Document Type
Journal Article
Date of this Version
12-17-2004
Publication Source
Journal of Biological Chemistry
Volume
279
Issue
51
Start Page
53828
Last Page
53839
DOI
10.1074/jbc.M408472200
Abstract
Rho (rhodopsin; opsin plus 11-cis-retinal) is a prototypical G protein-coupled receptor responsible for the capture of a photon in retinal photoreceptor cells. A large number of mutations in the opsin gene associated with autosomal dominant retinitis pigmentosa have been identified. The naturally occurring T4R opsin mutation in the English mastiff dog leads to a progressive retinal degeneration that closely resembles human retinitis pigmentosa caused by the T4K mutation in the opsin gene. Using genetic approaches and biochemical assays, we explored the properties of the T4R mutant protein. Employing immunoaffinity-purified Rho from affected RHOT4R/T4R dog retina, we found that the mutation abolished glycosylation at Asn2, whereas glycosylation at Asn15 was unaffected, and the mutant opsin localized normally to the rod outer segments. Moreover, we found that T4R Rho* lost its chromophore faster as measured by the decay of meta-rhodopsin II and that it was less resistant to heat denaturation. Detergent-solubilized T4R opsin regenerated poorly and interacted abnormally with the G protein transducin (Gt). Structurally, the mutation affected mainly the “plug” at the intradiscal (extracellular) side of Rho, which is possibly responsible for protecting the chromophore from the access of bulk water. The T4R mutation may represent a novel molecular mechanism of degeneration where the unliganded form of the mutant opsin exerts a detrimental effect by losing its structural integrity.
Copyright/Permission Statement
This research was originally published in the Journal of Biological Chemistry. 2004; 279(51):53828-53839. © the American Society for Biochemistry and Molecular Biology.
Keywords
protein synthesis, post-translation modification, degradation
Recommended Citation
Zhu, L., Jang, G., Jastrzebska, B., Filipek, S., Pearce-Kelling, S. E., Aguirre, G. D., Stenkamp, R. E., Acland, G. M., & Palczewski, K. (2004). A Naturally Occurring Mutation of the Opsin Gene (T4R) in Dogs Affects Glycosylation and Stability of the G Protein-Coupled Receptor. Journal of Biological Chemistry, 279 (51), 53828-53839. http://dx.doi.org/10.1074/jbc.M408472200
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Date Posted: 06 May 2015
This document has been peer reviewed.