POSTTRANSLATIONAL MODIFICATIONS OF POTATO VIRUS A MOVEMENT RELATED PROTEINS CP AND VPg

(2002): Detection of the potyviral genome linked protein VPg in virions and its phosphorylation by host kinases. the potyvirus capsid protein by protein kinase CK2 and its relevance for virus infection. Abbreviations aa: amino acid ATP: adenosine triphosphate bp: base pair BSA: bovine serum albumin CD: circular dichroism CIP: cylindrical inclusion protein CK2: casein kinase II CP: coat protein d: deoxy dd: dideoxy DMC: divalent metal cation DNA: deoxyribonucleic acid DRB: 5,6-dicloro-1-(β-D-ribofuranosyl)benzimidazole ds: double stranded EDTA: ethylenediaminetetraacetic acid EM: electron microscopy ER: endoplasmic reticulum GTP: guanosine triphosphate HC-pro helper component proteinase icDNA: infectious complementary DNA IPTG: isopropyl-β-D-thiogalactopyranoside kb: kilobase kDa: kilodalton MAPK: mitogen-activated protein kinases MP: movement protein MPR: movement related protein MW: molecular weight nt: nucleotide NIa: proteinase part of NIa NIa –tot: VPg + proteinase part intermediate NIb: RNA dependent RNA polymerase NLS: nuclear localization signal NTP: nucleoside triphosphate mCKII maize CKII ORF: open reading frame PAGE: polyacrylamide gel electrophoresis PVA: Potato virus A PV: poliovirus RC: replication complex RdRP: RNA-dependent RNA polymerase RNA: ribonucleic acid RNAi: RNA interference rmCK2: recombinant maize casein kinase 2 subunit RNase: ribonuclease SAP: shrimp alkaline phosphatase SAR: systemic acquired resistance tCK2: tobacco CK2 TEV: tobacco etch virus TMV: tobacco mosaic virus UMP: uridine monophosphate UTP: uridine triphosphate VPg: viral genome linked protein wt: wild type 5 " I've learned to think like a virus; no neurons, a lot of sex, and a lot of errors. " John J. Holland. ABSTRACT Protein kinases are known to be involved in the regulation of the virion assembly, rep-lication, and dissociation of numerous animal viruses. In contrast, there is a knowledge of scarce regarding the role of protein phosphorylation in the infection cycle. Potato virus A (PVA) is a positive-strand RNA virus, which belongs to the genus Poty-virus; family Potyviridae. The present work describes how the PVA movement-related proteins CP and VPg, when phosphorylated by protein kinase, function in the viral movement and replication cycle. In this study, coat protein (CP) and viral genome linked protein (VPg) are shown to be under the regulation of tobacco protein kinases in vitro and in vivo. This finding suggests a mechanism to regulate the formation and stability of viral ribonucleoprotein complexes. This study also shows that VPg bound to virions can interact with host kinases. The VPg is known to support vascular movement with a different efficiency in tobacco and in potato. Detailed biochemical analysis reveals variations between different …