Growth factor receptor-bound protein 14 undergoes light-dependent intracellular translocation in rod photoreceptors: functional role in retinal insulin receptor activation.

Published

Journal Article

Growth factor receptor-bound protein 14 (Grb14) is involved in growth factor receptor tyrosine kinase signaling. Here we report that light causes a major redistribution of Grb14 among the individual subcellular compartments of the retinal rod photoreceptor. Grb14 is localized predominantly to the inner segment, nuclear layer, and synapse in dark-adapted rods, whereas in the light-adapted rods, Grb14 redistributed throughout the entire cell, including the outer segment. The translocation of Grb14 requires photoactivation of rhodopsin, but not signaling through the phototransduction cascade, and is not based on direct Grb14-rhodopsin interactions. We previously hypothesized that Grb14 protects light-dependent insulin receptor (IR) activation in rod photoreceptors against dephosphorylation by protein tyrosine phosphatase 1B. Consistent with this hypothesis, we failed to observe light-dependent IR activation in Grb14(-/-) mouse retinas. Our studies suggest that Grb14 translocates to photoreceptor outer segments after photobleaching of rhodopsin and protects IR phosphorylation in rod photoreceptor cells. These results demonstrate that Grb14 can undergo subcellular redistribution upon illumination and suggest that rhodopsin photoexcitation may trigger signaling events alternative to the classical transducin activation.

Full Text

Duke Authors

Cited Authors

  • Rajala, A; Daly, RJ; Tanito, M; Allen, DT; Holt, LJ; Lobanova, ES; Arshavsky, VY; Rajala, RVS

Published Date

  • June 23, 2009

Published In

Volume / Issue

  • 48 / 24

Start / End Page

  • 5563 - 5572

PubMed ID

  • 19438210

Pubmed Central ID

  • 19438210

Electronic International Standard Serial Number (EISSN)

  • 1520-4995

Digital Object Identifier (DOI)

  • 10.1021/bi9000062

Language

  • eng

Conference Location

  • United States