Complement component 2: Difference between revisions

Latest revision as of 05:30, 16 February 2025

Complement Component 2[edit]

Complement Component 2 (C2) is a protein of the complement system, which is part of the innate immune system. The complement system is a group of proteins that play a crucial role in immune response by enhancing the ability of antibodies and phagocytic cells to clear pathogens from an organism. C2 is a key component in the classical pathway of complement activation.

Structure[edit]

Complement Component 2 is a serine protease that is encoded by the C2 gene in humans. The protein is synthesized as a single-chain precursor and is cleaved into two fragments, C2a and C2b, upon activation. The structure of C2 is characterized by several domains that are important for its function in the complement cascade.

Function[edit]

C2 plays a pivotal role in the classical pathway of complement activation. Upon activation by the C1 complex, C2 is cleaved by C1s into C2a and C2b. The C2a fragment combines with C4b to form the C3 convertase (C4b2a), which is essential for the cleavage of C3 into C3a and C3b. This step is crucial for the amplification of the complement response and the opsonization of pathogens.

Clinical Significance[edit]

Deficiencies in Complement Component 2 can lead to increased susceptibility to infections and autoimmune diseases. C2 deficiency is a rare genetic disorder that can result in recurrent bacterial infections and is associated with conditions such as systemic lupus erythematosus (SLE).

Related Pages[edit]

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-'''Complement component 2''' (C2) is a protein that plays a significant role in the [[immune system]] and is a part of the [[complement system]], which is a complex innate immune mechanism responsible for enhancing the ability of antibodies and phagocytic cells to clear pathogens from an organism. C2 is involved in the classical and lectin pathways of complement activation.
+{{DISPLAYTITLE:Complement Component 2}}
-==Structure and Function==
+== Complement Component 2 ==
-C2 is synthesized in the liver and is present in the blood serum as a single polypeptide chain. Upon activation by the [[C1 complex]] in the classical pathway or by [[mannose-binding lectin]] (MBL) in the lectin pathway, C2 interacts with activated [[Complement component 4|C4]] to form the C4b2a complex, also known as the C3 convertase of the classical and lectin pathways. This enzyme complex cleaves [[Complement component 3|C3]], leading to the generation of the opsonin C3b, and the initiation of a series of reactions that culminate in the formation of the membrane attack complex (MAC), which can lyse pathogen cell membranes.
+[[File:Protein_C2_PDB_2i6q.png|thumb|right|300px|Structure of Complement Component 2]]
-==Genetics==
+'''Complement Component 2''' (C2) is a protein of the [[complement system]], which is part of the [[innate immune system]]. The complement system is a group of proteins that play a crucial role in [[immune response]] by enhancing the ability of [[antibodies]] and [[phagocytic cells]] to clear pathogens from an organism. C2 is a key component in the [[classical pathway]] of complement activation.
-The gene encoding C2 is located on chromosome 6 in humans, within the major histocompatibility complex (MHC) class III region. Genetic variations in the C2 gene can lead to deficiencies in the C2 protein, which are associated with an increased susceptibility to certain infections and autoimmune diseases.
-==Clinical Significance==
+== Structure ==
-C2 deficiency is one of the most common complement deficiencies and is associated with a variety of autoimmune and infectious diseases, including [[systemic lupus erythematosus]] (SLE), recurrent bacterial infections, and increased susceptibility to type III hypersensitivity reactions. Diagnosis of C2 deficiency typically involves serum assays to measure the levels of complement proteins, and genetic testing can be used to identify mutations in the C2 gene.
+Complement Component 2 is a serine protease that is encoded by the [[C2 gene]] in humans. The protein is synthesized as a single-chain precursor and is cleaved into two fragments, C2a and C2b, upon activation. The structure of C2 is characterized by several domains that are important for its function in the complement cascade.
-==Treatment and Management==
+== Function ==
-Management of conditions associated with C2 deficiency focuses on treating the underlying infections and autoimmune conditions. In some cases, replacement therapy with fresh frozen plasma, which contains functional complement proteins, may be used to temporarily restore complement activity.
+C2 plays a pivotal role in the classical pathway of complement activation. Upon activation by the [[C1 complex]], C2 is cleaved by [[C1s]] into C2a and C2b. The C2a fragment combines with [[C4b]] to form the [[C3 convertase]] (C4b2a), which is essential for the cleavage of [[C3]] into C3a and C3b. This step is crucial for the amplification of the complement response and the opsonization of pathogens.
-==Research Directions==
+== Clinical Significance ==
-Ongoing research is aimed at better understanding the molecular mechanisms underlying C2 function and its role in disease. This includes studies on the genetic basis of C2 deficiency and the development of novel therapeutic approaches to modulate complement activity in diseases associated with complement dysregulation.
+Deficiencies in Complement Component 2 can lead to increased susceptibility to infections and autoimmune diseases. C2 deficiency is a rare genetic disorder that can result in recurrent bacterial infections and is associated with conditions such as [[systemic lupus erythematosus]] (SLE).
+== Related Pages ==
+* [[Complement system]]
+* [[Classical pathway]]
+* [[C3 convertase]]
+* [[Immune system]]
+* [[Systemic lupus erythematosus]]
+[[Category:Complement system]]
 [[Category:Immune system]]
-[[Category:Complement system]]
+[[Category:Proteins]]
-{{Immunology-stub}}