The g-aminobutyric acid transporter (GAT-1) isoform of the g-aminobutyric acid and the betaine (BGT) transporters exhibit distinct apical and basolateral distributions when introduced into Madin-Darby canine kidney cells (Pietrini, G., Suh, Y. J., Edelman, L., Rudnick, G.,and Caplan, M. J. (1994) J. Biol. Chem. 269, 4668–4674). We have investigated the presence of sorting signals in their COOH-terminal cytosolic domains by expression in Madin-Darby canine kidney cells of mutated and chimeric transporters. Whereas truncated GAT-1 (DC-GAT) maintained the original functional activity and apicallocalization, either the removal (DC-myc BGT) or the substitution (BGS chimera) of the cytosolic tail of BGT generated proteins that accumulated in the endoplasmic reticulum. Moreover, we have found that the cytosolic tail of BGT redirected apical proteins, the polytopic GAT-1 (GBS chimera) and the monotopic human nerve growth factor receptor, to the basolateral surface.These results suggest the presence of basolateral sorting information in the cytosolic tail of BGT. We have further shown that information necessary for the exit of BGT from the endoplasmic reticulum and for the basolateral localization of the GBS chimera is contained in a short segment, rich in basic residues, within the cytosolic tail of BGT.
Sorting of two polytopic proteins, the gamma-aminobutyric acid and betaine transporters, in polarized epithelial cells / C. Perego, A. Bulbarelli, R. Longhi, M. Caimi, A. Villa, M.J. Caplan, G. Pietrini. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 272:10(1997 Mar 07), pp. 6584-6592. [10.1074/jbc.272.10.6584]
Sorting of two polytopic proteins, the gamma-aminobutyric acid and betaine transporters, in polarized epithelial cells
C. PeregoPrimo
;A. BulbarelliSecondo
;G. PietriniUltimo
1997
Abstract
The g-aminobutyric acid transporter (GAT-1) isoform of the g-aminobutyric acid and the betaine (BGT) transporters exhibit distinct apical and basolateral distributions when introduced into Madin-Darby canine kidney cells (Pietrini, G., Suh, Y. J., Edelman, L., Rudnick, G.,and Caplan, M. J. (1994) J. Biol. Chem. 269, 4668–4674). We have investigated the presence of sorting signals in their COOH-terminal cytosolic domains by expression in Madin-Darby canine kidney cells of mutated and chimeric transporters. Whereas truncated GAT-1 (DC-GAT) maintained the original functional activity and apicallocalization, either the removal (DC-myc BGT) or the substitution (BGS chimera) of the cytosolic tail of BGT generated proteins that accumulated in the endoplasmic reticulum. Moreover, we have found that the cytosolic tail of BGT redirected apical proteins, the polytopic GAT-1 (GBS chimera) and the monotopic human nerve growth factor receptor, to the basolateral surface.These results suggest the presence of basolateral sorting information in the cytosolic tail of BGT. We have further shown that information necessary for the exit of BGT from the endoplasmic reticulum and for the basolateral localization of the GBS chimera is contained in a short segment, rich in basic residues, within the cytosolic tail of BGT.Pubblicazioni consigliate
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