Expression and function of LAT1, a neutral amino acid exchanger, in renal porcine epithelial cell line LLC-PK1

• Type: Article in International Scientific Journal
• Date: 2005

Authors

soares-da-silva, p (Author) FMUP; Maria Paula Serrão (Author) FMUP; Sonia Fraga (Author) Other; Pinho, MJ (Author) Other

Journal

Title: Acta Physiologica Scandinavica

Vol. 185 No. 1

Pages: 71-78

ISSN: 0001-6772

Publisher: Blackwell

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 8 Citations

Other information

Authenticus ID: P-000-1DW

DOI: 10.1111/j.1365-201x.2005.01451.x

Abstract (EN): Aim: The present study examined the expression of LAT1 and the functional characteristics of the inward and outward [C-14] L-leucine transporter in the renal porcine epithelial cell line LLC-PK1. Methods: LLC-PK1 cells were cultured in polycarbonate filters and accumulation and transepithelial flux of the substrate monitored with [14C] L-leucine. LAT1 transcripts were examined by RT-PCR. LAT1 protein was detected by immunoblotting. Results: The accumulation of [C-14] L-leucine in the cell and the [C-14] L-leucine transepithelial flux were four- and twofold, respectively, when the substrate was added from the basal cell side, suggesting that the basolateral membrane is endowed with a high density of transport units, when compared with the apical membrane. Increases in the transepithelial flux of [C-14] L-leucine by unlabelled L-leucine were also more pronounced when unlabelled L-leucine was added from the basolateral membrane. In the absence of Na+, unlabelled L-leucine Increased the basal and apical fractional outflow of [C-14] L-leucine, this being similar at pH 7.4 and pH 6.2. RT-PCR and immunoblotting detected LAT1 transcript and protein, respectively. Conclusion: LLC-PK1 cells are endowed with the LAT1 transcript and protein and transport L-leucine through the Na+-independent and pH-insensitive LAT1 transporter. The density of transporter units in LLC-PK1 cells may be higher at the basolateral membranes, although be also present in the apical membranes.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8