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Studies on membrane topology, N-glycosylation and functionality of SARS-CoV membrane protein

2009; BioMed Central; Volume: 6; Issue: 1 Linguagem: Inglês

10.1186/1743-422x-6-79

1743-422X

Daniel Voß, Susanne Pfefferle, Christian Drosten, Lea Stevermann, Elisabetta Traggiai, Antonio Lanzavecchia, Stephan Becker,

Viral gastroenteritis research and epidemiology

The glycosylated membrane protein M of the severe acute respiratory syndrome associated coronavirus (SARS-CoV) is the main structural component of the virion and mediates assembly and budding of viral particles. The membrane topology of SARS-CoV M and the functional significance of its N-glycosylation are not completely understood as is its interaction with the surface glycoprotein S. Using biochemical and immunofluorescence analyses we found that M consists of a short glycosylated N-terminal ectodomain, three transmembrane segments and a long, immunogenic C-terminal endodomain. Although the N-glycosylation site of M seems to be highly conserved between group 1 and 3 coronaviruses, studies using a recombinant SARS-CoV expressing a glycosylation-deficient M revealed that N-glycosylation of M neither influence the shape of the virions nor their infectivity in cell culture. Further functional analysis of truncated M proteins showed that the N-terminal 134 amino acids comprising the three transmembrane domains are sufficient to mediate accumulation of M in the Golgi complex and to enforce recruitment of the viral spike protein S to the sites of virus assembly and budding in the ERGIC.