DEFA5

Last updated
DEFA5
Protein DEFA5 PDB 1zmp.png
Available structures
PDB Ortholog search: PDBe RCSB
Identifiers
Aliases DEFA5 , DEF5, HD-5, defensin alpha 5, alpha defensin 5
External IDs OMIM: 600472; MGI: 3711900; HomoloGene: 128604; GeneCards: DEFA5; OMA:DEFA5 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_021010

NM_001177481

RefSeq (protein)

NP_066290

NP_001170952

Location (UCSC) Chr 8: 7.06 – 7.06 Mb Chr 8: 21.56 – 21.56 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Defensin, alpha 5 (DEFA5) also known as human alpha defensin 5 (HD5) is a protein that in humans is encoded by the DEFA5 gene. [5] [6] DEFA5 is expressed in the Paneth cells of the ileum. [7]

Defensins are a family of microbicidal and cytotoxic peptides (antimicrobial peptides; AMP) that are involved in host defense, and help to maintain homeostasis of intestinal microbiota. DEFA5 is the main AMP that controls the enteric microbiota composition by selective killing of bacterial pathogens while preserving commensals. [8]

Structure

Defensins are small cationic peptides linked via three intra-molecular disulfide bridges, and contain six intra-molecular cysteine residues which form an unalterable and specific pattern of disulfide bridges which protects them from proteolysis and maintains function in the intestinal lumen. [9] [10] Members of the defensin family are highly similar in protein sequence and distinguished by a conserved cysteine motif.

Gene and tissue distribution

Several of the human alpha defensin genes appear to be clustered on chromosome 8. The protein encoded by this gene, α-defensin-5, is highly expressed in the secretory granules of Paneth cells of the ileum. [5]

Function

In addition to antimicrobial activity, inactivation and neutralization of several bacterial toxins, especially an inhibitory potency against Clostridioides difficile toxins were reported. [11] [12] α-defensin-5 is able to inhibit all three C. difficile toxins A (TcdA), B (TcdB) and CDT in the concentration-dependent manner, and inhibitory mechanism is different for each of them. TcdA and TcdB are inhibited by co-precipitation with DEFA5, and CDT is inhibited by the inactivation of the CDTb pore. [13] In addition to toxin neutralization, DEFA5 is capable to directly kill C. difficile cells by damaging the bacterial wall. [14]

References

  1. 1 2 3 ENSG00000285251 GRCh38: Ensembl release 89: ENSG00000164816, ENSG00000285251 Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000061845 Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. 1 2 "Entrez Gene: DEFA5 defensin, alpha 5, Paneth cell-specific".
  6. Jones DE, Bevins CL (January 1993). "Defensin-6 mRNA in human Paneth cells: implications for antimicrobial peptides in host defense of the human bowel". FEBS Letters. 315 (2): 187–92. doi: 10.1016/0014-5793(93)81160-2 . PMID   8417977. S2CID   45099115.
  7. Zhao C, Wang I, Lehrer RI (November 1996). "Widespread expression of beta-defensin hBD-1 in human secretory glands and epithelial cells". FEBS Letters. 396 (2–3): 319–22. doi: 10.1016/0014-5793(96)01123-4 . PMID   8915011. S2CID   22367037.
  8. Bevins CL, Salzman NH (May 2011). "Paneth cells, antimicrobial peptides and maintenance of intestinal homeostasis". Nature Reviews. Microbiology. 9 (5): 356–68. doi:10.1038/nrmicro2546. PMID   21423246. S2CID   39332656.
  9. Ganz T, Lehrer RI (August 1994). "Defensins". Current Opinion in Immunology. 6 (4): 584–9. doi:10.1016/0952-7915(94)90145-7. PMID   7946046.
  10. Selsted ME, Harwig SS (March 1989). "Determination of the disulfide array in the human defensin HNP-2. A covalently cyclized peptide". The Journal of Biological Chemistry. 264 (7): 4003–7. doi: 10.1016/S0021-9258(19)84952-9 . PMID   2917986.
  11. Kim C, Slavinskaya Z, Merrill AR, Kaufmann SH (October 2006). "Human alpha-defensins neutralize toxins of the mono-ADP-ribosyltransferase family". The Biochemical Journal. 399 (2): 225–9. doi:10.1042/BJ20060425. PMC   1609915 . PMID   16817779.
  12. Giesemann T, Guttenberg G, Aktories K (June 2008). "Human alpha-defensins inhibit Clostridium difficile toxin B". Gastroenterology. 134 (7): 2049–58. doi: 10.1053/j.gastro.2008.03.008 . PMID   18435932.
  13. Korbmacher M, Fischer S, Landenberger M, Papatheodorou P, Aktories K, Barth H (2020). "Human α-Defensin-5 Efficiently Neutralizes Clostridioides difficile Toxins TcdA, TcdB, and CDT". Frontiers in Pharmacology. 11: 1204. doi: 10.3389/fphar.2020.01204 . PMC   7435013 . PMID   32903430.
  14. Furci L, Baldan R, Bianchini V, Trovato A, Ossi C, Cichero P, Cirillo DM (March 2015). Morrison RP (ed.). "New role for human α-defensin 5 in the fight against hypervirulent Clostridium difficile strains". Infection and Immunity. 83 (3): 986–95. doi:10.1128/IAI.02955-14. PMC   4333456 . PMID   25547793.

Further reading