Influenza A virus matrix protein M1 (M1)

The Influenza A virus matrix protein M1 is the most abundant structural protein in the virus, forming a helical matrix layer beneath the viral envelope that maintains virion integrity and supports interactions with the cytoplasmic tails of hemagglutinin (HA) and neuraminidase (NA) as well as viral ribonucleoproteins (vRNPs). Structurally, it consists of an N-terminal domain (NTD) rich in alpha-helices and a flexible C-terminal domain (CTD) that enables oligomerization into single- or multi-layered helical assemblies, with pH-dependent conformational changes critical for uncoating during cell entry. M1 plays multifaceted roles across the viral lifecycle, including facilitating endosomal disassembly via host factors like HDAC6, suppressing viral mRNA transcription in the nucleus, promoting vRNP nuclear export, and driving membrane curvature for assembly and budding at the plasma membrane. Its conservation, especially in key residues for pH sensing and interactions, underscores its essentiality for viral replication, transmissibility, and pathogenicity in influenza A infections across avian and mammalian hosts. These properties position M1 as a promising antiviral target, though specific inhibitors remain underdeveloped.

Other names

Matrix protein 1