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{{For the|the aircraft|Grumman C-2 Greyhound}}{{Short description|Protein
{{More footnotes needed|date=April 2023}}
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{{Infobox_gene}}
'''Complement C2''' is a [[protein]] that in humans is encoded by the ''C2'' [[gene]].<ref name="entrez">{{cite web | title = Entrez Gene: C2 complement component 2| url = https://www.ncbi.nlm.nih.gov/
The '''
== Function ==
In the [[classical complement pathway|classical]] and [[lectin pathway|lectin]] pathways of [[complement activation]], formation of the [[C3-convertase]] and [[C5-convertase]]s requires binding of C2 to an activated surface-bound [[C4b]] in the presence of [[magnesium|Mg<sup>2+</sup>]]; the resultant C4bC2 complex is cleaved by [[C1s]] or [[MASP2 (protein)|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 structure.
C2b is the smallest
== Complement Component 2 Deficiency ==
[[File:Protein_C2_PDB_2i6q.png|thumb|'''Complement C2''' is a protein that in humans is encoded by the C2 gene.]]
'''In the Molecular Biology,''' the [https://www.sciencedirect.com/topics/medicine-and-dentistry/complement-component-c2 deficiency of Complement Component 2 i] s a disorder that causes a major effect in the immune system, resulting in a form of immunodeficiency. This effect results in an inability to protect the body against any foreign invader. Complement component 2 deficiency is also connected with an increased risk of developing autoimmune disorders, such as systemic vasculitis. Complement deficiencies is a challenge to understand due to insufficient clinical trails. Using a hemolytic-plaque assay, RNA extraction, and blot analysis, it is fair to note that complement component 2 deficiency is a result of pre-translational regulatory detect in C2 gene expression.<ref>Ippolito A, Wallace DJ, Gladman D, Fortin PR, Urowitz M, Werth V, et al. Auto-antibodies in systemic lupus erythematosus: comparison of historical and current assessment of seropositivity. Lupus (2011) 20:250–5. doi:10.1177/0961203310385738</ref> This detects a lack of synthesis within the C2 protein. This deficiency can be further understood by incorporating plasma protein deficiencies, especially those in tissue macrophages. It is also important to note that Complement component 2 deficiency can be caused by genetic and environmental factors. In genetic inheritance, Autosomal recessive conditions are inherited with mutations in both copies of the gene where parents of autosomal recessive condition typically do not show symptoms.
== Development of SLE ==
Complement component 2 deficiency is associated with an increased risk of developing autoimmune disorders, with females more likely to have SLE. Systemic lupus erythematosus (lupus) is a chronic autoimmune disease that causes inflammation and tissue damage, affecting many parts of the body. Lupus can range from mild to severe and can cause inflammation in organs, such as joints, skin, kidneys, and brain. The severity of the disorder varies.
C2 is an important component of both the classical and lectin pathways of complement activation, and is essential for first line defense against [https://bmcimmunol.biomedcentral.com/articles/10.1186/1471-2172-11-43 microbial infection.] It binds to MBL or ficolins to form the C3 convertase C4b2a. In C2 deficiency, C3 is not efficiently cleaved, leading to limited deposition of C3 fragments on immune complexes and apoptotic cells, leading to chronic activation of the complement system.
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Patients and parents should be educated on the symptoms of serious illness and seek care immediately. Vaccination is an important preventive measure for the deficiency of complement component 2. Early diagnosis, antibiotic prophylaxis, and vaccinations can help prevent life-threatening infections in hereditary C2 deficiency.
== Promoting Health Care Outcomes ==
The interprofessional team must be aware of the clinical features of patients with complement deficiency or immunodeficiency, and refer them to allergist/immunologists when necessary. Infection prevention and treatment of infections are key for complement deficiencies.<ref>{{cite web | url=https://primaryimmune.org/about-primary-immunodeficiencies/specific-disease-types/complement-deficiencies#:~:text=Treatment%20of%20Complement%20Deficiencies&text=Currently%2C%20there%20are%20no%20specific,of%20patients%20with%20these%20deficiencies
Patient organizations build public awareness and support research to improve patients' lives. Patient organizations provide access to information, resources, and support.
