1.A.19.1.2
Matrix protein M2 of 96 aas and 1 TMS.  Forms a proton-selective ion channel that is necessary for the efficient release of the viral genome during virus entry. After attaching to the cell surface, the virion enters the cell by endocytosis. Acidification of the endosome triggers M2 ion channel activity. The influx of protons into the virion interior is believed to disrupt interactions between the viral ribonucleoprotein (RNP), matrix protein 1 (M1), and lipid bilayers, thereby freeing the viral genome from interaction with viral proteins and enabling RNA segments to migrate to the host cell nucleus, where influenza virus RNA transcription and replication occur. Also plays a role in viral proteins secretory pathway. The cytoplasmic tail of Influenza A virus hemagglutinin and membrane lipid composition change the mode of M1 protein association with the lipid bilayer (Kordyukova et al. 2021). Universal scFv antibodies against the influenza M2 protein have been prepaired (Kumar et al. 2023).