title: Polymorphism of alpha-actinin from human blood platelets. Homodimeric and heterodimeric forms.
abstract: In purified solutions of alpha-actinin from human blood platelets, three polypeptides a, b and c, of approximately 100 kDa, were observed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. They were identified as alpha-actinin subunits on the basis of their cross-reactivity with antibodies against skeletal muscle alpha-actinin and their interaction with F-actin. After electrophoresis in the absence of sodium dodecyl sulfate, six forms were observed: aa, ab, bb, ac, bc, cc. The similarity between the one-dimensional peptide maps of a and b and the absence of b in the presence of calcium-dependent protease inhibitors indicated that b is probably derived from the a subunit. The c subunit differs from the a subunit. The results provide evidence that there are actually only two platelet alpha-actinin subunits a and c which give rise to three isoforms: two homodimers aa and cc, and one heterodimer ac.
mesh_terms: D000185:Actinin / Q000097:blood*; D000818:Animals; D001792:Blood Platelets / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D046911:Macromolecular Substances; D009124:Muscle Proteins / Q000097:blood*; D010446:Peptide Fragments / Q000032:analysis; D011817:Rabbits
chemical_list: D046911:Macromolecular Substances; D009124:Muscle Proteins; D010446:Peptide Fragments; D000185:Actinin