J. Biol. Chem., Vol. 263, Issue 14, 6534-6537, 05, 1988

1,2-Diacylglycerols, but not phorbol esters, activate a potential inhibitory pathway for protein kinase C in GH3 pituitary cells. Evidence for involvement of a sphingomyelinase

RN Kolesnick and S Clegg
Department of Medicine, Memorial Sloan-Kettering Cancer Center, Cornell University Medical College, New York 10021.

It has been suggested that sphingoid bases may serve as physiologic inhibitors of protein kinase C. Because 1,2-diacylglycerols, but not phorbol esters, enhance sphingomyelin degradation via a sphingomyelinase in GH3 pituitary cells (Kolesnick, R. N. (1987) J. Biol. Chem. 262, 16759-16762), the effects of phorbol esters, 1,2- diacylglycerols, and sphingomyelinase on protein kinase C activation were assessed. Under basal conditions, the inactive cytosolic form of protein kinase C predominated. 1,2-Diacylglycerols stimulated transient protein kinase C redistribution to the membrane. 1,2-Dioctanoylglycerol (200 micrograms/ml) reduced cytosolic protein kinase C activity to 67% of control from 72 to 48 pmol.min-1.10(6) cells-1 and enhanced membrane- bound activity to 430% of control from 6 to 25 pmol.min-1.10(6) cells-1 after 4 min of stimulation. Thereafter, protein kinase C activity returned to the cytosol. In contrast, the phorbol ester, 12-O- tetradecanoylphorbol-13-acetate (TPA), stimulated redistribution to the membrane without return to the cytosol. Exogenous sphingomyelinase reduced membrane-bound protein kinase C activity to 30% of control, yet did not alter cytosolic activity. Sphingomyelinase, added after phorbol ester-induced redistribution was completed, restored activity to the cytosol. In these studies, TPA (10(-8) M) reduced cytosolic activity to 62% of control and elevated membrane-bound protein kinase C activity to 650% of control. Sphingomyelinase restored cytosolic activity to 84% of control and reduced membrane-bound activity to 297% of control. Similarly, the free sphingoid bases, sphingosine, sphinganine, and phytosphingosine, reversed phorbol ester-induced protein kinase C redistribution. Since 1,2-diacylglycerols activate a sphingomyelinase and sphingomyelinase action can reverse protein kinase C activation, these studies suggest that a pathway involving a sphingomyelinase might comprise a physiologic negative effector system for protein kinase C. Further, the failure of phorbol esters to activate this system might account for some differences between these agents.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				F.-X. Contreras, A.-V. Villar, A. Alonso, R. N. Kolesnick, and F. M. Goni Sphingomyelinase Activity Causes Transbilayer Lipid Translocation in Model and Cell Membranes J. Biol. Chem., September 26, 2003; 278(39): 37169 - 37174. [Abstract] [Full Text] [PDF]

				H. Wang, A. E. Giuliano, and M. C. Cabot Enhanced de Novo Ceramide Generation through Activation of Serine Palmitoyltransferase by the P-Glycoprotein Antagonist SDZ PSC 833 in Breast Cancer Cells Mol. Cancer Ther., July 1, 2002; 1(9): 719 - 726. [Abstract] [Full Text] [PDF]

				A. Senchenkov, D. A. Litvak, and M. C. Cabot Targeting Ceramide Metabolism--a Strategy for Overcoming Drug Resistance J Natl Cancer Inst, March 7, 2001; 93(5): 347 - 357. [Abstract] [Full Text] [PDF]

				A. Titievsky, I. Titievskaya, M. Pasternack, K. Kaila, and K. Tornquist Sphingosine Inhibits Voltage-operated Calcium Channels in GH4C1 Cells J. Biol. Chem., January 2, 1998; 273(1): 242 - 247. [Abstract] [Full Text] [PDF]

				K. Graf, P. Koehne, M. Grafe, M. Zhang, W. Auch-Schwelk, and E. Fleck Regulation and Differential Expression of Neutral Endopeptidase 24.11 in Human Endothelial Cells Hypertension, August 1, 1995; 26(2): 230 - 235. [Abstract] [Full Text]

				M. J. Jones and A. W. Murray Evidence That Ceramide Selectively Inhibits Protein Kinase C-alpha Translocation and Modulates Bradykinin Activation of Phospholipase D J. Biol. Chem., March 10, 1995; 270(10): 5007 - 5013. [Abstract] [Full Text] [PDF]

				C. Carsberg, H. Warenius, and P. Friedmann Ultraviolet radiation-induced melanogenesis in human melanocytes. Effects of modulating protein kinase C J. Cell Sci., January 9, 1994; 107(9): 2591 - 2597. [Abstract] [PDF]

				S Mathias, A Younes, C. Kan, I Orlow, C Joseph, and R. Kolesnick Activation of the sphingomyelin signaling pathway in intact EL4 cells and in a cell-free system by IL-1 beta Science, January 22, 1993; 259(5094): 519 - 522. [Abstract] [PDF]

				K. Dressler, S Mathias, and R. Kolesnick Tumor necrosis factor-alpha activates the sphingomyelin signal transduction pathway in a cell-free system Science, March 27, 1992; 255(5052): 1715 - 1718. [Abstract] [PDF]