The NS5A-binding heat shock proteins HSC70 and HSP70 play distinct roles in the hepatitis C viral life cycle

Ronik Khachatoorian; Ekambaram Ganapathy; Yasaman Ahmadieh; Nicole Wheatley; Christopher Sundberg; Chun-Ling Jung; Vaithilingaraja Arumugaswami; Santanu Raychaudhuri; Asim Dasgupta; Samuel W French

doi:10.1016/j.virol.2014.02.016

The NS5A-binding heat shock proteins HSC70 and HSP70 play distinct roles in the hepatitis C viral life cycle

Virology. 2014 Apr:454-455:118-27. doi: 10.1016/j.virol.2014.02.016. Epub 2014 Feb 28.

Affiliations

¹ Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: RnKhch@ucla.edu.
² Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: GEkambaram@ucla.edu.
³ Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States of America. Electronic address: YasAhmadieh@ucla.edu.
⁴ Molecular Biology Interdepartmental Ph.D. Program (MBIDP), Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Molecular Biology Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: Wheatley.NM@gmail.com.
⁵ Department of Human Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: Christopher.Sundberg@gmail.com.
⁶ Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: CLJung@mednet.ucla.edu.
⁷ Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Department of Surgery, Regenerative Medicine Institute at Cedars-Sinai Medical Center, Los Angeles, CA, United States of America. Electronic address: Vaithi.Arumugaswami@cshs.org.
⁸ Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: SRaychau@ucla.edu.
⁹ Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: Dasgupta@ucla.edu.
¹⁰ Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America; UCLA AIDS Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America. Electronic address: SFrench@mednet.ucla.edu.

Abstract

We previously identified HSP70 and HSC70 in complex with NS5A in a proteomic screen. Here, coimmunoprecipitation studies confirmed NS5A/HSC70 complex formation during infection, and immunofluorescence studies showed NS5A and HSC70 to colocalize. Unlike HSP70, HSC70 knockdown did not decrease viral protein levels. Rather, intracellular infectious virion assembly was significantly impaired by HSC70 knockdown. We also discovered that both HSC70 nucleotide binding and substrate binding domains directly bind NS5A whereas only the HSP70 nucleotide binding domain does. Knockdown of both HSC70 and HSP70 demonstrated an additive reduction in virus production. This data suggests that HSC70 and HSP70 play discrete roles in the viral life cycle. Investigation of these different functions may facilitate developing of novel strategies that target host proteins to treat HCV infection.

Keywords: Assembly; HCV; HSC70; HSP70; IRES; NS5A.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

HSP70 Heat-Shock Proteins / metabolism*
Hepacivirus / physiology*
Host-Pathogen Interactions*
Humans
Immunoprecipitation
Microscopy, Confocal
Protein Binding
Viral Nonstructural Proteins / metabolism*
Virus Assembly
Virus Replication

Substances

HSP70 Heat-Shock Proteins
Viral Nonstructural Proteins
NS-5 protein, hepatitis C virus

The NS5A-binding heat shock proteins HSC70 and HSP70 play distinct roles in the hepatitis C viral life cycle

Authors

Affiliations

Abstract

Publication types

MeSH terms

Substances

Grants and funding