Dephosphorylation by protein phosphatase 2A regulates visual pigment regeneration and the dark adaptation of mammalian photoreceptors.
Proc Natl Acad Sci U S A
; 114(45): E9675-E9684, 2017 11 07.
Article
em En
| MEDLINE
| ID: mdl-29078372
ABSTRACT
Resetting of G-protein-coupled receptors (GPCRs) from their active state back to their biologically inert ground state is an integral part of GPCR signaling. This "on-off" GPCR cycle is regulated by reversible phosphorylation. Retinal rod and cone photoreceptors arguably represent the best-understood example of such GPCR signaling. Their visual pigments (opsins) are activated by light, transduce the signal, and are then inactivated by a GPCR kinase and arrestin. Although pigment inactivation by phosphorylation is well understood, the enzyme(s) responsible for pigment dephosphorylation and the functional significance of this reaction remain unknown. Here, we show that protein phosphatase 2A (PP2A) acts as opsin phosphatase in both rods and cones. Elimination of PP2A substantially slows pigment dephosphorylation, visual chromophore recycling, and ultimately photoreceptor dark adaptation. These findings demonstrate that visual pigment dephosphorylation regulates the dark adaptation of photoreceptors and provide insights into the role of this reaction in GPCR signaling.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosforilação
/
Regeneração
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Células Fotorreceptoras Retinianas Cones
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Adaptação à Escuridão
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Proteína Fosfatase 2
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Epitélio Pigmentado da Retina
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Mamíferos
Limite:
Animals
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2017
Tipo de documento:
Article