Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali, Punjab 140306, India.
Biochem Soc Trans. 2021 Feb 26;49(1):455-465. doi: 10.1042/BST20200836.
The integrity of the plasma membranes is extremely crucial for the survival and proper functioning of the cells. Organisms from all kingdoms of life employ specialized pore-forming proteins and toxins (PFPs and PFTs) that perforate cell membranes, and cause detrimental effects. PFPs/PFTs exert their damaging actions by forming oligomeric pores in the membrane lipid bilayer. PFPs/PFTs play important roles in diverse biological processes. Many pathogenic bacteria secrete PFTs for executing their virulence mechanisms. The immune system of the higher vertebrates employs PFPs to kill pathogen-infected cells and transformed cancer cells. The most obvious consequence of membrane pore-formation by the PFPs/PFTs is the killing of the target cells due to the disruption of the permeability barrier function of the plasma membranes. PFPs/PFTs can also activate diverse cellular processes that include activation of the stress-response pathways, induction of programmed cell death, and inflammation. Upon attack by the PFTs, host cells may also activate pathways to repair the injured membranes, restore cellular homeostasis, and trigger inflammatory immune responses. In this article, we present an overview of the diverse cellular responses that are triggered by the PFPs/PFTs, and their implications in the process of pathogen infection and immunity.
细胞膜的完整性对于细胞的生存和正常功能至关重要。所有生命领域的生物都利用专门的形成孔的蛋白质和毒素（PFPs 和 PFTs）来穿孔细胞膜，并造成有害影响。PFPs/PFTs 通过在膜脂双层中形成寡聚体孔来发挥其破坏作用。PFPs/PFTs 在多种生物过程中发挥重要作用。许多致病性细菌分泌 PFTs 以执行其毒力机制。高等脊椎动物的免疫系统利用 PFPs 杀死受病原体感染的细胞和转化的癌细胞。PFPs/PFTs 形成膜孔最明显的后果是由于破坏了质膜的通透性屏障功能，导致靶细胞死亡。PFPs/PFTs 还可以激活多种细胞过程，包括应激反应途径的激活、程序性细胞死亡的诱导和炎症。宿主细胞受到 PFTs 的攻击后，也可能激活修复受损膜、恢复细胞内稳态和引发炎症免疫反应的途径。在本文中，我们概述了 PFPs/PFTs 引发的多种细胞反应及其在病原体感染和免疫过程中的意义。
