We find them here, we find them there: functional bacterial amyloid

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Protein amyloid deposits are linked to neurodegenerative diseases, exhibiting cytotoxicity, uncontrolled deposition, and polymorphism.
• These features suggest a lack of biological optimization and evolutionary pressure in pathogenic amyloids.
• However, the cross-beta self-organization principle is employed by nature for creating strong, pliable materials.

Purpose of the Study:

• To contrast pathogenic and in vitro-formed amyloids with functional amyloids.
• To highlight the prevalence and characteristics of bacterial functional amyloids.
• To discuss challenges and future perspectives in identifying and characterizing functional amyloid proteins.

Main Methods:

• Comparative analysis of pathogenic, in vitro-formed, and functional amyloids.
• Review of case studies on directed nucleation and tailor-made proteins for amyloid conformation.
• Focus on bacterial amyloid systems.

Main Results:

• Functional amyloids are widespread in nature (humans, invertebrates, fungi, bacteria), often being the rule in bacteria.
• Optimized, tailor-made proteins enable directed nucleation for specific, robust amyloid assemblies.
• Functional amyloids possess distinct properties compared to pathogenic or in vitro-formed counterparts.

Conclusions:

• Nature employs optimized functional amyloids for material applications, contrasting with pathogenic forms.
• Bacterial functional amyloids represent a significant area for study.
• Challenges remain in the purification and analysis of in vivo-formed functional amyloids, necessitating further research.