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Polarized amino acid transport by an epithelial cell line of renal origin (LLC-PK1). The basolateral systems.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 1982 Jun 25; Vol. 257 (12), pp. 6802-8. - Publication Year :
- 1982
-
Abstract
- The transport of three neutral amino acid analogs has been studied in an epithelial cell line from a pig kidney. 2-Aminoisobutyric acid is accumulated by LLC-PK1 cells against a concentration gradient through a mechanism with several features of a carrier-mediated process. The influx is accounted for by a saturable Na+-dependent and nonsaturable Na+-independent process. The total influx of 2-(methylamino)isobutyric acid is also mediated through Na+-dependent and Na+-independent systems. Part of the Na+-dependent influx of 2-aminoisobutyric acid was competitively inhibited by 2-(methylamino)isobutyric acid (Ki = 4.2 mM).l Selectivity studies indicate that the 2-(methylamino)isobutyric acid-sensitive part of 2-aminoisobutyric acid influx is mediated through the A system, whereas the insensitive part occurs through the ASC system. Cycloleucine transport also involves a Na+-dependent and Na+-independent process. The Na+-dependent influx is completely inhibited by 2-aminoisobutyric acid but not perceptibly by 2-(methylamino)isobutyric acid. This influx probably represents entry through the ASC system. The Na+-independent component is completely inhibited by 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid, a specific substrate for the L system. Uptake studies from either side of the monolayers indicate that these transport systems are exclusively located in basolateral membranes of the cultured renal cells.
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 257
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 7085605