Zap70 controls the interaction of talin with integrin to regulate the chemotactic directionality of T-cell migration

Aberrant lymphocyte infiltration is crucial for many disorders such as tumor immune escape and autoimmunity. In this study, we have investigated T-cell migration in a three-dimensional collagen matrix containing tumor spheroids and by using micro-Slide chemotaxis and found that Zap70 regulates directionality during cell chemotaxis. Jurkat cells actively migrated toward SDF-1, nutrition, and spheroids of MCF-7 breast carcinoma cells embedded in collagen matrix. Inhibition of Zap70 activity impaired transmigration and mu-Slide chemotaxis but not the random movement of T cells in the collagen/fibronectin matrix. P116 cells, a Zap70 deficient variant of Jurkat, showed active random movement but failed to migrate against chemoattractants. P116 cells exhibited a reduced polarization of cell morphology, showing less lamellipodia formation accompanied with a fast pseudopod turnover rate. Instead of direct interacting with F-actin, Zap70 formed a complex with talin which is an integrin scaffold for F-actin. SDF-1 enhanced Zap70 phosphorylation and also stimulated binding of talin and beta1 integrin activation. P116 cells showed reduced complex of talin and beta1 integrin in parallel with impaired integrin activation. Collectively, Zap70 modulates integrin activation by interacting with talin, which contributes to directionality of T-cell migration, severing as a potential target for anti-inflammation therapy.