DEFA6
Description
The DEFA6 (defensin alpha 6) is a protein-coding gene located on chromosome 8.
Defensin, alpha 6 (DEFA6) also known as human alpha defensin 6 (HD6) is a human protein that is encoded by the DEFA6 gene. DEFA6 is expressed in the Paneth cells of the ileum.
== Function == The alpha defensins are a family of microbicidal and cytotoxic peptides that defend the host against bacteria and viruses. HD6 has poor antibacterial potency. However, HD6 affords protection against invasion by enteric bacterial pathogens by self-assembly to form fibrils and nanonets that surround and entangle bacteria. Several alpha defensin genes, including DEFA6, are clustered on chromosome 8.
Host-defense peptide that contributes to intestinal innate immunity and mediates homeostasis at mucosal surfaces by forming higher-order oligomers that capture bacteria and prevent microbial invasion of the epithelium (PubMed:15616305, PubMed:25158166, PubMed:25354318, PubMed:28026958, PubMed:17088326). After binding to bacterial surface proteins, undergoes ordered self-assembly to form fibril-like nanonets that surround and entangle bacteria and thereby prevent bacterial invasion across the epithelial barrier (PubMed:22722251). Entangles and agglutinates Gram-negative bacteria, such as E.coli, S.typhimurium and Y.enterocolitica, and Gram-positive bacteria such as L.monocytogenes, thereby protecting the intestine against invasion by enteric bacterial pathogens (PubMed:27076903, PubMed:25158166, PubMed:22722251). Blocks adhesion of C.albicans to intestinal epithelial cells and thereby suppresses fungal invasion of epithelial cells and biofilm formation (PubMed:28026958). Under reducing conditions and in an acidic environment similar to the intestinal milieu, exhibits inhibitory activity against anaerobic bacteria such as B.adolescentis, L.acidophilus and B.breve, as well as B.longum and S.thermophilus, possibly by leading to alterations in bacterial cell envelope structures (PubMed:25354318). The disulfide- linked oxidized form exhibits negligible antimicrobial activity against Gram-negative and Gram-positive bacteria, as compared to the enteric defensin DEFA5 (PubMed:15616305, PubMed:17088326). {ECO:0000269|PubMed:15616305, ECO:0000269|PubMed:17088326, ECO:0000269|PubMed:22722251, ECO:0000269|PubMed:25158166, ECO:0000269|PubMed:25354318, ECO:0000269|PubMed:27076903, ECO:0000269|PubMed:28026958}.
DEFA6 is also known as DEF6, HD-6.
