Fig 4. Inhibition by amino acids of [³H]L-serine transport into HEK cells expressing human ASCT1 and human ASCT2.

Transport was conducted as described in Materials and Methods. (A,C) Inhibition of [³H]L-serine transport by amino acids in HEK cells expressing human ASCT1; (B,D) Inhibition of [³H]L-serine transport by amino acids in HEK cells expressing human ASCT2. Values are percent control and are from a single experiment that was repeated 2–5 times. Curves were fitted using GraphPad Prism (see Table 5 for mean IC₅₀ values) with a one-site fit.