Transducin gamma-subunit sets expression levels of alpha- and beta-subunits and is crucial for rod viability.

Journal Article

Transducin is a prototypic heterotrimeric G-protein mediating visual signaling in vertebrate photoreceptor cells. Despite its central role in phototransduction, little is known about the mechanisms that regulate its expression and maintain approximately stoichiometric levels of the alpha- and betagamma-subunits. Here we demonstrate that the knock-out of transducin gamma-subunit leads to a major downregulation of both alpha- and beta-subunit proteins, despite nearly normal levels of the corresponding transcripts, and fairly rapid photoreceptor degeneration. Significant fractions of the remaining alpha- and beta-subunits were mislocalized from the light-sensitive outer segment compartment of the rod. Yet, the tiny amount of the alpha-subunit present in the outer segments of knock-out rods was sufficient to support light signaling, although with a markedly reduced sensitivity. These data indicate that the gamma-subunit controls the expression level of the entire transducin heterotrimer and that heterotrimer formation is essential for normal transducin localization. They further suggest that the production of transducin beta-subunit without its constitutive gamma-subunit partner sufficiently stresses the cellular biosynthetic and/or chaperone machinery to induce cell death.

Full Text

Duke Authors

Cited Authors

  • Lobanova, ES; Finkelstein, S; Herrmann, R; Chen, Y-M; Kessler, C; Michaud, NA; Trieu, LH; Strissel, KJ; Burns, ME; Arshavsky, VY

Published Date

  • March 26, 2008

Published In

Volume / Issue

  • 28 / 13

Start / End Page

  • 3510 - 3520

PubMed ID

  • 18367617

Electronic International Standard Serial Number (EISSN)

  • 1529-2401

Digital Object Identifier (DOI)

  • 10.1523/JNEUROSCI.0338-08.2008

Language

  • eng

Conference Location

  • United States