1. Alpha-subunit of farnesyltransferase is phosphorylated in vivo: effect of protein phosphatase-1 on enzymatic activity.
- Author
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Kumar A, Beresini MH, Dhawan P, and Mehta KD
- Subjects
- Animals, Antibody Specificity, Cell Line, Cytosol enzymology, Enzyme Inhibitors pharmacology, Farnesyltranstransferase, Immunoblotting, Immunoglobulin G, Kinetics, Macromolecular Substances, Marine Toxins, Oxazoles pharmacology, PC12 Cells, Phosphates metabolism, Phosphoprotein Phosphatases antagonists & inhibitors, Phosphorylation, Protein Phosphatase 1, Rats, Transferases chemistry, Transferases isolation & purification, Alkyl and Aryl Transferases, Phosphoprotein Phosphatases metabolism, Transferases metabolism
- Abstract
Farnesyltransferase is a heterodimer consisting of a 49 kDa alpha-subunit and a 46 kDa beta-subunit. In this report, we demonstrate that the endogenous heterodimeric farnesyltransferase protein is phosphorylated at the alpha-subunit in vivo and phosphorylation plays a role in the regulation of farnesyltransferase activity. In vivo 32P-labeling of PC-12 cells followed by immunoprecipitation with specific anti rat alpha-subunit IgG showed a labeled alpha-subunit protein band at an expected molecular mass of 49 kDa. Treatment of PC-12 cells with protein phosphatase inhibitor, Calyculin A, resulted in a decrease in FTase activity, and phophoserine/phosphothreonine-specific protein phosphatase-1 treatment of PC-12 and GM37 cell extracts resulted in 100% and 375% increase in farnesyltransferase activity, respectively, compared to untreated extracts.
- Published
- 1996
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