The GTP binding protein-dependent activation and deactivation of cGMP phosphodiesterase in rod photoreceptors

Conference · Sat Dec 31 23:00:00 EST 1988

OSTI ID:5518301

Yamazaki, Akio

Cyclic GMP (cGMP) has a crucial role in visual transduction. Recent electrophysiological studies clearly indicate the existence of cGMP-activated conductance in photoreceptor plasma membranes. In darkness, Na{sup +}, Ca{sup ++}, and Mg{sup ++} enter rod outer segments (ROS) through cGMP-activated channels while light closes channels by lowering cGMP concentrations through activation of cGMP phosphodiesterase (PDE). Many excellent reviews reference the mechanism of PDE activation in photoreceptors. However, recent progress in understanding the mechanisms regulating cGMP hydrolysis has raised an important question in the PDE-regulation: how does the three-dimensional movement of a subunit of transducin (retinal G protein) relate to the PDE activation Associated with that question, the mechanism of PDE regulation appears to vary at different stages of evolution, for example, frog and bovine photoreceptors. This review examines recent progress of the cGMP hydrolysis mechanism by focusing on the subunit interactions between transducin and PDE. 36 refs., 2 figs.

• Research Organization: Los Alamos National Lab., NM (USA)
• Sponsoring Organization: DOE/MA; DOHHS
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5518301
• Report Number(s): LA-UR-89-3232; CONF-8910253--1; ON: DE90000687
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ACTIVATION ENERGY
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
BODY
BODY AREAS
CATTLE
COWS
DOMESTIC ANIMALS
ENERGY
ENZYME ACTIVITY
ENZYMES
ESTERASES
EYES
FACE
FROGS
HEAD
HYDROLASES
MAMMALS
MEMBRANES
ORGANS
PHOSPHODIESTERASES
PHOTOSENSITIVITY
RODS
RUMINANTS
SENSE ORGANS
SENSITIVITY
VERTEBRATES