DEFA3
Description
The DEFA3 (defensin alpha 3) is a protein-coding gene located on chromosome 8.
DEFA3, also known as human alpha defensin 3, human neutrophil peptide 3 (HNP-3), or neutrophil defensin 3, is a human protein encoded by the DEFA3 gene. It belongs to the alpha defensin family of antimicrobial peptides. Defensins are a family of microbicidal and cytotoxic peptides involved in host defense. They are abundant in the granules of neutrophils and are also found in the epithelia of mucosal surfaces such as those of the intestine, respiratory tract, urinary tract, and vagina. Members of the defensin family share high similarity in protein sequence and are distinguished by a conserved cysteine motif. Several alpha defensin genes are clustered on chromosome 8. DEFA3 is found in the microbicidal granules of neutrophils and likely plays a role in phagocyte-mediated host defense. This peptide differs from defensin, alpha 1 by only one amino acid. The DEFA3 gene and the gene encoding defensin, alpha 1 are both subject to copy number variation.
DEFA3 is an effector molecule of the innate immune system that exhibits antibiotic-like properties against a wide range of infectious agents, including bacteria, fungi, and viruses. It neutralizes bacterial toxins such as Bacillus anthracis lethal factor, Clostridium difficile cytotoxin B, and leukocidin produced by Staphylococcus aureus. DEFA3 also blocks herpes simplex virus infection by interacting with envelope glycoprotein B, preventing its binding to heparan sulfate, the receptor for attachment.
DEFA3 is also known as DEF3, HNP-3, HNP3, HP-3, HP3.
