Related Experiment Video
Updated: Aug 7, 2026

Two Peeling Methods for the Isolation of Photoreceptor Cell Compartments in the Mouse Retina for Protein Analysis
Published on: December 7, 2021
An eye-specific G beta subunit essential for termination of the phototransduction cascade
P J Dolph1, H Man-Son-Hing, S Yarfitz
1Howard Hughes Medical Institute, University of California at San Diego, La Jolla 92093-0649.
Abstract:
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.
Related Concept Videos
The Retina
G Protein-coupled Receptors
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...
Activation and Inactivation of G Proteins
G-Protein Gated Ion Channels
Sensory organs,...
Anatomy of the Eyeball
Photoreceptors and Visual Pathways

