Receptors for tumor-promoting phorbol esters in rat ventral prostate.
The presence of tumor-promoting phorbol ester receptors in rat prostate was investigated by studying the binding of phorbol diester 12,13-dibutyrate (PDBu) in both soluble and particulate subcellular fractions. Binding of [3H]PDBu to the soluble fraction was optimal after the addition of phosphatidylserine (0.1 mg/ml) and Ca2+ (1 mM). Both subcellular fractions exhibited a single class of PDBu receptor (Kd between 97 and 128 nM) as shown by saturation binding experiments. Phorbol esters with tumor-promoting activity showed a higher affinity for these receptors than did endogenous ligands such as diacylglycerols whereas phorbol esters without tumor-promoting activity were ineffective even at concentrations as high as 1 microM. These properties are highly representative of protein kinase C activity.
Carmena
M J
MJ
Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá, Alcalá de Henares, Spain.
Garcia-Paramio
M P
MP
Prieto
J C
JC
D000818:Animals; D029742:Caenorhabditis elegans Proteins; D002118:Calcium / Q000494:pharmacology; D002352:Carrier Proteins; D008297:Male; D010703:Phorbol Esters; D010718:Phosphatidylserines / Q000494:pharmacology; D011467:Prostate / Q000378:metabolism*; D011493:Protein Kinase C; D051381:Rats; D017208:Rats, Wistar; D011955:Receptors, Drug / Q000032:analysis*; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010703:Phorbol Esters; D010718:Phosphatidylserines; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D011493:Protein Kinase C; D002118:Calcium