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===Transmembrane Region=== | ===Transmembrane Region=== | ||
| - | The IgM BCR is anchored to [https://en.wikipedia.org/wiki/B_cell B-cell] membranes through the <scene name='95/952714/Integral_region/11'>transmembrane region</scene> which is broken up into both extracellular and integral domains which sit on top of or span through the membrane, respectively. IgM BCR assembly requires dimerization of the <b><span class="text-brown">Ig alpha</span></b> and <b><span class="text-orange">Ig beta</span></b> subunits which embed within the B-cell membrane. The <scene name='95/952714/Ig_alpha_beta/5'>Ig alpha and beta heterodimer</scene> dimerizes within the extracellular region with a <scene name='95/952714/Extracellular_disulfide_bridge/6'>disulfide bridge</scene>. Additional dimerization is believed to occur within the integral region via a hydrogen bond; the involved residues and interaction have not been confirmed. Although the mechanism of disulfide bridge formation is still unknown, it is believed that <scene name='95/952714/Extracellular_glycosylation/2'>extracellular glycosylation</scene> via <b><span class="text-lightgreen">N-linked glycosylation</span></b> (NAGs) on various asparagine residues in the extracellular region of both the <b><span class="text-brown">alpha</span></b> and <b><span class="text-orange">beta</span></b> chains help facilitate this process. [https://en.wikipedia.org/wiki/Chaperone_(protein) Chaperone proteins] remain bound to the alpha and beta subunits until both dimerizations occur; at this point the rest of the BCR complex can be recruited. | + | The IgM BCR is anchored to [https://en.wikipedia.org/wiki/B_cell B-cell] membranes through the <scene name='95/952714/Integral_region/11'>transmembrane region</scene> which is broken up into both extracellular and integral domains which sit on top of or span through the membrane, respectively. IgM BCR assembly requires dimerization of the <b><span class="text-brown">Ig alpha</span></b> and <b><span class="text-orange">Ig beta</span></b> subunits which embed within the B-cell membrane. The <scene name='95/952714/Ig_alpha_beta/5'>Ig alpha and beta heterodimer</scene> dimerizes within the extracellular region with a <scene name='95/952714/Extracellular_disulfide_bridge/6'>disulfide bridge</scene>. Additional dimerization is believed to occur within the integral region via a hydrogen bond; the involved residues and interaction have not been confirmed. Although the mechanism of disulfide bridge formation is still unknown, it is believed that <scene name='95/952714/Extracellular_glycosylation/2'>extracellular glycosylation</scene> via <b><span class="text-lightgreen">N-linked glycosylation</span></b> (NAGs) on various asparagine residues in the extracellular region of both the <b><span class="text-brown">alpha</span></b> and <b><span class="text-orange">beta</span></b> chains help facilitate this process. [https://en.wikipedia.org/wiki/Chaperone_(protein) Chaperone proteins] remain bound to the alpha and beta subunits until both dimerizations occur; at this point the rest of the BCR complex can be recruited. <ref name="Dylke">PMID:17675166</ref> |
| - | After <b><span class="text-brown">Ig alpha</span></b>/<b><span class="text-orange">Ig beta</span></b> dimerization, the transmembrane helices of the heavy chains can embed within the B-cell membrane. The side chains of this <scene name='95/952714/Integral_helices_2/2'>4-pass integral helix structure</scene> are primarily hydrophobic side chains that allow for interactions with the hydrophobic tails in the [https://en.wikipedia.org/wiki/Lipid_bilayer phospholipid bilayer]. The 4 helices are primarily held together through hydrophobic interactions (Figure___); however, a total of 9 polar residues (picture that zooms in here??) between each of the heavy chains are included on the interior of the helix structure which interact with a few polar residues on the <b><span