Dynamic scaffolding in a G protein-coupled signaling system.
Cell
; 131(1): 80-92, 2007 Oct 05.
Article
em En
| MEDLINE
| ID: mdl-17923089
ABSTRACT
The INAD scaffold organizes a multiprotein complex that is essential for proper visual signaling in Drosophila photoreceptor cells. Here we show that one of the INAD PDZ domains (PDZ5) exists in a redox-dependent equilibrium between two conformations--a reduced form that is similar to the structure of other PDZ domains, and an oxidized form in which the ligand-binding site is distorted through formation of a strong intramolecular disulfide bond. We demonstrate transient light-dependent formation of this disulfide bond in vivo and find that transgenic flies expressing a mutant INAD in which PDZ5 is locked in the reduced state display severe defects in termination of visual responses and visually mediated reflex behavior. These studies demonstrate a conformational switch mechanism for PDZ domain function and suggest that INAD behaves more like a dynamic machine rather than a passive scaffold, regulating signal transduction at the millisecond timescale through cycles of conformational change.
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Base de dados:
MEDLINE
Assunto principal:
Visão Ocular
/
Sistemas do Segundo Mensageiro
/
Proteínas de Ligação ao GTP
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Proteínas de Drosophila
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Proteínas do Olho
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Domínios PDZ
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article