Gbeta5 is required for normal light responses and morphology of retinal ON-bipolar cells.
Gbeta5 exists as two splice variants, Gbeta5-S and Gbeta5-L, which interact with and stabilize the R7 members of the regulators of G-protein signaling (RGSs): RGS6, RGS7, RGS9, and RGS11. Although the role of Gbeta5-L and RGS9-1 is established in photoreceptors, the physiological functions of Gbeta5-S and other R7 RGS proteins remain unclear. We found that the electroretinogram of Gbeta5-/- mice lacks the b-wave component and that Gbeta5-S and RGS11 colocalize with Go alpha at the tips of the ON-bipolar cell dendrites. Unexpectedly, we found a significant reduction in the number of synaptic triads in the outer plexiform layer (OPL) of the Gbeta5-/- mice, which is evident at postnatal day 14. Transgenic expression of Gbeta5-L in rods failed to rescue the b-wave or the OPL defects. These results indicate that Gbeta5-S is indispensable for OPL integrity and normal light responses of the retina.
Rao
Anjali
A
Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia 23298, USA.
Dallman
Rebecca
R
Henderson
Scott
S
Chen
Ching-Kang
CK
D000818:Animals; D003623:Dark Adaptation / Q000235:genetics / Q000502:physiology*; D044387:GTP-Binding Protein beta Subunits / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010775:Photic Stimulation / Q000379:methods; D012160:Retina / Q000166:cytology / Q000502:physiology; D051245:Retinal Bipolar Cells / Q000166:cytology* / Q000502:physiology*
D044387:GTP-Binding Protein beta Subunits; C094668:Gnb5 protein, mouse