class="text-brown">Ig alpha</span></b> and <b><span class="text-orange">Ig beta</span></b> chains. Additional interactions between the <b><span class="text-brown">Ig alpha</span></b>/<b><span class="text-orange">Ig beta</span></b> dimer and the heavy chains occur in the constant region. | + | After <b><span class="text-brown">Ig alpha</span></b>/<b><span class="text-orange">Ig beta</span></b> dimerization, the transmembrane helices of the heavy chains can embed within the B-cell membrane. The side chains of this <scene name='95/952714/Integral_helices_2/2'>4-pass integral helix structure</scene> are primarily hydrophobic side chains that allow for interactions with the hydrophobic tails in the [https://en.wikipedia.org/wiki/Lipid_bilayer phospholipid bilayer]. The 4 helices are primarily held together through hydrophobic interactions (Figure___); however, a total of 9 polar residues (picture that zooms in here??) between each of the heavy chains are included on the interior of the helix structure which interact with a few polar residues on the <b><span class="text-brown">Ig alpha</span></b> and <b><span class="text-orange">Ig beta</span></b> chains. Additional interactions between the <b><span class="text-brown">Ig alpha</span></b>/<b><span class="text-orange">Ig beta</span></b> dimer and the heavy chains occur in the constant region. <ref name="Dylke"/> |
===Fc Region=== | ===Fc Region=== | ||
| Line 31: | Line 31: | ||
==References== | ==References== | ||
| - | <ref name="Su">PMID:35981043/ref> | + | <ref name="Su">PMID:35981043</ref> |
| - | <ref name="Tolar">PMID:35981020/ref> | + | <ref name="Tolar">PMID:35981020</ref> |
| - | <ref name="Ma">PMID:35981028/ref> | + | <ref name="Ma">PMID:35981028</ref> |
| - | <ref name="Dylke">PMID:17675166/ref> | + | <ref name="Dylke">PMID:17675166</ref> |
| - | <ref name="Zhou">PMID:20616231/ref> | + | <ref name="Zhou">PMID:20616231</ref> |
| - | <ref name="Bannish">PMID:11733573/ref> | + | <ref name="Bannish">PMID:11733573</ref> |
| - | <ref name="Sathe">PMID:32310455/ref> | + | <ref name="Sathe">PMID:32310455</ref> |
<references/> | <references/> | ||
Revision as of 23:47, 3 April 2023
Human B-cell Antigen Receptor: IgM BCR
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References
- ↑ 1.0 1.1 1.2 Dylke J, Lopes J, Dang-Lawson M, Machtaler S, Matsuuchi L. Role of the extracellular and transmembrane domain of Ig-alpha/beta in assembly of the B cell antigen receptor (BCR). Immunol Lett. 2007 Sep 15;112(1):47-57. PMID:17675166 doi:10.1016/j.imlet.2007.06.005
- ↑ Su Q, Chen M, Shi Y, Zhang X, Huang G, Huang B, Liu D, Liu Z, Shi Y. Cryo-EM structure of the human IgM B cell receptor. Science. 2022 Aug 19;377(6608):875-880. doi: 10.1126/science.abo3923. Epub 2022, Aug 18. PMID:35981043 doi:http://dx.doi.org/10.1126/science.abo3923
- ↑ Tolar P, Pierce SK. Unveiling the B cell receptor structure. Science. 2022 Aug 19;377(6608):819-820. PMID:35981020 doi:10.1126/science.add8065
- ↑ Ma X, Zhu Y, Dong, Chen Y, Wang S, Yang D, Ma Z, Zhang A, Zhang F, Guo C, Huang Z. Cryo-EM structures of two human B cell receptor isotypes. Science. 2022 Aug 19;377(6608):880-885. doi: 10.1126/science.abo3828. Epub 2022, Aug 18. PMID:35981028 doi:http://dx.doi.org/10.1126/science.abo3828
- ↑ Zhou T, Georgiev I, Wu X, Yang ZY, Dai K, Finzi A, Do Kwon Y, Scheid JF, Shi W, Xu L, Yang Y, Zhu J, Nussenzweig MC, Sodroski J, Shapiro L, Nabel GJ, Mascola JR, Kwong PD. Structural basis for broad and potent neutralization of HIV-1 by antibody VRC01. Science. 2010 Aug 13;329(5993):811-7. Epub 2010 Jul 8. PMID:20616231 doi:10.1126/science.1192819
- ↑ Bannish G, Fuentes-Pananá EM, Cambier JC, Pear WS, Monroe JG. Ligand-independent signaling functions for the B lymphocyte antigen receptor and their role in positive selection during B lymphopoiesis. J Exp Med. 2001 Dec 3;194(11):1583-96. PMID:11733573 doi:10.1084/jem.194.11.1583
- ↑ Sathe A, Cusick JK. Biochemistry, Immunoglobulin M. PMID:32310455
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