Addition of human melanopsin renders mammalian cells photoresponsive.
Nature
; 433(7027): 741-5, 2005 Feb 17.
Article
en En
| MEDLINE
| ID: mdl-15674244
ABSTRACT
A small number of mammalian retinal ganglion cells act as photoreceptors for regulating certain non-image forming photoresponses. These intrinsically photosensitive retinal ganglion cells express the putative photopigment melanopsin. Ablation of the melanopsin gene renders these cells insensitive to light; however, the precise role of melanopsin in supporting cellular photosensitivity is unconfirmed. Here we show that heterologous expression of human melanopsin in a mouse paraneuronal cell line (Neuro-2a) is sufficient to render these cells photoreceptive. Under such conditions, melanopsin acts as a sensory photopigment, coupled to a native ion channel via a G-protein signalling cascade, to drive physiological light detection. The melanopsin photoresponse relies on the presence of cis-isoforms of retinaldehyde and is selectively sensitive to short-wavelength light. We also present evidence to show that melanopsin functions as a bistable pigment in this system, having an intrinsic photoisomerase regeneration function that is chromatically shifted to longer wavelengths.
Palabras clave
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Opsinas de Bastones
/
Fototransducción
/
Luz
/
Neuronas
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Nature
Año:
2005
Tipo del documento:
Article
País de afiliación:
Reino Unido