A periodic network of G protein beta gamma subunit coexisting with cytokeratin filament in starfish oocytes.
Heterotrimeric G proteins are membrane-bound and carry signals from activated receptors on plasma membranes to cytoplasmic effector enzymes and channels. In starfish oocytes, the beta gamma subunit of G protein mediates 1-methyladenine stimulation of oocyte maturation. In order to investigate the localization of beta gamma subunits in starfish oocytes during oocyte maturation, we raised a monoclonal antibody against the beta subunit. By immunofluorescence microscopy using the antibody, immature oocytes show a network of fibers in the cytoplasm. The staining of fibers is beaded with a periodicity of 0.7 microns. The same staining pattern is obtained by anti-gamma subunit antibody. In addition, the fibers are stained by anti-cytokeratin antibody. These results indicate that the G protein beta gamma subunit coexists with cytokeratin filaments in starfish oocytes. Stimulation of oocyte maturation by 1-methyladenine causes the beta gamma subunit to be disassembled.
Chiba
K
K
Department of Life Science, Tokyo Institute of Technology, Yokohama, Japan.
Longo
F J
FJ
Kontani
K
K
Katada
T
T
Hoshi
M
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002417:Cattle; D003429:Cross Reactions; D005260:Female; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000378:metabolism* / Q000648:ultrastructure; D013215:Starfish
D000911:Antibodies, Monoclonal; D007633:Keratins; D019204:GTP-Binding Proteins