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

Conference · Sun Jan 01 00:00:00 EST 1989

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 Laboratory (LANL), Los Alamos, NM (United States)
• 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
• Resource Relation: Conference: 2. international conference on cyclic nucleotide phosphodiesterase, Tokushima (Japan), 4-6 Oct 1989
• Country of Publication: United States
• Language: English

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PHOSPHODIESTERASES
ENZYME ACTIVITY
ACTIVATION ENERGY
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EYES
FROGS
RODS
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
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550201* - Biochemistry- Tracer Techniques