“…In a previous paper, we have shown that CD38 ligation 1 The abbreviations used are: mAb, monoclonal antibody; TCR, T cell antigen receptor; PLC-␥1, phospholipase C-␥1; ZAP-70, -associated protein-70; MAP, mitogen-activated protein; Erk, extracellular signalregulated protein kinase; MEK, MAP kinase or Erk kinase, also known as MAP kinase kinase; PTK, protein-tyrosine kinase; ITAM, immunoreceptor tyrosine-based activation motif; JK, Jurkat; PAGE, polyacrylamide gel electrophoresis; PVDF, polyvinylidene difluoride; ECL, enhanced chemiluminescence; HRP, horseradish peroxidase; PdBu, 4␣results in activation of at least two PTK-controlled signaling pathways, the CD3-/ZAP-70/PLC-␥1-dependent cascade and the Raf-1/MAP kinase pathway, suggesting a functional relationship between signals delivered through CD38 and the TCR (21). This assumption was strengthened by our finding that, in Jurkat T cells, CD38-mediated signaling events as increases in [Ca 2ϩ ] i or CD69 expression require the presence of the TCR/ CD3 (22).…”