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PLoS Biol. 2012;10(12):e1001438. doi: 10.1371/journal.pbio.1001438. Epub 2012 Dec 4.

Crag is a GEF for Rab11 required for rhodopsin trafficking and maintenance of adult photoreceptor cells.

Author information

1
Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America.

Abstract

Rhodopsins (Rhs) are light sensors, and Rh1 is the major Rh in the Drosophila photoreceptor rhabdomere membrane. Upon photoactivation, a fraction of Rh1 is internalized and degraded, but it remains unclear how the rhabdomeric Rh1 pool is replenished and what molecular players are involved. Here, we show that Crag, a DENN protein, is a guanine nucleotide exchange factor for Rab11 that is required for the homeostasis of Rh1 upon light exposure. The absence of Crag causes a light-induced accumulation of cytoplasmic Rh1, and loss of Crag or Rab11 leads to a similar photoreceptor degeneration in adult flies. Furthermore, the defects associated with loss of Crag can be partially rescued with a constitutive active form of Rab11. We propose that upon light stimulation, Crag is required for trafficking of Rh from the trans-Golgi network to rhabdomere membranes via a Rab11-dependent vesicular transport.

PMID:
23226104
PMCID:
PMC3514319
DOI:
10.1371/journal.pbio.1001438
[Indexed for MEDLINE]
Free PMC Article

Conflict of interest statement

The authors have declared that no competing interests exist.

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