title: Disulfide-mediated oligomerization of Peripherin/Rds and Rom-1 in photoreceptor disk membranes. Implications for photoreceptor outer segment morphogenesis and degeneration.
abstract: Peripherin/Rds is a tetraspanning membrane protein that has been implicated in photoreceptor outer segment morphogenesis and inherited retinal degenerative diseases. Together with the structurally related protein, Rom-1, it forms a complex along the rims of rod and cone disc membranes. We have compared the oligomeric structure of these proteins from nonreduced and dithiothreitol reduced membranes by velocity sedimentation, SDS-gel electrophoresis, immunoaffinity chromatography, and chemical cross-linking. Under reducing conditions peripherin/Rds and Rom-1 existed as homomeric and heteromeric core complexes devoid of intermolecular disulfide bonds. Under nonreducing conditions core complexes associated through intermolecular disulfide bonds to form oligomers. One intermediate-size oligomer contained monomers and disulfide-linked dimers of peripherin/Rds and Rom-1, while larger oligomers consisted only of disulfide-linked peripherin/Rds dimers when analyzed on nonreducing SDS gels. Consistent with this result, disc membranes contained twice as much peripherin/Rds as Rom-1. Peripherin/Rds individually expressed in COS-1 cells also formed disulfide-linked oligomers bridged through Cys-150 residues, whereas Rom-1 showed little tendency to form oligomers. These results indicate that peripherin/Rds and Rom-1 associate noncovalently to form multisubunit core complexes. Peripherin/Rds containing core complexes interact through specific intermolecular disulfide bonds to form oligomers which may play a crucial role in photoreceptor disc morphogenesis and retinal degenerative diseases.
authors.affiliation: Department of Biochemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: C J
authors.initials: CJ
authors.lastname: Loewen
authors.forename: R S
authors.initials: RS
authors.lastname: Molday
mesh_terms: D000818:Animals; D019556:COS Cells; D002417:Cattle; D002498:Centrifugation; D002846:Chromatography, Affinity; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004220:Disulfides; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005033:Ethylmaleimide / Q000494:pharmacology; D005136:Eye Proteins / Q000737:chemistry / Q000378:metabolism*; D005404:Fixatives / Q000494:pharmacology; D005976:Glutaral / Q000494:pharmacology; D007381:Intermediate Filament Proteins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D064531:Peripherins; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D012374:Rod Cell Outer Segment / Q000737:chemistry / Q000378:metabolism*; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013997:Time Factors
chemical_list: D003432:Cross-Linking Reagents; D004220:Disulfides; D005136:Eye Proteins; D005404:Fixatives; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D064531:Peripherins; D013439:Sulfhydryl Reagents; D005033:Ethylmaleimide; D005976:Glutaral; D004229:Dithiothreitol