Abstract:Activation of T cells through the T cell antigen receptor (TCR) is essential for thymocyte development, T cells differentiation and the effector function of T cell. TCR associates with the MHC-peptide complex on the surface of antigen presenting cells, and transfer the signals into T cells, which includes the activation of proximal tyrosine kinases, the assembly of signaling complexes, and the induction of downstream MAPK, PKC and calcium signaling pathways. These signals activate transcription factors such as NFAT, NF-κB and AP-1, which induce the expression of important cytokines and proteins, essential for the activation of T cells. TCR signaling pathway is deliberately regulated by a complicated network which consist a spectrum of regulatory molecules. In this review,we focus on the latest research progresses in the regulation of TCR signaling and different cellular effector function mediated by this signaling pathway.