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Transepithelial taurine transport in caco-2 cell monolayers
S Roig-Pérez1, M Moretó, R Ferrer
1Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain.
The Journal of Membrane Biology
|September 10, 2005
Summary
Human intestinal cells accumulate taurine via a Na(+) and Cl(-) dependent mechanism. Apical influx exceeds basolateral efflux, allowing taurine accumulation against concentration gradients.
Area of Science:
- Cell Biology
- Physiology
- Biochemistry
Background:
- Taurine is a vital amino acid with diverse physiological roles.
- Understanding intestinal taurine transport is crucial for nutrient absorption and cellular homeostasis.
Purpose of the Study:
- To characterize the kinetic parameters of transepithelial taurine transport in human intestinal Caco-2 cells.
- To elucidate the mechanisms of apical and basolateral taurine uptake and efflux.
Main Methods:
- Utilized kinetic analysis of apical and basolateral uptake and efflux in Caco-2 cell monolayers.
- Investigated Na(+) and Cl(-) dependence and inhibition by beta-amino acids.
- Assessed saturable and non-saturable transport components and diffusive efflux.
Main Results:
- Basolateral taurine uptake is Na(+)/Cl(-) dependent and shares properties with the apical taurine transporter (TauT).
- Apical taurine uptake exhibits higher affinity (lower K(m)) and capacity (higher V(max)) than basolateral uptake.
- Taurine efflux is a passive, diffusive process, with lower rates than influx, enabling net accumulation.
Conclusions:
- Caco-2 cell basolateral taurine uptake involves a mechanism similar to the apical TauT system.
- Apical influx significantly exceeds basolateral efflux, facilitating intracellular taurine accumulation against a concentration gradient.
- These findings provide insights into intestinal amino acid transport and cellular energy metabolism.