Membrane fusion protein

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(Redirected from
Class I fusion protein
)

Membrane fusion proteins (not to be confused with chimeric or

retroviruses integrated into the host genome,[1] or solely by the host genome.[2] Post-transcriptional modifications made to the fusion proteins by the host, namely addition and modification of glycans and acetyl groups, can drastically affect fusogenicity (the ability to fuse).[3]

Fusion in eukaryotes

Eukaryotic genomes contain several

neurodevelopment. Fusion pathways are also involved in the development of musculoskeletal and nervous system tissues. Vesicle fusion events involved in neurotransmitter trafficking
also relies on the catalytic activity of fusion proteins.

SNARE family

The SNARE family include bona fide eukaryotic fusion proteins. They are only found in eukaryotes and their closest

Heimdallarchaeota.[4]

Retroviral

These proteins originate from the

endogenous retroviruses
. They are domesticated viral class I fusion proteins.

HAP2 family

vascular plants, and fruit flies. This protein is essential for gamete fusion in these organisms.[5]

Pathogenic viral fusion

Enveloped viruses readily overcome the thermodynamic barrier of merging two plasma membranes by storing kinetic energy in fusion (F) proteins. F proteins can be independently expressed on host cell surfaces which can either (1) drive the infected cell to fuse with neighboring cells, forming a

full emancipation of plasma membrane from the host cell. Some F components solely drive fusion while a subset of F proteins can interact with host factors. There are four groups of fusion proteins categorized by their structure and mechanism of fusion.[6]

Class I

Class I fusion proteins resemble influenzavirus hemagglutinin in their structure. Post-fusion, the active site has a trimer of α-helical coiled-coils. The binding domain is rich in α-helices and hydrophobic fusion peptides located near the N-terminus. Fusion conformation change can often be controlled by pH.[7][8]

Class II

Class II proteins are dominant in β-sheets and the catalytic sites are localized in the core region. The peptide regions required to drive fusion are formed from the turns between the β-sheets.[7][8]

Class III

Class III fusion proteins are distinct from I and II. They typically consist of 5 structural domains, where domain 1 and 2 localized to the C-terminal end often contain more β-sheets and domains 2-5 closer to the N-terminal side are richer in α-helices. In the pre-fusion state, the later domains nest and protect domain 1 (i.e. domain 1 is protected by domain 2, which is nested in domain 3, which is protected by domain 4). Domain 1 contains the catalytic site for membrane fusion.[7][8]

Class IV

Class IV fusion proteins, better known as

syncytia. They are the only known membrane fusion proteins found in non-enveloped viruses.[9][10]

Examples

Fusion protein Abbreviation Class Virus family Example viruses Reference
Coronavirus spike protein S I Coronaviridae
SARS-CoV, SARS-CoV-2
 [11][12]
Ebolavirus glycoprotein GP I Filoviridae
Sudan- ebolaviruses, Marburgvirus
 		[6][13]
Glycoprotein 41 Gp41 I
Retroviridae
 HIV [6][13]
Hemagglutinin H, HA, HN I Orthomyxoviridae, Paramyxoviridae
measles virus, mumps virus
 [6][13]
Alphavirus envelope protein E1 E1 II
Togaviridae
 Semliki Forest virus [6][13]
Flavivirus envelope protein E II Flaviviridae Dengue virus, West Nile virus [6][13]
Herpesvirus glycoprotein B gB III Herpesviridae HSV-1 [6][14]
VSV G G III Rhabdoviridae Vesicular stomatitis virus, rabies lyssavirus [6][14]
Fusion-associated small transmembrane protein FAST IV
Reoviridae
 Avian orthoreovirus [6][10]

See also

References

  1. TCDB
    database
  2. PMID 11744371
    .
  3. PMID 29878112
    .
  4. S2CID 218762979
    .
  5. PMID 28235200
    .
  6. ^
    PMID 25000995
    .
  7. ^
    PMID 19356922
    .
  8. ^
    PMID 18568847
    .
  9. PMID 10698932
    .
  10. ^
    PMID 25245455
    .
  11. PMID 27578435
    .
  12. PMID 34125455
    .
  13. ^
    PMID 26935856
    .
  14. ^
    PMID 26277251
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Membrane_fusion_protein&oldid=1195398970#Class_I"