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Title: Compartmentation of protein kinase C is regulated by Ca and phorbol esters

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6150281

In S49 lymphoma cells, both Ca and phorbol esters enhance the association of protein kinase C (PKC) with membranes. Ca alone (greater than or equal to 100 M) or the combination of Ca and a brief (10 min) exposure to phorbol 12-myristate,13-acetate (PMA) results in the association of approximately 40% of PKC with the membrane fraction. The Ca -induced translocation of PKC to membrane can be reversed by 1 mM EGTA. After the extraction of this EGTA-sensitive component of PKC, an integral compartment remains, which can be removed only by detergent (0.3% Triton X-100) solubilization of membranes. They have studied the effects of PMA on the Ca -dependent association of PKC into these two membrane compartments. If intact S49 cells are treated with PMA and fractionated with 100 M Ca , this EGTA-sensitive membrane compartment of PKC is rapidly decreased (t/sub 1/2/ = 2 minutes), and replaced by an increase in integral PKC. Ten minutes after the addition of 100 nM PMA to intact cells, the EGTA-sensitive membrane compartment of PKC activity is decreased from 1102 +/- 34 to 94 +/- 20 pmoles PO transferred/min/mg protein. During this same time interval, the integral compartment of PKC increases from 480 +/- 27 to 1293 +/- 41 pmol/min/mg protein. Their findings are consistent with a PMA-induced conversion of PKC from a loosely-associated (EGTA-sensitive) compartment to an integral membrane compartment.

Research Organization:
UCSD School of Medicine, La Jolla
OSTI ID:
6150281
Report Number(s):
CONF-870644-; TRN: 87-029121
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
Country of Publication:
United States
Language:
English