Sandbox Reserved 1786: Difference between revisions

[[Image:IgM_structure_overview_diagram.png|500 px|left|thumb|'''Figure 1. IgM BCR Structure Overview.''' Depiction of the IgM BCR expressed on the membrane of a B cell. Includes all major components including the α/β heterodimer, heavy and light chains, antigen binding sites, and the ITAM region for signal transduction.]]The IgM BCR consists of six separate chains (Figure 1) that make up three main domains in the molecule. A depiction of the IgM <scene name='95/952714/Colored_by_domain/3'>colored by domain</scene> shows two heavy and two light chains that together form the <b><span class="text-cyan">Fab region</span></b>, or variable fragment at the top of the molecule where the antigen binding sites are located. The two heavy chains extend below the <b><span class="text-cyan">Fab region</span></b> through the <b><span class="text-purple">Fc region</span></b> and eventually connect to the Igα/β heterodimer to form the <b><span class="text-orange">transmembrane region</span></b> which anchors the overall complex to the B cell. The overall structure, expression, and function of the IgM BCR is strongly influenced by the <b><span class="text-orange">transmembrane region</span></b> in which Ig α/β interactions as a heterodimer influence cell surface expression, receptor assembly, and effective signal transduction. <ref name="Tolar">Tolar P, Pierce SK. Unveiling the B cell receptor structure. Science. 2022 Aug 19;377(6608):819-820. doi: 10.1126/science.add8065. Epub 2022 Aug 18.[http://dx.doi.org/10.1126/science.add8065 DOI:10.1126/science.add8065</ref>, <ref name="Dylke">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. doi: 10.1016/j.imlet.2007.06.005. Epub 2007 Jul 23. [http://dx.doi.org/10.1016/j.imlet.2007.06.005 DOI:10.1016/j.imlet.2007.06.005</ref>. In each domain, interactions between individual chains are important to understand the complex as a whole. All future 3D depictions will be <scene name='95/952714/Colored_by_chain/8'>colored by chain</scene> as in Figure 1.