[Phospholipase A2: characteristics and function].

A Sedláková; A Kohút

Home/Archive/PubMed

PubMed · 9748759

[Phospholipase A2: characteristics and function].

A Sedláková·A Kohút

View original source ↗Export metadata ↓

Abstract

Phospholipase A2 (PLA2) hydrolyses membrane phospholipids (PL) and it may release arachidonic acid (AA)--the precursor of eicosanoids--from the sn-2 position. PLA2 and metabolites of its catalytic activity participate in many processes in the organism: metabolism of lipids, inflammation and immune reactions, membrane and tissue reparation, proliferation, and others. PLA2 as also an important element in the signal transduction. In the present article, PLA2 is characterised, classified into several types, and its mechanism of action together with its possible role in the disease processes are described. The attention is aimed at two forms of PLA2: The secretory (PLA2) of the type II which is associated with the inflammation injury, and the cytosolic PLA2 which is the main catalyst in the liberation of AA and which participates in the signal transduction. Other forms of PLA2 has been also described.

Explore related subjects

Arachidonic Acid Inflammation Phospholipases A Phospholipases A2 Signal Transduction Journal Article Review

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

A Sedláková, A Kohút. 1998. [Phospholipase A2: characteristics and function].. https://pubmed.ncbi.nlm.nih.gov/9748759/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2002

Arachidonate release and c-fos expression in various models of hypoxia and hypoxia-hypoglycemia in retinoic acid differentiated neuroblastoma cells.

Hypoxia-hypoglycemia has played an important role in inducing both phospholipase A2 activation and the expression of the early gene c-fos, in the neuroblastoma cell line SK-N-BE, after it has been differentiated by retinoic acid. Under hypoxic-hypoglycemic conditions, arachidonic acid release has found to be significant after 30 min, whereas c-fos expression has required at least 4 h. This model has been obtained by adding glycolytic inhibitor 2-deoxyglucose to the culture and by placing cells in an atmosphere containing 100% N2 for different time periods. This condition has been compared with two different models: NaCN and nitrogen have been used as hypoxic stimuli, without inhibiting the glycolytic pathway, but the same cell cultures have been used. Cell viability and the fall of cellular ATP levels have been evaluated in all the models, in order to monitor and compare the hypoxic cellular damage. Phospholipase A2 activation has been found to be significant in all conditions, even if to a different extent; but only hypoxia combined with the inhibition of the glycolytic pathway, has induced a significant expression of c-fos. It is very difficult to study hypoxic stimuli in 'in vitro' systems. Our study has compared three different models and the one combining gaseous hypoxia and hypoglycemic conditions seems to be very effective in stimulating early events involved in hypoxic phenomena such as phospholipase activation and the expression of the early gene c-fos.

Arachidonic Acid↗

PubMed2001

Crystal structures of human serum albumin complexed with monounsaturated and polyunsaturated fatty acids.

The primary ligands of human serum albumin (HSA), an abundant plasma protein, are non-esterified fatty acids. In vivo, the majority of fatty acids associated with the protein are unsaturated. We present here the first high-resolution crystal structures of HSA complexed with two important unsaturated fatty acids, the monounsaturated oleic acid (C18:1) and the polyunsaturated arachidonic acid (C20:4). Both compounds are observed to occupy the seven binding sites distributed across the protein that are also bound by medium and long-chain saturated fatty acids. Although C18:1 fatty acid binds each site on HSA in a conformation almost identical with that of the corresponding saturated compound (C18:0), the presence of multiple cis double bonds in C20:4 induces distinct binding configurations at some sites. The observed restriction on binding configurations plausibly accounts for differences in the pattern of binding affinities for the primary sites between polyunsaturated fatty acids and their saturated or monounsaturated counterparts.

Arachidonic Acid↗

PubMed2001

Brucella lipopolysaccharides induce cyclooxygenase-2 expression in monocytic cells.

Human brucellosis is characterized by the presence of both acute inflammatory episodes and chronic inflammation with granuloma formation. On this basis, the proinflammatory effects of smooth lipopolysaccharide of Brucella (S-LPS) were addressed and compared to those of LPS from Escherichia coli. For this purpose, the induction of cyclooxygenase-2 (COX-2), the production of the chemokine monocyte chemoattractant protein-1 (MCP-1), and the activation of the nuclear factor kappa B (NF-kappa B) were studied. S-LPS was found to induce both COX-2 expression and MCP-1 production; however, the potency of E. coli LPS exceeded that of Brucella S-LPS by some orders of magnitude. However, at concentrations above 1 microg/ml, all of the LPS produced comparable effects, including their ability to activate the NF-kappa B system. These observations help explain the inflammatory events associated with Brucella infection and the ability of Brucella to produce monocyte recruitment and granuloma formation.

Arachidonic Acid↗