Hepatitis C virus NS5A protein is phosphorylated by casein kinase II.
Hepatitis C virus (HCV) has a positive-strand RNA genome that encodes a polyprotein, which is post-translationally processed by cellular and viral proteinases into three structural and six non-structural (NS) proteins. The NS5A protein, expressed in mammalian cells, exists as two phosphorylated forms of 56 kDa and 58 kDa. In this study, we provide evidence for a stable association between NS5A and a protein kinase from rat-1 cells by affinity to immobilized glutathione-S-transferase (GST)-NS5A fusion protein. This protein kinase was associated through the N-terminus of NS5A and was not regulated by cell cycle. The GST-NS5A was also phosphorylated in vitro by the purified casein kinase II (CKII), a member of the CMCG kinase family. Since CKII and the NS5A-associated protein kinase have the same molecular size and property by In-gel kinase assay and an inhibitor treatment test, we conclude that HCV NS5A protein is phosphorylated by CKII.
Kim
J
J
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Taejon, 305-701, Korea.
Lee
D
D
Choe
J
J
D000818:Animals; D047390:Casein Kinase II; D002453:Cell Cycle; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D016174:Hepacivirus / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology; D006868:Hydrolysis; D008970:Molecular Weight; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D013997:Time Factors; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
D011993:Recombinant Fusion Proteins; D017361:Viral Nonstructural Proteins; D010768:Phosphoserine; D006493:Heparin; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases