RNAseq of Pim1/Pim2 double knockout vs wild-type CD8+ T cells expanded in IL2 or IL15

T cell antigen-receptor (TCR) and cytokine receptor engagement trigger large changes in Serine/Threonine kinase signalling networks to drive T cell activation and differentiation. The role of only few kinase signalling pathways have been studied in detail, and in this context, Pim kinases are an interesting, yet understudied, family of Serine/Threonine kinases, with reported roles in key processes including survival, proliferation, metabolism across a range of cell types. T lymphocytes predominantly express PIM1 and PIM2, which are rapidly induced by TCR, costimulation and cytokine signalling. Using high-resolution mass spectrometry and RNAseq we systematically examine the impact of Pim1/Pim2 double deficiency on in vitro differentiated cytotoxic T lymphocytes (CTL) expanded in the cytokines IL-2 and IL-15 to generate effector or memory T cells respectively. We find that Pim kinases are dispensable for IL-15-driven memory cell differentiation, but that Pim1/2-deficiency has a selective impact on the transcriptome and proteome of IL-2 driven effector CD8 T cells. ~75% of Pim kinase-regulated proteins were not predicted by differences in mRNA in IL-2 expanded CTL. These included proteins that are key for effector cell function: glucose transporters Slc2a1 and Slc2a3 and key effector molecules Granzyme A and B. We find that Pim kinases have this effect via control of protein translation. Another key finding was that the mRNA for key T cell homing receptors Ccr7, S1pr1 and CD62L was increased in Pim1/2-deficienct T cells and that this functionally enhancing homing to secondary lymphoid organs.