Type II phosphatidylinositol 4-kinase β associates with TCR-CD3 ζ chain in Jurkat cells

Phosphatidylinositol lipid signaling cascades are integral part of TCR-CD3 signaling. The mechanisms by which phosphatidylinositol kinases are coupled to TCR-CD3 complex remain elusive. Here we report an association of type II PtdIns 4-kinase with TCR-CD3 ζ chain upon cross-linking. Mapping studies have revealed that the C-terminal ITAM is critical for docking of the enzyme on the ζ chain. The association is shown to be tyrosyl phosphorylation dependent as mutation of Y-151 and Y-142 on the C-terminal ITAM disrupts interaction of the two proteins. Identification of the associated type II PtdIns 4-kinase revealed that the β isoform of the enzyme interacts with the ζ chain in vivo.