Abnormal photoresponses and light-induced apoptosis in rods lacking rhodopsin kinase
Abstract
Phosphorylation is thought to be an essential first step in the prompt deactivation of photoexcited rhodopsin. In vitro, the phosphorylation can be catalyzed either by rhodopsin kinase (RK) or by protein kinase C (PKC). To investigate the specific role of RK, we inactivated both alleles of the RK gene in mice. This eliminated the light-dependent phosphorylation of rhodopsin and caused the single-photon response to become larger and longer lasting than normal. These results demonstrate that RK is required for normal rhodopsin deactivation. When the photon responses of RK-/- rods did finally turn off, they did so abruptly and stochastically, revealing a first-order backup mechanism for rhodopsin deactivation. The rod outer segments of RK-/- mice raised in 12-hr cyclic illumination were 50% shorter than those of normal (RK+/+) rods or rods from RK-/- mice raised in constant darkness. One day of constant light caused the rods in the RK-/- mouse retina to undergo apoptotic degeneration. Mice lacking RK provide a valuable model for the study of Oguchi disease, a human RK deficiency that causes congenital stationary night blindness.
Additional Information
© 1999 by The National Academy of Sciences. Contributed by Melvin Simon, January 12, 1999. We thank members of the Caltech Transgenic Core Facility for their technical support. We also thank Wolfgang Baehr for the mouse retinal cDNA library. This work was supported by grants from the National Institute of Aging (M.I.S.), the National Eye Institute (D.A.B. and J.B.H.), the McKnight Foundation (D.A.B.), and the Ruth and Milton Steinbach fund (D.A.B.). Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. AF085240). C.-K.C. and M.E.B. contributed equally to this work. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.Attached Files
Published - CHEpnas99b.pdf
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Additional details
- PMCID
- PMC22360
- Eprint ID
- 810
- Resolver ID
- CaltechAUTHORS:CHEpnas99b
- National Institute of Aging
- National Eye Institute
- McKnight Foundation
- Ruth and Milton Steinbach fund
- Created
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2005-10-07Created from EPrint's datestamp field
- Updated
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2019-10-02Created from EPrint's last_modified field