Structure function relationship of Dexras1 and Dexamethasoneinduced modulation of Reproduction

Abstract

Dexras1 is involved in several pathophysiological conditions like cardiovascular diseases, cancer, biological rhythms, neurotransmitter release, obesity etc. It is sometimes baffling that this single protein is involved in so many signaling pathways. Dexras1 is a monomeric protein that acts like a GTPase. GTPase or G Proteins are GTP binding proteins that are involved in several cell signaling processes. G proteins are of two types: trimeric and monomeric. Trimeric proteins are consists of three subunits while the monomeric protein consist only one subunit. Ras is also a monomeric G protein superfamily member and this Ras family includes many members. In the present study we are focusing on a Ras superfamily member, Dexras1 also called as RasD1/AGS1. Most of the signaling processes occur after the interaction of G protein with cell surface receptors (GPCRs). In the year 1998 a new member of Ras superfamily was reported which showed signaling without the involvement of receptors. This protein is upregulated by Dexamethasone (synthetic glucocorticoid) in AtT20 cell lines and hence named as Dexras1. Dexras1 contains all the conserved domains of Ras superfamily (GTP binding domains, effector loop and CAAX site at C terminal). The Dexras1 is unique in terms of its N and C terminus from other members of Ras superfamily except a protein named RHES, which show 62% identity with Dexras1. Both of these proteins are involved in modulation of N type calcium channel proteins. It has been showed that the C terminal of Dexras1 interacts with nNOS but the exact role of the N terminal is still not known. The involvement of Dexras1 has been reported in many processes till date but the exact molecular mechanism of interaction of Dexras1 with other protein and signaling mechanisms at molecular level not yet explained. Researchers are still finding new functions. newline The present work focused on structure function relationship of Dexras1 on the bases of its structural analysis as pdb file of Dexras1 is not available in any database and