The complement activation takes place through one or more of the well-established (alternative, classical or lectin) pathways consisting of plasma and membrane-bound proteins. All three pathways converge at the level of complement C3 [https://doi.org/10.6072/H0.MP.A004235.01] and are controlled by regulators [https://doi.org/10.1038/ni.1923]. Complement C3 belongs to the alpha-2-macroglobulin family of proteins, and consists of a alpha-chain and an beta-chain. Cleavage of C3 which can be initiated by one or more of the above three distinct pathways, into C3b[Proteolysis@23-667,749-1663] and C3a [Proteolysis@672-748] is an important step in the complement activation cascade. Classical and lectin pathways, when activated with recognition of pathogens (or immune complexes) use C3-convertase [C4b2a] to cleave complement C3 into C3a and C3b [https://doi.org/10.1084/jem.125.2.359]. However, in alternative pathway a small fraction of the C3 molecules are hydrolyzed to C3(H20) exposing new binding sites. This hydrated C3 [C3(H20)] recruits complement factor B [fB], which is then cleaved by complement factor D [fD] to result in formation of the minor form of C3-convertase [C3(H20)Bb] that cleaves C3 into C3a and C3b [https://doi.org/10.1084/jem.154.3.856]. Further, addition of C3b to C3 convertase [C3bBb or C4b2a] results in C5 convertase [C3bBb3b or C4b2a3b], that cleaves complement C5 to C5a and C5b, is the last enzymatic step of the complement activation cascade [https://doi.org/10.1074/jbc.273.27.16828][https://www.ncbi.nlm.nih.gov/pubmed/?term=2387864]. During complement activation C5b interacts with complement C6, C7, C8 and C9 in a sequential and non-catalyzed manner to result in the formation of Terminal Complement Complex (TCC) [https://doi.org/10.1074/jbc.M111.219766]. The entire network is considered as a simple recognition and elimination system of host-immune complexes and apoptotic and/or pathogens, and therefore promotes host immune homeostasis. The complement system is also involved in cross-talk with other processes related to coagulation, lipid metabolism and cancer. However, many pathogens counteract complement attack through a range of different mechanisms, such acquisition of host complement regulators to the surface of pathogen, or secretion of complement inactivation factors. In order to have a holistic view of the entire complement network, Dr. John D.Lambris group (University of Pennsylvania) developed the Complement Map Database (CMAP) which is a unique repository focused on documented molecular interactions described within the complement cascade and between complement and other biological systems. Information contained in CMAP (http://www.complement.us/cmap/index.php)[https://doi.org/10.1093/bioinformatics/btt269] is entirely based on published experimental data and is fully revised by experts in the field. Further, the Signaling Gateway Molecule Pages -SGMP-( https://escholarship.org/uc/molecule_pages)[https://doi.org/10.1093/bioinformatics/btr190] has published a curated data on each protein involved in human complement activation pathways (refs. [https://doi.org/10.6072/H0.MP.A004235.01] [https://doi.org/10.6072/H0.MP.A004228.01] [https://doi.org/10.6072/H0.MP.A004276.01] [https://doi.org/10.6072/H0.MP.A004256.01] [https://doi.org/10.6072/H0.MP.A004240.01] [https://doi.org/10.6072/H0.MP.A008392.01] [https://doi.org/10.6072/H0.MP.A008391.01] [https://doi.org/10.6072/H0.MP.A004274.01] [https://doi.org/10.6072/H0.MP.A004275.01] [https://doi.org/10.6072/H0.MP.A004266.01] [https://doi.org/10.6072/H0.MP.A004267.01] [https://doi.org/10.6072/H0.MP.A004263.01] [https://doi.org/10.6072/H0.MP.A004234.01] [https://doi.org/10.6072/H0.MP.A004258.01] ). f3d c51 ae0 b4e c1d a6d ec2 ea9 baa ca2 f38 cf8 