Title | Arrestin competition influences the kinetics and variability of the single-photon responses of mammalian rod photoreceptors. |
Publication Type | Journal Article |
Year of Publication | 2009 |
Authors | Doan T, Azevedo AW, Hurley JB, Rieke F |
Journal | J Neurosci |
Volume | 29 |
Issue | 38 |
Pagination | 11867-79 |
Date Published | 2009 Sep 23 |
ISSN | 1529-2401 |
Keywords | Animals, Arrestin, G-Protein-Coupled Receptor Kinase 1, Kinetics, Markov Chains, Mice, Mice, Inbred C57BL, Mice, Knockout, Models, Neurological, Phosphorylation, Photic Stimulation, Photons, Retinal Rod Photoreceptor Cells, Rhodopsin, Signal Transduction, Time Factors |
Abstract | Reliable signal transduction via G-protein-coupled receptors requires proper receptor inactivation. For example, signals originating from single rhodopsin molecules vary little from one to the next, requiring reproducible inactivation of rhodopsin by phosphorylation and arrestin binding. We determined how reduced concentrations of rhodopsin kinase (GRK1) and/or arrestin1 influenced the kinetics and variability of the single-photon responses of mouse rod photoreceptors. These experiments revealed that arrestin, in addition to its role in quenching the activity of rhodopsin, can tune the kinetics of rhodopsin phosphorylation by competing with GRK1. This competition influenced the variability of the active lifetime of rhodopsin. Biasing the competition in favor of GRK1 revealed that rhodopsin remained active through much of the single-photon response under the conditions of our experiments. This long-lasting rhodopsin activity can explain the characteristic time course of single-photon response variability. Indeed, explaining the late time-to-peak of the variance required an active lifetime of rhodopsin approximately twice that of the G-protein transducin. Competition between arrestins and kinases may be a general means of influencing signals mediated by G-protein-coupled receptors, particularly when activation of a few receptors produces signals of functional importance. |
DOI | 10.1523/JNEUROSCI.0819-09.2009 |
Alternate Journal | J Neurosci |
PubMed ID | 19776273 |
PubMed Central ID | PMC2782834 |
Grant List | R01 EY006641 / EY / NEI NIH HHS / United States F32 EY006641 / EY / NEI NIH HHS / United States EY06641 / EY / NEI NIH HHS / United States T32GM-07270 / GM / NIGMS NIH HHS / United States T32 GM007270 / GM / NIGMS NIH HHS / United States P30 EY001730 / EY / NEI NIH HHS / United States EY01730 / EY / NEI NIH HHS / United States / / Howard Hughes Medical Institute / United States R01 EY011850 / EY / NEI NIH HHS / United States R01 EY011850-12 / EY / NEI NIH HHS / United States T32 EY007031 / EY / NEI NIH HHS / United States T32EY-07031 / EY / NEI NIH HHS / United States EY-11850 / EY / NEI NIH HHS / United States |