title: Nonspecific DNA Binding of cGAS N Terminus Promotes cGAS Activation.
abstract: The cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) mediates innate immune responses against invading pathogens, or against self-dsDNA, which causes autoimmune disorders. Upon nonspecific binding of cytosolic B-form DNA, cGAS synthesizes the second messenger 2'3'-cGAMP and triggers STING-dependent signaling to produce type I IFNs. The cGAS comprises less-conserved N-terminal residues and highly conserved nucleotidyltransferase/Mab21 domains. The function and structure of the well-conserved domains have been extensively studied, whereas the physiological function of the N-terminal domain of cGAS is largely uncharacterized. In this study we used a single-molecule technique combined with traditional biochemical and cellular assays to demonstrate that binding of nonspecific dsDNA by the N-terminal domain of cGAS promotes its activation. We have observed that the N terminus of human cGAS (hcGAS-N160) undergoes secondary structural change upon dsDNA binding in solution. Furthermore, we showed that thehcGAS-N160 helps full lengthhcGAS to expand the binding range on λDNA and facilitates its binding efficiency to dsDNA compared withhcGAS without the 160 N-terminal residues (hcGAS-d160). More importantly,hcGAS-N160 endows full lengthhcGAS relatively higher enzyme activity and stronger activation of STING/IRF3-mediated cytosolic DNA signaling. These findings strongly indicate that the N-terminal domain of cGAS plays an important role in enhancing its function.
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing 100871, China.|Peking-Tsinghua Center for Life Sciences, Beijing 100871, China; and.
authors.forename: Jianli
authors.identifier: 0000-0003-0100-1489
authors.initials: J
authors.lastname: Tao
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Jianshi
authors.identifier: 0000-0003-4697-8760
authors.initials: J
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Du
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Lian
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing 100871, China.|Peking-Tsinghua Center for Life Sciences, Beijing 100871, China; and.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China.|Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing 100871, China.|Peking-Tsinghua Center for Life Sciences, Beijing 100871, China; and.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; xdsu@pku.edu.cn jiangzf@pku.edu.cn.|Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking University, Beijing 100871, China.|Peking-Tsinghua Center for Life Sciences, Beijing 100871, China; and.
authors.forename: Zhengfan
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; xdsu@pku.edu.cn jiangzf@pku.edu.cn.|Biodynamic Optical Imaging Center, School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Su
mesh_terms: D000494:Allosteric Regulation; D059371:DNA, B-Form / Q000378:metabolism*; D004789:Enzyme Activation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007113:Immunity, Innate; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism; D007370:Interferon Type I / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009713:Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D000072417:Protein Domains / Q000235:genetics; D015202:Protein Engineering; D015398:Signal Transduction; D000099197:STING Protein; D000099235:Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase
chemical_list: D059371:DNA, B-Form; D050838:Interferon Regulatory Factor-3; D007370:Interferon Type I; D008565:Membrane Proteins; D009713:Nucleotidyltransferases; C494232:IRF3 protein, human; C532857:STING1 protein, human; D000099197:STING Protein; C578390:cGAS protein, human; D000099235:Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase