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Rim protein (RmP) is an ABC transporter of unknown function in rod outer segment discs. The human gene for RmP (ABCR) is affected in several recessive retinal degenerations. Here, we characterize the ocular phenotype in abcr knockout mice. Mice lacking RmP show delayed dark adaptation, increased all-trans-retinaldehyde (all-trans-RAL) following light(More)
Myosin VIIa functions in the outer retina, and loss of this function causes human blindness in Usher syndrome type 1B (USH1B). In mice with mutant Myo7a, melanosomes in the retinal pigmented epithelium (RPE) are distributed abnormally. In this investigation we detected many proteins in RPE cells that could potentially participate in melanosome transport,(More)
We have isolated and characterized three homologs of mammalian rds/peripherin from Xenopus retinae. One (xrds38) is likely the Xenopus ortholog, while the other two (xrds36 and -35) are more distant relatives. By immunocytochemical analysis of retinal sections, xrds38 is distributed in both rod and cone photoreceptors, while xrds36 and xrds35 are present in(More)
Rim protein (RmP) is a high-Mr membrane glycoprotein that has been localized to the rims of photoreceptor outer segment discs, but its molecular identity is unknown. Here, we describe the purification of RmP and present the sequence of its mRNA. RmP is a new member of the ATP-binding cassette (ABC) transporter superfamily. We show that RmP is expressed(More)
Visual arrestin (48 kDa) plays a role in the deactivation of rhodopsin by binding to the light-activated, phosphorylated form of the receptor. In bovine rod outer segments that were prepared in the presence of protease inhibitors, two faster migrating forms of arrestin, with apparent molecular masses of 46 and 44 kDa, were observed by Western blot analysis.(More)
One of the most disabling forms of retinal degeneration occurs in Usher syndrome, since it affects patients who already suffer from deafness. Mutations in the myosin VIIa gene (MYO7A) cause a major subtype of Usher syndrome, type 1B. Owing to the loss of function nature of Usher 1B and the relatively large size of MYO7A, we investigated a lentiviral-based(More)
Rim protein (RmP) is an integral membrane glycoprotein localized to the rims of photoreceptor outer-segment discs. It belongs to the ABC transporter superfamily, but its function in the retina has not been determined. The gene for human RmP (ABCR) is affected in several recessively inherited human retinal degenerations, including Stargardt's macular(More)
The protein content of melanosomes in the retinal pigment epithelium (RPE) was analyzed by mass spectrometry. More than 100 proteins were found to be common to two out of three variations of sample preparation. Some proteins normally associated with other organelles were detected. Several lysosomal enzymes were detected, with the presence of cathepsin D(More)
Calpain II was purified to apparent homogeneity from bovine neural retinas. It was found to be biochemically similar to brain calpain II, purified by the same procedure, with respect to: subunit mobility in SDS-polyacrylamide gel electrophoresis; Ca2+ sensitivity; inhibition by calpeptin and other cysteine protease inhibitors; and optimal pH. Semithin(More)
Calpains are calcium-activated proteinases which have been implicated in tissue differentiation and degeneration. The aims of the present study were: (1) to determine the relationship between postnatal age and calpain activity in the rat retina; (2) to test if calpain activity was aberrant in the RCS retina at different postnatal ages. Calpain activity was(More)