Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.
Microbiology (Reading). 2022 Mar;168(3). doi: 10.1099/mic.0.001154.
Pore-forming toxins (PFTs) are widely distributed in both Gram-negative and Gram-positive bacteria. PFTs can act as virulence factors that bacteria utilise in dissemination and host colonisation or, alternatively, they can be employed to compete with rival microbes in polymicrobial niches. PFTs transition from a soluble form to become membrane-embedded by undergoing large conformational changes. Once inserted, they perforate the membrane, causing uncontrolled efflux of ions and/or nutrients and dissipating the protonmotive force (PMF). In some instances, target cells intoxicated by PFTs display additional effects as part of the cellular response to pore formation. Significant progress has been made in the mechanistic description of pore formation for the different PFTs families, but in several cases a complete understanding of pore structure remains lacking. PFTs have evolved recognition mechanisms to bind specific receptors that define their host tropism, although this can be remarkably diverse even within the same family. Here we summarise the salient features of PFTs and highlight where additional research is necessary to fully understand the mechanism of pore formation by members of this diverse group of protein toxins.
孔形成毒素（PFTs）广泛分布于革兰氏阴性菌和革兰氏阳性菌中。PFTs 可以作为细菌在传播和宿主定植过程中利用的毒力因子，或者，它们可以被用来在多微生物生态位中与竞争微生物竞争。PFTs 通过发生大的构象变化，从可溶性形式转变为膜嵌入形式。一旦插入，它们就会穿孔膜，导致离子和/或营养物质的失控外排，并耗散质子动力势（PMF）。在某些情况下，被 PFT 中毒的靶细胞会显示出作为细胞对孔形成反应的一部分的其他效应。在不同的 PFT 家族的孔形成的机制描述方面已经取得了重大进展，但在某些情况下，对孔结构的完全理解仍然缺乏。PFTs 已经进化出识别机制来结合特定的受体，这些受体定义了它们的宿主趋向性，尽管即使在同一家族中，这种趋向性也可能非常多样化。在这里，我们总结了 PFTs 的显著特征，并强调了在充分理解这个多样化的蛋白毒素家族成员的孔形成机制方面还需要进一步研究的地方。
