A4D5C9 · A4D5C9_9INFB

Function

function

Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induce an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore.
Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization of about two third of the virus particles through clathrin-dependent endocytosis and about one third through a clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore.

Caution

Lacks conserved residue(s) required for the propagation of feature annotation.

Features

Showing features for site.

TypeIDPosition(s)Description
Site362-363Cleavage; by host

GO annotations

AspectTerm
Cellular Componentapical plasma membrane
Cellular Componenthost cell plasma membrane
Cellular Componentviral envelope
Cellular Componentvirion membrane
Molecular Functionhost cell surface receptor binding
Biological Processendocytosis involved in viral entry into host cell
Biological Processfusion of virus membrane with host endosome membrane
Biological Processfusion of virus membrane with host plasma membrane
Biological Processviral budding from plasma membrane
Biological Processvirion attachment to host cell

Keywords

Names & Taxonomy

Protein names

Gene names

    • Name
      HA

Organism names

  • Taxonomic identifier
  • Strain
    • Influenza B virus
  • Taxonomic lineage
    Viruses > Riboviria > Orthornavirae > Negarnaviricota > Polyploviricotina > Insthoviricetes > Articulavirales > Orthomyxoviridae > Betainfluenzavirus > Betainfluenzavirus influenzae > Influenza B virus

Accessions

  • Primary accession
    A4D5C9

Proteomes

Subcellular Location

Apical cell membrane
; Single-pass type I membrane protein
Cell membrane
; Single-pass type I membrane protein
Host apical cell membrane
; Single-pass type I membrane protein
Membrane
; Single-pass type I membrane protein
Virion membrane
; Single-pass type I membrane protein
Note: Targeted to the apical plasma membrane in epithelial polarized cells through a signal present in the transmembrane domain. Associated with glycosphingolipid- and cholesterol-enriched detergent-resistant lipid rafts.

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane550-574Helical

Keywords

PTM/Processing

Features

Showing features for disulfide bond, lipidation.

TypeIDPosition(s)Description
Disulfide bond75↔87
Disulfide bond506↔510
Lipidation581S-palmitoyl cysteine; by host
Lipidation584S-palmitoyl cysteine; by host

Post-translational modification

In natural infection, inactive HA is matured into HA1 and HA2 outside the cell by one or more trypsin-like, arginine-specific endoprotease secreted by the bronchial epithelial cells. One identified protease that may be involved in this process is secreted in lungs by club cells.
Palmitoylated.

Keywords

Interaction

Subunit

Homotrimer of disulfide-linked HA1-HA2.

Family & Domains

Features

Showing features for coiled coil.

TypeIDPosition(s)Description
Coiled coil400-452

Sequence similarities

Belongs to the influenza viruses hemagglutinin family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    585
  • Mass (Da)
    63,197
  • Last updated
    2007-04-03 v1
  • Checksum
    DD31477A18B6747D
MKAIIVLLMVVTSNADRICTGITSSNSPHVVKTATQGEVNVTGVIPLTTTPTKSHFANLKGTKTRGKLCPKCLNCTDLDVALGRPKCTGNIPSAKVSILHEVRPVTSGCFPIMHDRTKIRQLPNLLRGYERIRLSNHNVINAEKAPGGPYKIGTSGSCPNVTNGNGFFATMAWAVPKNENNKTATNSLTIEVPYICTEGEDQITVWGFHSDNEAQMAKLYGDSKPQKFTSSANGVTTHYVSQIGGFPNQTEDGGLPQSGRIVVDYMVQKSGKTGTITYQRGILLPQKVWCASGRSKVIKGSLPLIGEADCLHEKYGGLNKSKPYYTGEHAKAIGNCPIWVKTPLKLANGTKYRPPAKLLKERGFFGAIAGFLEGGWEGMIAGWHGYTSHGAHGVAVAADLKSTQEAINKITKNLNSLSELEVKNLQRLSGAMDELHNEILELDEKVDDLRADTISSQIELAVLLSNEGIINSEDEHLLALERKLKKMLGPSAVEIGNGCFETKHKCNQTCLDRIAAGTFNAGEFSLPTFDSLNITAASLNDDGLDNHTILLYYATAASSLAVTLMIAIFVVYMVSRDNVSCSICL

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
CY018677
EMBL· GenBank· DDBJ
ABL77134.1
EMBL· GenBank· DDBJ
Viral cRNA

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.
FeedbackHelp