Education

Research Interest

The focus of research interests in my laboratory is the regulation of epithelial tight junctions and cell-cell adhesion by intracellular signalling pathways.  The primary research interest involves delineating the role of phosphorylation of tight junction and adherens junction proteins (occludin, ZO-1, E-cadherin and ß-catenin) by protein kinases (Src kinases, PKC, FAK & MAPK) and proteins phosphatases (PP2A, PP1 and PTP1B) in the regulation of the assembly of tight junction and adherrens junction protein complexes and their interactions with the actin cytoskeleton.  Out come of these studies are important to understand the mechanisms involved in the pathogenesis of colon cancer, inflammatory bowel disease and alcoholic liver disease.

Current Techniques Uitilized:

• Culture of epithelial cells on Transwell inserts.
• Evaluation of tight junction permeability of epithelium.
• Site-directed mutagenesis.
• Construction of expression vectors, transfection and characterization of sub-clones.
• Confocal immunofluorescence localization of tight junction proteins.
• Production of proteins by recombinant technology and by in vitro transcription/translation.
• Identification of site of phosphorylation by Mass Spectrometry.
• Modeling and regulation of protein-protein interactions by in vitro binding studies.
• Actvity of protein kinases and protein phosphatases by immune-complex assays

Research Support

NIH R01 DK55532 (PI: R.K. Rao). ?Intestinal Mucosal Protection by Epidermal Growth Factor?. 1998-2009
NIH R01 AA12307 (PI: R. K. Rao). ?Mechanism of Endotoxin Absorption in Alcoholism?. 2000-2005
NIH R03 HD36512 (PI: R. K. Rao). ?Mucosal Protective Factors in Human Milk?. 2002-2004

Selected Publications

• Sheth P, Basuroy S, Li C, Naren P, Rao RK: Role of phosphatidylinositol 3-kinase in the oxidative stress-induced disruption of tight junctions in Caco-2 cells.  J. Biol. Chem. 278: 49239-49245, 2003.
• Basuroy S, Sheth P, Ray RM, Rao RK: Expression of kinase-inactive c-Src delays oxidative stress-induced disruption and accelerates calcium-induced assembly of tight junctions in Caco-2 cell monolayer.  J. Biol. Chem.  278: 11916-11924, 2003.
• Kale G, Naren AP, Sheth P, Rao RK: Tyrosine phosphorylation of occludin prevents its interactions with ZO-1, ZO-2 and ZO-3.  Biochem Biophys Res Commun  302: 324-329, 2003.
• Rao RK, Clayton LW: Regulation of protein phosphatase 2A by hydrogen peroxide and glutathionylation.  Biochem Biophys Res Commun  293:610-616, 2002.
• Rao RK, Rao VU, Karnaky K, Gupta A:  Role of tyrosine phosphorylation in dissociation of occludin.ZO-1 and E-cadherin.ß-catenin complexes from the cytoskeleton.  Biochem J. 368:471-481, 2002.
• Yellatyru C, Ghosh SK, Rao RK, Jennings LK, Hassid A, Rao GN:  A potential role for nuclear factor of activated T-cells in receptor tyrosine kinase and G-protein-coupled receptor agonist-induced cell proliferation.  Biochem J. 368:183-190, 2002.
• Atkinson K, Rao RK: Inhibition of protein tyrosine phosphatase in the mechanism of acetaldehyde-mediated disruption of epithelial tight junctions.  Am. J. Physiol.  280:G1280-G1288, 2001.
• Rao RK, Li L, Baker SS, Baker RD, Gupta A: Glutathione oxidation and inhibition of protein tyrosine phosphatase in hydrogen peroxide-induced increase in paracellular permeability. Am. J. Physiol  279: G332-G340, 2000.
• Rao RK, Baker RD, Baker SS: Epidermal growth factor delays oxidant-induced disruption of the intestinal epithelial barrier function. Biochem. Pharmacol.  57:685-697, 1999.
• Rao RK, Baker RD, Baker SS, Holycross M: Oxidant-induced disruption of the intestinal epithelial barrier function: Role of protein tyrosine phosphorylation. Am J Physiol 273:G812-G823, 1997.