title: Amino acid transporter B(0)AT1 (slc6a19) and ancillary protein: impact on function.
abstract: Amino acids play an important role in the metabolism of all organisms. Their epithelial re-absorption is due to specific transport proteins, such as B(0)AT1, a Na(+)-coupled neutral amino acid symporter belonging to the solute carrier 6 family. Here, a recently cloned fish orthologue, from the intestine of Salmo salar, was electrophysiologically characterized with the two-electrode voltage clamp technique, in Xenopus laevis oocytes heterologously expressing the transporter. Substrate specificity, apparent affinities and the ionic dependence of the transport mechanism were determined in the presence of specific collectrin. Results demonstrated that like the human, but differently from sea bass (Dicentrarchus labrax) orthologue, salmon B(0)AT1 needs to be associated with partner proteins to be correctly expressed at the oocyte plasma membrane. Cloning of sea bass collectrin and comparison of membrane expression and functionality of the B(0)AT1 orthologue transporters allowed a deeper investigation on the role of their interactions. The parameters acquired by electrophysiological and immunolocalization experiments in the mammalian and fish transporters contributed to highlight the dynamic of relations and impacts on transport function of the ancillary proteins. The comparative characterization of the physiological parameters of amino acid transporters with auxiliary proteins can help the comprehension of the regulatory mechanism of essential nutrient absorption.
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Margheritis
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Francesca Guia
authors.initials: FG
authors.lastname: Imperiali
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Cinquetti
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Vollero
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.|Interuniversity Center "The Protein Factory", Politecnico di Milano, ICRM-CNR Milano and Università dell'Insubria, Via Mancinelli 7, I-20131, Milan, Italy.
authors.forename: Genciana
authors.initials: G
authors.lastname: Terova
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Rimoldi
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Girardello
authors.affiliation: Department of Biotechnology and Life Science, University of Insubria, Via J.H. Dunant 3, 21100, Varese, Italy. elena.bossi@uninsubria.it.|Interuniversity Center "The Protein Factory", Politecnico di Milano, ICRM-CNR Milano and Università dell'Insubria, Via Mancinelli 7, I-20131, Milan, Italy. elena.bossi@uninsubria.it.
authors.forename: Elena
authors.initials: E
authors.lastname: Bossi
mesh_terms: D026905:Amino Acid Transport Systems / Q000378:metabolism*; D026921:Amino Acid Transport Systems, Neutral / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001492:Bass / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D020317:Salmo salar / Q000378:metabolism; D013379:Substrate Specificity; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D000596:Amino Acids; D002352:Carrier Proteins
keywords: Collectrin; Membrane transporter; Neutral amino acid transporters; TEVC; Xenopus laevis oocytes