Src Kinase,but Not the Src Kinase Family Member p56 lck,Mediates Stromal Cell-Derived Factor 1α/CXCL12-Induced Chemotaxis of a T Cell Line

Abstract

Stromal cell-derived factor 1 (SDF-1/CXCL12) is believed to mediate migration of leukocytes. To explore potential mechanisms, we evaluated the signal transduction pathways activated by SDF-1 in the Jurkat T cell line. Src kinase was phosphorylated and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) activated in a time-related fashion after SDF-1 stimulation. Chemotaxis of Jurkat cells was partially blocked by pretreatment with the src kinase inhibitor PP2 in a dose-dependent manner. Wiskott-Aldrich Syndrome Protein (WASP) regulates actin polymerization and cytoskeletal organization in T cells. We found WASP complexed to activated src after SDF-1 stimulation, suggesting a possible interacting role for src kinase and WASP in mediating SDF-1 action. J.CaM1.6 cells, which have lost expression of the src kinase p56^lck (lck), responded to chemotaxis induced by SDF-1 as well as the parental Jurkat cells. Because J.CaM1.6 cells respond as well as the parental cells to SDF-1 in terms of ERK activation and tyrosine phosphorylation of WASP after SDF-1 stimulation, it appears that src kinase, but not the src kinase family member lck, mediates chemotaxis of Jurkat cells in response to SDF-1 induction and that src kinase may link with WASP in this effect.