Tec kinase stimulates cell survival in transfected Hek293T cells and is regulated by the anti-apoptotic growth factor IGF-I in human neutrophils

ObjectivePreviously, we showed that the phosphatidylinositol-3 kinase (PI3K) pathway mediates the anti-apoptotic effects of IGF-I in human neutrophils independently of its down-stream target Akt. In this study, we investigated whether IGF-I regulates Tec kinase, an alternative down-stream target of PI3K, in neutrophils and whether this molecule is able to affect apoptosis.DesignWe investigated the translocation of Tec kinases in neutrophils after stimulation with IGF-I. Furthermore, we transiently and stably transfected Hek293T cells with constructs expressing different forms of Tec kinase and measured the level of cell survival and apoptosis/necrosis through trypan blue exclusion test and Annexin-V/propidium iodide labelling, respectively.ResultsWe show that IGF-I stimulates the translocation of Tec kinase to the membrane in neutrophils in a PI3K dependent matter. Overexpression of Tec kinase augments cell survival by inhibition of necrosis. The pro-survival effect is attenuated by the deletion of the kinase domain but not by inactivation of this domain by a single amino acid substitution.ConclusionTec kinase can act as a prosurvival factor and is regulated by IGF-I in human neutrophils through PI3K activation.

► We show that IGF-I translocate Tec kinase to the membrane in human neutrophils. ► The translocation of Tec kinase by IGF-I is PI3K dependent. ► Overexpression of Tec kinase in stably transfected Hek293T cells augments survival. ► The pro-survival effect is attenuated by the deletion of the kinase domain. ► We hypothesize that in Hek293T cells, Tec kinase functions as an adapter molecule.