Matrix protein 2

The M2 protein is a proton-selective ion channel protein, integral in the viral envelope of the influenza A virus. The channel itself is a homotetramer (consists of four identical M2 units), where the units are helices stabilized by two disulfide bonds. It is activated by low pH. M2 protein is encoded on the seventh RNA segment together with the matrix protein M1. Proton conductance by the M2 protein ininfluenza A is essential for viral replication.

The influenza A virus M2 protein is an integral membrane protein that functions as a proton-selective ion channel. It plays a crucial role in the viral replication cycle, particularly in the process of viral uncoating within endosomes. It is essential for maintaining the proper pH balance within the virus during its entry into host cells. The M2 protein is also a target for antiviral drugs, such as amantadine and rimantadine, although resistance to these drugs has become widespread. It is a homotetramer, meaning it is made up of 4 identical M2 protein subunits.