Cystinuria calls for heteromultimeric amino acid transporters.
The proteins rBAT (related to bo,+ amino acid transporter) and 4F2hc (the heavy chain of the surface antigen 4F2) are homologous proteins that induce amino acid transport in Xenopus oocytes. The role of rBAT in amino acid transport is substantiated by the fact that mutations in the gene encoding it cause cystinuria, a heritable disease characterised by high concentrations of cystine in the urine. Structural and functional evidence supports the hypothesis that both rBAT and 4F2hc proteins form part of heterodimeric amino acid transporters. There is new evidence that the functional unit of system y+L amino acid transporter is a disulfide bridge-dependent complex of 4F2hc with a Xenopus oocyte plasma membrane protein.
Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Spain. mpalacin@porthos.bio.ub.es
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Palacín
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Estévez
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Zorzano
D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D003555:Cystinuria / Q000378:metabolism*; D019281:Dimerization; D027261:Fusion Regulatory Protein-1; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009865:Oocytes
D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; D015703:Antigens, CD; D002352:Carrier Proteins; D027261:Fusion Regulatory Protein-1; D008562:Membrane Glycoproteins; C499489:SLC7A9 protein, human