• Authors: Shiloh, R., Gilad, Y., Ber, Y., Eisenstein, M., Aweida, D., Bialik, S., Cohen, S., Kimchi, A.
  • Year: 2018
  • Journal: Nat Commun 9 1759
  • Applications: in vitro / DNA / jetPEI, jetPRIME
  • Cell types:
    1. Name: A549
      Description: Human lung carcinoma cells, type II pneumocytes
      Known as: A-549
    2. Name: HCT 116
      Description: Human colon carcinoma cells
      Known as: HCT116


Autophagy is an intracellular degradation process essential for adaptation to metabolic stress. DAPK2 is a calmodulin-regulated protein kinase, which has been implicated in autophagy regulation, though the mechanism is unclear. Here, we show that the central metabolic sensor, AMPK, phosphorylates DAPK2 at a critical site in the protein structure, between the catalytic and the calmodulin-binding domains. This phosphorylation activates DAPK2 by functionally mimicking calmodulin binding and mitigating an inhibitory autophosphorylation, providing a novel, alternative mechanism for DAPK2 activation during metabolic stress. In addition, we show that DAPK2 phosphorylates the core autophagic machinery protein, Beclin-1, leading to dissociation of its inhibitor, Bcl-XL. Importantly, phosphorylation of DAPK2 by AMPK enhances DAPK2's ability to phosphorylate Beclin-1, and depletion of DAPK2 reduces autophagy in response to AMPK activation. Our study reveals a unique calmodulin-independent mechanism for DAPK2 activation, critical to its function as a novel downstream effector of AMPK in autophagy.

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