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- Title
Amino acid transport of y<sup>+</sup>L-type by heterodimers of 4F2hc/CD98 and members of the glycoprotein-associated amino acid transporter family.
- Authors
Pfeiffer, Rahel; Rossier, Grégoire; Spindler, Benjamin; Meier, Christian; Kühn, Lukas; Verrey, François
- Abstract
Amino acid transport across cellular membranes is mediated by multiple transporters with overlapping specificities. We recently have identified the vertebrate proteins which mediate Na+ -independent exchange of large neutral amino acids corresponding to transport system L. This transporter consists of a novel amino acid permease-related protein (LAT1 or AmAT-L-lc) which for surface expression and function requires formation of disulfide-linked heterodimers with the glycosylated heavy chain of the h4F2/CD98 surface antigen. We show that h4F2hc also associates with other mammalian light chains, e.g. y+ LAT1 from mouse and human which are ∼48% identical with LAT1 and thus belong to the same family of glycoprotein-associated amino acid transporters. The novel heterodimers form exchangers which mediate the cellular efflux of cationic amino acids and the Na+- dependent uptake of large neutral amino acids. These transport characteristics and kinetic and pharmaco- logical fingerprints identify them as y+ L-type transport systems. The mRNA encoding my+ LAT1 is detectable in most adult tissues and expressed at high levels in kidney cortex and intestine. This suggests that the y+ LAT14F2hc heterodimer, besides participating in amino acid uptake/secretion in many cell types, is the basolateral amino acid exchanger involved in trans- epithelial reabsorption of cationic amino acids; hence, its defect might be the cause of the human genetic disease lysinuric protein intolerance.
- Publication
EMBO Journal, 1999, Vol 18, Issue 1, p49
- ISSN
0261-4189
- Publication type
Academic Journal
- DOI
10.1093/emboj/18.1.49