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)

The Serratia marcescens hemolysin represents a new type of hemolysin and has been studied in great molecular detail with regard to structure, activation and secretion. It has nothing in common with the pore forming toxins of E. coli type (RTX toxins), the Staphylococcus aureus alpha-toxin or the thiol activated toxin of group A beta-hemolytic streptococci (Streptolysin O). Studies on erythrocytes, eukaryotic cells and artificial black lipid membranes, have shown that the mechanism of pore formation of ShlA is different form other pore forming toxins. The S. marcescens hemolysin proteins ShlB and ShlA exhibit protein sequence homologues in Proteus mirabilis, Haemophilus ducreyi, Edwardsiella tarda and Erwinia chrysantemi. Furthermore, sequence motifs present in ShlA and Shlb have been shown to be important for activity and secretion of the S. marcescens hemolysin. Thus, the S. marcescens hemolysin forms the prototype of a new class of hemolysins and of a new secretory mechanism. The uniqueness of this new mechanism is underlined by the fact that activation of ShlA by ShlB strictly requires phosphatidylethanolamine as a cofactor. New data implicate a conformational change in ShlA during activation. In addition, ShlA not only forms pores in erythrocytes but also in fibroblasts and epithelial cells. The cytotoxic action of ShlA is mainly determined by lysis of infected cells in vitro. In sublytic doses, as will normally be the situation in vivo, ShlA exerts additionally effects which are currently under investigation. The knowledge of the structure, activation, secretion and mode of action of S. marcescens hemolysin has implications for proteins, related in sequence or in mode of secretion and activation.
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PMID:Serratia type pore forming toxins. 1236 21

The Serratia marcescens hemolysin represents the prototype of a growing family of pore forming toxins. The available bacterial genome sequences reveal Serratia hemolysin homologues in additional species. However, only S. marcescens hemolysin has been studied in great molecular detail. This family of toxins has nothing in common with the pore forming toxins of E. coli type (RTX toxins), the Staphylococcus aureus alpha-toxin or the thiol activated toxin of group A beta-hemolytic streptococci (Streptolysin O). Studies on erythrocytes, eukaryotic cells and artificial black lipid membranes, have shown that the mechanism of pore formation of ShlA is different form other pore forming toxins. The S. marcescens hemolysin proteins ShlB and ShlA, exhibit protein sequence homologues in Proteus mirabilis, Haemophilus ducreyi, Yersinia pestis, Yersinia enterocolitica, Edwardsiella tarda, Photorhabdus luminescens and Xylella fastidiosa . The family of Serratia type pore forming toxins show a unique secretory mechanism which has been described as a two partner secretion system (TPSS) or type V-secretion system. Not only Serratia type pore forming toxins are secreted via TPSS but also adhesins from Bordetella pertussis, Erwinia chrysanthemi and Haemophilus influenzae. The uniqueness of the Serratia family is underlined by the fact that activation of ShlA by ShlB strictly requires phosphatidylethanolamine as a cofactor. And, quite unusual, ShlA undergoes a conformational change during activation.
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PMID:The family of Serratia type pore forming toxins. 1610 33