Our current efforts focus on the role of two visual arrestins (Arr1 and Arr2) in retinal degeneration and in orchestrating the trafficking of Rh1 rhodopsin. Arr1 has been implicated in the light-dependent endocytosis of Rh1, while Arr2 is essential for the fast deactivation of the visual response. To explore the trafficking of Arr1 in live photoreceptors, we have generated transgenic flies expressing GFP-tagged Arr1. We show that Arr1-GFP displays light-dependent internalization only in pupal, but not in adult photoreceptors.
To explore whether Rh1 becomes endocytozed in adult photoreceptors, we have investigated the light-dependent endocytosis of Rh1 using transgenic flies expressing mCherry tagged Rh1. We have established the role of both Arr1 and Arr2 in orchestrating the internalization of Rh1 in vivo. We would like to explore the use of endocytosis of Rh1 as a model for insights into trafficking of G-protein coupled receptors (GPCR), whose studies have been limited to the cell culture system. We will employ genome wide association study in combination with reverse genetics to identify genetic network that regulates endocytosis and trafficking of Rh1 in vivo. We are well versed with experimental strategies related to the biochemical and molecular analyses proposed here for the study. We hope insights we gain in Drosophila will broaden our understanding into the trafficking of GPCRs in vivo.