AAM-B Interacts with Nonstructural 4B and Regulates Hepatitis C Virus Propagation

• Published in: PloS one 2015-07, Vol.10 (7), p.e0132839-e0132839
• Main Authors: Park, Eun-Mee, Lim, Yun-Sook, Ahn, Byung-Yoon, Hwang, Soon B
• Format: Article
• Language: English
• Subjects: Cell culture; Cell Line, Tumor; Cellular manufacture; Cytoplasm; Gene expression; Gene Expression Regulation; Genomes; Hepacivirus - genetics; Hepacivirus - growth & development; Hepacivirus - metabolism; Hepatitis; Hepatitis C; Hepatitis C virus; Hepatocytes - metabolism; Hepatocytes - ultrastructure; Hepatocytes - virology; Host-Pathogen Interactions; Humans; Immunofluorescence; Immunoglobulins; Infectious diseases; Kinases; Laboratories; Life sciences; Lipid Droplets - metabolism; Lipid Droplets - ultrastructure; Lipid Droplets - virology; Lipid metabolism; Lipid Metabolism - genetics; Lipids; Lymphocytes B; Membrane Proteins - genetics; Membrane Proteins - metabolism; Metabolism; Methyltransferases - genetics; Methyltransferases - metabolism; Penicillin; Physiological aspects; Plasmids; Propagation; Proteins; Ribonucleic acid; RNA; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Signal Transduction; siRNA; Viral Nonstructural Proteins - genetics; Viral Nonstructural Proteins - metabolism; Virus Replication - genetics; Viruses
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0132839

Hepatitis C virus (HCV) usurps host cellular lipid metabolism for production of infectious virus particles. Recently, we have screened a siRNA library targeting host factors that control lipid metabolism and lipid droplet (LD) formation in cell culture grown HCV (HCVcc)-infected cells. Of 10 final candidates, we selected the gene encoding AAM-B for further characterization. We showed that siRNA-mediated knockdown of AAM-B impaired HCV propagation in Jc1-infected cells. More precisely, knockdown of AAM-B abrogated production of infectious HCV particles in both Jc1 RNA electroporated cells and Jc1-infected cells. It is worth noting that knockdown of AAM-B exerted no effect on lipid droplet formation. Moreover, AAM-B interacted with nonstructural 4B (NS4B) through the C-terminal region of NS4B. Protein interplay between AAM-B and NS4B was verified in the context of HCV replication. Using either transient or stable expression of AAM-B, we verified that AAM-B colocalized with NS4B in the cytoplasm. Immunofluorescence data further showed that AAM-B might be involved in recruitment of NS4B to sites in close proximity to LDs to facilitate HCV propagation. Collectively, this study provides new insight into how HCV utilizes cellular AAM-B to facilitate viral propagation.