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Phorbol Ester and the Actions of Phosphatidylinositol 4,5-bisphosphate Specific Phospholipase C and Protein Kinase C in Microsomes Prepared from Cultured Cardiomyocytes

Overview
Publisher Springer
Specialty Biochemistry
Date 1991 Jun 26
PMID 1656201
Citations 5
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Abstract

Microsomes were prepared from cultured neonatal rat cardiomyocytes. Incubation of microsomes in buffer containing 5 microM CaCl2, 5 mM cholate and 100 nM [3H-]Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5) P2) resulted in the formation of [3H-]InsP3. GTP-gamma-S (125 microM) stimulated the production of [3H-]InsP3. Microsomes prepared from phorbol ester-treated (100 nM phorbol 12-myristate 13-acetate, PMA) cardiomyocytes showed decreased activities of basal as well as GTP-gamma-S-stimulated [3H-]PtdIns(4,5)P2 hydrolysis. In the microsomes a 15 kD protein was demonstrated to be the major substrate phosphorylated by intrinsic protein kinase C, which was activated by 0.5 mM Ca2+. Addition of phorbol ester (100 nM PMA) enhanced the 32P-incorporation into the 15 kD protein. Protein kinase C, purified from rat brain, in the presence of Ca2+, diglyceride, and phosphatidylserine did not change the phosphorylation pattern any further. In conclusion, it was shown that phorbol ester pretreatment of neonatal rat cardiomyocytes reduces microsomal GTP-gamma-S-stimulated PtdIns(4,5)P2-specific phospholipase C activity, as estimated with exogenous substrate, and that in cardiomyocyte microsomes phorbol ester activates protein kinase C-induced 15 kD protein phosphorylation. The results indicate that phorbol ester may down-regulate alpha 1-adrenoceptor mediated PtdIns(4,5)P2 hydrolysis by activation of protein kinase C-induced 15 kD protein phosphorylation.

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References
1.
Michell B, Kirk C . G-protein control of inositol phosphate hydrolysis. Nature. 1986; 323(6084):112-3. DOI: 10.1038/323112b0. View

2.
Malviya A, Louis J, Zwiller J . Separation from protein kinase C--a calcium-independent TPA-activated phosphorylating system. FEBS Lett. 1986; 199(2):213-6. DOI: 10.1016/0014-5793(86)80482-3. View

3.
Steinberg S, Chow Y, Robinson R, Bilezikian J . A pertussis toxin substrate regulates alpha 1-adrenergic dependent phosphatidylinositol hydrolysis in cultured rat myocytes. Endocrinology. 1987; 120(5):1889-95. DOI: 10.1210/endo-120-5-1889. View

4.
Meij J, Lamers J . Alpha-1-adrenergic stimulation of phosphoinositide breakdown in cultured neonatal rat ventricular myocytes. Mol Cell Biochem. 1989; 88(1-2):73-5. DOI: 10.1007/BF00223426. View

5.
Manalan A, Jones L . Characterization of the intrinsic cAMP-dependent protein kinase activity and endogenous substrates in highly purified cardiac sarcolemmal vesicles. J Biol Chem. 1982; 257(17):10052-62. View