Acta Physiologica 2010; Volume 200, Supplement 681
Abstracts of the 61st National Congress of the Italian Physiological Society
THE ADAPTOR PROTEIN PDZK1/NHERF3 INTERACTS WITH THE GLUTAMATE TRANSPORTER EAAC1 AND CONTROLS ITS SURFACE ACTIVITY IN EPITHELIAL CELLS
Abstract number: P31
SALA1 S, DI CAIRANO1 ES, FANTIN1 G, SACCHI1 VF, ANZAI2 N, PEREGO1 C
1Dept of Molecular Sciences Applied to Biosystems, Universit degli Studi di Milano, Italy
2Dept of Pharmacology and Toxicology, Kyorin University, Tokyo, Japan
In epithelia, the glutamate transporter EAAC1/EAAT3 mediates the absorption of dicarboxylic amino acids and has been involved in dicarboxylic aminoaciduria, a rare disease in which glutamate and aspartate accumulate in urine. EAAC1 cell-surface distribution is regulated by interaction with accessory proteins, which remain to be identified. By means of yeast two hybrid system, we identified the PDZ domain containing protein 1 (PDZK1), an adaptor protein involved in the apical domain organization of epithelia. The interaction was confirmed by affinity chromatography and co-immunoprecipitation experiments. Immunostaining of pig jejunum with antisera against PDZK1 and EAAC1 revealed co-localization between the two proteins in the apical domain of enterocytes and in sub-apical vesicular compartments.
PDZK1 not only co-localized but also functionally interacted with the transporter, because its presence increased the glutamate uptake in MDCK cells expressing wild type EAAC1, but not a mutant transporter lacking the PDZ interaction sequence.
Taken together, these results demonstrate that PDZK1 functionally interacts with EAAC1 and modulates its cell-surface activity.
To cite this abstract, please use the following information:
Acta Physiologica 2010; Volume 200, Supplement 681 :P31