title: Structural biology of the membrane attack complex.
abstract: The complement system is an intricate network of serum proteins that mediates humoral innate immunity through an amplification cascade that ultimately leads to recruitment of inflammatory cells or opsonisation or killing of pathogens. One effector arm of this network is the terminal pathway of complement, which leads to the formation of the membrane attack complex (MAC) composed of complement components C5b, C6, C7, C8 and C9. Upon formation of C5 convertases via the classical or alternative pathways of complement activation, C5b is generated from C5 by proteolytic cleavage, nucleating a series of association and polymerisation reactions of the MAC-constituting complement components that culminate in pore formation of pathogenic membranes. Recent structures of MAC components and homologous proteins significantly increased our understanding of oligomerisation, membrane association and integration, shedding light onto the molecular mechanism of this important branch of the innate immune system.
authors.affiliation: Center for Chronic Immunodeficiency, University Medical Center Freiburg, Breisacher Straße 117, 79106, Freiburg, Germany, andreas.sonnen@uniklinik-freiburg.de.
authors.forename: Andreas F-P
authors.initials: AF
authors.lastname: Sonnen
authors.forename: Philipp
authors.initials: P
authors.lastname: Henneke
mesh_terms: D000818:Animals; D015938:Complement Membrane Attack Complex / Q000737:chemistry* / Q000378:metabolism; D003165:Complement System Proteins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D052899:Pore Forming Cytotoxic Proteins / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D055503:Protein Multimerization
chemical_list: D015938:Complement Membrane Attack Complex; D052899:Pore Forming Cytotoxic Proteins; D003165:Complement System Proteins