title: Sumoylation-promoted enterovirus 71 3C degradation correlates with a reduction in viral replication and cell apoptosis.
abstract: Enterovirus 71 (EV71), a member of the Picornaviridae family, may cause serious clinical manifestations associated with the central nervous system. Enterovirus 3C protease is required for virus replication and can trigger host cell apoptosis via cleaving viral polyprotein precursor and cellular proteins, respectively. Although the role of the 3C protease in processing viral and cellular proteins has been established, very little is known about the modulation of EV71 3C function by host cellular factors. Here, we show that sumoylation promotes EV71 3C protein ubiquitination for degradation, correlating with a decrease of EV71 in virus replication and cell apoptosis. SUMO E2-conjugating enzyme Ubc9 was identified as an EV71 3C-interacting protein. Further studies revealed that EV71 3C can be SUMO (small ubiquitin-like modifier)-modified at residue Lys-52. Sumoylation down-regulated 3C protease activity in vitro and also 3C protein stability in cells, in agreement with data suggesting 3C K52R protein induced greater substrate cleavage and apoptosis in cells. More importantly, the recombinant EV71 3C K52R virus infection conferred more apoptotic phenotype and increased virus levels in culture cells, which also correlated with a mouse model showing increased levels of viral VP1 protein in intestine and neuron loss in the spinal cord with EV71 3C K52R recombinant viral infection. Finally, we show that EV71 3C amino acid residues 45-52 involved in Ubc9 interaction determined the extent of 3C sumoylation and protein stability. Our results uncover a previously undescribed cellular regulatory event against EV71 virus replication and host cell apoptosis by sumoylation at 3C protease.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Shu-Chuan
authors.initials: SC
authors.lastname: Chen
authors.forename: Luan-Yin
authors.initials: LY
authors.lastname: Chang
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Wang
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Chen
authors.forename: Kuo-Feng
authors.initials: KF
authors.lastname: Weng
authors.forename: Shin-Ru
authors.initials: SR
authors.lastname: Shih
authors.forename: Hsiu-Ming
authors.initials: HM
authors.lastname: Shih
mesh_terms: D000086042:3C Viral Proteases; D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D004770:Enterovirus / Q000201:enzymology / Q000502:physiology*; D004769:Enterovirus Infections / Q000473:pathology / Q000821:virology; D054884:Host-Pathogen Interactions; D051379:Mice; D020125:Mutation, Missense; D055550:Protein Stability; D058207:Sumoylation; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases