Viroporin that forms a homopentameric ion channel displaying low ion selectivity (PubMed:18369195, PubMed:22621926, PubMed:25100835, PubMed:27817112). May play a role in virus morphogenesis and pathogenicity at various stages of the viral life cycle. Accumulates at the membrane of the Golgi apparatus in infected cells and may facilitate virus release by modifying the secretory pathway (PubMed:15105532, PubMed:23229815). May enhance host membrane permeability and disrupt cellular ion homeostasis, which can be sensed as damage-associated molecular patterns/danger signals, triggering NLRP3 inflammasome activation and inflammatory immune response (PubMed:23229815). Also inhibits host TNFA-mediated signaling pathway and may delay apoptosis, allowing time for the virus to replicate (PubMed:17494063). Channel activity is inhibited by copper (PubMed:22621926). Also inhibited by small-molecule pyronin B (PubMed:25100835). Homopentamer forming a funnel-like pore (PubMed:18036342, PubMed:18369195, PubMed:22621926). Interacts with glycoprotein G; this interaction occurs on the surface of virion particles and infected cells (PubMed:18036342). Interacts with host BCAP31 (via C-terminus); this interaction is direct (PubMed:25854864). Present in very small amount in the virion. Detected in lipid rafts of host Golgi apparatus membrane. Four species of SH have been detected in infected cell cytoplasm: a 7.5 kDa non-glycosylated form (SH0), a 13-15 kDa form that contains one or two N-linked carbohydrate side chains of the high-mannose type (SHg), a 21-30 kDa polylactosaminoglycan-modified form of the protein (SHp), and the isoform generated by alternative translational initiation (PubMed:2649692). Of these different forms, SH0 is by far the most abundant protein detected during virus infection (PubMed:2649692). Tyrosine phosphorylated. Produced by alternative initiation at Met-23 of isoform SH and gives rise to a 4.6 kDa truncated form of the non-glycosylated protein. Belongs to the orthopneumovirus small hydrophobic protein family.