Abstract
Purpose: :
The ability of retina to generate and process light responses is essentially dependent on G protein signaling. RGS proteins of the R7 subfamily (R7 RGS) are highly expressed in the retina and are critical for timely G protein signal termination. We have recently found that a new membrane protein called R7 Binding Protein (R7BP) forms complexes with all R7 RGS proteins in retina neurons. The goal of this study was to study the distribution of R7BP and analyze the effect of its elimination on the expression of R7 RGS proteins.
Methods: :
R7BP knockout mice were generated by gene targeting technology. Expression and localization of R7BP across retina neurons were determined by serial sectioning with Western blotting. Expression levels of R7 RGS proteins in wild type and R7BP knockout retinas were compared by Western blotting.
Results: :
We found that R7BP distribution replicated the distribution of Galpha(o) protein, which is abundantly expressed in bipolar cells. However, knockout of R7BP had no effect on the expression levels of R7 RGS proteins, indicating that R7 RGS proteins do not require complex formation with R7BP for their stability in the neurons of the retina.
Conclusions: :
Co-localization of Galpha(o) proteins with R7BP in the bipolar cells of the retina suggest a possible role for R7BP in the regulation of bipolar cell signaling by affecting R7 RGS protein localization rather than expression levels.
Keywords: retina • transgenics/knock-outs • gene/expression