TY - JOUR
T1 - Activation of ATM kinase by ROS generated during ionophore-induced mitophagy in human T and B cell malignancies
AU - Sarkar, Aloke
AU - Gandhi, Varsha
N1 - Funding Information:
We are thankful to Dr David Chen, UT Southwestern Medical Center, Dallas, TX, for providing us PcDNA-YFP-FLAG-WT and S1981A plasmids. FACS analysis was performed in the MD Anderson Cancer Center South Campus Flow Cytometry & Cell Sorting Core (supported by NCI Grant P30CA016672). We thank Stephanie Deming of Scientific Publications, Research Medical Library, MD Anderson Cancer Center, for editing the manuscript.
Funding Information:
This work was supported in part by a grant from the CLL Global Research Foundation (to V.G.) and by the NIH/NCI through MD Anderson’s Cancer Center Support Grant, CA016672. Acknowledgements
Funding Information:
We are thankful to Dr David Chen, UT Southwestern Medical Center, Dallas, TX, for providing us PcDNA-YFP-FLAG-WT and S1981A plasmids. FACS analysis was performed in the MD Anderson Cancer Center South Campus Flow Cytometry & Cell Sorting Core (supported by NCI Grant P30CA016672). We thank Stephanie Deming of Scientific Publications, Research Medical Library, MD Anderson Cancer Center, for editing the manuscript.
Publisher Copyright:
© 2020, Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2021/1
Y1 - 2021/1
N2 - Ataxia telangiectasia mutated (ATM), a critical DNA damage sensor, also possesses non-nuclear functions owing to its presence in extra-nuclear compartments, including peroxisomes, lysosomes, and mitochondria. ATM is frequently altered in several human cancers. Recently, we and others have shown that loss of ATM is associated with defective mitochondrial autophagy (mitophagy) in ataxia–telangiectasia (A–T) fibroblasts and B-cell lymphomas. Further, we reported that ATM protein but not ATM kinase activity is required for mitophagy. However, the mechanism of ATM kinase activation during ionophore-induced mitophagy is unknown. In the work reported here, using several ionophores in A–T and multiple T-cell and B-cell lymphoma cell lines, we show that ionophore-induced mitophagy triggers oxidative stress–induced ATMSer1981 phosphorylation through ROS activation, which is different from neocarzinostatin-induced activation of ATMSer1981, Smc1Ser966, and Kap1Ser824. We used A–T cells overexpressed with WT or S1981A (auto-phosphorylation dead) ATM plasmids and show that ATM is activated by ROS-induced oxidative stress emanating from ionophore-induced mitochondrial damage and mitophagy. The antioxidants N-acetylcysteine and glutathione significantly inhibited ROS production and ATMSer1981 phosphorylation but failed to inhibit mitophagy as determined by retroviral infection with mt-mKeima construct followed by lysosomal dual-excitation ratiometric pH measurements. Our data suggest that while ATM kinase does not participate in mitophagy, it is activated via elevated ROS.
AB - Ataxia telangiectasia mutated (ATM), a critical DNA damage sensor, also possesses non-nuclear functions owing to its presence in extra-nuclear compartments, including peroxisomes, lysosomes, and mitochondria. ATM is frequently altered in several human cancers. Recently, we and others have shown that loss of ATM is associated with defective mitochondrial autophagy (mitophagy) in ataxia–telangiectasia (A–T) fibroblasts and B-cell lymphomas. Further, we reported that ATM protein but not ATM kinase activity is required for mitophagy. However, the mechanism of ATM kinase activation during ionophore-induced mitophagy is unknown. In the work reported here, using several ionophores in A–T and multiple T-cell and B-cell lymphoma cell lines, we show that ionophore-induced mitophagy triggers oxidative stress–induced ATMSer1981 phosphorylation through ROS activation, which is different from neocarzinostatin-induced activation of ATMSer1981, Smc1Ser966, and Kap1Ser824. We used A–T cells overexpressed with WT or S1981A (auto-phosphorylation dead) ATM plasmids and show that ATM is activated by ROS-induced oxidative stress emanating from ionophore-induced mitochondrial damage and mitophagy. The antioxidants N-acetylcysteine and glutathione significantly inhibited ROS production and ATMSer1981 phosphorylation but failed to inhibit mitophagy as determined by retroviral infection with mt-mKeima construct followed by lysosomal dual-excitation ratiometric pH measurements. Our data suggest that while ATM kinase does not participate in mitophagy, it is activated via elevated ROS.
KW - ATM kinase
KW - Leukemia
KW - Lymphoma
KW - Mitophagy
KW - ROS
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U2 - 10.1007/s11010-020-03917-1
DO - 10.1007/s11010-020-03917-1
M3 - Article
C2 - 32996079
AN - SCOPUS:85091732766
SN - 0300-8177
VL - 476
SP - 417
EP - 423
JO - Molecular and Cellular Biochemistry
JF - Molecular and Cellular Biochemistry
IS - 1
ER -