This gene encodes a secreted protein belonging to the complement factor H protein family. It binds to Pseudomonas aeruginosa elongation factor Tuf together with plasminogen, which is proteolytically activated. It is proposed that Tuf acts as a virulence factor by acquiring host proteins to the pathogen surface, controlling complement, and facilitating tissue invasion. Mutations in this gene are associated with an increased risk of atypical hemolytic-uremic syndrome.