Ficolins are pattern recognition receptors that bind to acetyl groups present in the carbohydrates of bacterial surfaces and mediate activation of the lectin pathway of the complement cascade.
The combination of collagen-like and fibrinogen-like domain allows the protein to form a basic subunit containing a triple helical tail and a trio of globular heads.
[2] Ficolins are produced in the liver by hepatocytes and in the lung by alveolar cells type II, neutrophils and monocytes.
[4] Ficolins recognise carbohydrate structures on pathogens' surfaces as their pathogen-associated molecular pattern (PAMP) and activate the lectin pathway of the complement cascade.
[3] Three ficolins have been identified in humans: Ficolin-1 and ficolin-2 are encoded be a gene localised on chromosome 9 (9q34) and they share approximately 80% identity in amino sequence.