The function of ENSG00000164816 (DEFA5, defensin alpha 5) is as follows. Host-defense peptide that maintains sterility in the urogenital system (PubMed:12021776, PubMed:12660734, PubMed:15616305, PubMed:19589339, PubMed:22359618, PubMed:22573326, PubMed:25354318, PubMed:25782105, PubMed:30808760). Has antimicrobial activity against a wide range of bacteria, including Gram-negative E.coli, P.aeruginosa and S.typhimurium, and Gram-positive E.aerogenes, S.aureus, B.cereus, E.faecium and L.monocytogenes (PubMed:12021776, PubMed:15616305, PubMed:19589339, PubMed:22359618, PubMed:22573326, PubMed:25354318, PubMed:30808760). Confers resistance to intestinal infection by S.typhimurium (PubMed:12660734). Exhibits antimicrobial activity against enteric commensal bacteria such as B.adolescentis, L.acidophilus, B.breve, L.fermentum, B.longum and S.thermophilus (PubMed:25354318). Binds to bacterial membranes and causes membrane disintegration (PubMed:25782105). Induces the secretion of the chemokine IL-8 by intestinal epithelial cells (PubMed:19589339). Binds to B.antracis lef/lethal factor, a major virulence factor from B.anthracis, and neutralizes its enzymatic activity (PubMed:22573326). {ECO:0000269|PubMed:12021776, ECO:0000269|PubMed:12660734, ECO:0000269|PubMed:15616305, ECO:0000269|PubMed:19589339, ECO:0000269|PubMed:22359618, ECO:0000269|PubMed:22573326, ECO:0000269|PubMed:25354318, ECO:0000269|PubMed:25782105, ECO:0000269|PubMed:30808760}. (Microbial infection) Acts as a target for S.flexneri infection by binding to the bacterium, possibly via bacterial surface proteins, and thereby augmenting infectivity via enhanced bacterial adhesion and invasion of epithelial cells and tissues. .