Listeria monocytogenes phosphatidylinositol-specific phospholipase C has evolved for virulence by greatly reduced activity on GPI anchors (Proc Natl Acad Sci, 2005, 102:12927-12931)

報告日期: 2006/05/23
報告時間: 16:00/16:50
報告學生: 鄒志成
講評老師: 鄧景浩
附件下載:

 

Listeria monocytogenes phosphatidylinositol-specific

phospholipase C has evolved for virulence by

greatly reduced activity on GPI anchors

Speaker鄒志成

Commentator鄧景浩  老師

Time16:00-17:00  5/23/2006  

  Listeria monocytogenes is a ubiquitous food-borne gram-positive bacterium, responsible for life-threatening infections in humans and animals. It is a facultatively intracellular pathogen that is able to enter and multiply in both professional and nonprofessional phagocytes such as epithelial cells or hepatocytes. Several virulence factors have been found to promote this intracellular adaptation. L. monocytogenes phosphatidylinositol-specific phospholipase  C (PI-PLC) play a important role in escape from host cell vacuoles. L. monocytogenes PI-PLC (LmPI-PLC) is comparable with Bacillus cereus PI-PLC (BcPI-PLC) in its ability to cleave PI; however, its activity on GPI-anchored proteins is much lower. The major difference between LmPI-PLC and BcPI-PLC is that the latter has an extra b-strand (Vb) in the C-terminal region. The Vb b-strand provides contacts for the glycan linker of GPI-anchored proteins, which presumably enhances its ability to cleave GPI anchors. In this study, the authors show that, of all the known bacterial PI-PLCs, those from listeriae are the only ones that lack the b-strand. Expression of B. cereus PI-PLC in L. monocytogenes, which has strong activity on GPI-anchored proteins, inhibited bacterial escape from a vacuole and cell-to-cell spread, resulting in greatly reduced virulence in mice. The authors report that L. monocytogenes PI-PLC has evolved for intracellular growth and virulence by a specific structural modification that leads to greatly reduced activity on GPI-anchored proteins.

References

Sandra. J., Wadsworth, and H. Goldfine. 2002. Mobilization of Protein Kinase C in Macrophages Induced Listeria monocytogenes  Affects Its Internalization And Escape from the Phagosome. . Infect. Immun. 70: 4650–4660.

Zhengyu. W., Lauren. A., Zenewicz, and H. Goldfine. 2005. Listeria monocytogenes phosphatidylinositol-specific phospholipase C has evolved for virulence by greatly reduced activity on GPI anchors. Proc. Natl. Acad. Sci. USA. 102: 12927-12931.