Recoverin improves rod-mediated vision by enhancing signal transmission in the mouse retina.
Vision in dim light requires that photons absorbed by rod photoreceptors evoke signals that reliably propagate through the retina. We investigated how a perturbation in rod physiology affects propagation of those signals in the retina and ultimately visual sensitivity. Recoverin is a protein in rods that prolongs phototransduction and enhances visual sensitivity. It is not present in neurons postsynaptic to rods, yet we found that light-evoked responses of rod bipolar and ganglion cells were shortened when measured in recoverin-deficient retinas. Unexpectedly, the effect of recoverin on postsynaptic signals could not be explained by its effect on phototransduction. Instead, it is an effect of recoverin downstream of phototransduction in rods that prolongs signal transmission and enhances visual sensitivity. An important implication of our findings is that the recovery phase of the rod photoresponse does not contribute significantly to visual sensitivity near absolute threshold.
Sampath
Alapakkam P
AP
Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA.
Strissel
Katherine J
KJ
Elias
Rajesh
R
Arshavsky
Vadim Y
VY
McGinnis
James F
JF
Chen
Jeannie
J
Kawamura
Satoru
S
Rieke
Fred
F
Hurley
James B
JB
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D008074:Lipoproteins / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D051603:Recoverin; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D014785:Vision, Ocular / Q000502:physiology*
D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; C496732:Rcvrn protein, mouse; D051603:Recoverin