DAPK2 regulates oxidative stress in cancer cells by preserving mitochondrial function.
Death-associated protein kinase (DAPK) 2 is a serine/threonine kinase that belongs to the DAPK family. Although it shows significant structural differences from DAPK1, the founding member of this protein family, DAPK2 is also thought to be a putative tumour suppressor. Like DAPK1, it has been implicated in programmed cell death, the regulation of autophagy and diverse developmental processes. In contrast to DAPK1, however, few mechanistic studies have been carried out on DAPK2 and the majority of these have made use of tagged DAPK2, which almost invariably leads to overexpression of the protein. As a consequence, physiological roles of this kinase are still poorly understood. Using two genetically distinct cancer cell lines as models, we have identified a new role for DAPK2 in the regulation of mitochondrial integrity. RNA interference-mediated depletion of DAPK2 leads to fundamental metabolic changes, including significantly decreased rate of oxidative phosphorylation in combination with overall destabilised mitochondrial membrane potential. This phenotype is further corroborated by an increase in the production of mitochondrial superoxide anions and increased oxidative stress. This then leads to the activation of classical stress-activated kinases such as ERK, JNK and p38, which is observed on DAPK2 genetic ablation. Interestingly, the generation of oxidative stress is further enhanced on overexpression of a kinase-dead DAPK2 mutant indicating that it is the kinase domain of DAPK2 that is important to maintain mitochondrial integrity and, by inference, for cellular metabolism.
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
C R
CR
Schlegel
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
M L
ML
Georgiou
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
M B
MB
Misterek
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
S
S
Stöcker
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
E R
ER
Chater
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
C E
CE
Munro
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
O E
OE
Pardo
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
M J
MJ
Seckl
Department of Surgery and Cancer, Imperial College London, Faculty of Medicine, Hammersmith Hospital Campus, ICTEM, Du Cane Road, London W12 0NN, UK.
A P
AP
Costa-Pereira
D045744:Cell Line, Tumor; D064550:Death-Associated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism*; D018384:Oxidative Stress / Q000235:genetics / Q000502:physiology; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism
D017382:Reactive Oxygen Species; D064550:Death-Associated Protein Kinases