a5f fe4 cf0 c78 ea0 Gngipain-1 Two isoforms exists (C4BPA and C4BPB). C1q is composed of 18 polypeptide chains: six A-chains, six B-chains, and six C-chains. Type your comment here f47 f1b Small inhbitor of complement enzymes A factor H-, FHL-1-, and plasminogen-binding surface protein of Candida albicans Complement C5 ITGAM and ITGB2 Peptide fragment from complement C3 Streptococcal C5a peptidase f1b AAM51537|780 Peptide fragment from complement C3 Complement C4 exists in two isoforms, C4-A and C4-B. Peptide fragment from complement C3 f1b f1b Alternative C5 convertase Complex Components C3b Bb T. foetus extracellular cysteine proteinase Complement C8 exhists in 3 isoforms. f1b Complex Components C4b C2b Complex Components C3b Bb CFP ITGB2 and ITGAX A factor H-, FHL-1-, and plasminogen-binding surface protein of Candida albicans Complex Components C3b Bb Classical C5 convertase Complex Components C4b C2b C3b Complement Factor D Small inhbitor of complement enzymes f1b Peptide fragment from complement C3 Small inhbitor of complement enzymes Alternative C5 convertase and CFP complex Complex Components C3b Bb CFP P Complement factor B's fragment Ba COMPLEX Complex of hydrated C3 molecule and a proteolytic fragment from CFB. CFD cleaves CFB in to Ba and Bb. Then Bb combines with C3(H20), a C3 Convertase. 10.6072/H0.MP.A004263.01 DOI Integrin beta-2. UCSD Molecule Pages. 2013 Dinasarapu AR Chandrasekhar A Hajishengallis G Subramaniam S 10.6072/H0.MP.A004258.01 DOI Properdin. UCSD Molecule Pages. 2014 Min J, Chandrasekhar A Dinasarapu AR Kemper C Subramaniam S 10.6072/H0.MP.A004235.01 DOI Complement C3 UCSD Molecule Pages, 1 (2), 34-48. (doi: 10.6072/H0.MP.A004235.01) 2012 Dinasarapu AR, Chandrasekhar A, Sahu A, Subramaniam S 10.6072/H0.MP.A004256.01 DOI Complement factor H. UCSD Molecule Pages, 1 (2), 71-86 2012 Dinasarapu A Chandrasekhar A Jozsi M Subramaniam S 10.6072/H0.MP.A004240.01 DOI Complement C5. UCSD Molecule Pages , 1 (2), 61-70. 2012 Chandrasekhar A Dinasarapu AR Isenman D.E Subramaniam S 10.6072/H0.MP.A004267.01 DOI H-Ficolin. UCSD Molecule Pages. 2013 Chandrasekhar A Dinasarapu AR Cedzyaski M Subramaniam S 10.6072/H0.MP.A008392.01 DOI MAp44. UCSD Molecule Pages. 2013 Chandrasekhar A Dinasarapu AR Matsushita M Subramaniam S complement system pathway PW:0000502 Pathway Ontology 23661693 PubMed CMAP: Complement Map Database. Bioinformatics 2013 Yang K Dinasarapu AR Reis ES Deangelis RA Ricklin D Subramaniam S Lambris JD 10.6072/H0.MP.A008391.01 DOI MASP-3. UCSD Molecule Pages. 2013 Chandrasekhar A Dinasarapu AR Matsushita M Subramaniam S 10.6072/H0.MP.A004275.01 DOI MASP-2. UCSD Molecule Pages. 2013 Chandrasekhar A Dinasarapu AR Thielens N Subramaniam S 10.6072/H0.MP.A004228.01 DOI Complement C1q subcomponent subunit A. UCSD Molecule Pages, 1 (2), 49-60 2012 Chandrasekhar A Dinasarapu AR Tenner AJ Subramaniam S 20720586 PubMed Complement: a key system for immune surveillance and homeostasis. Nat Immunol 2010 Ricklin D Hajishengallis G Yang K Lambris JD 10.6072/H0.MP.A004274.01 DOI MASP-1. UCSD Molecule Pages. 2013 Chandrasekhar A Dinasarapu AR Matsushita M Subramaniam S 21505029 PubMed Signaling gateway molecule pages--a data model perspective. Bioinformatics 2011 Dinasarapu AR Saunders B Ozerlat I Azam K Subramaniam S 10.6072/H0.MP.A004276.01 DOI Mannose/mannan-binding lectin. UCSD Molecule Pages 2013 Dinasarapu AR Chandrasekhar A Fujita T Subramaniam S 10.6072/H0.MP.A004234.01 DOI Complement C2. UCSD Molecule Pages. 2013 Dinasarapu AR Chandrasekhar A Inal J Subramaniam S 10.6072/H0.MP.A004266.01 DOI L-Ficolin. UCSD Molecule Pages, 2 (1), 37-44. 2013 Chandrasekhar A Dinasarapu AR Thiel S Subramaniam S 10904115 PubMed C1q: structure, function, and receptors. Immunopharmacology 2000 Kishore U Reid KB