Chapter 9 Fusion of Viral Envelopes with Cellular Membranes.

Area of Science:

• Virology
• Cell Biology
• Biochemistry

Background:

• Viruses utilize specific glycoproteins embedded in their lipid bilayer envelope to interact with host cells.
• Viral envelopes originate from host cell membranes, retaining similar lipid compositions.
• Viral glycoproteins mediate both cell surface binding and membrane fusion, crucial for viral entry.

Purpose of the Study:

• To review characteristic membrane fusion activities across different viruses.
• To discuss mechanisms of viral membrane fusion, particularly low pH-induced fusion.
• To highlight the role of hydrophobic segments in viral fusion.

Main Methods:

• Review of characteristic features of viral membrane fusion.
• Discussion of mechanisms, focusing on low pH-induced fusion.
• Analysis of viral glycoprotein interactions with target cell membranes.

Main Results:

• Viral glycoproteins bind to target cell receptors, initiating interaction.
• The hydrophobic segment of viral glycoproteins plays a critical role by inserting into the lipid bilayer.
• Fusion mechanisms vary, with some viruses using a single glycoprotein (e.g., influenza HA) and others using separate proteins (e.g., Sendai virus F and HN).

Conclusions:

• The insertion of a hydrophobic segment into the target cell's lipid bilayer is a key step in viral membrane fusion.
• Understanding these fusion mechanisms is vital for comprehending viral entry and developing antiviral strategies.
• Viral glycoproteins are essential for mediating the complex process of cell entry through membrane fusion.