== Clinical Significance ==
Photosensitive patients with C2 type I deficiency have poor prognosis. C2 type I deficiency is caused by a 28-base pair gene deletion, resulting in premature termination codon and lack of C2 protein. Patients with LE associated with complement C4 or C2 deficiencies have a better prognosis than those without inherited deficiencies. Complement component 2 deficiency increases risk of autoimmune disorders which may be managed by receiving the adequate care. Clinically, this is significant since Complement component 2 deficiency increases the risk of recurrent bacterial infections, which may be life-threatening.
== Other names ==
This gene is also known as:
* ARMD14
* C3/C5 convertase
* {{proper name|CO2}}
* Complement component 2
* Complement component C2
== References ==
=== Citations ===
<small>1. Jonsson G, Truedsson L, Sturfelt G, Oxelius VA, Braconier JH, Sjoholm AG. Hereditary C2 deficiency in Sweden: frequent occurrence of invasive infection, atherosclerosis, and rheumatic disease. Medicine (Baltimore). 2005Jan;84(1):23-34. doi: 10.1097/01.md.0000152371.22747.1e. Citation on PubMed (https://pubmed.ncb i.nlm.nih.gov/15643297)▼
{{reflist}}
Sjöholm AG, Jönsson G, Braconier JH, Sturfelt G, Truedsson L. Complement deficiency and disease: an update. Mol Immunol. 2006 Jan;43(1-2):78-85. doi: 10.1016/j.molimm.2005.06.025. PMID: 16026838.▼
=== Bibliography ===
3. Wen L, Atkinson JP, Giclas PC. Clinical and laboratory evaluation of complement deficiency. J Allergy Clin Immunol. 2004 Apr;113(4):585-93; quiz 594. doi: 10.1016/j.jaci.2004.02.003. PMID: 15100659.▼
{{refbegin}}
4. Chen HH, Tsai LJ, Lee KR, Chen YM, Hung WT, Chen DY. Genetic association of complement component 2 polymorphism with systemic lupus erythematosus. Tissue Antigens. 2015 Aug;86(2):122-33. doi: 10.1111/tan.12602. Epub 2015 Jul 14. PMID: 26176736.</small>▼
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▲* Complement+2 at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Sjöholm AG, Jönsson G, Braconier JH, Sturfelt G, Truedsson L. Complement deficiency and disease: an update. Mol Immunol. 2006 Jan;43(1-2):78-85. doi: 10.1016/j.molimm.2005.06.025. PMID
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{{refend}}
== Further reading ==
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* {{cite journal | vauthors = Lappin DF, Guc D, Hill A, McShane T, Whaley K | title = Effect of interferon-gamma on complement gene expression in different cell types | journal = The Biochemical Journal | volume = 281 | issue = Pt 2 | pages = 437–442 | date = Jan 1992 | pmid = 1531292 | pmc = 1130704 | doi = 10.1042/bj2810437}}
* {{cite journal | vauthors = Johnson CA, Densen P, Hurford RK, Colten HR, Wetsel RA | title = Type I human complement C2 deficiency. A 28-base pair gene deletion causes skipping of exon 6 during RNA splicing | journal = The Journal of Biological Chemistry | volume = 267 | issue = 13 | pages = 9347–9353 | date = May 1992 | doi = 10.1016/S0021-9258(19)50430-6 | pmid = 1577763 | doi-access = free }}
* {{cite journal | vauthors = Lappin DF, Birnie GD, Whaley K | title = Interferon-mediated transcriptional and post-transcriptional modulation of complement gene expression in human monocytes | journal = European Journal of Biochemistry | volume = 194 | issue = 1 | pages = 177–184 | date = Nov 1990 | pmid = 1701385 | doi = 10.1111/j.1432-1033.1990.tb19443.x | doi-access =
* {{cite journal | vauthors = Horiuchi T, Macon KJ, Kidd VJ, Volanakis JE | title = cDNA cloning and expression of human complement component C2 | journal = Journal of Immunology | volume = 142 | issue = 6 | pages = 2105–2111 | date = Mar 1989 | doi = 10.4049/jimmunol.142.6.2105 | pmid = 2493504 | s2cid = 45538303 | doi-access = free }}
