Immunochemical analysis of subunit structures of 1,4-dihydropyridine receptors associated with voltage-dependent Ca2+ channels in skeletal, cardiac, and smooth muscles.
Previous purification studies of the 1,4-dihydropyridine receptor associated with the calcium channel of rabbit skeletal muscle had shown that it is composed of a large glycoprotein of Mr 140,000-145,000 associated with a smaller component of Mr 32,000-34,000. Specific antisera have now been prepared against the larger component (anti-140 serum) and the smaller one (anti-32 serum). The specificity of these two antisera has been analyzed by immunoblot assays with microsomal preparations of rabbit skeletal muscle. Under disulfide-reducing conditions the anti-140 serum specifically labeled a polypeptide of Mr 140,000 while the anti-32 serum labeled three polypeptides of Mr 32,000, 29,000, and 26,000. Under nonreducing conditions both the anti-140 and the anti-32 sera specifically recognized a single large polypeptide of Mr 170,000. The same type of approach showed that the dihydropyridine receptor in cardiac and smooth muscles had a polypeptide composition similar to that found in skeletal muscle with a large polypeptide of Mr 170,000-176,000 made of two different chains of about Mr 140,000 and 34,000-32,000 associated by disulfide bridges.
D000818:Animals; D000936:Antigen-Antibody Complex; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D003106:Colon / Q000378:metabolism; D004095:Dihydropyridines; D007106:Immune Sera; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008861:Microsomes / Q000378:metabolism; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D011725:Pyridines / Q000378:metabolism*; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000302:isolation & purification / Q000378:metabolism*
D000936:Antigen-Antibody Complex; D015220:Calcium Channels; D004095:Dihydropyridines; D007106:Immune Sera; D007473:Ion Channels; D046911:Macromolecular Substances; D011725:Pyridines; D011978:Receptors, Nicotinic; C038806:1,4-dihydropyridine; D002118:Calcium