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Steroidogenic acute regulatory protein expression is dependent upon post-translational effects of cAMP-dependent protein kinase A.

Authors :
Clark BJ
Ranganathan V
Combs R
Source :
Molecular and cellular endocrinology [Mol Cell Endocrinol] 2001 Feb 28; Vol. 173 (1-2), pp. 183-92.
Publication Year :
2001

Abstract

Tropic hormones acutely stimulate adrenal and gonadal steroidogenesis by activation of the cAMP-dependent protein kinase A (PKA) signaling pathway and subsequent induction of Steroidogenic Acute Regulatory (StAR) protein (StAR) expression. We present a comparative study of StAR regulation in mouse adrenocortical Y1 and the derived PKA mutant Kin-8 cell lines to evaluate the PKA requirement for StAR expression. A parallel increase in StAR steady-state mRNA and protein was observed in Y1 cells. StAR mRNA was induced in 8-Br-cAMP-treated Kin-8 cells with maximal expression levels approx. 50% of that observed in Y1 cells. However, a corresponding increase in StAR protein, as detected by Western analysis, was absent in the Kin-8 cells. A similar distribution of StAR mRNA in active polysome fractions was observed for both 8-Br-cAMP-treated Y1 and Kin-8 cells, as well as a 2-fold increase in incorporation of [35S]methionine into StAR, which indicated translation was not blocked in Kin-8 cells. Together these data indicate that PKA functions at the post-translational level to regulate StAR expression and we propose that phosphorylation of StAR by PKA contributes to protein stability

Details

Language :
English
ISSN :
0303-7207
Volume :
173
Issue :
1-2
Database :
MEDLINE
Journal :
Molecular and cellular endocrinology
Publication Type :
Academic Journal
Accession number :
11223189
Full Text :
https://doi.org/10.1016/s0303-7207(00)00410-x