Electrogenic amino acid exchange via the rBAT transporter

FEBS Letters

Jalal, Fairouze¹  Coady, Michael J.¹  Berteloot, Alfred¹  Lemay, Guy¹  Chen, Xingzhen¹  Lapointe, Jean-Yves¹ 

[1] Groupe de recherche en transport membranaire, Université de Montréal, CP 6128 Succursale Centre-ville, Montréal, Que. H3 C 3J7, Canada

关键词: Amino acid transport;    Counterexchange;    Expression cloning;    Oocyte;    Xenopus laevis;   

DOI  :  10.1016/0014-5793(94)01262-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A cDNA clone was isolated from rabbit renal cortex using DNA-mediated expression cloning, which caused alanine-dependent outward currents when expressed in Xenopus oocytes. The cDNA encodes rBAT, a Na-independent amino acid transporter previously cloned elsewhere. Exposure of cDNA-injected oocytes to neutral amino acids led to voltage-dependent outward currents, but inward currents were seen upon exposure to basic amino acids. Assuming one charge/alanine, the outward current represented 38% of the rate of uptake of radiolabelled alanine, and was significantly reduced by prolonged preincubation of oocytes in 5 mM alanine. The currents were shown to be due to countertransport of basic amino acids for external amino acids using the cut-open oocyte system. This transport represents a major mode of action of this protein, and may help in defining a physiological role for rBAT in the apical membrane of renal and intestinal cells.

【 授权许可】

Unknown