Heat Shock Protein 72 Is Associated with the Hepatitis C Virus Replicase Complex and Enhances Viral RNA Replication

• Published in: The Journal of biological chemistry Vol. 285; no. 36; pp. 28183 - 28190
• Main Authors: Chen, Yin-Ju, Chen, Yu-Hsuan, Chow, Lu-Ping, Tsai, Ya-Hui, Chen, Pei-Hong, Huang, Chi-Ying F., Chen, Wei-Tzu, Hwang, Lih-Hwa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03.09.2010; American Society for Biochemistry and Molecular Biology
• Subjects: Cell Line; Heat Shock Protein; Hepacivirus - enzymology; Hepacivirus - metabolism; Hepacivirus - physiology; Hepatitis C Virus; HSC70 Heat-Shock Proteins - metabolism; HSP72 Heat-Shock Proteins - metabolism; Humans; Lentivirus; Mass Spectrometry (MS); Microbiology; NS5A; Positive-strand RNA Viruses; RNA, Viral - biosynthesis; RNA-Dependent RNA Polymerase - metabolism; shRNA; Tandem Affinity Purification; Viral Nonstructural Proteins - chemistry; Viral Nonstructural Proteins - metabolism; Viral Replication; Virus Replication; Positive-strand RNA Viruses; Viral Replication; Tandem Affinity Purification; shRNA; NS5A; Mass Spectrometry (MS); Lentivirus; Heat Shock Protein; Hepatitis C Virus
• DOI: 10.1074/jbc.M110.118323
• ISSN: 0021-9258; 1083-351X

The NS5A protein of the hepatitis C virus (HCV) is an integral component of the viral replicase. It also modulates cellular signaling and perturbs host interferon responses. The multifunctional characteristics of NS5A are mostly attributed to its ability to interact with various cellular proteins. This study aimed to identify the novel cellular factors that interact with NS5A and decipher the significance of this interaction in viral replication. The NS5A-interacting proteins were purified by the tandem affinity purification (TAP) procedure from cells expressing NS5A and identified by mass spectrometry. The chaperone protein Hsp72 was identified herein. In vivo protein-protein interaction was verified by co-immunoprecipitation and an in situ proximity ligation assay. In addition to NS5A, Hsp72 was also associated with other members of the replicase complex, NS3 and NS5B, suggesting that it might be directly involved in the HCV replication complex. Hsp72 plays a positive regulatory role in HCV RNA replication by increasing levels of the replicase complex, which was attributed either to the increased stability of the viral proteins in the replicase complex or to the enhanced translational activity of the internal ribosome entry site of HCV. The fact that the host chaperone protein Hsp72 is involved in HCV RNA replication may represent a therapeutic target for controlling virus production.