3u0c

Structural highlights

Function

IPAB_SHIFL Effector proteins function to alter host cell physiology and promote bacterial survival in host tissues. Forms a pore with IpaC, which is inserted into the host cell membrane through the Mxi/Spa apparatus, during cell contact. This pore probably allows the translocation of IpaA. IpaB has also been found to be necessary and sufficient to activate macrophage apoptosis by binding to interleukin-1 beta converting enzyme (ICE). Has also been shown to be important, along with IpaD, to block or regulate secretion through the Mxi/Spa translocon in the presence or absence of the secretion signal, respectively. Through interaction with host human MAD2L2, constitutively activates the anaphase-promoting complex APC and induces a cell cycle arrest to prevent epithelial renewal in order to promote bacterial colonization.^{[1] [2]}

References

1. ↑ Iwai H, Kim M, Yoshikawa Y, Ashida H, Ogawa M, Fujita Y, Muller D, Kirikae T, Jackson PK, Kotani S, Sasakawa C. A bacterial effector targets Mad2L2, an APC inhibitor, to modulate host cell cycling. Cell. 2007 Aug 24;130(4):611-23. PMID:17719540 doi:10.1016/j.cell.2007.06.043
2. ↑ Thirumalai K, Kim KS, Zychlinsky A. IpaB, a Shigella flexneri invasin, colocalizes with interleukin-1 beta-converting enzyme in the cytoplasm of macrophages. Infect Immun. 1997 Feb;65(2):787-93. PMID:9009343