RGS9-1 phosphorylation and Ca2+.
The duration of photoresponses in vertebrate rods and cones is controlled at the level of GTP hydrolysis by a GTPase accelerating protein (GAP) whose catalytic core is provided by RGS9-1. RGS9-1 is in turn regulated by phosphorylation on serine 475, in a reaction that is dependent on Ca2+. In living mice, the level of phosphorylation at this site is reduced by light. Thus RGS9-1 phosphorylation provides a potential mechanism by which light-regulated changes in intracellular [Ca2+] may feed back on phototransduction through effects on the lifetime of activated G protein and cGMP phosphodiesterase.
Wensel
Theodore G
TG
Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA. twensel@bcm.tmc.edu
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008027:Light; D008954:Models, Biological; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D020710:RGS Proteins / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction
D020710:RGS Proteins; C116925:regulator of g-protein signaling 9; D006160:Guanosine Triphosphate; D002118:Calcium