* {{cite journal | vauthors = Cole FS, Whitehead AS, Auerbach HS, Lint T, Zeitz HJ, Kilbridge P, Colten HR | title = The molecular basis for genetic deficiency of the second component of human complement | journal = The New England Journal of Medicine | volume = 313 | issue = 1 | pages = 11–16 | date = Jul 1985 | pmid = 2582254 | doi = 10.1056/NEJM198507043130103 }}
* {{cite journal | vauthors = Bentley DR | title = Primary structure of human complement component C2. Homology to two unrelated protein families | journal = The Biochemical Journal | volume = 239 | issue = 2 | pages = 339–345 | date = Oct 1986 | pmid = 2949737 | pmc = 1147286 | doi = 10.1042/bj2390339}}
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* {{cite journal | vauthors = Kam CM, McRae BJ, Harper JW, Niemann MA, Volanakis JE, Powers JC | title = Human complement proteins D, C2, and B. Active site mapping with peptide thioester substrates | journal = The Journal of Biological Chemistry | volume = 262 | issue = 8 | pages = 3444–3451 | date = Mar 1987 | doi = 10.1016/S0021-9258(18)61371-7 | pmid = 3546307 | doi-access = free }}
* {{cite journal | vauthors = Wu LC, Morley BJ, Campbell RD | title = Cell-specific expression of the human complement protein factor B gene: evidence for the role of two distinct 5'-flanking elements | journal = Cell | volume = 48 | issue = 2 | pages = 331–342 | date = Jan 1987 | pmid = 3643061 | doi = 10.1016/0092-8674(87)90436-3 | s2cid = 32752642 }}
* {{cite journal | vauthors = Gagnon J | title = Structure and activation of complement components C2 and factor B | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 306 | issue = 1129 | pages = 301–309 | date = Sep 1984 | pmid = 6149575 | doi = 10.1098/rstb.1984.0091 | bibcode = 1984RSPTB.306..301G | doi-access =
* {{cite journal | vauthors = Bentley DR, Porter RR | title = Isolation of cDNA clones for human complement component C2 | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 81 | issue = 4 | pages = 1212–1215 | date = Feb 1984 | pmid = 6199794 | pmc = 344796 | doi = 10.1073/pnas.81.4.1212 | bibcode = 1984PNAS...81.1212B | doi-access = free }}
* {{cite journal | vauthors = Parkes C, Gagnon J, Kerr MA | title = The reaction of iodine and thiol-blocking reagents with human complement components C2 and factor B. Purification and N-terminal amino acid sequence of a peptide from C2a containing a free thiol group | journal = The Biochemical Journal | volume = 213 | issue = 1 | pages = 201–209 | date = Jul 1983 | pmid = 6555044 | pmc = 1152109 | doi = 10.1042/bj2130201}}
* {{cite journal | vauthors = Kerr MA, Gagnon J | title = The purification and properties of the second component of guinea-pig complement | journal = The Biochemical Journal | volume = 205 | issue = 1 | pages = 59–67 | date = Jul 1982 | pmid = 6922702 | pmc = 1158446 | doi =
* Liu C-C, Ahearn JM. Complement and systemic lupus erythematosus. 7th ed. In: Wallace DJ, Hahn BH, editors. Dubois’ Lupus Erythematosus. (Chap. 13), Philadelphia: Lippincott Williams & Wilkins (2007). p.
* Grammatikos AP, Tsokos GC. Immunodeficiency and autoimmunity: lessons from systemic lupus erythematosus. Trends Mol Med (2012) 18:101–8. [[doi:
* Ippolito A, Wallace DJ, Gladman D, Fortin PR, Urowitz M, Werth V, et al. Auto-antibodies in systemic lupus erythematosus: comparison of historical and current assessment of seropositivity. Lupus (2011) 20:250–5. [[doi:10.1177/0961203310385738]]
* Outer surface lipoproteins from the Lyme disease spirochete exploit the molecular switch mechanism of the complement protease C1s. arrigues et al.Journal of Biological ChemistrySeptember 29, 2022
* Paip2A inhibits translation by competitively binding to the RNA recognition motifs of PABPC1 and promoting its dissociation from the poly(A) tail
* Sagae et al.Journal of Biological ChemistryMarch 17, 2022
{{refend}}
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[[Category:Complement system]]
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