Influenza A virus is a major public health threat, killing more than 30,000 people per year in the USA. Influenza A virus has one of sixteen possible Hemagglutinin (HA) surface proteins and one of nine possible neuraminidase (NA) surface proteins. The Hemagglutinin protein facilitates viral attachment while neuraminidase is involved in viral release. These proteins also elicit immune responses that prevent infection or independently reduce viral replication.
Function:
Catalyzes the removal of terminal sialic acid residues from viral and cellular glycoconjugates. Cleaves off the terminal sialic acids on the glycosylated HA during virus budding to facilitate virus release. Additionally helps virus spread through the circulation by further removing sialic acids from the cell surface. These cleavages prevent self-aggregation and ensure the efficient spread of the progeny virus from cell to cell. Otherwise, infection would be limited to one round of replication. Described as a receptor-destroying enzyme because it cleaves a terminal sialic acid from the cellular receptors. May facilitate viral invasion of the upper airways by cleaving the sialic acid moieties on the mucin of the airway epithelial cells. Likely to plays a role in the budding process through its association with lipid rafts during intracellular transport. May additionally display a raft-association independent effect on budding. Plays a role in the determination of host range restriction on replication and virulence. Sialidase activity in late endosome/lysosome traffic seems to enhance virus replication (By similarity).
Subunit:
Homotetramer (By similarity).
Subcellular Location:
Virion membrane (By similarity). Host apical cell membrane; Single-pass type II membrane protein (By similarity). Note=Preferentially accumulates at the apical plasma membrane in infected polarized epithelial cells, which is the virus assembly site. Uses lipid rafts for cell surface transport and apical sorting. In the virion, forms a mushroom-shaped spike on the surface of the membrane (By similarity).
Post-translational modifications:
N-glycosylated (By similarity).
Similarity:
Belongs to the glycosyl hydrolase 34 family.
SWISS:
A8C8J7
Gene ID:
N/A
Database links:
http://www.ncbi.nlm.nih.gov/protein/229891193
UniProtKB/Swiss-Prot: A8C8J7.1
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