Title of article :
R9AP stabilizes RGS11-G β5 and accelerates the early light response of ON-bipolar cell
Author/Authors :
BRETT G. JEFFREY، نويسنده , , CATHERINE W. MORGANS، نويسنده , , THERESA PUTHUSSERY، نويسنده , , THEODORE G. WENSEL، نويسنده , , NEAL S. BURKE، نويسنده , , R. LANE BROWN and ROBERT M. DUVOISIN، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2010
Abstract :
The rate-limiting step in the recovery of the photoreceptor light response is the hydrolysis of GTP by transducin, a reaction that is accelerated by the RGS9-Gb5 complex, and its membrane anchor, R9AP. Similar complexes, including RGS7, RGS11, and Gb5, are found in retinal ON-bipolar cell dendrites. Here, we present evidence that R9AP is also expressed in the dendritic tips of ON-bipolar cells. Immunofluorescent staining for R9AP revealed a punctate pattern of labeling in the outer plexiform layer, where it colocalized with mGluR6. In photoreceptors, R9AP is required for proteolytic stability of the entire regulator of G protein signaling complex, and we found that genetic deletion of R9AP also results in a marked reduction in the levels of RGS11 and Gb5 in the bipolar cell dendrites; the level of RGS7 was unaffected, suggesting the presence of another interaction partner to stabilize RGS7. To determine the effect of R9AP deletion on the response kinetics of ON-bipolar cells, we compared the electroretinogram (ERG) between wild-type and R9AP-deficient mice. The ERG b-wave, reflecting ON-bipolar cell activity, was delayed and larger in the R9AP-deficient mice. Our data indicate that R9AP is required for stable expression of RGS11-Gb5 in ON-bipolar cell dendrites. Furthermore, they suggest that the RGS11-Gb5-R9AP complex accelerates the initial ON-bipolar cell response to light.
Keywords :
Electroretinogram , RGS proteins , Retina , ERG b-wave
Journal title :
Visual Neuroscience
Journal title :
Visual Neuroscience