A phosphorylation-sensitive anti-rhodopsin monoclonal antibody reveals light-induced phosphorylation of rhodopsin in the photoreceptor cell body.
Rho-1C5, a monoclonal antibody sensitive to phosphorylation of rhodopsin, bound to the retinal photoreceptor cell body region of dark-adapted but not light-adapted 8 to 13-day-old-rats. There was no cell body labeling visible either before or after this time, although the photoreceptor outer segments were labeled at all times from postnatal day 5 (PN5) onwards, in both light and dark adapted retinas. However, opsin was detectable in the photoreceptor cell body region from birth onwards using another rhodopsin antibody binding to a site unaffected by phosphorylation. Competitive inhibition radioimmunoassays also indicated light-dependent differences in Rho-1C5 binding at PN8 and adult. Biochemical studies showed light-dependent phosphorylation of rhodopsin at PN8, PN13 (just after eye opening) and adult. These data indicate that rhodopsin can be phosphorylated in a light-regulated manner early in development before eye opening and imply that photoactive chromophores can attach to opsin in the cell body as well as the outer segment.
Hicks
D
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Laboratory of Neurobiology, Rockefeller University, New York, NY.
Barnstable
C J
CJ
D000818:Animals; D000911:Antibodies, Monoclonal; D001345:Autoradiography; D001667:Binding, Competitive; D007150:Immunohistochemistry; D010766:Phosphorylation; D010786:Photoreceptor Cells / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D012168:Retinal Pigments / Q000378:metabolism*; D012243:Rhodopsin / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D012168:Retinal Pigments; D012243:Rhodopsin