L-Glutamate in the extracellular space regulates endogenous D-aspartate homeostasis in rat pheochromocytoma MPT1 cells.
Arch Biochem Biophys
; 424(1): 89-96, 2004 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-15019840
ABSTRACT
In previous studies [FEBS Lett. 434 (1998) 231, Arch. Biochem. Biophys. 404 (2002) 92], we demonstrated for the first time that D-aspartate (D-Asp) is synthesized in cultured mammalian cell lines, such as pheochromocytoma 12 (PC12) and its subclone, MPT1. Our current focus is analysis of the dynamics of D-Asp homeostasis in these cells. In this communication, we show that L-glutamate (Glu) and L-Glu transporter substrates in the extracellular space regulate the homeostasis of endogenous D-Asp in MPT1 cells. D-Asp is apparently in dynamic homeostasis, whereby endogenous D-Asp is constantly released into the extracellular space by an undefined mechanism, and continuously and intensively taken up into cells by an L-Glu transporter. Under these conditions, L-Glu and its transporter substrates in the medium may competitively inhibit the uptake of D-Asp via the transporter, resulting in accumulation of the amino acid in the extracellular space. We additionally demonstrate that DL-TBOA, a well-established L-Glu transporter inhibitor, is taken up by the transporter during long time intervals, but not on a short time-scale.
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Base de dados:
MEDLINE
Assunto principal:
Ácido Aspártico
/
Ácido Glutâmico
/
Cisteína
Limite:
Animals
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article