Ireton K, Payrastre B, Cossart P
Unité des Interactions Bactéries-Cellules, 28 rue du Dr. Roux, Institut Pasteur, 75724 Paris, Cedex 15, France.
J Biol Chem. 1999 Jun 11;274(24):17025-32. doi: 10.1074/jbc.274.24.17025.
The Gram-positive pathogen Listeria monocytogenes induces its own internalization into some non-phagocytic mammalian cells by stimulating host tyrosine phosphorylation, phosphoinositide (PI) 3-kinase activity, and rearrangements in the actin cytoskeleton. Entry into many cultured cell lines is mediated by the bacterial protein InlB. Here we investigate the role of InlB in regulating mammalian signal transduction and cytoskeletal structure. Treatment of Vero cells with purified InlB caused rapid and transient increases in the lipid products of the PI 3-kinase p85-p110, tyrosine phosphorylation of the mammalian adaptor proteins Gab1, Cbl, and Shc, and association of these proteins with p85. InlB also stimulated large scale changes in the actin cytoskeleton (membrane ruffling), which were PI 3-kinase-dependent. These results identify InlB as the first reported non-mammalian agonist of PI 3-kinase and demonstrate similarities in the signal transduction events elicited by this bacterial protein and known agonists such as epidermal growth factor.
革兰氏阳性病原菌单核细胞增生李斯特菌通过刺激宿主酪氨酸磷酸化、磷酸肌醇（PI）3激酶活性以及肌动蛋白细胞骨架重排，诱导自身内化进入一些非吞噬性哺乳动物细胞。进入许多培养细胞系是由细菌蛋白InlB介导的。在此，我们研究InlB在调节哺乳动物信号转导和细胞骨架结构中的作用。用纯化的InlB处理Vero细胞会导致PI 3激酶p85 - p110的脂质产物迅速且短暂增加，哺乳动物衔接蛋白Gab1、Cbl和Shc的酪氨酸磷酸化，以及这些蛋白与p85的结合。InlB还刺激肌动蛋白细胞骨架发生大规模变化（膜皱褶），这依赖于PI 3激酶。这些结果确定InlB是首个被报道的PI 3激酶非哺乳动物激动剂，并证明了这种细菌蛋白引发的信号转导事件与已知激动剂（如表皮生长因子）之间的相似性。
