Alpha-defensin
IPR016327
Definition
Mammalian alpha-defensins are expressed primarily in leukocytes and epithelia. They play an important role in the innate and adaptive immune response to microbial infection. There are six cysteine residues and one glycine residue, for an atypical SS-bulge, which are totally conserved in the otherwise diverse sequences of all known mammalian alpha-defensins. There is also a conserved pair of oppositely charged residues (Arg/Glu) that form a salt bridge across a protruding loop in the molecule. The primary function of the salt bridge in HD5 is to ensure correct processing of proHD5 and subsequent stabilisation of mature alpha-defensin in vivo PMID:18499668. Human neutrophil alpha-defensins (HNPs) are synthesized in vivo as inactive precursor proteins, i.e. preproHNPs. A series of sequential proteolytic events excise the N-terminal inhibitory pro peptide, leading to defensin maturation and storage in azurophilic granules PMID:17355880. Human alpha-defensin-1 (HNP1) is a small antimicrobial peptide, which is cytotoxic to tumour cells in vitro and shows inhibitory activity for pathologic neovascularisation in vivo. Intracellularly expressed HNP1 induces tumour cell apoptosis, consequently inhibiting its growth. It might be involved in the host immune response to tumours and as such is a promising basis for HNP1-based gene therapy for cancer PMID:18566229.
5 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
Loading the interactive Seroatlas explorer...