ATP5B Is an Essential Factor for Hepatitis B Virus Entry.

Area of Science:

• Virology
• Hepatology
• Molecular Biology

Background:

• Understanding hepatitis B virus (HBV) factors is key to comprehending its life cycle, pathogenesis, and developing antiviral therapies.
• Sodium taurocholate co-transporting peptide (NTCP) was recently identified as essential for HBV entry, enabling in vitro infection models.
• The precise molecular mechanisms of HBV entry remain incompletely understood, necessitating further investigation of involved molecules.

Purpose of the Study:

• To identify novel essential factors involved in hepatitis B virus (HBV) entry into host cells.
• To investigate the role of ATP synthase subunit beta (ATP5B) in the HBV life cycle.

Main Methods:

• Utilized a human hepatocellular carcinoma (HCC) cell line expressing NTCP for in vitro HBV infection studies.
• Assessed the cell surface expression and binding properties of ATP5B with HBV pre-S1 peptide.
• Performed knockdown of ATP5B in HBV-infectible HepG2 cells to evaluate its impact on infectivity.

Main Results:

• Identified ATP synthase subunit beta (ATP5B) as a novel essential factor for HBV entry.
• Demonstrated that ATP5B is expressed on the cell surface of HCC cell lines and binds to myristoylated preS1 peptide.
• Knockdown of ATP5B significantly reduced HBV infectivity and decreased the formation of covalently closed circular DNA (cccDNA) in NTCP-expressing HepG2 cells.

Conclusions:

• ATP5B is a critical host factor mediating HBV entry into cells.
• ATP5B's interaction with the HBV preS1 domain suggests a direct role in the initial infection process.
• Targeting ATP5B may represent a potential therapeutic strategy for inhibiting HBV infection.