AOAH


Description

The AOAH (acyloxyacyl hydrolase) is a protein-coding gene located on chromosome 7.

Acyloxyacyl hydrolase, also known as AOAH, is a eukaryotic protein encoded by the AOAH gene. AOAH is produced by macrophages (including Kupffer cells and microglia), dendritic cells (especially in the colon), NK cells, ILC1 cells, neutrophils and renal proximal tubule cells. The AOAH gene has been found in many invertebrates and in all vertebrates studied to date except fish. Although mice have other well-established mechanisms for preventing LPS signaling, none of these has prevented long-term persistence of stimulatory LPS in animals that lack AOAH. The enzyme's 2 disulfide-linked subunits are encoded by a single mRNA. The smaller subunit is a member of the saposin-like (SAPLIP) protein family and the larger subunit, which contains the active site serine, is a GDSL lipase. The enzyme's 3D structure and catalytic mechanism were reported by Gorelik et al. Acyloxyacyl hydrolase (AOAH) is a lipase that selectively releases the secondary (acyloxyacyl-linked) fatty acyl chains from the hexaacyl lipid A moiety found in many bacterial lipopolysaccharides (LPSs, also called endotoxins). The resulting tetraacyl LPS is non-stimulatory and can be a potent inhibitor of LPS sensing via the MD-2--Toll-like Receptor 4 (TLR4). The enzyme's other known substrates include bacterial lipopeptides and several host glycerolipids, including lyso-and oxidized phospholipids. Absence of the enzyme in genetically engineered mice has been associated with distinctive phenotypes. AOAH-deficient animals are unable to inactivate even small amounts of LPS in most tissues; the LPS remains bioactive and may pass from cell to cell in vivo for many weeks.

Removes the secondary (acyloxyacyl-linked) fatty acyl chains from the lipid A region of bacterial lipopolysaccharides (PubMed:1883828, PubMed:8089145, PubMed:29343645). By breaking down LPS, terminates the host response to bacterial infection and prevents prolonged and damaging inflammatory responses (By similarity). In peritoneal macrophages, seems to be important for recovery from a state of immune tolerance following infection by Gram-negative bacteria (By similarity).

AOAH is also known as -.

Associated Diseases


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