title: Metabolic sensor AMPK directly phosphorylates RAG1 protein and regulates V(D)J recombination.
abstract: The ability to sense metabolic stress is critical for successful cellular adaptation. In eukaryotes, the AMP-activated protein kinase (AMPK), a highly conserved serine/threonine kinase, functions as a critical metabolic sensor. AMPK is activated by the rising ADP/ATP and AMP/ATP ratios during conditions of energy depletion and also by increasing intracellular Ca(2+). In response to metabolic stress, AMPK maintains energy homeostasis by phosphorylating and regulating proteins that are involved in many physiological processes including glucose and fatty acid metabolism, transcription, cell growth, mitochondrial biogenesis, and autophagy. Evidence is mounting that AMPK also plays a role in a number of pathways unrelated to energy metabolism. Here, we identify the recombination-activating gene 1 protein (RAG1) as a substrate of AMPK. The RAG1/RAG2 complex is a lymphoid-specific endonuclease that catalyzes specific DNA cleavage during V(D)J recombination, which is required for the assembly of the Ig and T-cell receptor genes of the immune system. AMPK directly phosphorylates RAG1 at serine 528, and the phosphorylation enhances the catalytic activity of the RAG complex, resulting in increased cleavage of oligonucleotide substrates in vitro, or increased recombination of an extrachromosomal substrate in a cellular assay. Our results suggest that V(D)J recombination can be regulated by AMPK activation, providing a potential new link between metabolic stress and development of B and T lymphocytes.
authors.affiliation: Laboratory of Obesity and Aging Research, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Jee-Hyun
authors.initials: JH
authors.lastname: Um
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Brown
authors.forename: Samarendra K
authors.initials: SK
authors.lastname: Singh
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Marjan
authors.initials: M
authors.lastname: Gucek
authors.forename: Baeck-Seung
authors.initials: BS
authors.lastname: Lee
authors.forename: Megan A
authors.initials: MA
authors.lastname: Luckey
authors.forename: Myung K
authors.initials: MK
authors.lastname: Kim
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Barry P
authors.initials: BP
authors.lastname: Sleckman
authors.forename: Martin
authors.initials: M
authors.lastname: Gellert
authors.forename: Jay H
authors.initials: JH
authors.lastname: Chung
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D060152:V(D)J Recombination
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D009841:Oligonucleotides; C499311:RAG2 protein, human; C064658:RAG-1 protein; D012694:Serine; D055372:AMP-Activated Protein Kinases
keywords: energy coupling; immune diversity