Abstract
The recent cloning of ATA2, a cDNA displaying characteristics identical to the System A transporter, has provided the first molecular tool for study of System A-mediated amino acid transport in liver. Despite the 233 ± 9 and 472 ± 11% increase in System A transport activity following partial hepatectomy at 6 and 12 h, respectively, the steady-state level of ATA2 mRNA did not show a corresponding marked increase. Examination of the kinetic properties of System A following partial hepatectomy revealed a K(m) of 0.26 ± 0.04 mM which is consistent with the reported K(m) for ATA2. These results indicate that a System A transporter present in regenerating liver and ATA2 are identical, but that the increase in System A activity following partial hepatectomy does not result from an increase in steady-state levels of ATA2 mRNA. These observations suggest that ATA2-mediated transport of amino acids is regulated at the posttranscriptional level. (C) 2000 Academic Press.
Original language | English (US) |
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Pages (from-to) | 729-732 |
Number of pages | 4 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 278 |
Issue number | 3 |
DOIs | |
State | Published - Nov 30 2000 |
Keywords
- ATA2
- Amino acid transport
- Liver regeneration
- Partial hepatectomy
- SA1
- System A
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology