Skip to main content

Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors.

Publication ,  Journal Article
Dexter, PM; Lobanova, ES; Finkelstein, S; Spencer, WJ; Skiba, NP; Arshavsky, VY
Published in: eNeuro
2018

The heterotrimeric G-protein transducin mediates visual signaling in vertebrate photoreceptor cells. Many aspects of the function of transducin were learned from knock-out mice lacking its individual subunits. Of particular interest is the knockout of its rod-specific γ-subunit (Gγ1). Two studies using independently generated mice documented that this knockout results in a considerable >60-fold reduction in the light sensitivity of affected rods, but provided different interpretations of how the remaining α-subunit (Gαt) mediates phototransduction without its cognate Gβ1γ1-subunit partner. One study found that the light sensitivity reduction matched a corresponding reduction in Gαt content in the light-sensing rod outer segments and proposed that Gαt activation is supported by remaining Gβ1 associating with other Gγ subunits naturally expressed in photoreceptors. In contrast, the second study reported the same light sensitivity loss but a much lower, only approximately sixfold, reduction of Gαt and proposed that the light responses of these rods do not require Gβγ at all. To resolve this controversy and elucidate the mechanism driving visual signaling in Gγ1 knock-out rods, we analyzed both mouse lines side by side. We first determined that the outer segments of both mice have identical Gαt content, which is reduced ∼65-fold from the wild-type (WT) level. We further demonstrated that the remaining Gβ1 is present in a complex with endogenous Gγ2 and Gγ3 subunits and that these complexes exist in wild-type rods as well. Together, these results argue against the idea that Gαt alone supports light responses of Gγ1 knock-out rods and suggest that Gβ1γ1 is not unique in its ability to mediate vertebrate phototransduction.

Duke Scholars

Altmetric Attention Stats
Dimensions Citation Stats

Published In

eNeuro

DOI

EISSN

2373-2822

Publication Date

2018

Volume

5

Issue

3

Location

United States

Related Subject Headings

  • Vision, Ocular
  • Transducin
  • Retinal Rod Photoreceptor Cells
  • Photic Stimulation
  • Mice, Knockout
  • Mice, Inbred C57BL
  • Male
  • GTP-Binding Protein gamma Subunits
  • Female
  • Animals
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Dexter, P. M., Lobanova, E. S., Finkelstein, S., Spencer, W. J., Skiba, N. P., & Arshavsky, V. Y. (2018). Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors. ENeuro, 5(3). https://doi.org/10.1523/ENEURO.0144-18.2018
Dexter, Paige M., Ekaterina S. Lobanova, Stella Finkelstein, William J. Spencer, Nikolai P. Skiba, and Vadim Y. Arshavsky. “Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors.ENeuro 5, no. 3 (2018). https://doi.org/10.1523/ENEURO.0144-18.2018.
Dexter PM, Lobanova ES, Finkelstein S, Spencer WJ, Skiba NP, Arshavsky VY. Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors. eNeuro. 2018;5(3).
Dexter, Paige M., et al. “Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors.ENeuro, vol. 5, no. 3, 2018. Pubmed, doi:10.1523/ENEURO.0144-18.2018.
Dexter PM, Lobanova ES, Finkelstein S, Spencer WJ, Skiba NP, Arshavsky VY. Transducin β-Subunit Can Interact with Multiple G-Protein γ-Subunits to Enable Light Detection by Rod Photoreceptors. eNeuro. 2018;5(3).

Published In

eNeuro

DOI

EISSN

2373-2822

Publication Date

2018

Volume

5

Issue

3

Location

United States

Related Subject Headings

  • Vision, Ocular
  • Transducin
  • Retinal Rod Photoreceptor Cells
  • Photic Stimulation
  • Mice, Knockout
  • Mice, Inbred C57BL
  • Male
  • GTP-Binding Protein gamma Subunits
  • Female
  • Animals