Bacteria often reside in multicellular communities, called biofilms, held together by an extracellular matrix. In many bacteria, the major proteinaceous component of the biofilm are amyloid fibers. Amyloids are highly stable and structured protein aggregates which were known mostly to be associated with neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. In recent years, microbial amyloids were identified also in other species and shown to play major roles in microbial physiology and virulence. For example, amyloid fibers assemble on the bacterial cell surface as a part of the extracellular matrix and are extremely important to the scaffolding and structural integrity of biofilms, which contribute to microbial resilience and resistance. Furthermore, microbial amyloids play fundamental nonscaffold roles that contribute to the development of biofilms underlying numerous persistent infections. Here, we review several nonscaffold roles of bacterial amyloid proteins, including bridging cells during collective migration, acting as regulators of cell fate, as toxins against other bacteria or against host immune cells, and as modulators of the hosts’ immune system. These overall points on the complexity of the amyloid fold in encoding numerous activities, which offer approaches for the development of a novel repertoire of antivirulence therapeutics.

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功能性细菌淀粉样蛋白在基因调控、毒性和免疫调节中的新作用

细菌通常存在于称为生物膜的多细胞群落中，由细胞外基质结合在一起。在许多细菌中，生物膜的主要蛋白质成分是淀粉样纤维。淀粉样蛋白是高度稳定和结构化的蛋白质聚集体，已知其主要与神经退行性疾病有关，例如阿尔茨海默氏症、帕金森氏症和亨廷顿氏病。近年来，在其他物种中也发现了微生物淀粉样蛋白，并证明其在微生物生理学和毒力中起主要作用。例如，淀粉样蛋白纤维作为细胞外基质的一部分聚集在细菌细胞表面，对生物膜的支架和结构完整性极其重要，这有助于微生物的弹性和抵抗力。此外，微生物淀粉样蛋白发挥着基本的非支架作用，有助于形成许多持续感染背后的生物膜。在这里，我们回顾了细菌淀粉样蛋白的几种非支架作用，包括在集体迁移过程中桥接细胞、作为细胞命运的调节剂、作为对抗其他细菌或宿主免疫细胞的毒素，以及作为宿主免疫系统的调节剂。这些关于淀粉样蛋白折叠在编码众多活动中的复杂性的总体观点，为开发新型抗病毒疗法提供了方法。作为对抗其他细菌或宿主免疫细胞的毒素，以及宿主免疫系统的调节剂。这些关于淀粉样蛋白折叠在编码众多活动中的复杂性的总体观点，为开发新型抗病毒疗法提供了方法。作为对抗其他细菌或宿主免疫细胞的毒素，以及宿主免疫系统的调节剂。这些关于淀粉样蛋白折叠在编码众多活动中的复杂性的总体观点，为开发新型抗病毒疗法提供了方法。