Abstract
Following tropic hormone challenge, steroidogenic tissues utilize PKA to phosphorylate unique subsets of proteins necessary to facilitate steroidogenesis. This includes the PKA-dependent expression and activation of the steroidogenic acute regulatory protein (STAR), which mediates the rate-limiting step of steroidogenesis by inducing the transfer of cholesterol from the outer to the inner mitochondrial membrane. Since both type I and type II PKA are present in steroidogenic tissues, we have utilized cAMP analog pairs that preferentially activate each PKA subtype in order to examine their impact on STAR synthesis and activity. In MA-10 mouse Leydig tumor cells Star gene expression is more dependent upon type I PKA, while the post-transcriptional regulation of STAR appears subject to type II PKA. These experiments delineate the discrete effects that type I and type II PKA exert on STAR-mediated steroidogenesis, and suggest complimentary roles for each subtype in coordinating steroidogenesis.
Original language | English (US) |
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Pages (from-to) | 94-103 |
Number of pages | 10 |
Journal | Molecular and Cellular Endocrinology |
Volume | 300 |
Issue number | 1-2 |
DOIs | |
State | Published - Mar 5 2009 |
Funding
We would like to acknowledge Yuping Sun for her technical assistance. This research was supported by funds from the NIH grant # HD-17481 and grant # B1-0028 from the Robert A. Welch Foundation (to D.M.S.).
Keywords
- Leydig
- PKA
- STAR
- Steroidogenesis
- cAMP
- cAMP-dependent protein kinase
ASJC Scopus subject areas
- Endocrinology
- Molecular Biology
- Biochemistry