Review Article

Small G Proteins Dexras1 and RHES and Their Role in Pathophysiological Processes

Figure 5

Dexras1 activates photic response and suppresses nonphotic response. Dexras1 activate the photic response by signalling pathways that regulate extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK). The ternary complex (nNOS, CAPON, and Dexras1 bound to GDP) receives an external signal of light through NMDA receptor and leads to S-nitrosylation of Dexras1 on cysteine 11, an apparent prerequisite for GTP binding by which it becomes active to produce downstream signalling and produce photic response. In absence of external signal, light input, Dexras1 suppresses the nonphotic response by limiting the capacity of Pituitary Adenylate Cyclase (PAC so PAC1) to get activated; hence MAPKs/ERK is not activated and photic response not produced.
308535.fig.005