Phospholipase A2, membrane associated

Also known as: GIIC sPLA2, Group IIA phospholipase A2, Non-pancreatic secretory phospholipase A2, Phosphatidylcholine 2-acylhydrolase 2A, PLA2G2A, P14555

Phospholipase A2, membrane-associated (PLA2G2A), also known as Group IIA secretory phospholipase A2 (GIIC sPLA2), is a calcium-dependent enzyme that catalyzes the hydrolysis of the sn-2 ester bond of membrane glycerophospholipids, releasing free fatty acids and lysophospholipids. Its mechanism of action is primarily extracellular, targeting bacterial membranes and host cell phospholipids. The enzyme exhibits potent bactericidal activity by disrupting bacterial cell wall integrity, particularly against Gram-positive bacteria. Additionally, PLA2G2A generates lipid mediators such as arachidonic acid, which serve as precursors for pro-inflammatory eicosanoids, thereby amplifying inflammatory signaling cascades. Its activity is tightly regulated by calcium ion concentration and post-translational modifications. Key research findings indicate that PLA2G2A plays a dual role in host defense and inflammatory pathology. In antimicrobial defense, it directly kills bacteria and synergizes with other innate immune components. In inflammation, elevated PLA2G2A levels are associated with conditions such as rheumatoid arthritis, sepsis, and atherosclerosis, where it contributes to tissue damage and chronic inflammation. Experimental studies also suggest involvement in tissue regeneration, though mechanisms remain under investigation. The enzyme's expression is induced by pro-inflammatory cytokines (e.g., IL-1β, TNF-α) and is elevated in various inflammatory diseases, making it a potential biomarker. Clinically, PLA2G2A is considered an experimental target for therapeutic intervention in inflammatory and infectious diseases. Inhibitors of sPLA2 enzymes have been explored in preclinical models to reduce inflammation and tissue injury, though none have advanced to approved clinical use. Its role in antimicrobial defense also raises considerations for selective targeting to avoid compromising host immunity. Further research is needed to clarify its context-dependent functions and therapeutic potential. For research purposes only — not medical advice.

Key data

Mechanism of action

Secretory calcium-dependent phospholipase A2 that primarily targets extracellular phospholipids with implications in host antimicrobial defense, inflammatory response and tissue regeneration (PubMed:10455175, PubMed:10681567, PubMed:2925633). Hydrolyzes the ester bond of the fatty acyl group attached at sn-2 position of phospholipids (phospholipase A2 activity) with preference for phosphatidylethanolamines and phosphatidylglycerols over phosphatidylcholines (PubMed:10455175, PubMed:10681567). Contributes to lipid remodeling of cellular membranes and generation of lipid mediators involved in pathogen clearance. Displays bactericidal activity against Gram-positive bacteria by directly hydrolyzing phospholipids of the bacterial membrane (PubMed:10358193, PubMed:11694541). Upon sterile inflammation, targets membrane phospholipids of extracellular mitochondria released from activated platelets, generating free unsaturated fatty acids such as arachidonate that is used by neighboring leukocytes to synthesize inflammatory eicosanoids such as leukotrienes. Simultaneously, by compromising mitochondrial membrane integrity, promotes the release in circulation of potent damage-associated molecular pattern molecules that activate the innate immune response (PubMed:25082876). Plays a stem cell regulator role in the intestinal crypt. Within intracellular compartment mediates Paneth cell differentiation and its stem cell supporting functions by inhibiting Wnt signaling pathway in intestinal stem cell (ICS). Secreted in the intestinal lumen upon inflammation, acts in an autocrine way and promotes prostaglandin E2 synthesis that stimulates Wnt signaling pathway in ICS cells and tissue regeneration (By similarity). May play a role in the biosynthesis of N-acyl ethanolamines that regulate energy metabolism and inflammation. Hydrolyzes N-acyl phosphatidylethanolamines to N-acyl lysophosphatidylethanolamines, which are further cleaved by a lysophospholipase D to release N-acyl ethanolamines (PubMed:14998370). Independent of its catalytic activity, acts as a ligand for integrins (PubMed:18635536, PubMed:25398877). Binds to and activates integrins ITGAV:ITGB3, ITGA4:ITGB1 and ITGA5:ITGB1 (PubMed:18635536, PubMed:25398877). Binds to a site (site 2) which is distinct from the classical ligand-binding site (site 1) and induces integrin conformational changes and enhanced ligand binding to site 1 (PubMed:25398877). Induces cell proliferation in an integrin-dependent manner (PubMed:18635536)

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