Abstrait

Structural and Functional Analysis of Rhodopsin- A G- Protein Coupled Receptor

Shanker DM

Cell signaling and signal transduction are very important for a cell so that it can govern basic and advanced cellular activities in a well-coordinated manner. The activities of cells include anabolic and catabolic activities, response to their microenvironment and external environment, response to various ligands either beneficial for cell or harmful for cell and other physiological activities (sight, touch, taste, pain, anxiety, anger etc). Transduction involves the binding of extracellular signaling molecules and ligands to cell-surface receptors that trigger events inside the cell. Among the various types of receptors studied GPCRs are considered to be of utmost importance. The members of this large family of proteins are activated by a spectrum of structurally diverse ligands, and have been shown to modulate the activity of different signaling pathways in a ligand specific manner. They play a key role in regulating cell activity and physiological function. GPCR malfunction is responsible for a wide range of diseases including nephrogenic diabetes insipidus, and hyperthyroidism and a large proportion of drugs on the market target these receptors. The knowledge of GPCRs structure and function is very important for elucidating the molecular mechanisms underlying effective signal transduction and diseases and for performing structure-based drug design. Since structural data are restricted to only a handful of GPCRs, a major population of researchers is engaged in deducing the structures of various GPCRs. The main aim of this text is to introduce the fundamentals of GPCRs with emphasis on structure and function of rhodopsin, a well studied GPCR belonging to the rhodopsin family of GPCR and responsible for vision in vertebrates.