Header

UZH-Logo

Maintenance Infos

Na+-independent lysine transport in human intestinal Caco-2 cells.


Thwaites, D T; Markovich, D; Murer, H; Simmons, N L (1996). Na+-independent lysine transport in human intestinal Caco-2 cells. Journal of Membrane Biology, 151(3):215-224.

Abstract

The nature of transepithelial and cellular transport of the dibasic amino acid lysine in human intestinal epithelial Caco-2 cells has been characterized. Intracellular accumulation of lysine across both the apical and basolateral membranes consists of a Na+-independent, membrane potential-sensitive uptake. Na+-independent lysine uptake at the basolateral membrane exceeds that at the apical membrane. Lysine uptake consists of both saturable and nonsaturable components. Na+-independent lysine uptake at both membranes is inhibited by lysine, arginine, alanine, histidine, methionine, leucine, cystine, cysteine and homoserine. In contrast, proline and taurine are without inhibitory effects at both membranes. Fractional Na+-independent lysine efflux from preloaded epithelial layers is greater at the basolateral membrane and shows trans-stimulation across both epithelial borders by lysine, arginine, alanine, histidine, methionine, and leucine but not proline and taurine. Na+-independent lysine influx (10 micron) in the presence of 10 mm homoserine shows further concentration dependent inhibition by lysine. Taken together, these data are consistent with lysine transport being mediated by systems bo,+, y+ and a component of very low affinity (nonsaturable) at both membranes. The relative contribution to lysine uptake at each membrane surface (at 10 micron lysine), normalized to total apical uptake (100%), is apical bo,+ (47%), y+ (27%) and the nonsaturable component (26%), and basal bo,+ (446%), y+ (276%) and the nonsaturable component (20%). Northern analysis shows hybridization of Caco-2 poly(A)+RNA with a human rBAT cDNA probe.

Abstract

The nature of transepithelial and cellular transport of the dibasic amino acid lysine in human intestinal epithelial Caco-2 cells has been characterized. Intracellular accumulation of lysine across both the apical and basolateral membranes consists of a Na+-independent, membrane potential-sensitive uptake. Na+-independent lysine uptake at the basolateral membrane exceeds that at the apical membrane. Lysine uptake consists of both saturable and nonsaturable components. Na+-independent lysine uptake at both membranes is inhibited by lysine, arginine, alanine, histidine, methionine, leucine, cystine, cysteine and homoserine. In contrast, proline and taurine are without inhibitory effects at both membranes. Fractional Na+-independent lysine efflux from preloaded epithelial layers is greater at the basolateral membrane and shows trans-stimulation across both epithelial borders by lysine, arginine, alanine, histidine, methionine, and leucine but not proline and taurine. Na+-independent lysine influx (10 micron) in the presence of 10 mm homoserine shows further concentration dependent inhibition by lysine. Taken together, these data are consistent with lysine transport being mediated by systems bo,+, y+ and a component of very low affinity (nonsaturable) at both membranes. The relative contribution to lysine uptake at each membrane surface (at 10 micron lysine), normalized to total apical uptake (100%), is apical bo,+ (47%), y+ (27%) and the nonsaturable component (26%), and basal bo,+ (446%), y+ (276%) and the nonsaturable component (20%). Northern analysis shows hybridization of Caco-2 poly(A)+RNA with a human rBAT cDNA probe.

Statistics

Citations

Dimensions.ai Metrics
29 citations in Web of Science®
31 citations in Scopus®
Google Scholar™

Altmetrics

Additional indexing

Item Type:Journal Article, refereed
Communities & Collections:04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
Dewey Decimal Classification:570 Life sciences; biology
Scopus Subject Areas:Life Sciences > Biophysics
Life Sciences > Physiology
Life Sciences > Cell Biology
Language:English
Date:1 June 1996
Deposited On:11 Feb 2008 12:22
Last Modified:23 Jan 2022 08:49
Publisher:Springer
ISSN:0022-2631
OA Status:Closed
Publisher DOI:https://doi.org/10.1007/s002329900072
PubMed ID:8661509
Full text not available from this repository.