Identification of a unique monocarboxylate transporter (MCT3) in retinal pigment epithelium.
Biochem Biophys Res Commun
; 234(1): 90-4, 1997 May 08.
Article
em En
| MEDLINE
| ID: mdl-9168967
ABSTRACT
The retinal pigment epithelium transports lactate between two tissue compartments, the interphotoreceptor matrix and the choriocapillaris. In this report we describe a 2.45-kb cDNA isolated from a chick cDNA RPE library that encodes a membrane protein found only in RPE cells. The deduced protein has 542 amino acids with twelve putative membrane spanning domains. The cDNA has been designated MCT3 based on its 45% identity in amino acid sequence and structural similarity with the monocarboxylate transporters MCT1 and MCT2. Stable transfectants (pCl-neo/MCT3), made in a rat thyroid epithelial cell line (FRTL-5), express MCT3 RNA. Transfectants had enhanced pyruvate uptake (used as a measure of lactate uptake) which was proton-dependent and inhibited by alpha-cyano-4-hydroxycinnamate. In summary, MCT3's unique expression in RPE cells, multiple potential phosphorylation sites, and basolateral distribution suggest that MCT3 may regulate lactate levels in the interphotoreceptor space.
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Base de dados:
MEDLINE
Assunto principal:
Epitélio Pigmentado Ocular
/
Proteínas de Transporte
/
Ácido Láctico
Idioma:
En
Ano de publicação:
1997
Tipo de documento:
Article