Detail of "2442-61-7"

Reference

Factors influencing chelator-stable, detergent-extractable, phorbol diester-induced membrane association of protein kinase C

Factors influencing chelator-stable, detergent-extractable, phorbol diester-induced membrane association of protein kinase C. Differences between calcium-induced and phorbol ester-stabilized membrane bindings of protein kinase C. Gopalakrishna, Rayudu; Barsky, Sanford H.; Thomas, Thomas P.; Anderson, Wayne B. (Sch. Med., Univ. California, Los Angeles, CA 90024, USA). J. Biol. Chem., 261(35), 16438-45 (English) 1986. CODEN: JBCHA3. ISSN: 0021-9258. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Phorbol ester-induced membrane binding of protein kinase C [9026-43-1] was studied using homogenates, as well as isolated membranes and purified enzyme. Addn. of TPA (I) [16561-29-8] to the homogenates of parietal yolk sac cells and NIH 3T3 cells in the presence of Ca2+ resulted in plasma membrane binding of protein kinase C which subsequently remained bound to the membrane independent of Ca2+. Although protein kinase C was activated by TPA in the absence of Ca2+ and by diolein [2442-61-7] in the presence of Ca2+, both these agents when added to homogenates under these resp. conditions had no effect on membrane assocn. of protein kinase C. However, under these conditions relatively weak binding of protein kinase C was found if purified protein kinase C was used with isolated membranes. Binding studies using purified protein kinase C and washed membranes showed that the binding of the TPA-kinase complex to membranes required phospholipids and reached satn. at 0.1 unit (24 ng of protein kinase C)/mg of parietal yolk sac cell membrane protein. Phorbol ester treatment of cells in media with and without Ca2+ showed that the TPA-induced increase in membrane-assocd. protein kinase C was regulated by Ca2+ levels even in intact cells. TPA-stabilized membrane binding of protein kinase C differs in several aspects from the previously reported Ca2+-induced reversible binding. TPA-stabilized binding of protein kinase C to isolated membranes is temp. dependent, relatively high in the plasma membrane-enriched fraction, saturable at physiol. levels of protein kinase C, requires the presence of both membrane protein(s) and phospholipids, and further requires the addn. of phospholipid micelles. In contrast, Ca2+-induced reversible binding is more rapid, not appreciably influenced by temp., not selective for a particular subcellular fraction, not saturable with physiol. amts. of protein kinase C, exhibits trypsin-insensitive membrane binding sites, and requires membrane phospholipids but not added phospholipid micelles.

Further characterization of tumor promoter-mediated activation of protein kinase C

Further characterization of tumor promoter-mediated activation of protein kinase C. Couturier, Anne; Bazgar, Shah; Castagna, Monique (Inst. Rech. Sci. Cancer, Villejuif 94802, Fr.). Biochem. Biophys. Res. Commun., 121(2), 448-55 (English) 1984. CODEN: BBRCA9. ISSN: 0006-291X. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Tumor-promoting phorbol esters activated Ca-sensitive, phospholipid-dependent protein kinase [9026-43-1] C in a reconstituted system. Teleocidin (I) [78474-55-2], a tumor promoter, and mezerein [34807-41-5] also activated the mouse brain enzyme. Chem. unrelated tumor promoters such as TCDD [1746-01-6], anthralin [1143-38-0], and phenobarbital [50-06-6] were devoid of effect. 1,2-Diolein [2442-61-7] strongly activated the enzyme whereas 1,3-diolein [2465-32-9] and 1,2-distearin [1188-58-5] were poor activators, and 1,3-distearin [504-40-5] was inactive. Although tumor promoter- or diacylglycerol-mediated activation of protein kinase C was obsd. in the presence of 0.5 mM EGTA, the reaction required traces of Ca. Tumor promoters did not prevent an inhibitory action of antipsychotic phenothiazines and local anesthetics.