Nonsteroidal Antiestrogen Suppresses Protein Kinase C. Its Inhibitory Effect on Interaction of Substrate Protein with Membrane.

1 January 1991

journal article
Published by Japan Society for Cell Biology in Cell Structure and Function

Vol. 16 (4) , 273-281
https://doi.org/10.1247/csf.16.273

Abstract

The mechanism by which nonsteroidal antiestrogen inhibits Ca(2+)- and phospholipid-dependent protein kinase (PKC) activity was investigated. Antiestrogenic agents, clomiphene and tamoxifen, inhibited the PKC-dependent phosphorylation of histone and r-annexin I in a dose-dependent manner. Ki values for the agents were different for two substrate proteins. The inhibitory action of the agents depended on the membrane-substrate protein interaction. Phosphorylation of cytoplasmic proteins obtained from rat uterus and mammary gland, including annexin I, by endogenous PKC was also inhibited by low concentrations of these agents. These results suggest that the inhibitory action of nonsteroidal antiestrogens occurs through their inhibitory effect on the membrane-substrate protein interaction.

Keywords

PROTEIN KINASE C

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