FIGURE 9.
Model of early signal transduction in T cells. Upon TCR stimulation, activated ZAP-70 directly phosphorylates of LAT tyrosine 191 and indirectly mediates the phosphorylation of LAT tyrosine 132 via a mechanism that occurs with slower kinetics than LAT tyrosine 191. Once phosphorylated, LAT associates with several proteins, including PLC-γ1 and the SLP-76-Vav-Itk complex. The recruitment of these proteins to LAT results in the phosphorylation of tyrosine 783 on PLC-γ1, leading to the activation of this protein.