SYK and systemic lupus erythematosus: The increased PP2A level regulates various signaling pathways that play essential roles in the pathogenesis of SLE.9 In SLE, PP2A was shown to dephosphorylate Elf-1 at Thr231 and to regulate the expression of CD3ζ and FcRγ in SLE.127 T cells have an FcRγ-phosphorylated spleen tyrosine kinase (pSyk) pathway that enhances the activity of the early CD3/TCR signaling pathway.128 Consistent with this, Syk positively regulated the expression of PP2A in T cells from patients with SLE.129