Title : Beyond the rate-limiting step of rod and cone phototransduction: emerging roles of RGS proteins in mammalian vision.

Speaker: Dr. Ching-Kang Jason Chen

Host: Prof. Mingyao Liu

When: 2012-10-23 14:00

Where: Conference Room 534, School of Life Sciences

Abstract：We use biochemical, electrophysiological, and genetic tools to study the biology of vertebrate retinal photoreceptors. These post-mitotic and highly differentiated cells transduce visible light into electrical signals. Two types of morphologically distinctive photoreceptors are found in the retina. Rod photoreceptors, responsible for dim light vision due to their higher sensitivity, transduce light relatively slower. Cone photoreceptors, responsible for daytime vision and color vision, are less sensitive but transduce light much faster than rods. The biochemical reactions linking photon absorption to the generation of neural signals is a canonical G-protein signal transduction pathway called phototransduction, in which rod and cone photoreceptors use cGMP as a second messenger. Certain proteins are used by both photoreceptors but each type of cells expresses distinct sets of proteins for the task. Our long-term goal is to recount the molecular basis of the differences in sensitivity and response kinetics in rod and cone phototransduction. Our short-term aims are to determine the rate-limiting steps in the recovery of rod phototransduction pathway and to delineate the function of GRK7, a seventh member of the G-protein coupled receptor kinase family found in cone photoreceptors of several mammalian species including human.