title: Processing of the HTLV-II envelope precursor glycoprotein gp63 by furin is essential for cell fusion activity.
abstract: To investigate the relationship between the fusogenic properties of HTLV-II and the processing of the envelope precursor glycoprotein gp63, recombinant cowpox virus expressing this protein was used to infect a range of cell lines derived from different species. Syncytium formation and gp63 processing were observed in all cells with the exception of LoVo cells, which are known to have a dysfunctional form of the endoprotease, furin. Furin has been shown to be necessary for the processing of a number of viral envelope glycoproteins, and gp63 contains a consensus sequence (305)Arg-Arg-Arg-Arg, which is a furin substrate motif. Pulse-chase studies demonstrated gp63 processing in Vero but not in LoVo cells. In addition it could be shown that expression of recombinant furin restored the processing of gp63 to gp46 in LoVo cells, and this resulted in syncytium formation. Our findings suggest that furin plays a pivotal role in cleavage of the HTLV-II envelope gp63, which in turn is a prerequisite for the fusogenic properties of the virus.
authors.affiliation: Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Masashi
authors.initials: M
authors.lastname: Tatsumi
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Ogawa-Goto
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Takahashi
authors.forename: Asato
authors.initials: A
authors.lastname: Kojima
authors.forename: Takuya
authors.initials: T
authors.lastname: Iwasaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kurata
authors.forename: Tetsutaro
authors.initials: T
authors.lastname: Sata
authors.forename: Toshiyuji
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Noreen
authors.initials: N
authors.lastname: Sheehy
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagashima
authors.forename: William W
authors.initials: WW
authors.lastname: Hall
mesh_terms: D000818:Animals; D002522:Chlorocebus aethiops; D045683:Furin; D006367:HeLa Cells; D015367:Human T-lymphotropic virus 2 / Q000502:physiology*; D006801:Humans; D008561:Membrane Fusion / Q000502:physiology*; D011498:Protein Precursors / Q000378:metabolism*; D013381:Subtilisins / Q000502:physiology*; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000378:metabolism*
chemical_list: D011498:Protein Precursors; D014759:Viral Envelope Proteins; D013381:Subtilisins; D045683:Furin