Phospholipase C - T 1 Association with CD 3 Structure in T Cells

Recently, we and others have reported tyrosine phosphorylation of phospholipase C-3'1 (PLC3,1) enzyme after CD3 activation ofT cells, and have proposed that PLC'yl mediates signal transduction through the T cell receptor (TCR/CD3). Here, using immunoblotting and immune complex PLC assays, we show that CD3 stimulation of Jurkat cells induces the association of PLC3,1 enzyme with CD3 complex. PLC activity is also found to co-precipitate with the CD3~" chain from activated cells. In addition, in vitro PLC assays show that CD3 activation leads to about 10-fold stimulation of PLC't'I activity. These results, along with the observation that Jurkat cells preferentially express PLC3'I, indicate that PLC3,1 participates in CD3 signaling.