Format

Send to

Choose Destination
Biochem J. 2006 Jan 1;393(Pt 1):421-30.

The orphan transporter v7-3 (slc6a15) is a Na+-dependent neutral amino acid transporter (B0AT2).

Author information

1
School of Biochemistry & Molecular Biology, Australian National University, Canberra, ACT 0200, Australia.

Abstract

Transporters of the SLC6 (solute carrier 6) family play an important role in the removal of neurotransmitters in brain tissue and in amino acid transport in epithelial cells. In the present study, we demonstrate that mouse v7-3 (slc6a15) encodes a transporter for neutral amino acids. The transporter is functionally and sequence related to B(0)AT1 (slc6a19) and was hence named B(0)AT2. Leucine, isoleucine, valine, proline and methionine were recognized by the transporter, with values of K(0.5) (half-saturation constant) ranging from 40 to 200 microM. Alanine, glutamine and phenylalanine were low-affinity substrates of the transporter, with K(0.5) values in the millimolar range. Transport of neutral amino acids via B(0)AT2 was Na+-dependent, Cl--independent and electrogenic. Superfusion of mouse B(0)AT2-expressing oocytes with amino acid substrates generated robust inward currents. Na+-activation kinetics of proline transport and uptake under voltage clamp suggested a 1:1 Na+/amino acid co-transport stoichiometry. Susbtrate and co-substrate influenced each other's K(0.5) values, suggesting that they share the same binding site. A mouse B(0)AT2-like transport activity was detected in synaptosomes and cultured neurons. A potential role of B(0)AT2 in transporting neurotransmitter precursors and neuromodulators is proposed.

PMID:
16185194
PMCID:
PMC1383701
DOI:
10.1042/BJ20051273
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center