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Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation.

Publication ,  Journal Article
Krispel, CM; Sokolov, M; Chen, Y-M; Song, H; Herrmann, R; Arshavsky, VY; Burns, ME
Published in: J Gen Physiol
September 2007

For over a decade, phosducin's interaction with the betagamma subunits of the G protein, transducin, has been thought to contribute to light adaptation by dynamically controlling the amount of transducin heterotrimer available for activation by photoexcited rhodopsin. In this study we directly tested this hypothesis by characterizing the dark- and light-adapted response properties of phosducin knockout (Pd- / -) rods. Pd- / - rods were notably less sensitive to light than wild-type (WT) rods. The gain of transduction, as measured by the amplification constant using the Lamb-Pugh model of activation, was 32% lower in Pd- / - rods than in WT rods. This reduced amplification correlated with a 36% reduction in the level of transducin betagamma-subunit expression, and thus available heterotrimer in Pd- / - rods. However, commonly studied forms of light adaptation were normal in the absence of phosducin. Thus, phosducin does not appear to contribute to adaptation mechanisms of the outer segment by dynamically controlling heterotrimer availability, but rather is necessary for maintaining normal transducin expression and therefore normal flash sensitivity in rods.

Duke Scholars

Published In

J Gen Physiol

DOI

ISSN

0022-1295

Publication Date

September 2007

Volume

130

Issue

3

Start / End Page

303 / 312

Location

United States

Related Subject Headings

  • Vision, Ocular
  • Transducin
  • Time Factors
  • Retinal Rod Photoreceptor Cells
  • Protein Subunits
  • Physiology
  • Phosphorylation
  • Phosphoproteins
  • Mice, Knockout
  • Mice, Inbred C57BL
 

Citation

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Krispel, C. M., Sokolov, M., Chen, Y.-M., Song, H., Herrmann, R., Arshavsky, V. Y., & Burns, M. E. (2007). Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation. J Gen Physiol, 130(3), 303–312. https://doi.org/10.1085/jgp.200709812
Krispel, Claudia M., Maxim Sokolov, Yen-Ming Chen, Hongman Song, Rolf Herrmann, Vadim Y. Arshavsky, and Marie E. Burns. “Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation.J Gen Physiol 130, no. 3 (September 2007): 303–12. https://doi.org/10.1085/jgp.200709812.
Krispel CM, Sokolov M, Chen Y-M, Song H, Herrmann R, Arshavsky VY, et al. Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation. J Gen Physiol. 2007 Sep;130(3):303–12.
Krispel, Claudia M., et al. “Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation.J Gen Physiol, vol. 130, no. 3, Sept. 2007, pp. 303–12. Pubmed, doi:10.1085/jgp.200709812.
Krispel CM, Sokolov M, Chen Y-M, Song H, Herrmann R, Arshavsky VY, Burns ME. Phosducin regulates the expression of transducin betagamma subunits in rod photoreceptors and does not contribute to phototransduction adaptation. J Gen Physiol. 2007 Sep;130(3):303–312.

Published In

J Gen Physiol

DOI

ISSN

0022-1295

Publication Date

September 2007

Volume

130

Issue

3

Start / End Page

303 / 312

Location

United States

Related Subject Headings

  • Vision, Ocular
  • Transducin
  • Time Factors
  • Retinal Rod Photoreceptor Cells
  • Protein Subunits
  • Physiology
  • Phosphorylation
  • Phosphoproteins
  • Mice, Knockout
  • Mice, Inbred C57BL