Arrestin translocation is induced at a critical threshold of visual signaling and is superstoichiometric to bleached rhodopsin.

Published

Journal Article

Light induces massive translocation of major signaling proteins between the subcellular compartments of photoreceptors. Among them is visual arrestin responsible for quenching photoactivated rhodopsin, which moves into photoreceptor outer segments during illumination. Here, for the first time, we determined the light dependency of arrestin translocation, which revealed two key features of this phenomenon. First, arrestin translocation is triggered when the light intensity approaches a critical threshold corresponding to the upper limits of the normal range of rod responsiveness. Second, the amount of arrestin entering rod outer segments under these conditions is superstoichiometric to the amount of photoactivated rhodopsin, exceeding it by at least 30-fold. We further showed that it is not the absolute amount of excited rhodopsin but rather the extent of downstream cascade activity that triggers translocation. Finally, we demonstrated that the total amount of arrestin in the rod cell is nearly 10-fold higher than previously thought and therefore sufficient to inactivate the entire pool of rhodopsin at any level of illumination. Thus, arrestin movement to the outer segment leads to an increase in the free arrestin concentration and thereby may serve as a powerful mechanism of light adaptation.

Full Text

Duke Authors

Cited Authors

  • Strissel, KJ; Sokolov, M; Trieu, LH; Arshavsky, VY

Published Date

  • January 25, 2006

Published In

Volume / Issue

  • 26 / 4

Start / End Page

  • 1146 - 1153

PubMed ID

  • 16436601

Pubmed Central ID

  • 16436601

Electronic International Standard Serial Number (EISSN)

  • 1529-2401

Digital Object Identifier (DOI)

  • 10.1523/JNEUROSCI.4289-05.2006

Language

  • eng

Conference Location

  • United States