[{"@context":"http:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/wiki.edu.vn\/en\/wiki24\/myelin-associated-glycoprotein-wikipedia\/#BlogPosting","mainEntityOfPage":"https:\/\/wiki.edu.vn\/en\/wiki24\/myelin-associated-glycoprotein-wikipedia\/","headline":"Myelin-associated glycoprotein &#8211; Wikipedia","name":"Myelin-associated glycoprotein &#8211; Wikipedia","description":"From Wikipedia, the free encyclopedia Protein-coding gene in the species Homo sapiens Myelin-associated glycoprotein (MAG, Siglec-4) is a type 1","datePublished":"2022-04-22","dateModified":"2022-04-22","author":{"@type":"Person","@id":"https:\/\/wiki.edu.vn\/en\/wiki24\/author\/lordneo\/#Person","name":"lordneo","url":"https:\/\/wiki.edu.vn\/en\/wiki24\/author\/lordneo\/","image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/c9645c498c9701c88b89b8537773dd7c?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Enzyklop\u00e4die","logo":{"@type":"ImageObject","@id":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","url":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/en.wikipedia.org\/wiki\/Special:CentralAutoLogin\/start?type=1x1","url":"https:\/\/en.wikipedia.org\/wiki\/Special:CentralAutoLogin\/start?type=1x1","height":"1","width":"1"},"url":"https:\/\/wiki.edu.vn\/en\/wiki24\/myelin-associated-glycoprotein-wikipedia\/","about":["Wiki"],"wordCount":5024,"articleBody":"From Wikipedia, the free encyclopediaProtein-coding gene in the species Homo sapiensMyelin-associated glycoprotein (MAG, Siglec-4) is a type 1 transmembrane protein glycoprotein localized in periaxonal Schwann cell and oligodendrocyte membranes, where it plays a role in glial-axonal interactions. MAG is a member of the SIGLEC family of proteins and is a functional ligand of the NOGO-66 receptor,  NgR.[5] MAG is believed to be involved in myelination during nerve regeneration in the  PNS[6] and is vital for the long-term survival of the myelinated axons following myelinogenesis.[7] In the  CNS MAG is one of three main myelin-associated inhibitors of axonal regeneration after injury,[8] making it an important protein for future research on neurogenesis in the CNS.Table of ContentsStructure[edit]Adhesion[edit]Function[edit]Myelin-axon interactions[edit]Inhibition of nerve regeneration[edit]Rho kinase pathway[edit]See also[edit]External links[edit]References[edit]Structure[edit]MAG is a 100 kDA glycoprotein.[9] Uncleaved MAG is a complete transmembrane form, which acts as a signaling and adhesion molecule.[10] MAG can also act as a signaling molecule as a soluble protein after it has been proteolytically shed. This form of the protein is called dMAG.[11]Adhesion[edit]MAG has an extended conformation of five  immunoglobulin (Ig) domains and a homodimeric arrangement involving membrane-proximal domains Ig4 and Ig5. MAG-oligosaccharide complex structures and biophysical assays show how MAG engages axonal gangliosides at domain Ig1.[12]Function[edit]Myelin-axon interactions[edit]MAG is a critical protein in the formation and maintenance of myelin sheaths. MAG is localized on the inner membrane of the myelin sheath and interacts with axonal membrane proteins to attach the myelin sheath to the axon.[13]. Mutations to the MAG gene are implicated in demyelination diseases such as multiple sclerosis.[14]Inhibition of nerve regeneration[edit]Axons in the central nervous system do not regenerate after injury the same way that axons in the peripheral nervous system do. [15] The mechanism responsible for inhibited neuroregeneration is regulated by three main proteins, one of which is MAG.[16][17] The exact mechanism through which MAG inhibits neuroregeneration appears to be through binding of  NgR. This receptor is also bound by  Nogo protein, suggesting that the mechanism of myelin-associated inhibition of axon regeneration through  NgR the has redundant ligands[clarification needed], furthering the inhibition.[18] MAG binds with high affinity to NgR, suggesting that it is equally as responsible for inhibition of axon regeneration as Nogo.[19]Rho kinase pathway[edit]Once MAG (or Nogo) has bound to NgR, NgR activates the  rho kinase (ROCK) pathway. The activation of the rho kinase pathway leads to the phosphorylation of proteins which inhibit neurite outgrowth.[20]See also[edit]External links[edit]References[edit]^ a b c GRCh38: Ensembl release 89: ENSG00000105695 &#8211; Ensembl, May 2017^ a b c GRCm38: Ensembl release 89: ENSMUSG00000036634 &#8211; Ensembl, May 2017^ &#8220;Human PubMed Reference:&#8221;. National Center for Biotechnology Information, U.S. National Library of Medicine.