Updated project metadata. Whole proteome and phosphoproteome analysis of T-cells isolated from PTPN2 wild-type and knock-out micestrongly linked amplified T cell numbers to increased proliferation mediated by transcriptional activation of the signal transducer and activator of transcription (STAT) protein family. Subsequent analysis confirmed improved proliferation and survival but not an increase in initial engraftment to be the cause of higher T cell numbers upon adoptive transfer.