M2 protein

M2 protein is an integral membrane protein found in the Influenza A virus. It plays a crucial role in the viral life cycle and is a target for antiviral drug development.

Structure

The M2 protein is a homotetramer, meaning it is composed of four identical subunits. Each subunit is a single-pass transmembrane protein, with a short extracellular domain, a transmembrane domain, and a larger cytoplasmic domain. The transmembrane domain forms a proton-selective ion channel, which is essential for the virus's life cycle.

Function

The M2 protein has several functions in the influenza virus life cycle. Its primary role is as a proton channel. After the virus enters a host cell, the acidic environment in the endosome causes the M2 channel to open, allowing protons to flow into the virus particle. This acidification triggers the uncoating of the virus, releasing the viral RNA into the cell.

In addition to its role as a proton channel, the M2 protein also plays a role in virus assembly and release. The cytoplasmic domain of the M2 protein interacts with the viral matrix protein M1, helping to incorporate the M2 protein into the virus particle.

Antiviral drug target

Because of its essential role in the viral life cycle, the M2 protein is a target for antiviral drugs. Two drugs, amantadine and rimantadine, were previously used to inhibit the M2 proton channel, preventing the virus from uncoating and replicating. However, most strains of the influenza A virus are now resistant to these drugs.

See also

• Influenza A virus
• Antiviral drug
• Viral life cycle