Calcium transport is critical for the activation of transcription pathways that drive T cell proliferation and function. On page 651, Feske and colleagues show that Ca2+ release–activated Ca2+ (CRAC) channels in the plasma membrane are the major, if not only, pathway for T cell receptor–activated calcium influx in T cells. The mechanism of activation and identity of these CRAC channels continues to elude researchers.
The authors analyzed channels in T cells from patients with a form of severe congenital immunodeficiency (SCID) that is characterized by impaired T cell activation and a near total lack of calcium influx. Using electrophysiological techniques, they showed that the lack of calcium influx was due to a complete failure of CRAC channel opening, and not a consequence of dysregulated intracellular calcium stores or aberrant expression of other suspected ion channels. The authors believe that the CRAC channels...
