eye-specific G beta subunit essential for termination of the phototransduction cascade

• Published in: Nature (London) Vol. 370; no. 6484; pp. 59 - 61
• Main Authors: Dolph, P.J, Man-Son-Hing, H, Yarfitz, S, Colley, N.J, Deer, J.R, Spencer, M, Hurley, J.B, Zuker, C.S
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 07-07-1994
• Subjects: Animals; Biological and medical sciences; Calcium - metabolism; Cell physiology; Drosophila melanogaster; Electrophysiology; Eye - metabolism; Fundamental and applied biological sciences. Psychology; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; In Vitro Techniques; Kinetics; Light; Molecular and cellular biology; mutants; Mutation; Neural Conduction; Photoreceptor Cells, Invertebrate - metabolism; photoreceptors; Rhodopsin - metabolism; Vision, photoreception; Photoreception; GTP; Cell function; Insecta; Beta-Peptide chain; Drosophilidae; Eye; Binding protein; Signal transduction; Arthropoda; Invertebrata; Drosophila melanogaster; Diptera; G protein
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/370059a0

Heterotrimeric G proteins couple various receptors to intracellular effector molecules. Although the role of the G alpha subunit in effector activation, guanine nucleotide exchange and GTP hydrolysis has been well studied the cellular functions of the G beta subunits are less well understood. G beta gamma dimers bind G alpha subunits and anchor them to the membrane for presentation to the receptor. In specific systems, the G beta subunits have also been implicated in direct coupling to ion channels and to effector molecules. We have isolated Drosophila melanogaster mutants defective in an eye-specific G-protein beta-subunit (G beta e), and show here that the beta-subunit is essential for G-protein-receptor coupling in vivo. Remarkably, G beta mutants are also severely defective in the deactivation of the light response, demonstrating an essential role for the G beta subunit in terminating the active state of this signalling cascade.