Figure 2.

Simplified view of  TCR signaling in T cells. After TCR stimulation, several pathways are initiated which ultimately result in T cell activation, proliferation and expression of cytokines such as IL-2 and IFN-γ. The main transcription factors involved are AP-1, NFAT, and NF-κB. AP-1 is activated by a MAPK cascade. NF-κB is activated by PKCθ-dependent activation of the IKK complex and subsequent IκB degradation, and Ca²⁺ also contributes to NF-κB activation. NFAT is activated by Ca²⁺ influx which activates the NFAT-dephosphorylating phosphatase calcineurin. Only the major pathways are displayed here and represent a simplified view of TCR signaling. Details are described in the text.