TRP trapped in fly signaling web.
In the Drosophila eye, photoactivation of rhodopsin leads to the opening of the light-sensitive cation influx channels TRP and TRPL. This response is extremely rapid and results in depolarization of the photoreceptor cells followed by Ca(2+)-mediated feedback regulation of the visual signaling cascade. The mechanisms that facilitate the rapid kinetics of activation and feedback regulation are poorly understood. However, the recent discovery that most of the proteins that function in fly phototransduction associate into a supramolecular complex permits a re-evaluation of the mechanisms underlying the activation and regulation of the cascade. The central player in the signaling complex is INAD, a protein with five protein-interaction motifs known as PDZ domains. The INAD complex does not appear to be a particle, but a massive signaling web composed of an INAD polymer with which some of the target proteins associate through complex multivalent interactions.
Montell
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Department of Biological Chemistry, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA. cmontell@bs.jhmi.edu
D000818:Animals; D015220:Calcium Channels / Q000737:chemistry / Q000502:physiology*; D004330:Drosophila / Q000502:physiology*; D017956:Photoreceptor Cells, Invertebrate / Q000737:chemistry / Q000502:physiology*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000502:physiology*; D050052:TRPC Cation Channels
D015220:Calcium Channels; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1