Areas of Interest
The focus of our laboratory is to understand the G protein coupled receptor- mediated signaling of protein hormones in sex hormone producing target tissues on a molecular level. One of our current efforts is directed towards the post-transcriptional regulation of LH receptor mRNA expression through a newly identified mRNA binding protein, LRBP. The tools used for these studies include SiRNA, RNA mobility gel shift assay, yeast two hybrid analysis and structural studies of RNA-protein interactions. These studies are directed towards understanding how cells regulate mRNA expression by controlling the degradation rate through its interaction with specific mRNA binding proteins.
Another ongoing study focuses on post-translational modifications of the LH receptor and their role in ligand-receptor interaction, receptor turn over and intracellular signaling. The specific processes being examined are palmitoylation, phosphorylation and glycosylation. The biological effects of these modifications are examined on the receptor processing, receptor internalization, recycling and intracellular degradation.
A third area of interest of the laboratory centers on biochemical studies on the mechanism by which androgens disrupt ovarian follicle development that leads to impaired ovum development, a common cause of reproductive failure in the humans These studies are carried out using primary cultures of human and rat granulose cells. Our efforts focus on signaling pathways and their cross talk involved in cell cycle progression from G1 to S phase, cell growth and proliferation. The signaling pathways being examined include PKA-ERK-mediated down stream targets as well as PI3 kinase-mTOR pathway in response to FSH and insulin. We are exploring the mechanism by which androgens disrupts these signaling pathways since these disruptions has been shown to be associated with infertility in the human.
Honors & Awards
1995-1996 Outstanding Teacher Recognition Award
1999 Distinguished Faculty Achievement Award
2006 MI Scientist of the Year, Impressions 5 Science Museum
Munshi, U.M., Pogozheva, I.D, and Menon, K.M.J. Highly Conserved Serine in the Third Transmembrane Helix of the Luteinizing Hormone/Human Chorionic Gonadotropin Receptor Regulates Activation. Biochemistry 42, 13, 3708-3715 (2003)
Nair, A.K. and Menon, K.M.J. Isolation and Characterization of a Novel trans-Factor for Luteinizing Hormone Receptor mRNA from Ovary. J. Biol. Chem. 279, 14937-14944 (2004) PMID: 14749336
Menon, K.M.J., Munshi, U.M., Clouser, C.L., Nair, A.K. Regulation of Luteinizing Hormone/Human Chorionic Gonadotropin Receptor Expression: A Perspective. Biol. Reprod. 70, 861-866 (2004). PMID: 14668203
Munshi, U., Clouser, C.L., Peegel, H., Menon, K.M.J. Evidence that palmitoylation of the carboxyl terminus cysteine residues of the human luteinizing hormone receptor regulates post-endocytic processing. Mol Endocrinol, 19(3): 749-758 (2005)
Nair, A.K. and Menon, K.M.J. Regulation of Luteinizing Hormone Receptor Expression in the Ovary: Evidence of mRNA Translational Suppression by a Hormonally Regulated mRNA Binding Protein. J. Biol. Chem. 280 (52) 42809-42816 (2005)
Towns, R., and Menon, K.M.J. The role of cyclic AMP response element binding protein in trans-activation of scavenger receptor class B type I promoter in transfected cells and in primary cultures of rat theca interstitital cells. Mol Cell Endocrinol 245, 23-30(2005)
Nair, AK and Menon, KMJ. Regulation of Luteinizing Hormone Receptor Expression Binding Protein and Its Endogenous Association With Luteinizing Hormone Receptor mRNA In the Ovary. J. Biol. Chem. 280: 42809-42816 (2005)
Kayampilly, P.P. and Menon, K.M.J. Dihydrotestosterone Inhibits Insulin-stimulated cyclin D2 mRNA Expression and Cell Proliferation in Rat Ovarian Granulosa Cells by Reducing the Phosphorylation of Insulin Receptor Substrate-1. Endocrinology 147 (1):464-471 (2006).