Effects of Clostridium perfringens phospholipase C in mammalian cells


Flores-Diaz, M; Thelestam, M; Clark, GC; Titball, RW; Alape-Giron, A; (2004) Effects of Clostridium perfringens phospholipase C in mammalian cells. [Conference or Workshop Item]

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Abstract

Clostridium perfringens phospholipase C (Cp-PLC), the major virulence factor in the pathogenesis of gas gangrene, is a Zn2+ metalloenzyme with lecithinase and sphingomyelinase activities. Its structure shows an N-terminal domain containing the active site. and a C-terminal Ca2- binding domain required for membrane interaction. Although the knowledge of the structure of Cp-PLC and its interaction with aggregated phospholipids has advanced significantly, an understanding of the effects of Cp-PLC in mammalian cells is still incomplete. Cp-PLC binds to artificial bilayers containing cholesterol and sphingomyelin or phosphatidylcholine (PC) and degrades them, but glycoconjugates present in biological membranes influence its binding or positioning toward its substrates. Studies with Cp-PLC variants harboring single amino-acid substitutions have revealed that the active site. the Ca2+ binding region, and the membrane interacting surface are required for cytotoxic and haemolytic activity. Cp-PLC causes plasma membrane disruption at high concentrations, whereas at low concentrations it perturbs phospholipid metabolism. induces DAG generation, PKC activation, Ca2+ mobilization, and activates arachidonic acid metabolism. The cellular susceptibility to Cp-PLC depends on the composition of the plasma membrane and the capacity to up-regulate PC synthesis. The composition of the plasma membrane determines whether Cp-PLC can bind and acquire its active conformation, and thus the extent of phospholipid degradation. The capacity of PC synthesis and the availability of precursors determine whether the cell can replace the degraded phospholipids. Whether the perturbations of signal transduction processes caused by Cp-PLC play a role in cytotoxicity is not clear. However, these perturbations in endothelial cells, platelets and neutrophils lead to the uncontrolled production of intercellular mediators and adhesion molecules, which inhibits bacterial clearance and induces thrombotic events, thus favouring bacterial growth and spread in the host tissues. (C) 2003 Elsevier Ltd. All rights reserved.

Item Type: Conference or Workshop Item
Keywords: bacterial toxins, muscular diseases, molecular models, skeletal muscle, cell survival, CHINESE-HAMSTER OVARY, CTP-PHOSPHOCHOLINE CYTIDYLYLTRANSFERASE, PLATELET-ACTIVATING-FACTOR, SITE-DIRECTED MUTAGENESIS, TOXIN-INDUCED, HEMOLYSIS, DIRECT MEMBRANE DAMAGE, ALPHA-TOXIN, GAS-GANGRENE, PHOSPHATIDYLCHOLINE BIOSYNTHESIS, ARACHIDONIC-ACID
Faculty and Department: Faculty of Infectious and Tropical Diseases > Dept of Pathogen Molecular Biology
PubMed ID: 16701508
Web of Science ID: 220997500008
URI: http://researchonline.lshtm.ac.uk/id/eprint/6533

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