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Light-induced translocation of Drosophila visual Arrestin2 depends on Rac2

  1. Craig Montell 1
  1. Center for Sensory Biology, Departments of Biological Chemistry and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205

  1. Edited by King-Wai Yau, The Johns Hopkins School of Medicine, Baltimore, MD, and accepted by the Editorial Board January 23, 2010 (received for review June 9, 2009)

Abstract

Photoreceptor cells are remarkable in their ability to adjust their sensitivity to light over a wide range of intensities. Rapid termination of the photoresponse is achieved in part by shuttling proteins in and out of the light-transducing compartment of the photoreceptor cells. One protein that undergoes light-dependent translocation is the rhodopsin regulatory protein arrestin. However, the mechanisms coupling rhodopsin to arrestin movement are poorly understood. Here we show that light-dependent shuttling of the major arrestin in Drosophila photoreceptor cells, Arrestin2 (Arr2), occurs independently of known elements of the phototransduction cascade. Disruptions of the trimeric G protein, phospholipase Cβ, the TRP channel, or the Na+/Ca2+ exchanger did not influence Arr2 localization. Rather, we found that loss of the small GTPase Rac2 severely impaired Arr2 movement and prolonged the termination of the photoresponse. Our findings demonstrate that light-induced translocation of Arr2 occurs through a noncanonical rhodopsin/Rac2 pathway, which is distinct from the classical phototransduction cascade.

Footnotes

  • 1To whom correspondence should be addressed. E-mail: cmontell{at}jhmi.edu.

  • Author contributions: R.E., D.K., and C.M. designed research; R.E., D.K., and R.L. performed research; R.E., D.K., and C.M. analyzed data; and R.E., D.K., and C.M. wrote the paper.

  • The authors declare no conflict of interest.

  • This article is a PNAS Direct Submission. K.-W.Y. is a guest editor invited by the Editorial Board.

  • This article contains supporting information online at www.pnas.org/cgi/content/full/0906386107/DCSupplemental.

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