Curli

3X2R

Probiotic-associated therapeutic curli hybrids (PATCH)

Curli are proteinaceous extracellular fibers produced by certain Enterobacteriaceae bacteria, including Escherichia coli and Salmonella. These fibers are a major component of the bacterial extracellular matrix and play a crucial role in biofilm formation, adhesion to surfaces, and interaction with host cells.

Structure and Composition

Curli fibers are composed primarily of the protein subunit CsgA, which polymerizes into amyloid fibers. The assembly of curli is a complex process involving several proteins encoded by the csg operon. The major components of the curli biogenesis machinery include:

• CsgA: The major structural subunit of curli fibers.
• CsgB: A nucleator protein that initiates the polymerization of CsgA.
• CsgC, CsgE, CsgF, and CsgG: Accessory proteins involved in the secretion and assembly of curli fibers.

Function

Curli fibers contribute to the ability of bacteria to form biofilms, which are communities of microorganisms that adhere to surfaces and are embedded in a self-produced extracellular matrix. Biofilms provide bacteria with increased resistance to environmental stresses, including desiccation, antibiotics, and the host immune system. Curli fibers also mediate adhesion to various surfaces, including host tissues, which is important for bacterial colonization and infection.

Role in Disease

Curli fibers are implicated in the pathogenesis of several bacterial infections. In urinary tract infections, for example, curli fibers facilitate the adhesion of Escherichia coli to the urinary tract epithelium. In gastrointestinal infections, curli fibers contribute to the colonization of the intestinal mucosa by Salmonella.

Research and Applications

Curli fibers have been studied extensively for their role in biofilm formation and bacterial pathogenesis. They are also of interest in the field of nanotechnology due to their amyloid properties, which can be harnessed for the development of novel biomaterials.

Related Pages

• Biofilm
• Escherichia coli
• Salmonella
• Amyloid
• Bacterial extracellular matrix
• csg operon