title: Redox proteomic identification of visual arrestin dimerization in photoreceptor degeneration after photic injury.
abstract: OBJECTIVE
  Light-induced oxidative stress is an important risk factor for age-related macular degeneration, but the downstream mediators of photoreceptor and retinal pigment epithelium cell death after photic injury are unknown. Given our previous identification of sulfhydryl/disulfide redox status as a factor in photoreceptor survival, we hypothesized that formation of one or more disulfide-linked homo- or hetero-dimeric proteins might signal photoreceptor death after light-induced injury.
  
  
  METHODS
  Two-dimensional (non-reducing/reducing) gel electrophoresis of Wistar rat retinal homogenates after 10 hours of 10,000 lux (4200°K) light in vivo, followed by mass spectrometry identification of differentially oxidized proteins.
  
  
  RESULTS
  The redox proteomic screen identified homodimers of visual arrestin (Arr1; S antigen) after toxic levels of light injury. Immunoblot analysis revealed a light duration-dependent formation of Arr1 homodimers, as well as other Arr1 oligomers. Immunoprecipitation studies revealed that the dimerization of Arr1 due to photic injury was distinct from association with its physiological binding partners, rhodopsin and enolase1. Systemic delivery of tris(2-carboxyethyl)phosphine, a specific disulfide reductant, both decreased Arr1 dimer formation and protected photoreceptors from light-induced degeneration in vivo.
  
  
  CONCLUSIONS
  These findings suggest a novel arrestin-associated pathway by which oxidative stress could result in cell death, and identify disulfide-dependent dimerization as a potential therapeutic target in retinal degeneration.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lieven
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Ribich
authors.forename: Megan E
authors.initials: ME
authors.lastname: Crowe
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Levin
mesh_terms: D000818:Animals; D019393:Arrestin / Q000378:metabolism*; D019390:Arrestins / Q000378:metabolism*; D019281:Dimerization; D015180:Electrophoresis, Gel, Two-Dimensional; D015151:Immunoblotting; D047468:Immunoprecipitation; D008027:Light / Q000009:adverse effects; D008297:Male; D013058:Mass Spectrometry; D020221:Optic Nerve Injuries / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010786:Photoreceptor Cells / Q000378:metabolism / Q000473:pathology*; D040901:Proteomics / Q000379:methods*; D011833:Radiation Injuries, Experimental / Q000150:complications / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012162:Retinal Degeneration / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins
chemical_list: C000605256:Arrb1 protein, rat; D019393:Arrestin; D019390:Arrestins; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins