Role for the target enzyme in deactivation of photoreceptor G protein in vivo

Science. 1998 Oct 2;282(5386):117-21. doi: 10.1126/science.282.5386.117.

Abstract

Heterotrimeric guanosine 5'-triphosphate (GTP)-binding proteins (G proteins) are deactivated by hydrolysis of the GTP that they bind when activated by transmembrane receptors. Transducin, the G protein that relays visual excitation from rhodopsin to the cyclic guanosine 3',5'-monophosphate phosphodiesterase (PDE) in retinal photoreceptors, must be deactivated for the light response to recover. A point mutation in the gamma subunit of PDE impaired transducin-PDE interactions and slowed the recovery rate of the flash response in transgenic mouse rods. These results indicate that the normal deactivation of transducin in vivo requires the G protein to interact with its target enzyme.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3',5'-Cyclic-GMP Phosphodiesterases / genetics
  • 3',5'-Cyclic-GMP Phosphodiesterases / metabolism*
  • Animals
  • Cyclic Nucleotide Phosphodiesterases, Type 6
  • Electroretinography
  • Enzyme Activation
  • Female
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Guanosine Triphosphate / metabolism
  • Hydrolysis
  • Light
  • Male
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Point Mutation
  • Retina / cytology
  • Retina / physiology
  • Retinal Degeneration
  • Rod Cell Outer Segment / metabolism*
  • Transducin / metabolism*
  • Transgenes
  • Vision, Ocular*

Substances

  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate
  • 3',5'-Cyclic-GMP Phosphodiesterases
  • Cyclic Nucleotide Phosphodiesterases, Type 6
  • Pde6b protein, mouse
  • Transducin