1. Alterations in the photoactivation pathway of rhodopsin mutants associated with retinitis pigmentosa
- Author
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Bosch Presegué, Laia, Ramon Portés, Eva|||0000-0002-0786-2792, Toledo, Darwin, Cordomí Montoya, Arnau, Garriga Solé, Pere|||0000-0003-4234-8382, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. GBMI - Grup de Biotecnologia Molecular i Industrial, and Universitat Politècnica de Catalunya. IMEM - Innovació, Modelització i Enginyeria en (BIO) Materials
- Subjects
Retina -- Malalties ,Metarhodopsin ,Rodopsina ,genetic structures ,Ciències de la visió::Biologia ocular [Àrees temàtiques de la UPC] ,sense organs ,Retinitis pigmentosa -- etiology ,Retinosi pigmentària - Abstract
The visual photoreceptor rhodopsin undergoes a series of conformational changes upon light activation, eventually leading to the active metarhodopsin II conformation, which is able to bind and activate the G-protein, transducin. We have previously shown that mutant rhodopsins G51V and G89D, associated with retinitis pigmentosa, present photobleaching patterns characterized by the formation of altered photointermediates whose nature remained obscure. Our current detailed UV–visible spectroscopic analysis, together with functional characterization, indicate that these mutations influence the relative stability of the different metarhodopsin photointermediates by altering their equilibria and maintaining the receptor in a nonfunctional light-induced conformation that may be toxic to photoreceptor cells. We propose that G51V and G89D shift the equilibrium from metarhodopsin I towards an intermediate, recently named as metarhodopsin Ib, proposed to interact with transducin without activating it. This may be one of the causes contributing to the molecular mechanisms underlying cell death associated with some retinitis pigmentosa mutations.
- Published
- 2011