Post-translational regulation of steroidogenic acute regulatory protein by cAMP-dependent protein kinase A
| Autor: | Velvizhi Ranganathan, Barbara J. Clark, Rebecca Combs |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
endocrine system
Messenger RNA Steroidogenic acute regulatory protein 8-Bromo Cyclic Adenosine Monophosphate Translation (biology) General Medicine Biology Phosphoproteins Molecular biology Cyclic AMP-Dependent Protein Kinases Cell Line Mice Endocrinology Methionine Cell culture Polysome Adrenal Cortex Cyclic AMP Animals Post-translational regulation RNA Messenger Signal transduction Protein kinase A Protein Processing Post-Translational |
| Zdroj: | Endocrine research. 26(4) |
| ISSN: | 0743-5800 |
| Popis: | Adrenal steroid production is stimulated by adrenocorticotropin hormone activation of the cAMP-dependent protein kinase A (PKA) signaling pathway and subsequent induction of Steroidogenic Acute Regulatory (StAR) protein expression. Herein we have compared StAR mRNA and protein levels in 8-Br-cAMP-treated mouse adrenocortical Y1 and the derived PKA mutant Kin-8 cell lines to evaluate the PKA requirement in StAR expression. StAR mRNA was induced by 8-Br-cAMP-treatment of both Y1 and Kin-8 cells with maximal expression levels in Kin-8 cells approximately 50% of that observed in Y1 cells. StAR protein levels, as detected by Western analysis, were concomitantly increased in Y1 cells but were not detected in the Kin-8 cells. StAR mRNA colocalized with the active polysome fractions in both 8-Br-cAMP-treated Y1 and Kin-8 cells, indicating translation was not blocked in Kin-8 cells. Consistent with this data, a 2-fold increase in incorporation of [35S]methionine into StAR was also observed after 8-Br-cAMP treatment of both cell lines. Since StAR protein levels were not sufficient to detect by Western analysis, 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. |
| Databáze: | OpenAIRE |
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