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 humans. These studies are carried out using primary cultures of human and rat granulosa 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 downstream targets as well as PI3 kinase-mTOR pathway in response to FSH and insulin. We are exploring the mechanism by which androgens disrupt these signaling pathways, since these disruptions have been shown to be associated with infertility in the human.
Honors & Awards
Michigan Scientist of the Year, Impression 5 Science Museum, 2006
Distinguished Faculty Achievement Award, University of Michigan, 1999
Outstanding Teacher Recognition Award, University of Michigan, 1995–1996
SREBP Plays a Regulatory Role in LH/hCG Receptor mRNA Expression in Human Granulosa-Lutein cells.
Li YX, Guo X, Gulappa T, Menon B, Menon KMJ.
J Clin Endocrinol Metab. 2019; 104: 4783–92.
miR-122 Regulates LHR Expression in Rat Granulosa Cells by Targeting Insig1 mRNA.
Menon B, Guo X, Garcia N, Gulappa T, Menon KMJ.
Endocrinology. 2018; 159: 2075–82.
Regulation of Luteinizing Hormone Receptor mRNA Expression in the Ovary: The Role of miR-122.
Menon KMJ, Menon B, Gulappa T.
Vitam Horm. 2018; 107: 67–87.
LHCGR Expression During Follicle Stimulating Hormone-Induced Follicle Growth Is Negatively Regulated by Eukaryotic Initiation Factor 5A.
Gulappa T, Menon B, Menon KMJ.
Endocrinology. 2017; 158: 2672–9.
Molecular regulation of LHCGR expression by miR-122 during follicle growth in the rat ovary.
Menon B, Gulappa T, Menon KM.
Mol Cell Endocrinol. 2017; 442: 81–9.
miR-122 Regulates LH Receptor Expression by Activating Sterol Response Element Binding Protein in Rat Ovaries.
Menon B, Gulappa T, Menon KM.
Endocrinology. 2015; 156: 3370–80.
Hypusination of eukaryotic initiation factor 5A via cAMP-PKA-ERK1/2 pathway is required for ligand-induced downregulation of LH receptor mRNA expression in the ovary.
Gulappa T, Menon B, Menon KM.
Mol Cell Endocrinol. 2015; 413: 90–5.
For a list of publications from PubMed, click HERE