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

• Type: Article in International Scientific Journal
• Date: 2002

Authors

Pedro Gomes (Author) Other; soares-da-silva, p (Author) FMUP

Journal

Title: Journal of Membrane Biology

Vol. 186

Pages: 63-80

ISSN: 0022-2631

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 26 Citations

Scopus - 31 Citations

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 18