The protein that forms bacterial pili (fimbriae). Fimbriae have been most extensively studied in Porphyromonas (Bacteroides) gingivalis, the bacterium responsible for periodontal disease. The main fimbrillin (~195 aa) is the product of the fimA gene of which there are five variants; the virulence varies according to the type being expressed. A second type of fimbrillin (~350 aa, product of the mfa1 gene) is also known. Fimbriae are required for attachment (through integrins) and invasion of the gingival mucosa. Fimbriae are not restricted to P. gingivalis, are important virulence factors for some strains of E. coli, and are found in Salmonella, Shigella, and various other pathogenic bacteria.
Subjects: Medicine and Health.