title: The Marburg virus surface protein GP is phosphorylated at its ectodomain.
abstract: Marburg virus, a filovirus, contains only one transmembrane protein (GP) which is responsible for receptor recognition on target cells. GP, a type I membrane protein of approximately 220 kDa, is acylated and highly glycosylated carrying N- and O-linked sugar side chains. GP is transported through the exocytotic pathway toward the plasma membrane where budding of virions takes place. In the trans-Golgi network, GP is proteolytically activated by the prohormone convertase furin into two subunits GP(1) and GP(2). In the present paper, we provide evidence that GP undergoes an additional posttranslational modification; it is phosphorylated at its ectodomain. Phosphorylation takes place at serine residues between amino acid 260 and 273. The respective serines are located in conserved recognition sites for luminal protein kinases (protein kinase CK II and Golgi casein kinase). Consistent with this data, it was found that GP was phosphorylated in the Golgi apparatus of the expressing HeLa cells before cleavage of the molecule. GP is the first example of a viral glycoprotein with a phosphorylated ectodomain.
authors.affiliation: Institut für Virologie der Philipps-Universität Marburg, Robert-Koch-Str. 17, Marburg, 35037, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Sänger
authors.forename: Elke
authors.initials: E
authors.lastname: Mühlberger
authors.forename: Beate
authors.initials: B
authors.lastname: Lötfering
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Klenk
authors.forename: Stephan
authors.initials: S
authors.lastname: Becker
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D016679:Genome, Viral; D006056:Golgi Apparatus / Q000821:virology; D006367:HeLa Cells; D006801:Humans; D029024:Marburgvirus / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012694:Serine / Q000737:chemistry; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C081324:GP-protein, Marburg virus; D014759:Viral Envelope Proteins; D012694:Serine