title: Endoplasmic Reticulum Protein SCAP Inhibits Dengue Virus NS2B3 Protease by Suppressing Its K27-Linked Polyubiquitylation.
abstract: Dengue viruses (DENVs) are an emerging threat to global public health. The NS2B3 protease complex of DENV has recently been shown to cleave the antiviral protein STING and thereby subvert the innate immune signaling to facilitate virus replication. Whether host cells have a mechanism to counteract this virus-mediated immunosuppression is unclear. We discovered that the K27-linked polyubiquitination of NS3 protein facilitates its recruitment of NS2B, the formation of NS2B3, and consequently the enhanced cleavage of STING. However, an endoplasmic reticulum (ER) protein, SCAP, through binding to NS2B protein, inhibits the ubiquitination of NS3, rendering NS2B3 protease incapable of binding and cleaving STING. Importantly, ectopic expression of SCAP impaired DENV infection, whereas silencing of SCAP potentiated DENV infection. Collectively, this study uncovered a novel function of SCAP of counteracting the inhibitory action of DENV NS2B3 protease on STING signaling, suggesting that modulation of SCAP levels may have therapeutic implications.IMPORTANCEThis study reports the first ubiquitylation target protein in DENV, the NS3 protein, and the unique role of K27-linked polyubiquitylation in NS3's ability to recruit NS2B and formation of the NS2B3 protease complex. Additionally, this study identified novel functions of the ER protein SCAP: one is to compete with NS2B for binding to STING, and the other is to inhibit the ubiquitination of NS3. Both of these functions protect STING from being cleaved by the NS2B3 protease and thus contribute to host antiviral response.
authors.affiliation: State Key Laboratory of Molecular Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Molecular Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Lele
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Viral Disease and Vaccine Translational Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Sun
authors.affiliation: Key Laboratory of Medical Reprogramming Technology, Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Molecular Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Senlin
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Molecular Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Molecular Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Huansha
authors.initials: H
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Medical Genetics and School of Life Sciences, Central South University, Changsha, Hunan Province, China.
authors.forename: Zanxian
authors.initials: Z
authors.lastname: Xia
authors.affiliation: Viral Disease and Vaccine Translational Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China xjin@ips.ac.cn cwang01@sibs.ac.cn.
authors.forename: Xia
authors.initials: X
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Molecular Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China xjin@ips.ac.cn cwang01@sibs.ac.cn.|School of Life Science and Technology, China Pharmaceutical University, Nanjing, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
mesh_terms: D000072283:A549 Cells; D000330:Aedes; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D003716:Dengue Virus / Q000276:immunology / Q000472:pathogenicity*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D025821:Polyubiquitin / Q000037:antagonists & inhibitors; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D012697:Serine Endopeptidases / Q000378:metabolism*; D054875:Ubiquitination; D014709:Vero Cells; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors*; D014779:Virus Replication; D000099197:STING Protein; D000085242:Viral Proteases
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D025821:Polyubiquitin; D034741:RNA, Small Interfering; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C080102:NS2B protein, flavivirus; C102196:SREBP cleavage-activating protein; C532857:STING1 protein, human; D000099197:STING Protein; C504449:NS3 protease, dengue virus; D000085242:Viral Proteases
keywords: K27-polyubiquitin; NS2B3; SCAP; STING; dengue virus; innate immunity