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Oligomeric structure of a renal cystine transporter: implications in cystinuria
Author(s) -
Wang Yan,
Tate Suresh S.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00685-3
Subject(s) - cystinuria , xenopus , cystine , brush border , amino acid , biochemistry , chemistry , cysteine , transporter , cotransporter , membrane , biology , microbiology and biotechnology , sodium , gene , enzyme , vesicle , organic chemistry
Homologous proteins (NBAT) which mediate sodium‐independent transport of neutral as well as basic amino acids and cystine when expressed in Xenopus oocytes were recently cloned from mammalian kidneys. Mutations in human NBAT have been implicated in cystinuria. Here, we show that rat kidney and jejunal brush border membrane NBAT (85 kDa) is found in association with a 50 kDa protein. The association involves one or more interprotein disulfide bonds. Rabbit kidney brush border membranes and membranes of NBAT cRNA‐injected Xenopus oocytes also contain such heterodimers. Our data suggest that the heterodimer is the minimal functional unit of NBAT‐mediated amino acid transport and that the NBAT‐associated 50 kDa protein could play a role in cystinuria.