PTPA and systemic lupus erythematosus: Additionally, the increase in intracellular serine/threonine protein phosphatase 2A (PP2A) activity in lupus T cells contributes to aberrant TCR signaling due to the utilization of the FcεRIγ chain instead of the native CD3ζ chain via Elf-1 dephosphorylation [27,28], diverting to another re-wiring mechanism that triggers higher calcium influx into lupus T cells, which activates cytoplasmic calcineurin.