T cells get energized

Many cell types use AMPK (AMP-activated protein kinase) to signal that energy reserves are low so more energy generation is needed. But, say Tamás et al. on page 1665, T cells also use AMPK to signal that energy will be needed in the near future, for attacking target cells, proliferating or churning out cytokines.

When cellular energy is in short supply—due, for example, to nutrient deficiency or metabolic stress—rising levels of AMP and falling levels of ATP trigger the activation of AMPK. AMPK then activates ATP-generating pathways, such as fatty acid oxidation. Tamás and colleagues now show that this pathway is also activated in T cells when their energy reserves dwindle. This is the first demonstration of physiological AMPK regulation in T cells.

But T cells turned on AMPK not...