Investigative Ophthalmology & Visual Science, Vol 29, 419-428, Copyright © 1988 by Association for Research in Vision and Ophthalmology

ARTICLES AND REPORTS

Evidence against the role of rhodopsin in rod outer segment binding to RPE cells

DW Laird and RS Molday
Department of Biochemistry, University of British Columbia, Canada.

The possible role of rhodopsin in the binding and phagocytosis of rod outer segments (ROS) by cultured bovine retinal pigment epithelial (RPE) cells was studied using both quantitative phagocytosis assays and electron microscopy. In inhibition studies an immunoaffinity purified 2- 39 N-terminal rhodopsin glycopeptide, a synthetic 1-16 peptide analogue of rhodopsin and purified, unsealed ROS disc membranes were found to be ineffective in inhibiting the binding of 125I-labeled ROS to RPE cells. A two-fold excess of unlabeled intact ROS, however, inhibited 125I- labeled ROS binding to RPE cells by over 40%. In another series of experiments, rhodopsin on the surface of fixed ROS was densely labeled with gold-dextran particles conjugated to an N-terminal-specific (rho 4D2) rhodopsin monoclonal antibody or its F(ab')2 fragment in an effort to block binding and phagocytosis by RPE cells. As visualized by both transmission and scanning electron microscopy using secondary and backscatter electron imaging, these antibody-gold-dextran-labeled ROS were effectively phagocytized by RPE cells. These results provide compelling evidence that rhodopsin in the ROS plasma membrane does not function as the ligand for recognition by RPE cells.

This article has been cited by other articles:

				R. L. Bernardos, L. K. Barthel, J. R. Meyers, and P. A. Raymond Late-Stage Neuronal Progenitors in the Retina Are Radial Muller Glia That Function as Retinal Stem Cells J. Neurosci., June 27, 2007; 27(26): 7028 - 7040. [Abstract] [Full Text] [PDF]

				H. Zhuang and H. Matsunami Synergism of Accessory Factors in Functional Expression of Mammalian Odorant Receptors J. Biol. Chem., May 18, 2007; 282(20): 15284 - 15293. [Abstract] [Full Text] [PDF]

				K. D. Rhee, A. Ruiz, J. L. Duncan, W. W. Hauswirth, M. M. LaVail, D. Bok, and X.-J. Yang Molecular and Cellular Alterations Induced by Sustained Expression of Ciliary Neurotrophic Factor in a Mouse Model of Retinitis Pigmentosa Invest. Ophthalmol. Vis. Sci., March 1, 2007; 48(3): 1389 - 1400. [Abstract] [Full Text] [PDF]

				A. Garelli, N. P. Rotstein, and L. E. Politi Docosahexaenoic Acid Promotes Photoreceptor Differentiation without Altering Crx Expression. Invest. Ophthalmol. Vis. Sci., July 1, 2006; 47(7): 3017 - 3027. [Abstract] [Full Text] [PDF]

				C. Bobu, C. M. Craft, M. Masson-Pevet, and D. Hicks Photoreceptor organization and rhythmic phagocytosis in the nile rat arvicanthis ansorgei: a novel diurnal rodent model for the study of cone pathophysiology. Invest. Ophthalmol. Vis. Sci., July 1, 2006; 47(7): 3109 - 3118. [Abstract] [Full Text] [PDF]

				G. W. Shi, J. Chen, F. Concepcion, K. Motamedchaboki, P. Marjoram, R. Langen, and J. Chen Light Causes Phosphorylation of Nonactivated Visual Pigments in Intact Mouse Rod Photoreceptor Cells J. Biol. Chem., December 16, 2005; 280(50): 41184 - 41191. [Abstract] [Full Text] [PDF]

				F. Mansergh, N. C. Orton, J. P. Vessey, M. R. Lalonde, W. K. Stell, F. Tremblay, S. Barnes, D. E. Rancourt, and N. T. Bech-Hansen Mutation of the calcium channel gene Cacna1f disrupts calcium signaling, synaptic transmission and cellular organization in mouse retina Hum. Mol. Genet., October 15, 2005; 14(20): 3035 - 3046. [Abstract] [Full Text] [PDF]

				K. D. Rhee, O. Goureau, S. Chen, and X.-J. Yang Cytokine-Induced Activation of Signal Transducer and Activator of Transcription in Photoreceptor Precursors Regulates Rod Differentiation in the Developing Mouse Retina J. Neurosci., November 3, 2004; 24(44): 9779 - 9788. [Abstract] [Full Text] [PDF]

				Y. Liang, D. Fotiadis, S. Filipek, D. A. Saperstein, K. Palczewski, and A. Engel Organization of the G Protein-coupled Receptors Rhodopsin and Opsin in Native Membranes J. Biol. Chem., June 6, 2003; 278(24): 21655 - 21662. [Abstract] [Full Text] [PDF]

				D. Tian and S. Lev Cellular and Developmental Distribution of Human Homologues of the Drosophilia rdgB Protein in the Rat Retina Invest. Ophthalmol. Vis. Sci., June 1, 2002; 43(6): 1946 - 1953. [Abstract] [Full Text] [PDF]

				W. Feng, D. Yasumura, M. T. Matthes, M. M. LaVail, and D. Vollrath Mertk Triggers Uptake of Photoreceptor Outer Segments during Phagocytosis by Cultured Retinal Pigment Epithelial Cells J. Biol. Chem., May 3, 2002; 277(19): 17016 - 17022. [Abstract] [Full Text] [PDF]

				Q. Liu, J. Zhou, S. P. Daiger, D. B. Farber, J. R. Heckenlively, J. E. Smith, L. S. Sullivan, J. Zuo, A. H. Milam, and E. A. Pierce Identification and Subcellular Localization of the RP1 Protein in Human and Mouse Photoreceptors Invest. Ophthalmol. Vis. Sci., January 1, 2002; 43(1): 22 - 32. [Abstract] [Full Text] [PDF]