Premium
Role of rBAT Gene Products in Cystinuria
Author(s) -
Miyamoto Ken–ichi,
Katai Kanako,
Tatsumi Sawako,
Sone Kanako,
Segawa Hiroko,
Takada Kazumi,
Yamamoto Hironori,
Taketani Yutaka,
Morita Kyoko,
Kanayama Hiroomi,
Kagawa Susumu,
Takeda Eiji
Publication year - 1996
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1111/j.1442-2042.1996.tb00354.x
Subject(s) - arginine , mutant , amino acid , biochemistry , leucine , cystine , cystinuria , biology , microbiology and biotechnology , gene , cysteine , enzyme
To investigate whether rBAT gene products function as a crystine transporter component or as a transport activator, we microinjected several C–terminal deletion mutants of rBAT cRNA into Xenopus oocytes, and measured transport activity for arginine, leucine and cystine in the presence and absence of sodium. Wild type rBAT significantly stimulated the uptake of all 3 amino acids 10–20 fold compared to control mutants. On the other hand, no mutant, except a Δ511–685 mutant, stimulated the uptake of these amino acids. However, the Δ511–685 mutant significantly increased the uptake of arginine. In the presence of sodium, the Δ511–685 mutant also increased the uptake of leucine. The Δ511–685 mutant did not stimulate crystine uptake in the presence and absence of sodium. Furthermore, inhibition of L–arginine uptake by L–homoserine was seen only in the presence of sodium. These results suggest that mutant rBAT stimulates the endogenous amino acid transport system y + in oocytes. Finally, rBAT gene products, as the primary cause of cystinuria, may function as activators of the amino acid transport system in renal brush border membrane.