title: NIRF, a novel ubiquitin ligase, interacts with hepatitis B virus core protein and promotes its degradation.
abstract: Hepatitis B virus (HBV) core protein (HBc) is a major component of viral nucleocapsid and a multifunctional protein involved in viral maturation and release. It is unstable and present in cells at low level because of K96 lysine residue, which is a ubiquitin acceptor site. Np95/ICBP90-like RING finger protein (NIRF) has auto-ubiquitination activity which is the hallmark of a ubiquitin ligase. In the present study, ubiquitin ligase, NIRF, binds to HBc and leads to the proteasome-mediated degradation of HBc in vivo. NIRF down-regulates HBc protein level, resulting in the decrease of the amount of HBV particles in supernatant of HepG2.2.15 cells. However knockdown of NIRF significantly increases endogenous HBc protein level, leading to HBV release. The results reveal that NIRF interacts with HBc and promotes the degradation of HBc in vivo. The pathway of NIRF-mediated ubiquitin-proteasome affects the release of HBV particles by controlling the amounts of HBc. It indicates that NIRF may participate in the maturation of HBV.
authors.affiliation: Key Laboratory of Clinical Laboratory Diagnostics of Ministry of Education, Faculty of Laboratory Medicine, Department of Cell Biology and Medical Genetics, Chongqing Medical University, No. 1, Medical College Road, Chongqing, 400016, China.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Qian
authors.forename: Fangmin
authors.initials: F
authors.lastname: Jin
authors.forename: Lei
authors.initials: L
authors.lastname: Chang
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.forename: Huimin
authors.initials: H
authors.lastname: Peng
authors.forename: Changzhu
authors.initials: C
authors.lastname: Duan
mesh_terms: D056945:Hep G2 Cells; D006512:Hepatitis B Core Antigens / Q000276:immunology* / Q000378:metabolism*; D006515:Hepatitis B virus / Q000276:immunology*; D022781:Hepatocytes / Q000276:immunology / Q000821:virology; D054884:Host-Pathogen Interactions; D006801:Humans; D025941:Protein Interaction Mapping; D044767:Ubiquitin-Protein Ligases / Q000276:immunology* / Q000378:metabolism*
chemical_list: D006512:Hepatitis B Core Antigens; C465619:UHRF2 protein, human; D044767:Ubiquitin-Protein Ligases