Role for the target enzyme in deactivation of photoreceptor G protein in vivo.
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.
Tsang
S H
SH
Edward S. Harkness Eye Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
Burns
M E
ME
Calvert
P D
PD
Gouras
P
P
Baylor
D A
DA
Goff
S P
SP
Arshavsky
V Y
VY
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; D004596:Electroretinography; D004789:Enzyme Activation; D005260:Female; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D008027:Light; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017354:Point Mutation; D012160:Retina / Q000166:cytology / Q000502:physiology; D012162:Retinal Degeneration; D012374:Rod Cell Outer Segment / Q000378:metabolism*; D015293:Transducin / Q000378:metabolism*; D019076:Transgenes; D014785:Vision, Ocular
D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; C517438:Pde6b protein, mouse; D015293:Transducin