Mechanistic Basis for the Failure of Cone Transducin to Translocate: Why Cones Are Never Blinded by Light
Open Access
- 19 May 2010
- journal article
- Published by Society for Neuroscience in Journal of Neuroscience
- Vol. 30 (20), 6815-6824
- https://doi.org/10.1523/jneurosci.0613-10.2010
Abstract
The remarkable ability of our vision to function under ever-changing conditions of ambient illumination is mediated by multiple molecular mechanisms regulating the light sensitivity of rods and cones. One such mechanism involves massive translocation of signaling proteins, including the G-protein transducin, into and out of the light-sensitive photoreceptor outer segment compartment. Transducin translocation extends the operating range of rods, but in cones transducin never translocates, which is puzzling because cones typically function in much brighter light than rods. Using genetically manipulated mice in which the rates of transducin activation and inactivation were altered, we demonstrate that, like in rods, transducin translocation in cones can be triggered when transducin activation exceeds a critical level, essentially saturating the photoresponse. However, this level is never achieved in wild-type cones: their superior ability to tightly control the rates of transducin activation and inactivation, responsible for avoiding saturation by light, also accounts for the prevention of transducin translocation at any light intensity.This publication has 69 references indexed in Scilit:
- Functional interchangeability of rod and cone transducin α-subunitsProceedings of the National Academy of Sciences of the United States of America, 2009
- Structure of cone photoreceptorsProgress in Retinal and Eye Research, 2009
- Functional comparison of RGS9 splice isoforms in a living cellProceedings of the National Academy of Sciences of the United States of America, 2008
- Electrostatic and Lipid Anchor Contributions to the Interaction of Transducin with Membranes: MECHANISTIC IMPLICATIONS FOR ACTIVATION AND TRANSLOCATIONOnline Journal of Public Health Informatics, 2008
- Mouse Cones Require an Arrestin for Normal Inactivation of PhototransductionNeuron, 2008
- Mechanism of light‐induced translocation of arrestin and transducin in photoreceptors: Interaction‐restricted diffusionIUBMB Life, 2007
- Phosducin Regulates the Expression of Transducin βγ Subunits in Rod Photoreceptors and Does Not Contribute to Phototransduction AdaptationThe Journal of general physiology, 2007
- Physiological Properties of Rod Photoreceptor Cells in Green-sensitive Cone Pigment Knock-in MiceThe Journal of general physiology, 2007
- Subunit Dissociation and Diffusion Determine the Subcellular Localization of Rod and Cone TransducinsJournal of Neuroscience, 2007
- Phototransduction in mouse rods and conesPflügers Archiv - European Journal of Physiology, 2007