^ &#8220;Mouse PubMed Reference:&#8221;. National Center for Biotechnology Information, U.S. National Library of Medicine.^ Quarles RH (March 2007). &#8220;Myelin-associated glycoprotein (MAG): past, present and beyond&#8221;. Journal of Neurochemistry. 100 (6): 1431\u201348. doi:10.1111\/j.1471-4159.2006.04319.x. PMID\u00a017241126. S2CID\u00a01544418.^ Barton DE, Arquint M, Roder J, Dunn R, Francke U (October 1987). &#8220;The myelin-associated glycoprotein gene: mapping to human chromosome 19 and mouse chromosome 7 and expression in quivering mice&#8221;. Genomics. 1 (2): 107\u201312. doi:10.1016\/0888-7543(87)90002-4. PMID\u00a02447011.^ Bjartmar C, Yin X, Trapp BD (1999). &#8220;Axonal pathology in myelin disorders&#8221;. Journal of Neurocytology. 28 (4\u20135): 383\u201395. doi:10.1023\/a:1007010205037. PMID\u00a010739578. S2CID\u00a040528071.^ McKerracher L, David S, Jackson DL, Kottis V, Dunn RJ, Braun PE (October 1994). &#8220;Identification of myelin-associated glycoprotein as a major myelin-derived inhibitor of neurite growth&#8221;. Neuron. 13 (4): 805\u201311. doi:10.1016\/0896-6273(94)90247-x. PMID\u00a07524558. S2CID\u00a028429007.^ Lopez PH (2014). &#8220;Role of myelin-associated glycoprotein (siglec-4a) in the nervous system&#8221;. Advances in Neurobiology. 9: 245\u201362. doi:10.1007\/978-1-4939-1154-7_11. ISBN\u00a0978-1-4939-1153-0. PMID\u00a025151382.^ Vinson M, Strijbos PJ, Rowles A, Facci L, Moore SE, Simmons DL, Walsh FS (June 2001). &#8220;Myelin-associated glycoprotein interacts with ganglioside GT1b. A mechanism for neurite outgrowth inhibition&#8221;. The Journal of Biological Chemistry. 276 (23): 20280\u20135. doi:10.1074\/jbc.M100345200. PMID\u00a011279053.^ Tang S, Shen YJ, DeBellard ME, Mukhopadhyay G, Salzer JL, Crocker PR, Filbin MT (September 1997). &#8220;Myelin-associated glycoprotein interacts with neurons via a sialic acid binding site at ARG118 and a distinct neurite inhibition site&#8221;. The Journal of Cell Biology. 138 (6): 1355\u201366. doi:10.1083\/jcb.138.6.1355. PMC\u00a02132563. PMID\u00a09298990.^ Pronker MF, Lemstra S, Snijder J, Heck AJ, Thies-Weesie DM, Pasterkamp RJ, Janssen BJ (December 2016). &#8220;Structural basis of myelin-associated glycoprotein adhesion and signalling&#8221;. Nature Communications. 7: 13584. Bibcode:2016NatCo&#8230;713584P. doi:10.1038\/ncomms13584. PMC\u00a05150538. PMID\u00a027922006.^ Lopez PH (2014). &#8220;Role of myelin-associated glycoprotein (siglec-4a) in the nervous system&#8221;. Advances in Neurobiology. 9: 245\u201362. doi:10.1007\/978-1-4939-1154-7_11. ISBN\u00a0978-1-4939-1153-0. PMID\u00a025151382.^ Pronker MF, Lemstra S, Snijder J, Heck AJ, Thies-Weesie DM, Pasterkamp RJ, Janssen BJ (December 2016). &#8220;Structural basis of myelin-associated glycoprotein adhesion and signalling&#8221;. Nature Communications. 7: 13584. Bibcode:2016NatCo&#8230;713584P. doi:10.1038\/ncomms13584. PMC\u00a05150538. PMID\u00a027922006.^ Gage FH, Temple S (October 2013). &#8220;Neural stem cells: generating and regenerating the brain&#8221;. Neuron. 80 (3): 588\u2013601. doi:10.1016\/j.neuron.2013.10.037. PMID\u00a024183012.^ McKerracher L, David S, Jackson DL, Kottis V, Dunn RJ, Braun PE (October 1994). &#8220;Identification of myelin-associated glycoprotein as a major myelin-derived inhibitor of neurite growth&#8221;. Neuron. 13 (4): 805\u201311. doi:10.1016\/0896-6273(94)90247-x. PMID\u00a07524558. S2CID\u00a028429007.^ Mukhopadhyay G, Doherty P, Walsh FS, Crocker PR, Filbin MT (September 1994). &#8220;A novel role for myelin-associated glycoprotein as an inhibitor of axonal regeneration&#8221;. Neuron. 13 (3): 757\u201367. doi:10.1016\/0896-6273(94)90042-6. PMID\u00a07522484. S2CID\u00a0928929.^ Domeniconi M, Cao Z, Spencer T, Sivasankaran R, Wang K, Nikulina E, Kimura N, Cai H, Deng K, Gao Y, He Z, Filbin M (July 2002). &#8220;Myelin-associated glycoprotein interacts with the Nogo66 receptor to inhibit neurite outgrowth&#8221;. Neuron. 35 (2): 283\u201390. doi:10.1016\/s0896-6273(02)00770-5. PMID\u00a012160746. S2CID\u00a017970421.^ Liu BP, Fournier A, GrandPr\u00e9 T, Strittmatter SM (August 2002). &#8220;Myelin-associated glycoprotein as a functional ligand for the Nogo-66 receptor&#8221;. Science. 297 (5584): 1190\u20133. Bibcode:2002Sci&#8230;297.1190L. doi:10.1126\/science.1073031. PMID\u00a012089450. S2CID\u00a01357777.^ Kaplan DR, Miller FD (May 2003). &#8220;Axon growth inhibition: signals from the p75 neurotrophin receptor&#8221;. Nature Neuroscience. 6 (5): 435\u20136. doi:10.1038\/nn0503-435. PMID\u00a012715005. S2CID\u00a040563260.  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