Further, nuclear localization of Itk and TCR-CD3-mediated IL-2 production were significantly down-regulated following expression of the Rch1alpha-P242A mutant, implicating a role for Rch1alpha in the nuclear translocation of Itk..     ///    "TCR-CD3 stimulation of Jurkat T cells resulted in increased Itk/Rch1alpha complex formation, recruitment of karyopherin beta to the protein complex and Rch1alpha tyrosine phosphorylation. "    ///    We observed constitutive nuclear localization of Itk that was up-regulated following either TCR-CD3 stimulation or over-expression of wild-type Rch1alpha in T cells. 