title: The co-chaperone and reductase ERdj5 facilitates rod opsin biogenesis and quality control.
abstract: Mutations in rhodopsin, the light-sensitive protein of rod cells, are the most common cause of autosomal dominant retinitis pigmentosa (ADRP). Many rod opsin mutations, such as P23H, lead to misfolding of rod opsin with detrimental effects on photoreceptor function and viability. Misfolded P23H rod opsin and other mutations in the intradiscal domain are characterized by the formation of an incorrect disulphide bond between C185 and C187, as opposed to the correct and highly conserved C110-C187 disulphide bond. Therefore, we tested the hypothesis that incorrect disulphide bond formation might be a factor that affects the biogenesis of rod opsin by studying wild-type (WT) or P23H rod opsin in combination with amino acid substitutions that prevent the formation of incorrect disulphide bonds involving C185. These mutants had altered traffic dynamics, suggesting a requirement for regulation of disulphide bond formation/reduction during rod opsin biogenesis. Here, we show that the BiP co-chaperone and reductase protein ERdj5 (DNAJC10) regulates this process. ERdj5 overexpression promoted the degradation, improved the endoplasmic reticulum mobility and prevented the aggregation of P23H rod opsin. ERdj5 reduction by shRNA delayed rod opsin degradation and promoted aggregation. The reductase and co-chaperone activity of ERdj5 were both required for these effects on P23H rod opsin. Furthermore, mutations in these functional domains acted as dominant negatives that affected WT rod opsin biogenesis. Collectively, these data identify ERdj5 as a member of the proteostasis network that regulates rod opsin biogenesis and supports a role for disulphide bond formation/reduction in rod opsin biogenesis and disease.
authors: UCL Institute of Ophthalmology, London EC1V 9EL, UK.
authors: Dimitra
authors: D
authors: Athanasiou
authors: UCL Institute of Ophthalmology, London EC1V 9EL, UK.
authors: Dalila
authors: D
authors: Bevilacqua
authors: UCL Institute of Ophthalmology, London EC1V 9EL, UK.
authors: Monica
authors: M
authors: Aguila
authors: UCL Institute of Ophthalmology, London EC1V 9EL, UK.
authors: Caroline
authors: C
authors: McCulley
authors: UCL Institute of Ophthalmology, London EC1V 9EL, UK.
authors: Naheed
authors: N
authors: Kanuga
authors: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma 371-8511, Japan and.
authors: Takao
authors: T
authors: Iwawaki
authors: Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
authors: J Paul
authors: JP
authors: Chapple
authors: UCL Institute of Ophthalmology, London EC1V 9EL, UK, michael.cheetham@ucl.ac.uk.
authors: Michael E
authors: ME
authors: Cheetham
mesh_terms: D045744:Cell Line, Tumor; D004220:Disulfides / Q000737:chemistry; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005786:Gene Expression Regulation; D050956:HSP40 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D018832:Molecular Chaperones / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D066329:Protein Aggregates; D017510:Protein Folding; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012243:Rhodopsin / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection
chemical_list: C471179:DNAJC10 protein, human; D004220:Disulfides; D050956:HSP40 Heat-Shock Proteins; D018832:Molecular Chaperones; D066329:Protein Aggregates; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D012243:Rhodopsin