title: Characterization of a slow-migrating component of the rabies virus matrix protein strongly associated with the viral glycoprotein.
abstract: We investigated multiple forms of rabies virus matrix (M) protein. Under non-reducing electrophoretic conditions, we detected, in addition to major bands of monomer forms (23- and 24-kDa) of M protein, an M antigen-positive slow-migrating minor band (about 54 kDa) in both the virion and infected cells. Relative contents of the 54-kDa and monomer components in the virion were about 20-30% and 70-80% of the whole M protein, respectively, while the content of the 54-kDa component was smaller (about 10-20% of the total M protein) in the cell than in the virion. The 54-kDa components could be extracted from the infected cells with sodium deoxycholate, but they were quite resistant to extraction with 1% nonionic detergents by which most monomer components were solubilized. The 54-kDa component was precipitated more efficiently than the monomer by a monoclonal antibody (mAb; #3-9-16), which recognized a linear epitope located at the N-terminal of the M protein. The mAb #3-9-16 coprecipitated the viral glycoprotein (G), which was demonstrated to be due to strong association between the G and 54-kDa component of the M protein. Monomers and the 54-kDa polypeptide migrated to the same isoelectric point (pI) in twodimensional (2-D) gel electrophoresis, implicating that the 54-kDa component was composed of component(s) of the same pI as that of the M protein monomers. From these results, we conclude that the M antigen-positive 54-kDa polypeptide is a homodimer of M protein, taking an N-terminal-exposed conformation, and is strongly associated with the viral glycoprotein. Possible association with a membrane microdomain of the cell will be discussed.
authors.affiliation: Department of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nakahara
authors.forename: Harufusa
authors.initials: H
authors.lastname: Toriumi
authors.forename: Takashi
authors.initials: T
authors.lastname: Irie
authors.forename: Takuo
authors.initials: T
authors.lastname: Takahashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ameyama
authors.forename: Masami
authors.initials: M
authors.lastname: Mizukoshi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kawai
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D002460:Cell Line; D006224:Cricetinae; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D000939:Epitopes; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology; D007526:Isoelectric Point; D008970:Molecular Weight; D011485:Protein Binding; D011487:Protein Conformation; D011820:Rabies virus / Q000737:chemistry*; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000276:immunology; D014763:Viral Matrix Proteins / Q000737:chemistry* / Q000276:immunology; D014764:Viral Proteins / Q000737:chemistry / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D000939:Epitopes; D006023:Glycoproteins; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C064951:glycoprotein G, Rabies virus