Young John A T, Collier R John
Infectious Disease Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Annu Rev Biochem. 2007;76:243-65. doi: 10.1146/annurev.biochem.75.103004.142728.
Anthrax toxin consists of three nontoxic proteins that self-assemble at the surface of receptor-bearing mammalian cells or in solution, yielding a series of toxic complexes. Two of the proteins, called Lethal Factor (LF) and Edema Factor (EF), are enzymes that act on cytosolic substrates. The third, termed Protective Antigen (PA), is a multifunctional protein that binds to receptors, orchestrates the assembly and internalization of the complexes, and delivers them to the endosome. There, the PA moiety forms a pore in the endosomal membrane and promotes translocation of LF and EF to the cytosol. Recent advances in understanding the entry process include insights into how PA recognizes its two known receptors and its ligands, LF and EF; how the PA:receptor interaction influences the pH-dependence of pore formation; and how the pore functions in promoting translocation of LF and EF across the endosomal membrane.
炭疽毒素由三种无毒蛋白质组成，它们在带有受体的哺乳动物细胞表面或溶液中自行组装，产生一系列有毒复合物。其中两种蛋白质，称为致死因子（LF）和水肿因子（EF），是作用于胞质底物的酶。第三种称为保护性抗原（PA），是一种多功能蛋白质，它与受体结合，协调复合物的组装和内化，并将它们递送至内体。在那里，PA部分在内体膜上形成一个孔，并促进LF和EF转运至胞质溶胶。最近在理解进入过程方面的进展包括对PA如何识别其两种已知受体及其配体LF和EF的深入了解；PA与受体的相互作用如何影响孔形成的pH依赖性；以及孔在促进LF和EF跨内体膜转运中如何发挥作用。
