In situ assay of light-stimulated G protein activity in Drosophila photoreceptor G protein beta mutants.

Nansi Colley // Publications // Dec 02 1994

PubMed ID: 7982946

Author(s): Yarfitz SL, Running Deer JL, Froelick G, Colley NJ, Hurley JB. In situ assay of light-stimulated G protein activity in Drosophila photoreceptor G protein beta mutants. J Biol Chem. 1994 Dec 2;269(48):30340-4.

Journal: The Journal Of Biological Chemistry, Volume 269, Issue 48, Dec 1994

An in situ 35S-labeled guanosine 5′-3-O-(thio)triphosphate (GTP gamma S) binding procedure was developed to assay light-stimulated G protein activity in Drosophila compound eyes. We found that Drosophila with mutations in G beta e, an abundant photoreceptor-specific G protein beta subunit essential for photoexcitation, are defective in light-stimulated [35S]GTP gamma S binding. We confirmed that G beta e interacts with a GTP-binding protein by demonstrating that immunoprecipitation of G beta e is sensitive to GTP gamma S. These results suggest that G beta e functions as the beta subunit of a heterotrimeric G protein that couples photoactivation of rhodopsin to downstream components in the Drosophila phototransduction cascade.