayfish

[摘要]

Interaction of G-protein with photoactivated rhodopsin (Rh^∗) in crayfish photoreceptor membranes was investigated by immunoprecipitation using an antibody against rhodopsin. Two kinds of protein were co-precipitated with rhodopsin. One is an α subunit of class-q G-protein (42 kDa, CGqα) which showed light-induced, dose-dependent binding to rhodopsin, and the other is an actin-like protein (44 kDa) with light-independent binding. Most of the CGqα was available for binding to Rh^∗ but was dissociated from Rh^∗ in the presence of GTPγS. These findings demonstrate that, in the crayfish photoreceptor, a Gq class of G-protein is activated by Rh^∗.

[学科分类] 生物化学/生物物理

[关键词] Photoreceptor membrane;Rhodopsin;G-protein;Gq;Signal transduction;Phospholipase C;Crayfish;Procambarus clarkii;ATPγS;Adenosine 5'-O-[3-thiotriphosphate];G-protein;GTP-Binding protein;GDPβS;guanosine 5'O-[2-thiodiphosphate];GTPγS;guanosine 5'-O-[3-thiotriphosphate];Gt;rod transducin;HPLC;high-performance liquid chromatography;PDE;phosphodiesterase;PLC;phospholipase C;SDS-PAGE;sodium dodecyl sulphate-polyacrylamide gel electrophoresis