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Regulation of deactivation of photoreceptor G protein by its target enzyme and cGMP.

Publication ,  Journal Article
Arshavsky VYu; Bownds, MD
Published in: Nature
June 4, 1992

The photoreceptor G protein, transducin, is one of the class of heterotrimeric G proteins that mediates between membrane receptors and intracellular enzymes or ion channels. Light-activated rhodopsin catalyses the exchange of GDP for GTP on multiple transducin molecules. Activated transducin then stimulates cyclic GMP phosphodiesterase by releasing an inhibitory action of the phosphodiesterase gamma-subunits. This leads to a decrease in cGMP levels in the rod, and closure of plasma membrane cationic channels gated by cGMP. In this and other systems, turn-off of the response requires the GTP bound to G protein to be hydrolysed by an intrinsic GTPase activity. Here we report that the interaction of transducin with cGMP phosphodiesterase, specifically with its gamma-subunits, accelerates GTPase activity by several fold. Thus the gamma-subunits of the phosphodiesterase serve a function analogous to the GTPase-activating proteins that regulate the class of small GTP-binding proteins. The acceleration can be partially suppressed by cGMP, most probably through the non-catalytic cGMP-binding sites of phosphodiesterase alpha and beta-subunits. This cGMP regulation may function in light-adaptation of the photo-response as a negative feedback that decreases the lifetime of activated cGMP phosphodiesterase as light causes decreases in cytoplasmic cGMP.

Duke Scholars

Published In

Nature

DOI

ISSN

0028-0836

Publication Date

June 4, 1992

Volume

357

Issue

6377

Start / End Page

416 / 417

Location

England

Related Subject Headings

  • Transducin
  • Rod Cell Outer Segment
  • Rhodopsin
  • Recombinant Proteins
  • Photoreceptor Cells
  • Light
  • Kinetics
  • Guanosine Triphosphate
  • General Science & Technology
  • GTP Phosphohydrolases
 

Citation

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ICMJE
MLA
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Arshavsky VYu, & Bownds, M. D. (1992). Regulation of deactivation of photoreceptor G protein by its target enzyme and cGMP. Nature, 357(6377), 416–417. https://doi.org/10.1038/357416a0
Arshavsky VYu, and M. D. Bownds. “Regulation of deactivation of photoreceptor G protein by its target enzyme and cGMP.Nature 357, no. 6377 (June 4, 1992): 416–17. https://doi.org/10.1038/357416a0.
Arshavsky VYu, Bownds MD. Regulation of deactivation of photoreceptor G protein by its target enzyme and cGMP. Nature. 1992 Jun 4;357(6377):416–7.
Arshavsky VYu, and M. D. Bownds. “Regulation of deactivation of photoreceptor G protein by its target enzyme and cGMP.Nature, vol. 357, no. 6377, June 1992, pp. 416–17. Pubmed, doi:10.1038/357416a0.
Arshavsky VYu, Bownds MD. Regulation of deactivation of photoreceptor G protein by its target enzyme and cGMP. Nature. 1992 Jun 4;357(6377):416–417.
Journal cover image

Published In

Nature

DOI

ISSN

0028-0836

Publication Date

June 4, 1992

Volume

357

Issue

6377

Start / End Page

416 / 417

Location

England

Related Subject Headings

  • Transducin
  • Rod Cell Outer Segment
  • Rhodopsin
  • Recombinant Proteins
  • Photoreceptor Cells
  • Light
  • Kinetics
  • Guanosine Triphosphate
  • General Science & Technology
  • GTP Phosphohydrolases