TABLE 2.
l-[3H]alanine uptake mediated by wild-type and mutant ASCT1 and ASCT2 transporters
| Expt | Exogenous receptor assayeda | l-[3H]alanine uptake (nmol/min/mg of protein)a |
|---|---|---|
| 1b | pcDNA3.1 | 25.9 ± 8.9 |
| mASCT2 | 56.3 ± 6.5 | |
| mASCT2.N167H | 42.9 ± 8.9 | |
| mASCT2.N230H | 41.2 ± 4.5 | |
| mASCT2.N167H-N230H | 39.6 ± 7.8 | |
| 2 | pcDNA3.1 | 13.8 ± 2.4 |
| hASCT1 | 20.3 ± 4.6 | |
| mASCT1 | 21.1 ± 0.8 | |
| hASCT2 | 22.1 ± 2.9 | |
| mASCT2 | 24.0 ± 1.8 |
a
The initial rates of l-[3H]alanine transport were measured in HEK293T cells transiently transfected with either the empty vector (pcDNA3.1) or the receptor expression vectors. Uptake of l-[3H]alanine was measured for 1 min at 37°C in medium containing sodium. The data are presented as mean uptake ± standard deviation of quadriplicate measurements.
b
In experiment 1, the wild-type and mutant mASCT2 proteins were myc tagged.