Na+-independent transporters, LAT-2 and b(0,+), exchange L-DOPA with neutral and basic amino acids in two clonal renal cell lines

• Tipo: Artigo em Revista Científica Internacional
• Data: 2002

Autores

Pedro Gomes (Autor) Outra; soares-da-silva, p (Autor) FMUP

Revista

Título: Journal of Membrane Biology

Vol. 186

Páginas: 63-80

ISSN: 0022-2631

Editora: Springer Nature

Indexação

ISI Web of Knowledge - 26 Citações

Scopus - 31 Citações

Outras Informações

ID Authenticus: P-000-Q0Z

DOI: 10.1007/s00232-001-0136-8

Abstract (EN): The present study examined the functional characteristics Of L-DOPA transporters in two functionally different clonal subpopulations of opossum kidney (OKLC and OKHC) cells. The uptake Of L-DOPA was largely Na+-independent, though in OKHC cells a minor component (similar to15%) required extracellular Na+. At least two Na+-independent transporters appear to be involved in L-DOPA uptake. One of these transporters has a broad specificity for small and large neutral amino acids, is stimulated by acid pH and inhibited by 2-aminobicyclo(2,2,1)-heptane-2-carboxylic acid (BCH; OKLC, K-i = 291 muM; OKHC, K-i = 380 muM). The other Na+-independent transporter binds neutral and basic amino acids and also recognizes the di-amino acid cystine. [C-14]-L-DOPA efflux from OKLC and OKHC cells over 12 min corresponded to a small amount of intracellular [C-14]-L-DOPA. L-Leucine, nonlabelled L-DOPA, BCH and L-arginine, stimulated the efflux Of [C-14]-L-DOPA in a Na+-independent manner. It is suggested that L-DOPA uses at least two major transporters, systems LAT-2 and b(0,+). The transport Of L-DOPA by LAT-2 corresponds to a Na+-independent transporter with a broad specificity for small and large neutral amino acids, stimulated by acid pH and inhibited by BCH. The transport Of L-DOPA by system b(0,+) is a Na+-independent transporter for neutral and basic amino acids that also recognizes cystine. LAT-2 was found equally important at the apical and basolateral membranes, whereas system b(0,+) had a predominant distribution in apical membranes.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 18