Genetic, molecular and functional analyses of factor I - an inhibitor of the complement system
Factor I (FI) is a serine protease that inhibits the complement system by cleaving activated C3 and C4 complement proteins, in the presence of cofactors. Mutations in the gene coding for FI have been identified in complete FI deficient- and atypical hemolytic uremic syndrome (aHUS) patients. The mutations were introduced in recombinantly expressed proteins, purified and analyzed in functional ass