Interaction between the protein InIB of Listeria monocytogenes and lipoteichoic acid:: a novel mechanism of protein association at the surface of Gram-positive bacteria
Interaction between the protein InIB of Listeria monocytogenes and lipoteichoic acid:: a novel mechanism of protein association at the surface of Gram-positive bacteria
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DOI：
10.1046/j.1365-2958.1999.01652.x
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发表时间：
1999-12-01
影响因子：
3.6
通讯作者：
Cossart, P
中科院分区：
文献类型：
--
作者：
Jonquières, R;Bierne, H;Cossart, P
InIB是一种单核细胞增生李斯特菌蛋白，足以促进进入多种哺乳动物细胞。InIB的最后232个氨基酸结构域（Csa）已被证明介导附着在细菌表面上，尽管其序列并不表明任何已知的与细菌表面结合的机制。InIB存在于细菌表面和培养上清液中。正如最近已经证明的，两种形式的InIB，可溶性和表面结合，可以触发宿主细胞中的信号。为了阐明这两种形式中每一种的具体作用，重要的是要了解InIB如何与细菌表面结合。使用显微镜，我们发现的证据表明，InIB是部分埋在细胞壁层，并使用分馏实验，我们证明，InIB协会与细菌细胞质膜。此外，使用纯化的脂磷壁酸（LTA）和三种多肽InIB、Csa或InIB Δ Csa，（InIB缺少最后232个氨基酸），我们证明LTA是InIB的Csa结构域的配体。这些结果提供了脂磷壁酸和参与粘附和信号传导的细菌蛋白之间相互作用的第一个证据，并突出了革兰氏阳性菌表面蛋白质缔合的新机制。
InIB is a Listeria monocytogenes protein that is sufficient to promote entry in a variety of mammalian cells. The last 232-amino-acid domain (Csa) of InIB has been shown to mediate attachment on the listerial surface, although its sequence does not suggest any known mechanism of association to the bacterial surface. InIB is present both on the bacterial surface and in culture supernatants. As has been recently demonstrated, both forms of InIB, soluble and surface-bound, can trigger signalling in host cells. To elucidate the specific role of each of the two forms, it was important to understand how InIB associates with the bacterial surface. Using microscopy, we find evidence that InIB is partially buried in the cell wall layer, and using fractionation experiments we demonstrate that InIB associates with the bacterial cytoplasmic membrane. Moreover, using purified lipoteichoic acid (LTA) and the three polypeptides InIB, Csa, or InIB Delta Csa (InIB lacking the last 232 amino acids), we demonstrate that LTA is a ligand for the Csa domain of InIB, These results provide the first evidence at an interaction between lipoteichoic acids and a bacterial protein involved in adhesion and signalling, and highlight a new mechanism of protein association on the surface of Gram-positive bacteria.