Factors influencing chelator-stable, detergent-extractable, phorbol diester-induced membrane association of protein kinase C. Differences between Ca2+-induced and phorbol ester-stabilized membrane bindings of protein kinase C.

摘要: One of the early events associated with treatment cells by tumor promotor phorbol esters is tight association protein kinase C to plasma membrane. To better understand factors that regulate this process, ester-induced membrane binding was studied using homogenates, as well isolated membranes and purified enzyme. Addition 12-O-tetradecanoylphorbol 13-acetate (TPA) homogenates parietal yolk sac NIH 3T3 in presence Ca2+ resulted which subsequently remained bound independent Ca2+. Although activated TPA absence diolein Ca2+, both these agents when added under respective conditions had no effect on C. However, relatively weak found if used membranes. Binding studies washed showed TPA-kinase complex required phospholipids reached saturation at 0.1 unit (24 ng C)/mg cell protein. Phorbol ester media without TPA-induced increase membrane-associated regulated levels even intact cells. TPA-stabilized differs several aspects from previously reported Ca2+-induced reversible binding. temperature dependent, high membrane-enriched fraction, saturable physiological C, requires protein(s) phospholipids, further addition phospholipid micelles. In contrast, more rapid, not appreciably influenced temperature, selective for a particular subcellular amounts exhibits trypsin-insensitive sites, but