title: Processing of the Ebola virus glycoprotein by the proprotein convertase furin.
abstract: In the present study, we have investigated processing and maturation of the envelope glycoprotein (GP) of Ebola virus. When GP expressed from vaccinia virus vectors was analyzed by pulse-chase experiments, the mature form and two different precursors were identified. First, the endoplasmic reticulum form preGPer, full-length GP with oligomannosidic N-glycans, was detected. preGPer (110 kDa) was replaced by the Golgi-specific form preGP (160 kDa), full-length GP containing mature carbohydrates. preGP was finally converted by proteolysis into mature GP1,2, which consisted of two disulfide-linked cleavage products, the amino-terminal 140-kDa fragment GP1, and the carboxyl-terminal 26-kDa fragment GP2. GP1,2 was also identified in Ebola virions. Studies employing site-directed mutagenesis revealed that GP was cleaved at a multibasic amino acid motif located at positions 497 to 501 of the ORF. Cleavage was blocked by a peptidyl chloromethylketone containing such a motif. GP is cleaved by the proprotein convertase furin. This was indicated by the observation that cleavage did not occur when GP was expressed in furin-defective LoVo cells but that it was restored in these cells by vector-expressed furin. The Reston subtype, which differs from all other Ebola viruses by its low human pathogenicity, has a reduced cleavability due to a mutation at the cleavage site. As a result of these observations, it should now be considered that proteolytic processing of GP may be an important determinant for the pathogenicity of Ebola virus.
authors.affiliation: Institut für Virologie, Philipps-Universität Marburg, 35011 Marburg, Germany. volchkov@mailer.uni-marburg.de
authors.forename: V E
authors.initials: VE
authors.lastname: Volchkov
authors.forename: H
authors.initials: H
authors.lastname: Feldmann
authors.forename: V A
authors.initials: VA
authors.lastname: Volchkova
authors.forename: H D
authors.initials: HD
authors.lastname: Klenk
mesh_terms: D000818:Animals; D002522:Chlorocebus aethiops; D004220:Disulfides / Q000378:metabolism; D029043:Ebolavirus / Q000378:metabolism / Q000472:pathogenicity; D045683:Furin; D006023:Glycoproteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D013381:Subtilisins / Q000378:metabolism*; D014709:Vero Cells; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D004220:Disulfides; D006023:Glycoproteins; D010446:Peptide Fragments; D014764:Viral Proteins; C110613:secreted glycoprotein, Ebola virus; D013381:Subtilisins; D045683:Furin