Viroporin that forms a ion channel probably displaying low ion selectivity (PubMed:24672047). Plays a role in counteracting host innate immunity by inhibiting TLR7/MyD88/TRAF6 signaling and STAT1 phosphorylation, leading to down-regulation of type-I IFN (PubMed:27131212, PubMed:29789500). Homooligomer (PubMed:24672047). Interacts with glycoprotein G (By similarity). Belongs to the metapneumovirus small hydrophobic protein family.