The vertebrate phototransduction cascade: amplification and termination mechanisms.
The biochemical cascade which transduces light into a neuronal signal in retinal photoreceptors is a heterotrimeric GTP-binding protein (G protein) signaling pathway called phototransduction. Works from psychophysicists, electrophysiologists, biochemists, and geneticists over several decades have come together to shape our understanding of how photon absorption leads to photoreceptor membrane hyperpolarization. The insights of phototransduction provide the foundation for a mechanistic account of signaling from many other G protein-coupled receptors (GPCR) found throughout nature. The application of reverse genetic techniques has strengthened many historic findings and helped to describe this pathway at greater molecular details. However, many important questions remain to be answered.
Chen
C K
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Virginia Commonwealth University, Department of Biochemistry, 1101 E. Marshall Street, Rm 2-032, Richmond, 23298-0614 VA, USA. cjchen@vcu.edu
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; D054815:Cyclic Nucleotide-Gated Cation Channels; D025461:Feedback, Physiological; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology; D017948:Retinal Rod Photoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D012243:Rhodopsin / Q000378:metabolism; D015293:Transducin / Q000378:metabolism; D014785:Vision, Ocular / Q000502:physiology*
D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels; D012243:Rhodopsin; D010727:Phosphoric Diester Hydrolases; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; C517431:PDE6B protein, human; D015293:Transducin; D002118:Calcium