Paths reunited: Initiation of the classical and lectin pathways of complement activation.
Understanding the structural organisation and mode of action of the initiating complex of the classical pathway of complement activation (C1) has been a central goal in complement biology since its isolation almost 50 years ago. Nevertheless, knowledge is still incomplete, especially with regard to the interactions between its subcomponents C1q, C1r and C1s that trigger activation upon binding to a microbial target. Recent studies have provided new insights into these interactions, and have revealed unexpected parallels with initiating complexes of the lectin pathway of complement: MBL-MASP and ficolin-MASP. Here, we develop and expand these concepts and delineate their implications towards the key aspects of complement activation via the classical and lectin pathways.
Wallis
Russell
R
Department of Infection, Immunity and Inflammation, University of Leicester, UK. rw73@le.ac.uk
Mitchell
Daniel A
DA
Schmid
Ralf
R
Schwaeble
Wilhelm J
WJ
Keeble
Anthony H
AH
D000818:Animals; D003172:Complement C1 / Q000276:immunology* / Q000378:metabolism; D003171:Complement Pathway, Classical; D037582:Complement Pathway, Mannose-Binding Lectin; D054884:Host-Pathogen Interactions / Q000276:immunology; D006801:Humans; D037601:Mannose-Binding Lectin / Q000276:immunology; D050606:Mannose-Binding Protein-Associated Serine Proteases / Q000276:immunology
D003172:Complement C1; D037601:Mannose-Binding Lectin; D050606:Mannose-Binding Protein-Associated Serine Proteases