title: An ATPase activity associated with the rotavirus phosphoprotein NSP5.
abstract: Interactions between NSP5 and NSP2 drive the formation of viroplasms, sites of genome replication and packaging in rotavirus-infected cells. The serine-threonine-rich NSP5 transitions between hypo- and hyper-phosphorylated isomers during the replication cycle. In this study, we determined that purified recombinant NSP5 has a Mg2+-dependent ATP-specific triphosphatase activity that generates free ADP and Pi (Vmax of 19.33 fmol of product/min/pmol of enzyme). The ATPase activity was correlated with low levels of NSP5 phosphorylation, suggestive of a possible link between ATP hydrolysis and an NSP5 autokinase activity. Mutagenesis showed that the critical residue (Ser67) needed for NSP5 hyperphosphorylation by cellular casein kinase-like enzymes has no role in the ATPase or autokinase activities of NSP5. Through its NDP kinase activity, the NSP2 octamer may support NSP5 phosphorylation by creating a constant source of ATP molecules for the autokinase activity of NSP5 and for cellular kinases associated with NSP5.
authors.affiliation: Laboratorio de Virologia, Facultad de Quimica y Biologia, Universidad de Santiago, Alameda 3363, casilla 33 correo 40, Santiago, Chile.
authors.forename: Tamara
authors.initials: T
authors.lastname: Bar-Magen
authors.forename: Eugenio
authors.initials: E
authors.lastname: Spencer
authors.forename: John T
authors.initials: JT
authors.lastname: Patton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017301:Ca(2+) Mg(2+)-ATPase / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012401:Rotavirus / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*