Characterization of phorbol diester binding to isolated cardiac myocytes.
There are specified and saturable binding sites for [20-3H]phorbol-12,13-dibutyrate on enzymatically dissociated rat cardiac myocytes. At 37 degrees C, maximal binding occurs within 20 min, with a KD of 3.9 nM and Bmax of 0.275 pmol/mg. [3H]Phorbol dibutyrate binding is blocked by 12-O-tetradecanoyl phorbol-13-acetate but not by 4 alpha-phorbol or 4 alpha-phorbol-12,13-dibutyrate. Dibucaine, tetracaine, chlorpromazine, and phospholipase C lowered phorbol binding through a competitive mechanism. Similarly, unsaturated (but not saturated) diacylglycerols competed with [3H]phorbol dibutyrate for the binding site. There was a progressive decline in specific binding of phorbol diesters to cardiac myocytes which occurred primarily during the first 3 weeks of postnatal life. Cardiac phorbol diester receptors may mediate protein kinase C-dependent effects on important cellular functions such as Ca2+ transport.
D000375:Aging; D000818:Animals; D001667:Binding, Competitive; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D004075:Diglycerides / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000378:metabolism; D011493:Protein Kinase C; D051381:Rats; D011919:Rats, Inbred Strains; D011955:Receptors, Drug; D011971:Receptors, Immunologic / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D004075:Diglycerides; D010703:Phorbol Esters; D011955:Receptors, Drug; D011971:Receptors, Immunologic; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C