Parietal-eye phototransduction components and their potential evolutionary implications

Johns Hopkins University, Baltimore, Maryland, United States
Science (Impact Factor: 31.48). 04/2006; 311(5767):1617-21. DOI: 10.1126/science.1123802
Source: PubMed

ABSTRACT The parietal-eye photoreceptor is unique because it has two antagonistic light signaling pathways in the same cell-a hyperpolarizing pathway maximally sensitive to blue light and a depolarizing pathway maximally sensitive to green light. Here, we report the molecular components of these two pathways. We found two opsins in the same cell: the blue-sensitive pinopsin and a previously unidentified green-sensitive opsin, which we name parietopsin. Signaling components included gustducin-alpha and Galphao, but not rod or cone transducin-alpha. Single-cell recordings demonstrated that Go mediates the depolarizing response. Gustducin-alpha resembles transducin-alpha functionally and likely mediates the hyperpolarizing response. The parietopsin-Go signaling pair provides clues about how rod and cone phototransduction might have evolved.

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Available from: Chih-Ying Su, Jul 03, 2015
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