The stimulatory adrenocorticotropin (ACTH) on steroidogenic gene action of transcription in the adrenal cortex is mediated through a cAMP/PKA-dependent pathway. We have demonstrated that the ACTH/cAMP-stimulated transcription of the human CYP17 gene (hCYP17) requires mitogen-activated protein kinase phosphatase 1 (MKP-1), an inactivator of extracellular-signal-related kinases 1/2 (ERK1/2). In human adrenocortical H295R cells, MKP-1 is rapidly induced by ACTH/cAMP and PKA can phosphorylate MKP-1 in vitro. We have also shown that inhibition of ERK1/2 activation mimics the stimulatory effect of ACTH/cAMP on hCYP17 gene expression. We postulate that ERK1/2 constitutively phosphorylates steroidogenic factor 1 (SF-1) and that in response to ACTH/cAMP, MKP-1 acts to dephosphorylate ERK1/2, thereby increasing hCYP17 transcription. Our previous studies have also demonstrated that SF-1, p54nrb and polypyrimidine tract binding protein-associated splicing factor (PSF) form a complex that is essential for cAMP-dependent transcription of hCYP17. Further, we have demonstrated that the corepressor mSin3A and a histone deacetylase (HDAC) interact with this complex and repress hCYP17 transcription. We hypothesize that dephosphorylation of SF-1 results in dissociation of mSin3A and the HDAC from the complex and recruitment of coactivators. This proposal aims to characterize the functional significance of MKP-1 activation and SF-1 dephosphorylation in ACTH/cAMP-stimulated hCYP17 gene transcription. Further, we will determine the mechanism by which SF-1 is constitutively phosphorylated and examine how phosphorylation of SF-1 represses hCYP17 expression. Finally, we will determine how the SF-1/p54nrb/PSF complex interacts with each other and how this complex interacts with corepressors/coactivators to allow for repression/activation of hCYP17. Using both biochemical and molecular techniques, including reporter gene transfection assays, chromatin immunoprecipitation, phosphatase/kinase activity assays, and mass spectrometry, our findings will provide insight into the mechanism by which the ACTH/cAMP pathway and the MAPK signaling cascade interact to ensure biosynthesis of adrenal hormones to meet physiological needs in humans. ? ?

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Endocrinology Study Section (END)
Program Officer
Okita, Richard T
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Georgia Institute of Technology
Schools of Arts and Sciences
United States
Zip Code
Lu, Jia Yang; Sewer, Marion B (2015) p54nrb/NONO regulates cyclic AMP-dependent glucocorticoid production by modulating phosphodiesterase mRNA splicing and degradation. Mol Cell Biol 35:1223-37
Li, Donghui; Dammer, Eric B; Sewer, Marion B (2012) Resveratrol stimulates cortisol biosynthesis by activating SIRT-dependent deacetylation of P450scc. Endocrinology 153:3258-68
Lucki, Natasha C; Sewer, Marion B (2010) The interplay between bioactive sphingolipids and steroid hormones. Steroids 75:390-9
Li, Donghui; Sewer, Marion B (2010) RhoA and DIAPH1 mediate adrenocorticotropin-stimulated cortisol biosynthesis by regulating mitochondrial trafficking. Endocrinology 151:4313-23
Sewer, Marion B; Jagarlapudi, Srinath (2009) Complex assembly on the human CYP17 promoter. Mol Cell Endocrinol 300:109-14
Sewer, Marion B; Li, Donghui; Dammer, Eric B et al. (2008) Multiple Signaling Pathways Coordinate CYP17 Gene Expression in the Human Adrenal Cortex. Acta Chim Slov 55:53-57
Dammer, Eric B; Sewer, Marion B (2008) Phosphorylation of CtBP1 by cAMP-dependent protein kinase modulates induction of CYP17 by stimulating partnering of CtBP1 and 2. J Biol Chem 283:6925-34
Urs, Aarti N; Dammer, Eric; Kelly, Samuel et al. (2007) Steroidogenic factor-1 is a sphingolipid binding protein. Mol Cell Endocrinol 265-266:174-8
Sewer, Marion B; Dammer, Eric B; Jagarlapudi, Srinath (2007) Transcriptional regulation of adrenocortical steroidogenic gene expression. Drug Metab Rev 39:371-88
Ozbay, Tuba; Rowan, Anne; Leon, Adam et al. (2006) Cyclic adenosine 5'-monophosphate-dependent sphingosine-1-phosphate biosynthesis induces human CYP17 gene transcription by activating cleavage of sterol regulatory element binding protein 1. Endocrinology 147:1427-37