Abstract
Chemokine signaling is critical for T cell function during homeostasis and inflammation and directs T cell polarity and migration through the activation of specific intracellular pathways. Here, we uncovered a previously uncharacterized role for the Abl family tyrosine kinases Abl and Arg in the regulation of T cell-dependent inflammatory responses and showed that the Abl family kinases were required for chemokine-induced T cell polarization and migration. Our data demonstrated that Abl and Arg were activated downstream of chemokine receptors and mediated the chemokine-induced tyrosine phosphorylation of human enhancer of filamentation 1 (HEF1), an adaptor protein that is required for the activity of the guanosine triphosphatase Rap1, which mediates cell adhesion and migration. Phosphorylation of HEF1 by Abl family kinases and activation of Rap1 were required for chemokine-induced T cell migration. Mouse T cells that lacked Abl and Arg exhibited defective homing to lymph nodes and impaired migration to sites of inflammation. These findings suggest that Abl family kinases are potential therapeutic targets for the treatment of T cell-dependent immune disorders that are characterized by chemokine-mediated inflammation.