Postsynaptic densities contain a subtype of protein kinase C.
Protein kinase C or an isoenzyme thereof appears to be a significant component of postsynaptic densities (PSDs) from rat brain. This cytoskeletal organelle binds 4 beta-phorbol 12,13-dibutyrate (PDBu) with a Bmax of about 20 pmol/mg protein and an apparent Kd of 3.3 nM. Ca2+ and phosphatidyl serine (PS) stimulated the endogenous phosphorylation of a subset of PSD polypeptides with Mr values between 16,000 and 22,000. Finally, a monospecific protein kinase C antibody reacted with a Mr 70,000 PSD polypeptide which migrated on SDS-PAGE slightly ahead of the Mr 77,000 purified enzyme. These data suggest that protein kinase C or a similar enzyme can be integrated into a cytoskeletal system and may play an important role in postsynaptic function.
D000818:Animals; D001921:Brain / Q000201:enzymology; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D007120:Immunochemistry; D010455:Peptides / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011955:Receptors, Drug; D011971:Receptors, Immunologic / Q000378:metabolism; D013379:Substrate Specificity; D013574:Synaptosomes / Q000201:enzymology*
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010455:Peptides; D011955:Receptors, Drug; D011971:Receptors, Immunologic; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D011493:Protein Kinase C