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.
Edward S. Harkness Eye Institute and Department of Biochemistry and Molecular Biophysics, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA.
S H
SH
Tsang
M E
ME
Burns
P D
PD
Calvert
P
P
Gouras
D A
DA
Baylor
S P
SP
Goff
V Y
VY
Arshavsky
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