ATM signals to TSC2 in the cytoplasm to regulate mTORC1 in response to ROS.
Ataxia-telangiectasia mutated (ATM) is a cellular damage sensor that coordinates the cell cycle with damage-response checkpoints and DNA repair to preserve genomic integrity. However, ATM also has been implicated in metabolic regulation, and ATM deficiency is associated with elevated reactive oxygen species (ROS). ROS has a central role in many physiological and pathophysiological processes including inflammation and chronic diseases such as atherosclerosis and cancer, underscoring the importance of cellular pathways involved in redox homeostasis. We have identified a cytoplasmic function for ATM that participates in the cellular damage response to ROS. We show that in response to elevated ROS, ATM activates the TSC2 tumor suppressor via the LKB1/AMPK metabolic pathway in the cytoplasm to repress mTORC1 and induce autophagy. Importantly, elevated ROS and dysregulation of mTORC1 in ATM-deficient cells is inhibited by rapamycin, which also rescues lymphomagenesis in Atm-deficient mice. Our results identify a cytoplasmic pathway for ROS-induced ATM activation of TSC2 to regulate mTORC1 signaling and autophagy, identifying an integration node for the cellular damage response with key pathways involved in metabolism, protein synthesis, and cell survival.
Alexander
Angela
A
Department of Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA.
Cai
Sheng-Li
SL
Kim
Jinhee
J
Nanez
Adrian
A
Sahin
Mustafa
M
MacLean
Kirsteen H
KH
Inoki
Ken
K
Guan
Kun-Liang
KL
Shen
Jianjun
J
Person
Maria D
MD
Kusewitt
Donna
D
Mills
Gordon B
GB
Kastan
Michael B
MB
Walker
Cheryl Lyn
CL
D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D008822:Mice, Transgenic; D046912:Multiprotein Complexes; D018384:Oxidative Stress; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011506:Proteins; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases; D014157:Transcription Factors / Q000378:metabolism*; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D011506:Proteins; D017382:Reactive Oxygen Species; C000624653:TSC2 protein, human; D014157:Transcription Factors; C000624654:Tsc2 protein, mouse; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D000076222:Mechanistic Target of Rapamycin Complex 1; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases; D000263:Adenylate Kinase