title: Novel protein kinase interacts with the Cucumber mosaic virus 1a methyltransferase domain.
abstract: The Cucumber mosaic virus (CMV)-encoded 1a protein has been implicated to play a role in replication of the viral genome along with 2a and one or more host factors. To identify the host cell factors interacting with CMV 1a, we used the yeast two-hybrid system using tobacco cDNA library. One of the cDNA clones encoded a protein homologous to the Arabidopsis putative protein kinase and was designated as Tcoi2 (Tobacco CMV 1a interacting protein 2). Tcoi2 specifically interacted with methyltransferase (MT) domain of CMV 1a protein in yeast cell. In vitro analyses using recombinant proteins showed that Tcoi2 also specifically interacted with CMV 1a MT domain. Tcoi2 did not have autophosphorylation activity but phosphorylated CMV 1a MT domain. Analysis of the subcellular localization of the Tcoi2 fused to GFP demonstrated that it is targeted to the endoplasmic reticulum. These results suggest Tcoi2 as a novel host factor that is capable of interacting and phosphorylating MT domain of CMV 1a protein.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, 1, 5-ga, Anam-dong, Sungbuk-gu, Seoul 136-701, Republic of Korea.
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Byung-Kook
authors.initials: BK
authors.lastname: Ham
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Paek
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D008780:Methyltransferases / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D010940:Plant Proteins; C508105:Tcoi2 protein, tobacco; D014764:Viral Proteins; C508104:1a protein, cucumber mosaic virus; D008780:Methyltransferases; D011494:Protein Kinases