Retinoids interphotoreceptor

The interphotoreceptor retinoid-binding protein (Borst et al., 1989) functions in the regeneration of rhodopsin in the mammalian visual cycle. It is exclusive to vertebrates yet contains a repeated structure that has been found singly in bacterial and plant tail-specific proteases (TSPc) (Silber et al., 1992) and the archaeal tricorn protease (Tamura et al., 1996). The eukaryotic homologs of TSPc are likely to be inactive as... 

The pigment epithelium of the retina receives all- fraws-retinol fromplasma RBP. It is then isomerized to ll-c(s-retinol, which may either be stored as ll-c(s-retinyl esters or oxidized to ll-c(s-retinaldehyde, which is transported to the photoreceptor cells bound to an interphotoreceptor retinoid binding protein. 

In the retinal pigment epithelium, palmitate is bound to the fatty acid binding site of the interphotoreceptor RBP, and the retinoid binding site has a high affinity for 11 -ds-retinaldehyde, which is to be transported to the photoreceptor cells. In the photoreceptor cells, the palmitate is displaced by docosahex-aenoic acid, which causes a conformational change in the protein, so that it no longer binds 11 -ds-retinaldehyde, which is delivered to the photoreceptor cells and binds all-fraws-retinol for transport back to the pigment epithelium. Here, the docosahexaenoic acid is displaced by palmitate, and the affinity of the protein for 11-ds-retinaldehyde is restored (Palczewski and Saari, 1997 Tschanz and Noy, 1997). 

Tschanz CL and Noy N (1997) Binding of retinol in both retinoid-binding sites of interphotoreceptor retinoid-binding protein (IRBP) is stabilized mainly by hydrophobic mtetActiom,. Journal of Biological Chemistry 272,30201-7. 

Retinal antigens, such as S-antigen (arrestin), interphotoreceptor retinoid-binding protein (IRBP), rhodopsin, recoverin, and phosduscin, appear to hold uveitogenic properties. Immunization with these antigens or their fragments can induce... 

Carlson, A., and Bok, D. (19%). I rornotion of the release of ll-ci s-retinal from cultured retinal pigment epithelium by interphotoreceptOr retinoid-binding protein. Biachemisiry 31, 9056-9062,... 

Chen, Y., Houghton, L.A., Brenna, J.T. and Noy, N. (1996) Docosahexaenoic acid modulates the interactions of the interphotoreceptor retinoid-binding protein with 11-cw-retinal. J. Biol. Chem. 271 20507-20515. 

Liou GI, Wang M, Matragoon S. 1994. Timing of interphotoreceptor retinoid-binding protein (IRBP) gene expression and hypomethylation in developing mouse retina. Dev Biol 161 345-356. 

Chen Y. Saari JC, Noy N. Interactions of all-frans-retinol and long-chain fatty acids with interphotoreceptor retinoid-binding protein. Biochemistry 1993 32 11,311-11,318. 

Measurement of Rates of Dissociation of Retinoids from the interphotoreceptor Retinoid-Binding Protein... 

Chen, Y. and Noy, N (1994) Retinoid specificity of interphotoreceptor retinoid-bmdmg protein. Biochemistry 33, 10,658-10,665... 

Bazan, N. G., Reddy, T. S, Redmond, T, M., Wiggert, B, and Chader, G J (1985) Endogenous fatty acids are covalently and noncovalently bound to interphotoreceptor retinoid binding protein in the monkey retina J. Biol. Ghent. 260, 13,677-13,680... 

Saan, J C., Teller, D C, Crabb, J. W, and Bredberg, L (1985) Properties of an interphotoreceptor retinoid-binding protein from bovine retina J Biol Ghent 260, 195-201... 

---