Phospholipase C-γ1 association with CD3 structure in T cells

Recently, we and others have reported tyrosine phosphorylation of phospholipase C-γ1 (PUCγ1) enzyme after CD3 activation of T cells, and have proposed that PLCγ1 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 PLCγ1 enzyme with CD3 complex. PLC activity is also found to co-precipitate with the CD3ζ chain from activated cells. In addition, in vitro PLC assays show that CD3 activation leads to about 10-fold stimulation of PLCγ1 activity. These results, along with the observation that Jurkat cells preferentially express PLCγ1, indicate that PLCγ1 participates in CD3 signaling.