Death-associated protein kinase increases glycolytic rate through binding and activation of pyruvate kinase

Abstract

Death-associated protein kinase (DAPk), a multi-domain serine/threonine kinase, regulates numerous cell death mechanisms and harbors tumor suppressor functions. In this study, we report that DAPk directly binds and functionally activates pyruvate kinase M2 (PKM2), a key glycolytic enzyme, which contributes to the regulation of cancer cell metabolism. PKM2 was identified as a novel binding partner of DAPk by a yeast two-hybrid screen. This interaction was validated in vitro by enzyme-linked immunosorbent assay using purified proteins and in vivo by co-immunoprecipitation of the two endogenous proteins from cells. In vitro interaction with full-length DAPk resulted in a significant increase in the activity of PKM2. Conversely, a fragment of DAPk harboring only the functional kinase domain (KD) could neither bind PKM2 in cells nor activate it in vitro. Indeed, DAPk failed to phosphorylate PKM2. Notably, transfection of cells, with a truncated DAPk lacking the KD, elevated endogenous PKM2 activity, suggesting that PKM2 activation by DAPk occurs independently of its kinase activity. DAPk-transfected cells displayed changes in glycolytic activity, as reflected by elevated lactate production, whereas glucose uptake remained unaltered. A mild reduction in cell proliferation was detected as well in these transfected cells. Altogether, this work identifies a new role for DAPk as a metabolic regulator, suggesting the concept of direct interactions between a tumor suppressor and a key glycolytic enzyme to limit cell growth. Moreover, the work documents a unique function of DAPk that is independent of its catalytic activity and a novel mechanism to activate PKM2 by protein-protein interaction.

Regulation of the Death-Associated Protein Kinase 1 Expression and Autophagy via ATF6 Requires Apoptosis Signal-Regulating Kinase 1

“…For example, DAPK1 recently has been reported to phosphorylate Beclin-1, a central player in autophagy and tumor suppression (23). DAPK1 activity also was implicated in the regulation of the pyruvate kinase M2, which is involved in driving the Warburg effect (24). Thus, dysfunction of DAPK1 or its expression may affect multiple cellular processes.…”

Emerging roles of PKM2 in cell metabolism and cancer progression

“…Mucin 1 and death-associated protein kinase bind to PKM2 and increase its catalytic activity, which leads to enhanced glycolysis in cancer cells [39, 40]. In contrast, the promyelocytic leukemia (PML) tumor suppressor protein reduces PKM2 activity [41].…”

Cancer metabolism meets systems biology: Pyruvate kinase isoform PKM2 is a metabolic master regulator

“…Death-associated protein kinase directly binds, phosphorylates and activates PKM2. [33] EGFR-activated extracellular signal-regulated kinase 2 (ERK2) binds PKM2 and phosphorylates PKM2. [10] While both phosphorylation events up-regulate glycolysis, the mechanism of regulation is different.…”