Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cytotoxic protein isolated from Pseudomonas aeruginosa damages the plasma membranes of many mammalian cells by forming pores. We studied binding of the 125I-cytotoxin and the resulting increase of cation permeability in erythrocytes of various mammalian species. The sensitivity of red blood cells was inversely related to the relative sphingomyelin content in their external surface. Thus, erythrocytes with a sphingomyelin to phosphatidylcholine ratio below 1 (dog, rat, rabbit and man) were sensitive, whereas red blood cells with a ratio above 1 (pig, cattle and sheep) were not attacked even with 100-fold higher cytotoxin concentrations. At 37 degrees C 6.8 +/- 1.2 x 10(3) molecules of 125I-cytotoxin were bound per rabbit erythrocyte (KD = 59 nM), whereas no binding occurred to cattle cells. Cleavage of sphingomyelin by sphingomyelinase C from Bacillus cereus (EC 3.1.4.12) triggered a dose-dependent enhancement in binding and permeability increase, particularly in red blood cells with a high proportion of sphingomyelin. The KDs for all animal species investigated were 53-60 nM. Pretreatment with mainly phosphatidylcholine-hydrolyzing phospholipases D from Streptomyces chromofuscus and cabbage (EC 3.1.4.4) or phospholipase C from Bacillus cereus (EC 3.1.4.3) did not influence the cytotoxin effect. The negative correlation between susceptibility and the proportion of sphingomyelin in plasma membranes suggests a binding site close to sphingomyelin.
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PMID:Pseudomonas aeruginosa cytotoxin: the influence of sphingomyelin on binding and cation permeability increase in mammalian erythrocytes. 250 11

Phosphatidylcholine breakdown has been shown to play a critical role in signal transduction involving generation of a number of second messengers [Exton, J.H., Biochim. Biophys. Acta, 1212 (1994) 26-42]. In the present report we demonstrate by immunofluorescence that short-treatment of C 6 glial cells with phosphatidylcholine-hydrolyzing phospholipase C (PC-PLC), changes the intracellular localization of protein kinase C (PKC) zeta from the cytoplasm to a perinuclear region. Western blot analysis also showed a redistribution of PKC zeta after incubation of cells with PC-PLC. To test whether these changes were accompanied by an activation of the enzyme, we measured the extent of phosphorylation of PKC zeta by immunoprecipitation from 32P-labelled cells. Short-treatment with PC-PLC resulted in enhanced phosphorylation of the higher Mr PKC zeta in C 6 glial cells.
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PMID:Addition of phosphatidylcholine-phospholipase C induces cellular redistribution and phosphorylation of protein kinase C zeta in C 6 glial cells. 896 6