Comparison of an endogenous protein kinase C substrate in rat aorta with rat brain MARCKS.
We have compared the properties of a rat aorta-derived protein kinase C substrate (p75) with those of 80 kDa kinase C substrates from rat brain (MARCKS) and rabbit aorta (p80). Rat aortic p75 appeared to be closely related to rat brain MARCKS on the basis of: solubility in perchloric acid and trichloroacetic acid, heat stability, isoelectric point (pI approximately 4.2), overall V8 protease phosphopeptide map, and immunocrossreactivity with an antibody directed against the N-terminal domain of MARCKS. However, p75 could be distinguished from rat brain MARCKS and from the rabbit aorta-derived p80 on the basis of its consistently more rapid electrophoretic mobility in SDS-containing gels, and in terms of a unique proteolytic phosphopeptide found in MARCKS but not in aortic p75. We conclude that p75 probably belongs to the family of protein kinase C substrates represented by MARCKS, and that differences in post-translational processing (glycosylation) or mRNA processing may account for the unique properties of the p75 protein in rat aortic tissue.
Zhao
D
D
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Calgary, Alberta, Canada.
Hollenberg
M D
MD
Severson
D L
DL
D000818:Animals; D000906:Antibodies; D001011:Aorta / Q000737:chemistry*; D001923:Brain Chemistry; D003429:Cross Reactions; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008970:Molecular Weight; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010472:Perchlorates; D011493:Protein Kinase C / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility
D000906:Antibodies; D047908:Intracellular Signaling Peptides and Proteins; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D010472:Perchlorates; D011506:Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D011493:Protein Kinase C