Xu, H., Lee, S.J., Suzuki, E., Dugan, K.D., Stoddard, A., Li, H.S., Chodosh, L.A., Montell, C. (2004). A lysosomal tetraspanin associated with retinal degeneration identified via a genome-wide screen. EMBO J. 23(4): 811--822.
FlyBase ID
FBrf0174603
Publication Type
Research paper
Abstract
The Drosophila visual system has provided a model to study phototransduction and retinal degeneration. To identify new candidate proteins that contribute to these processes, we conducted a genome-wide screen for genes expressed predominately in the eye, using DNA microarrays. This screen appeared to be comprehensive as it led to the identification of all 22 eye-enriched genes previously shown to function in phototransduction or implicated in retinal degeneration. In addition, we identified 93 eye-enriched genes whose roles have not been previously defined. One of the eye-enriched genes encoded a member of a large family of transmembrane proteins, referred to as tetraspanins. We created a null mutation in the eye-enriched tetraspanin, Sunglasses (Sun), which resulted in light-induced retinal degeneration. We found that the Sun protein was distributed primarily in lysosomes, and functioned in a long-known but poorly understood phenomenon of light-induced degradation of rhodopsin. We propose that lysosomal tetraspanins in mammalian cells may also function in the downregulation of rhodopsin and other G-protein-coupled receptors, in response to intense or prolonged agonist stimulation.
