Autosomal recessive retinitis pigmentosa and E150K mutation in the opsin gene.
Retinitis pigmentosa (RP) is a heterogeneous group of hereditary disorders of the retina caused by mutation in genes of the photoreceptor proteins with an autosomal dominant (adRP), autosomal recessive (arRP), or X-linked pattern of inheritance. Although there are over 100 identified mutations in the opsin gene associated with RP, only a few of them are inherited with the arRP pattern. E150K is the first reported missense mutation associated with arRP. This opsin mutation is located in the second cytoplasmic loop of this G protein-coupled receptor. E150K opsin expressed in HEK293 cells and reconstituted with 11-cis-retinal displayed an absorption spectrum similar to the wild type (WT) counterpart and activated G protein transducin slightly faster than WT receptor. However, the majority of E150K opsin showed a higher apparent molecular mass in SDS-PAGE and was resistant to endoglycosidase H deglycosidase. Instead of being transported to the plasma membrane, E150K opsin is partially colocalized with the cis/medial Golgi compartment markers such as GM130 and Vti1b but not with the trans-Golgi network. In contrast to the endoplasmic reticulum-retained adRP mutant, P23H opsin, Golgi-retained E150K opsin did not influence the proper transport of the WT opsin when coexpressed in HEK293 cells. This result is consistent with the recessive pattern of inheritance of this mutation. Thus, our study reveals a novel molecular mechanism for retinal degeneration that results from deficient export of opsin from the Golgi apparatus.
Zhu
Li
L
Department of Chemistry, University of Washington, Seattle, Washington 98195.
Imanishi
Yoshikazu
Y
Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
Filipek
Sławomir
S
International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland.
Alekseev
Andrei
A
Department of Ophthalmology, University of Washington, Seattle, Washington 98195.
Jastrzebska
Beata
B
Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
Sun
Wenyu
W
Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106.
Saperstein
David A
DA
Department of Ophthalmology, University of Washington, Seattle, Washington 98195.
Palczewski
Krzysztof
K
Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106. Electronic address: kxp65@case.edu.
D002460:Cell Line; D005808:Genes, Recessive; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D020125:Mutation, Missense; D021381:Protein Transport / Q000235:genetics; D012162:Retinal Degeneration / Q000209:etiology; D012172:Retinaldehyde; D012174:Retinitis Pigmentosa / Q000235:genetics*; D017299:Rod Opsins / Q000235:genetics*; D014162:Transfection
D017299:Rod Opsins; D012172:Retinaldehyde