Sci. Signal., 16 October 2012
Biophysics Feeling the Light
L. Bryan Ray
Science, Science Signaling, AAAS, Washington, DC 20005, USA
There has been a link missing in our understanding of the biochemical signaling mechanism initiated when photons are absorbed by rhodopsin in the photoreceptor cells of Drosophila eyes. Photoisomerization of rhodopsin activates a heterotrimeric guanine nucleotide–binding protein, which leads to activation of phospholipase C. But how phospholipase C activates the transient receptor potential (TRP) or the transient receptor potential–like (TRPL) ion channels that produce the rest of the cellular response has been unclear. Hardie and Franze (see the Perspective by Liman) propose that there is a physical mechanism at work. Atomic force microscopy revealed light-induced contractions of photoreceptor cells. Consistent with a physical coupling mechanism, manipulations of the membrane altered responses of the photoreceptor cells to light. Thus, physical changes in the membrane appear to couple phospholipase C activity to the opening of mechanosensitive TRP and TRPL channels.
Citation: L. B. Ray, Feeling the Light. Sci. Signal. 5, ec271 (2012).
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