Structural basis of retinal membrane guanylate cyclase regulation by GCAP1 and RD3.

ABSTRACT: Retinal membrane guanylate cyclases (RetGC1 and RetGC2) are expressed in photoreceptor rod and cone cells, where they promote the onset of visual recovery during phototransduction. The catalytic activity of RetGCs is regulated by their binding to regulatory proteins, guanylate cyclase activating proteins (GCAP1-5) and the retinal degeneration 3 protein (RD3). RetGC1 is activated by its binding to Ca²⁺-free/Mg²⁺-bound GCAP1 at low cytosolic Ca²⁺ levels in light-activated photoreceptors. By contrast, RetGC1 is inactivated by its binding to Ca²⁺-bound GCAP1 and/or RD3 at elevated Ca²⁺ levels in dark-adapted photoreceptors. The Ca²⁺ sensitive cyclase activation helps to replenish the cytosolic cGMP levels in photoreceptors durin

SUBMITTER: Ames JB 

PROVIDER: S-EPMC9493048 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature