Figure 9. Attenuation of serine-induced macropinocytosis by SLC38A5 knockdown.

SLC38A5 was silenced in MB231 cells with two different shRNAs. The experiments were done with stable cell clones: control (empty vector) and two shRNA clones. (A) Macropinocytosis was monitored with TMR-dextran in three different buffers (pH 7.5): NaCl, NaCl plus serine (1 mM), and NMDG (Na⁺-free) plus serine (1 mM). The fluorescent signals were quantified. *, P < 0.05; NS, not significant. (B) SLC38A5-specific macropinocytosis activity was calculated by subtracting the signals in NaCl from the signals in NaCl plus serine. *, P < 0.05; NS, not significant.