PIM1 and mantle cell lymphoma: On the other hand, PIM1 kinase is known to interact with the ribosomal protein RPS19, one of the KPT-185 targeted ribosomal proteins in MCL cells (Table 2), and depletion of RPS19 causes proteasomal degradation of PIM1 [39] and p27KIP stabilization, thus causing a block in cell-cycle progression regardless of p53 status [39].