Frawley BP, Tien XY, Hartmann SC, Wali RK, Niedziela SM, Davidson NO, Sitrin MD, Brasitus TA, Bissonnette M. TPA causes divergent responses of Ca(2+)-dependent and Ca(2+)-independent isoforms of PKC in the nuclei of Caco-2 cells.
BIOCHIMICA ET BIOPHYSICA ACTA 1994;
1222:301-5. [PMID:
8031867 DOI:
10.1016/0167-4889(94)90182-1]
[Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The present studies were undertaken to examine the expression of PKC isoforms within the nucleus of Caco-2 cells, a cell line widely used to investigate intestinal cell growth and differentiation, in order to begin to explore their roles in modulating gene expression. Purified nuclei were, therefore, prepared from Caco-2 cells and found to contain PKC-zeta, but not -alpha. The phorbol ester, 12-O-tetradecanoyl phorbol 13-acetate (TPA) caused an acute redistribution of PKC-alpha to the nucleus, but did not change the distribution of PKC-zeta. Chronic treatment with TPA down-regulated total PKC-alpha, but not -zeta. Moreover, in contrast to acute TPA treatment, after chronic treatment, nuclear PKC-alpha was no longer detectable, whereas nuclear PKC-zeta was unchanged. These studies demonstrate for the first time the constitutive expression and divergent responses to TPA of the Ca(2+)-dependent and Ca(2+)-independent isoforms of PKC in the nuclei of Caco-2 cells and suggest that these specific isoforms may be involved in modulating gene expression.
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