Calpain-5 Expression in the Retina Localizes to Photoreceptor Synapses.
Invest Ophthalmol Vis Sci
; 57(6): 2509-21, 2016 05 01.
Article
en En
| MEDLINE
| ID: mdl-27152965
PURPOSE: We characterize calpain-5 (CAPN5) expression in retinal and neuronal subcellular compartments. METHODS: CAPN5 gene variants were classified using the exome variant server, and RNA-sequencing was used to compare expression of CAPN5 mRNA in the mouse and human retina and in retinoblastoma cells. Expression of CAPN5 protein was ascertained in humans and mice in silico, in mouse retina by immunohistochemistry, and in neuronal cancer cell lines and fractionated central nervous system tissue extracts by Western analysis with eight antibodies targeting different CAPN5 regions. RESULTS: Most CAPN5 genetic variation occurs outside its protease core; and searches of cancer and epilepsy/autism genetic databases found no variants similar to hyperactivating retinal disease alleles. The mouse retina expressed one transcript for CAPN5 plus those of nine other calpains, similar to the human retina. In Y79 retinoblastoma cells, the level of CAPN5 transcript was very low. Immunohistochemistry detected CAPN5 expression in the inner and outer nuclear layers and at synapses in the outer plexiform layer. Western analysis of fractionated retinal extracts confirmed CAPN5 synapse localization. Western blots of fractionated brain neuronal extracts revealed distinct subcellular patterns and the potential presence of autoproteolytic CAPN5 domains. CONCLUSIONS: CAPN5 is moderately expressed in the retina and, despite higher expression in other tissues, hyperactive disease mutants of CAPN5 only manifest as eye disease. At the cellular level, CAPN5 is expressed in several different functional compartments. CAPN5 localization at the photoreceptor synapse and with mitochondria explains the neural circuitry phenotype in human CAPN5 disease alleles.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Células Fotorreceptoras
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Retinoblastoma
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Sinapsis
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ARN Neoplásico
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Calpaína
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Regulación Neoplásica de la Expresión Génica
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Neoplasias de la Retina
Límite:
Animals
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Female
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Humans
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Male
Idioma:
En
Revista:
Invest Ophthalmol Vis Sci
Año:
2016
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos