title: Phosphorylation of the TGBp1 movement protein of Potato virus X by a Nicotiana tabacum CK2-like activity.
abstract: The movement protein (MP) TGBp1 of the potexvirus Potato virus X (PVX) is a multifunctional protein required for cell-to-cell movement within the host plant. Recent work on other plant viruses has indicated that MP phosphorylation by host kinases can regulate MP function. In this study, we demonstrate that recombinant and native TGBp1 are phosphorylated by Nicotiana tabacum extracts from both PVX-infected and non-infected leaves. The phosphorylation activity present in plant extracts has distinctive characteristics of casein kinase 2 (CK2): it is inhibited by heparin, stimulated by polylysine, and uses either ATP or GTP as phosphoryl donors. We also demonstrate that TGBp1 is efficiently phosphorylated by recombinant tobacco CK2 alpha subunit and by partially purified tobacco CK2. Phosphopeptide mass mapping reveals that TGBp1 is phosphorylated in Ser-165, which is localized within a CK2 consensus sequence. Our results strongly suggest that a N. tabacum kinase of the CK2 family is involved in TBGp1 phosphorylation during the course of viral infection.
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, CONICET and FCEN-UBA, Buenos Aires, Argentina.
authors.forename: Natalia Andrea
authors.initials: NA
authors.lastname: Módena
authors.forename: Alicia Mercedes
authors.initials: AM
authors.lastname: Zelada
authors.forename: Florencia
authors.initials: F
authors.lastname: Conte
authors.forename: Alejandro
authors.initials: A
authors.lastname: Mentaberry
mesh_terms: D047390:Casein Kinase II / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017863:Potexvirus / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D011994:Recombinant Proteins / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D014026:Nicotiana / Q000201:enzymology*; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D011994:Recombinant Proteins; D014764:Viral Proteins; D012694:Serine; D047390:Casein Kinase II