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C1s
Complement component 1s (, '' C1 esterase'', ''activated complement C1s'', ''complement C overbar 1r'', ''C1s'') is a protein involved in the complement system. C1s is part of the C1 complex. In humans, it is encoded by the ''C1S'' gene. C1s cleaves C4 and C2, which eventually leads to the production of the classical pathway C3-convertase. See also * C1q - another part of the C1 complex * C1r - another part of the C1 complex * MASP-2 - a protein similar to C1s, part of the lectin pathway The lectin pathway or lectin complement pathway is a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce acti ... References Further reading * * * * * * * * * * * * * * * * * * * * External links * * Complement system EC 3.4.21 {{gene-12-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement Component 1r
Complement C1r subcomponent (, ''activated complement C1r'', ''C overbar 1r esterase'', ''C1r'') is a protein involved in the complement system of the innate immune system. In humans, C1r is encoded by the ''C1R'' gene. C1r along with C1q and C1s form the C1 complex, which is the first component of the serum complement system. C1r is an enzyme that activates C1s to its active form, by proteolytic cleavage. Clinical significance * Ehlers-Danlos syndrome Periodontal type is associated with mutations in the ''CR1'' gene Function C1r has been shown to interact Advocates for Informed Choice, doing business as, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex trai ... with C1s. C1r cleaves C1s to form the active form of C1s. References Further reading * * * * * * * * * * * * * * * * * * * * External li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Complement Pathway
The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune system. The classical complement pathway is initiated by antigen-antibody complexes with the antibody isotypes IgG and IgM. Following activation, a series of proteins are recruited to generate C3 convertase (C4b2b, historically referred C4b2a), which cleaves the C3 protein. The C3b component of the cleaved C3 binds to C3 convertase (C4b2b) to generate C5 convertase (C4b2b3b), which cleaves the C5 protein. The cleaved products attract phagocytes to the site of infection and tags target cells for elimination by phagocytosis. In addition, the C5 convertase initiates the terminal phase of the complement system, leading to the assembly of the membrane attack complex ( MAC). The membrane attack complex creates a pore on the target cell's membrane, inducing cell lysis and death. The classical complement pathway can also be activated by apoptotic cells, ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C1 Complex
The C1 complex (''complement component 1'', ''C1'') is a protein complex involved in the complement system. It is the first component of the classical complement pathway and is composed of the subcomponents C1q, C1r and C1s. Structure The C1 complex is composed of 1 molecule of C1q, 2 molecules of C1r and 2 molecules of C1s, or ''C1qr2s2''. Function Activation of the C1 complex initiates the classical complement pathway. This occurs when C1q binds to antigen-antibody complexes. The antibodies IgM or certain subclasses of IgG complexed with antigens are able to initiate the complement system: a single pentameric IgM can initiate the pathway, while several monomeric IgG molecules are needed. C1q can also be activated in other ways, for example by binding to pentraxins such as C-reactive protein C-reactive protein (CRP) is an annular (ring-shaped) pentameric protein found in blood plasma, whose circulating concentrations rise in response to inflammation. It is an acut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. It is part of the innate immune system, which is not adaptable and does not change during an individual's lifetime. The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small proteins that are synthesized by the liver, and circulate in the blood as inactive precursors. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. It is part of the innate immune system, which is not adaptable and does not change during an individual's lifetime. The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small proteins that are synthesized by the liver, and circulate in the blood as inactive precursors. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement Component 4
Complement component 4 (C4), in humans, is a protein involved in the intricate complement system, originating from the human leukocyte antigen (HLA) system. It serves a number of critical functions in immunity, tolerance, and autoimmunity with the other numerous components. Furthermore, it is a crucial factor in connecting the recognition pathways of the overall system instigated by antibody-antigen (Ab-Ag) complexes to the other effector proteins of the innate immune response. For example, the severity of a dysfunctional complement system can lead to fatal diseases and infections. Complex variations of it can also lead to schizophrenia. The C4 protein was thought to derive from a simple two-locus allelic model, which however has been replaced by a much more sophisticated multimodular RCCX gene complex model which contain long and short forms of the C4A or C4B genes usually in tandem RCCX cassettes with copy number variation, that somewhat parallels variation in the levels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement Component 2
