Loss of Puma protects mast cells from apoptosis induced by cytokine deprivation more potently than loss of Bim. Wt, Bim^−/−, Puma^−/− or Bim^−/−/Puma^−/− MLMCs and CTLMCs were deprived of cytokines, and cell viability was measured by staining with PI plus annexin V-FITC at 24 hours. N = 3-6 and results are presented as mean (± SD).