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Redistribution of protein kinase C to subcellular fractions other than plasma membrane

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6934361
12-0-Tetradecanoyl Phorbol-13-acetate (TPA) treatment of intact NIH 3T3 cells causes redistribution of protein kinase C (PKC) to the particulate fraction; predominantly with the plasma membrane. Part of the enzyme stabilized to particulate fractions can be recovered associated with the nuclear-cytoskeletal components. An apparently pure nuclear fraction (NF) prepared from NIH 3T3 cells contains 25% of the PKC activity when isolated in the presence of 1mM Ca/sup + +/. In untreated cells most of the activity bound to NF can be solubilized by chelators whereas in TPA treated cells this activity is not dissociated by chelators and can be recovered only by detergent extraction. Possible contamination by plasma membrane fragments is monitored by measurement of adenylate cyclase activity. The TPA induced redistribution of PKC to NF is not observed with HD 60 cells. Studies are in progress to further characterize the observed TPA-induced redistribution by immunohistochemical localization and endogenous phosphorylation of specific proteins in these subcellular fractions. Preliminary results indicate specific phosphorylation of a 20K protein with the NF prepared from TPA treated cells. These results suggest that tumor promoters may induce association (activation) of PKC with different particulate components to alter the availability of endogenous substrates. This may result in differential response by different cell types to treatment with TPA.
Research Organization:
National Institutes of Health, Bethesda, MD
OSTI ID:
6934361
Report Number(s):
CONF-8606151-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
Country of Publication:
United States
Language:
English