Trimeric G protein alpha subunits of the Gs and Gi families localized at the Golgi membrane.
The occurrence of individual G proteins within Golgi membranes from liver and from adrenal medulla were analyzed by Western blotting. Two splice variants of G alpha s and also G alpha i-3 were found in both tissues. Additionally, G alpha i-2, its 43-kDa splice variant and G alpha o were strongly labeled in Golgi of adrenal medulla. Golgi preparations of liver contained comparable quantities of G alpha i-2 and a second variant of 46 kDa, but no G alpha o was detected. Immunoelectron microscopic studies of the above Golgi preparations showed that both G alpha i-2 and G alpha i-3 are localized at multivesicular structures identified as Golgi complexes. The occurrence of two stimulatory G proteins (G alpha s-S and G alpha s-L) and three or four alpha subunits of the Gi/Go type as components of the Golgi membrane support the notion that formation of different vesicle types might be regulated by individual stimulatory and inhibitory G proteins.
Maier
O
O
Department of Cell Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Ehmsen
E
E
Westermann
P
P
D000313:Adrenal Medulla / Q000378:metabolism / Q000648:ultrastructure*; D017398:Alternative Splicing; D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D002458:Cell Fractionation / Q000379:methods; D019204:GTP-Binding Proteins / Q000032:analysis* / Q000096:biosynthesis; D014644:Genetic Variation; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure*; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure*; D008099:Liver / Q000378:metabolism / Q000648:ultrastructure*; D046911:Macromolecular Substances; D016253:Microscopy, Immunoelectron; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis
D046911:Macromolecular Substances; D019204:GTP-Binding Proteins; D000254:Sodium-Potassium-Exchanging ATPase