Human complement factor I: its expression by insect cells and its biochemical and structural characterisation

Local expression of complement factor I in breast cancer cells correlates with poor survival and recurrence

“…The expression of FI may face difficulties in cells other than hepatocytes due to insufficient cellular machinery for posttranslational processing, resulting in secretion of a precursor devoid of proteolytic activity [32]. Herein, we showed for the first time that breast Beside an obvious pro-tumor activity of endogenous complement inhibitors, there are also reports showing tumor-sustaining events driven by complement activation, such as mobilization of immune suppressor cells [6] and angiogenesis [7].…”

Complement factor I in health and disease

“…Once the protein is secreted, the signal peptide of 18 residues is cleaved off. FI can be expressed recombinantly in mammalian or insect cells but only partial proteolytic processing of the single chain FI precursor occurs under such conditions and only the processed protein has catalytic activity (Nilsson et al, 2007;Ullman et al, 1998;Wong et al, 1995). Mature FI is made up of an unique sequence of domains some of which share sequence similarity with domains found in complement and non-complement proteins.…”

Uncontrolled Zinc- and Copper-Induced Oligomerisation of the Human Complement Regulator Factor H and Its Possible Implications for Function and Disease

“…Haemolytically inactive C3 (C3u) was prepared by incubating native C3 in 200 mM hydrazine at 37°C for 1 h. 54 Protein concentrations were determined from absorption coefficients of 16.7 for FH, 12 for factor I and 9.4 for C3u (1%; 280 nm; 1 cm path length). 31,55,56 Proteins were dialysed into Hepes buffer for experiments, and their integrity was routinely checked by SDS-PAGE before and after scattering, ultracentrifugation and assays. Fig.…”