Different proteins are phosphorylated under acidic environments in Jurkat cells.

In order to test the ability of immune cells to grow under acidic conditions, Jurkat cells were cultured in medium at pH 6.3. At this acidic pH, the cells required approximately 2 days per generation, while the generation time was approximately 1 day for cells grown in near neutral medium. Western blot analysis using anti-phosphotyrosine antibody (4G10) showed that protein phosphorylation was affected by external pH. For example, the level of a 66-kDa phosphoprotein increased dramatically in acidic medium, whereas the amount of a 34-kDa phosphoprotein decreased. These results suggest that Jurkat cells use different signal pathways under acidic environments.