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Activation of cellular phospholipase A2 by Clostridium difficile toxin B
Author(s) -
Shoshan Maria Caspar,
Florin Inger,
Thelestam Monica
Publication year - 1993
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240520115
Subject(s) - toxin , clostridium difficile toxin a , pertussis toxin , cycloheximide , clostridium difficile toxin b , phospholipase a2 , phospholipase , arachidonic acid , phospholipase a , biology , biochemistry , phospholipase c , microfilament , microbiology and biotechnology , chemistry , enzyme , cell , clostridium difficile , receptor , g protein , cytoskeleton , protein biosynthesis , antibiotics
C. difficile toxin B is a potent cytotoxin known to disrupt the microfilaments of cultured cells. We have recently shown also increased phospholipase A2 activity in cells treated with toxin B. The activity was detected as a toxin‐induced, dose‐dependent release of 14 C‐arachidonic acid from prelabeled fibroblasts. Here is shown that the toxin elicited a 14 C‐arachidonic acid release in a cell mutant resistant to the toxin B effect on the microfilaments. The toxin‐induced release was further characterized using fibroblasts. Within 20 min high doses of toxin B (6 μg/ml) elicited a release which increased exponentially with time. Of the major membrane phospholipids the lipase activity affected mainly phosphatidyl ethanolamine. Neither cycloheximide nor pertussis toxin treatment of target cells inhibited the toxin‐induced release, while it could be increased with 12‐ O ‐tetradecanoylphorbol‐13‐acetate. Our results also suggest a toxin‐mediated increase in phospholipase C activity occurring at a later stage than the phospholipase A2 activation. We conclude that the ability of toxin B to induce phospholipase activation represents a hitherto unrecognized toxin B effect which is neither a cause nor a consequence of toxin‐induced microfilament disorganization.