title: Human Enterovirus Nonstructural Protein 2CATPase Functions as Both an RNA Helicase and ATP-Independent RNA Chaperone.
abstract: RNA helicases and chaperones are the two major classes of RNA remodeling proteins, which function to remodel RNA structures and/or RNA-protein interactions, and are required for all aspects of RNA metabolism. Although some virus-encoded RNA helicases/chaperones have been predicted or identified, their RNA remodeling activities in vitro and functions in the viral life cycle remain largely elusive. Enteroviruses are a large group of positive-stranded RNA viruses in the Picornaviridae family, which includes numerous important human pathogens. Herein, we report that the nonstructural protein 2CATPase of enterovirus 71 (EV71), which is the major causative pathogen of hand-foot-and-mouth disease and has been regarded as the most important neurotropic enterovirus after poliovirus eradication, functions not only as an RNA helicase that 3'-to-5' unwinds RNA helices in an adenosine triphosphate (ATP)-dependent manner, but also as an RNA chaperone that destabilizes helices bidirectionally and facilitates strand annealing and complex RNA structure formation independently of ATP. We also determined that the helicase activity is based on the EV71 2CATPase middle domain, whereas the C-terminus is indispensable for its RNA chaperoning activity. By promoting RNA template recycling, 2CATPase facilitated EV71 RNA synthesis in vitro; when 2CATPase helicase activity was impaired, EV71 RNA replication and virion production were mostly abolished in cells, indicating that 2CATPase-mediated RNA remodeling plays a critical role in the enteroviral life cycle. Furthermore, the RNA helicase and chaperoning activities of 2CATPase are also conserved in coxsackie A virus 16 (CAV16), another important enterovirus. Altogether, our findings are the first to demonstrate the RNA helicase and chaperoning activities associated with enterovirus 2CATPase, and our study provides both in vitro and cellular evidence for their potential roles during viral RNA replication. These findings increase our understanding of enteroviruses and the two types of RNA remodeling activities.
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Guang-Chuan
authors.initials: GC
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Xianlin
authors.initials: X
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Wenzhe
authors.initials: W
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China; State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Shu
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Cheng-Feng
authors.initials: CF
authors.lastname: Qin
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Yuanyang
authors.initials: Y
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D004770:Enterovirus / Q000201:enzymology*; D004769:Enterovirus Infections / Q000378:metabolism*; D006801:Humans; D018832:Molecular Chaperones / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics*; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology
chemical_list: D018832:Molecular Chaperones; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D000255:Adenosine Triphosphate; D020365:RNA Helicases