Complement C2 is a protein that in humans is encoded by the ''C2'' gene. The protein encoded by this gene is part of the classical pathway of the complement system, acting as a multi-domain serine protease. Deficiency of C2 has been associated with certain autoimmune diseases. Function In the classical and lectin pathways of complement activation, formation of the C3-convertase C3 convertase (''C4bC2b'', formerly ''C4b2a'') belongs to family of serine proteases and is necessary in innate immunity as a part of the complement system which eventuate in opsonisation of particles, release of inflammatory peptides, C5 conv ... and C5-convertases requires binding of C2 to an activated surface-bound C4b in the presence of Mg2+; the resultant C4bC2 complex is cleaved by C1s or MASP2 into C2a and C2b. It is thought that cleavage of C2 by C1s, while bound to C4b, results in a conformational rotation of C2b whereas the released C2a fragment may retain most of its original structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement Component 1q
The complement component 1q (or simply C1q) is a protein complex involved in the complement system, which is part of the innate immune system. C1q together with C1r and C1s form the C1 complex. Antibodies of the adaptive immune system can bind antigen, forming an antigen-antibody complex. When C1q binds antigen-antibody complexes, the C1 complex becomes activated. Activation of the C1 complex initiates the classical complement pathway of the complement system. The antibodies IgM and all IgG subclasses except IgG4 are able to initiate the complement system. Structure C1q is a 400 kDa protein formed from 18 peptide chains in 3 subunits of 6. Each 6 peptide subunit consists of a Y-shaped pair of triple peptide helices joined at the stem and ending in a globular non-helical head. The 80-amino acid helical component of each triple peptide contain many Gly-X-Y sequences, where X and Y are proline, isoleucine, or hydroxylysine; they, therefore, strongly resemble collagen fib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C3-convertase
C3 convertase (''C4bC2b'', formerly ''C4b2a'') belongs to family of serine proteases and is necessary in innate immunity as a part of the complement system which eventuate in opsonisation of particles, release of inflammatory peptides, C5 convertase formation and cell lysis. C3 convertase can be used to refer to the form produced in the alternative pathway (C3bBb) or the classical and lectin pathways (C4bC2b, formerly C4b2a). Once formed, both C3 convertases will catalyze the proteolytic cleavage of C3 into C3a and C3b (hence the name "C3-convertase"). The smaller fragment called C3a serves to increase vascular permeability and promote extravasation of phagocytes, while the larger C3b fragment can be used as an opsonin or bind to either type of C3 convertase to form the trimolecular C5 convertase to activate C5 for the membrane attack complex. Formation C3 convertase formation can occur in three different pathways: the classical, lectin, and alternative pathways. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MASP2 (protein)
Mannan-binding lectin serine protease 2 also known as mannose-binding protein-associated serine protease 2 (MASP-2) is an enzyme that in humans is encoded by the ''MASP2'' gene. Function The Ra-reactive factor (RARF) is a complement-dependent bactericidal factor that binds to the Ra and R2 polysaccharides expressed by certain enterobacteria. Alternate splicing of this gene results in two transcript variants encoding two RARF components that are involved in the mannan-binding lectin pathway of complement activation. The longer isoform is cleaved into two chains which form a heterodimer linked by a disulfide bond. The encoded proteins are members of the trypsin family of peptidases. MASP-2 is involved in the complement system. MASP-2 is very similar to the C1s molecule, of the classical complement pathway, and they are thought to have a common evolutionary ancestor. When the carbohydrate-recognising heads of MBL bind to specifically arranged mannose residues on the surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lectin Pathway
The lectin pathway or lectin complement pathway is a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce activated complement proteins further down the cascade. In contrast to the classical complement pathway, the lectin pathway does not recognize an antibody bound to its target. The lectin pathway starts with mannose-binding lectin (MBL) or ficolin binding to certain sugars. In this pathway, mannose-binding lectin binds to mannose, glucose, or other sugars with 3- and 4-OH groups placed in the equatorial plane, in terminal positions on carbohydrate or glycoprotein components of microorganisms including bacteria such as ''Salmonella'', ''Listeria'', and ''Neisseria'' strains. Fungal pathogens such as ''Candida albicans'' and ''Cryptococcus neoformans'' as well as some viruses such as HIV-1 and Respiratory syncytial virus (RSV) are bound by MBL. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C1 Esterase
C1, C01, C.I or C-1 may refer to: Arts and media * C1, a note-octave in music * C1 Television, a Mongolian television channel * Schecter C-1 Hellraiser FR, a guitar model * A Yamaha grand piano model * "C1", a slang expression in the video game ''Counter-Strike'', used to express agreement Biology and medicine Anatomy * Cervical vertebra 1, the first cervical vertebrae of the vertebral column * Cervical spinal nerve 1, a spinal nerve of the cervical segment Biochemistry * C1 complex, the first component of the classical complement pathway * C1 domain, an important secondary messenger protein domain * C1-inhibitor, a human serine protease inhibitor * C1 regulatory sequence for the insulin gene * Apolipoprotein C1, a human lipoprotein * Chlorophyll c1, a form of chlorophyll * Cytochrome C1, a precursor protein to Cytochrome C * Proanthocyanidin C1, a type of polyphenolic compound * Prostaglandin C1, a form of prostaglandins Other uses in biology and medicine * C1 and P1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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