Editors' ChoiceBiophysics

Feeling the Light

Science Signaling  16 Oct 2012:
Vol. 5, Issue 246, pp. ec271
DOI: 10.1126/scisignal.2003687

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.

R. C. Hardie, K. Franze, Photomechanical responses in Drosophila photoreceptors. Science 338, 260–263 (2012). [Abstract] [Full Text]

E. R. Liman, Putting the squeeze on phototransduction. Science 338, 200–201 (2012). [Abstract] [Full Text]