Heat‐resistant inhibitors of protein kinase C from bovine brain

Abstract

The complete 897-amino-acid sequence of chicken skeletal muscle .alpha.-actinin and the 856-amino-acid sequence (97% of the entire sequence) of chicken fibroblast .alpha.-actinin have been determined by cloning and sequencing the cDNAs. Genomic Southern analysis with the cDNA sequences shows that skeletal and fibroblast .alpha.-actinins are encoded by separate single-copy genes. RNA blot analyzes show that the skeletal .alpha.-actinin gene is expressed in the pectoralis muscle and that the fibroblast gene is expressed in the gizzard smooth muscle as well as in the fibroblast. The deduced skeletal .alpha.-actinin molecule has a calculated Mr of 104 .times. 103, and each .alpha.-actinin can be divided into three domains: (1) the NH2-terminal highly conserved actin-binding domain, which shows similarity to the product of the Duchenne''s muscular dystrophy locus; (2) the middle rod-shaped dimer-forming domain, which contains the spectrin-type repeat units; and (3) the COOH-terminal two EF-hand consensus regions. Comparison of the skeletal .alpha.-actinin sequence with the fibroblast and smooth muscle .alpha.-actinin sequences demonstrated that the EF-hand structure was conserved in all of these .alpha.-actinin sequences, despite the reported variability of the Ca2+ sensitivities of the actin-gelation by various .alpha.-actinin isoforms.