DPP-2

DPP-2, also called DPP7 or quiescent cell proline dipeptidase, is an intracellular serine protease isolated from CD26- Jurkat T cells after inhibitors of post-proline cleaving aminodipeptidases caused apoptosis in quiescent lymphocytes independent of CD26/DPPIV[1]. Mechanistically, DPP-2 cleaves N-terminal X-Pro dipeptides, and this cleavage can alter chemokines including RANTES, stroma-derived factor-1, and macrophage-derived chemokine[2]. DPP-2 supports cell-cycle quiescence because it is essential for maintaining lymphocytes and fibroblasts in G0, and its inhibition induces apoptosis through c-Myc and p53[3]. In chronic lymphocytic leukemia, DPP-2 inhibition-induced apoptosis identifies B-cell activation stage and predicts prognosis[4]. Compared with DPPIV/CD26, DPP-2 has similar substrate specificity but localizes to intracellular vesicles rather than the cell surface[2]. Compared with DPP-IV and DPP-VII, biochemical profiling defined distinct catalytic and inhibition properties among proline-specific dipeptidyl peptidases[5]. For experimental applications, a cell-permeable azabicyclo[3.3.0]octane-based DPP-2 inhibitor showed potency, selectivity, and quiescent lymphocyte death similar to less selective inhibitors[6].