title: Hepatitis C virus nonstructural protein NS3 binds to Sm-D1, a small nuclear ribonucleoprotein associated with autoimmune disease.
abstract: Hepatitis C virus (HCV) causes a persistent infection, chronic hepatitis, and leads to hepatocellular carcinoma. Nonstructural protein 3 (NS3) of HCV possesses protease, nucleoside triphosphatase, and helicase activities. Using the yeast two hybrid assay, we identified Sm-D1, a host protein that binds to NS3. Sm-D1 is a component of small nuclear ribonucleoprotein (snRNP) complexes which are associated with autoimmune disease. Sm-D1 has Gly-Arg (GR) repeats at the C terminus, which contains dimethylarginine modified by post-translational modification and may constitute an immunoreactive determinant. Deletion mutants revealed that the C-terminal region of Sm-D1 containing the GR repeats was the binding region for NS3, and the expression feature of Sm-D1 was affected by co-expression of NS3. Immunostaining assay demonstrated that NS3 was also present in the nucleus of cells overexpressing Sm-D1, although it was usually found in cytoplasm. The localization of NS3 could change following interaction with Sm-D1 and affect the function of Sm-D1.
authors.affiliation: High Tech Research Center, Kanazawa Medical University, Ishikawa 920-0293, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iwai
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Hasumura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nojima
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takegami
mesh_terms: D001327:Autoimmune Diseases / Q000378:metabolism*; D001665:Binding Sites; D002460:Cell Line; D016174:Hepacivirus / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection; D020798:Two-Hybrid System Techniques; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D017411:Ribonucleoproteins, Small Nuclear; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases