Linking TCR to Adhesion

Science's STKE  20 Mar 2001:
Vol. 2001, Issue 74, pp. tw6
DOI: 10.1126/stke.2001.74.tw6

Woods et al. report that the Tec family tyrosine kinase Itk is recruited to detergent insoluble membranes and phosphorylated upon TCR stimulation. This recruitment requires the kinase domain and plekstrin homology domains of Itk and is dependent of the activity of phosphatidylinositol 3-kinase (PI3K). To monitor β1 integrin function, the authors assayed adherence of Jurkat cells or human T cells stimulated with phytohemagglutinin to a fibronectin substrate. Enhanced binding of the cells was observed only during conditions in which an active form of Itk was recruited to the membrane and in which the tyrosine kinase Lck was activated. Integrin activation was inhibited by transfection of Jurkat cells or human T cells blasts with dominant negative forms of Itk. Thus, Itk appears to link TCR activation with the integrin-mediated signaling pathways controlling cell adhesion.

M. L. Woods, W. J. Kivens, M. A. Adelsman, Y. Qui, A. August, Y. Shimizu, A novel function for the Tec family tyrosine kinase Itk in activation of β1 integrins by the T-cell receptor. EMBO J. 20, 1232-1244 (2001). [Abstract] [Full Text]