32,000-Dalton subunit of the 1,4-dihydropyridine receptor.
Polyclonal antibodies to the 32,000-Da polypeptide of the 1,4-dihydropyridine receptor of the voltage-dependent Ca2+ channel have been produced and used to characterize the association of the 32,000-Da polypeptide (gamma subunit) with other subunits of the dihydropyridine receptor. The 32,000-Da polypeptide was found to copurify with alpha 1 and alpha 2 subunits at each step of the purification of the dihydropyridine receptor. Monoclonal antibodies against the alpha 1 and beta subunits immunoprecipitate the digitonin-solubilized dihydropyridine receptor as a multisubunit complex that includes the 32,000-Da polypeptide. Polyclonal antibodies generated against both the nonreduced and reduced forms of the alpha 2 subunit and the gamma subunit have been used to show that the 32,000-Da polypeptide is not a proteolytic fragment of a larger component of the dihydropyridine receptor and not disulfide linked to the alpha 2 subunit. Our results demonstrate that the 32,000-Da polypeptide (gamma subunit) is an integral and distinct component of the dihydropyridine receptor.
Campbell
K P
KP
Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City 52242.
Sharp
A H
AH
Leung
A T
AT
D000818:Animals; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D007163:Immunosorbent Techniques; D046911:Macromolecular Substances; D008970:Molecular Weight; D009132:Muscles / Q000032:analysis*; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000302:isolation & purification
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D046911:Macromolecular Substances; D011978:Receptors, Nicotinic