ADP-ribosylation of membrane proteins in cholinergic nerve terminals.
Lysed Torpedo synaptosomes or washed synaptosomal membranes were incubated with [32P]NAD+ and subjected to electrophoresis on SDS-polyacrylamide gels. More than eight membrane proteins were ADP-ribosylated. The most intensely labeled proteins were those of Mr = 62,000 and 82,000. Radiolabeling was more intense in synaptosomes than in other subcellular fractions. Cholera toxin caused ribosylation of additional synaptosomal proteins with Mr = 42,000 and (in some preparations) 49,000. Neither endogenous nor cholera toxin-catalyzed ADP-ribosylation required added guanyl nucleotides. Cholera toxin increased the adenylate cyclase activity of synaptosomal membranes, suggesting that the cholera toxin substrates are regulatory components of adenylate cyclase in these synaptosomes.
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002772:Cholera Toxin / Q000494:pharmacology; D004557:Electric Organ / Q000378:metabolism*; D004789:Enzyme Activation; D008565:Membrane Proteins / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000502:physiology; D013572:Synaptic Vesicles / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*; D014101:Torpedo
D008565:Membrane Proteins; D009702:Nucleoside Diphosphate Sugars; D011950:Receptors, Cholinergic; D009243:NAD; D000246:Adenosine Diphosphate Ribose; D002772:Cholera Toxin; D000262:Adenylyl Cyclases