Sandbox Reserved 1771
From Proteopedia
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=IgM B-cell Receptor= | =IgM B-cell Receptor= | ||
==Introduction== | ==Introduction== | ||
| - | + | The [https://en.wikipedia.org/wiki/B-cell_receptor human B-cell receptor](BCR) is a complex protein made up of three domains: extracellular, transmembrane, and intracellular. While the extracellular region makes up most of the protein, perhaps the most interesting interactions can be found in the transmembrane domain. Unlike other BCRs, the IgM BCR has a specific heavy chain interaction with the α-β subunit of the protein. BCRs are found on the surface of B-cells as membrane bound proteins (ref). In general the role of BCRs is to bind to foreign antigens and initiate the appropriate immune response. | |
==Structure== | ==Structure== | ||
<StructureSection load='4INS' size='350' side='right' caption='Human IgM B-Cell Receptor, 7XQ8 (edited)' scene='95/952699/Overview_rock/1'> | <StructureSection load='4INS' size='350' side='right' caption='Human IgM B-Cell Receptor, 7XQ8 (edited)' scene='95/952699/Overview_rock/1'> | ||
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===Transmembrane Interactions=== | ===Transmembrane Interactions=== | ||
| - | Many transmembrane interactions can be found within a IgM B-cell receptor. The <scene name='95/952699/Transmembrane_region/1'>α and β subunits</scene> have numerous interactions that keep them associated with each other. An overview of all residue interactions can be found <scene name='95/952699/Overview_hbonds_fixed/1'>here</scene>. At a cellular pH, various amino acid residues found in the transmembrane region are charged as well, which strengthens the overall interaction. For example, <scene name='95/952699/N155_e138_hbonds_fixed/1'>a hydrogen bond</scene> between residues N155 and E138, along with numerous other hydrogen bonds, works to stabilize the α-β chain interactions. Further down the chains, <scene name='95/952699/T166_e148_hbonds_fixed/1'>interactions</scene> between residues T166 and E148 also have strong hydrogen bonding. Overall, these hydrogen bonds and ion interactions work to maintain the association of the α-β chains. | + | Many transmembrane interactions can be found within a IgM B-cell receptor. The <scene name='95/952699/Transmembrane_region/1'>α and β subunits</scene> have numerous interactions that keep them associated with each other. An overview of all residue interactions can be found <scene name='95/952699/Overview_hbonds_fixed/1'>here</scene> (highlighted in green). At a cellular pH, various amino acid residues found in the transmembrane region are charged as well, which strengthens the overall interaction. For example, <scene name='95/952699/N155_e138_hbonds_fixed/1'>a hydrogen bond</scene> between residues N155 and E138, along with numerous other hydrogen bonds, works to stabilize the α-β chain interactions. Further down the chains, <scene name='95/952699/T166_e148_hbonds_fixed/1'>interactions</scene> between residues T166 and E148 also have strong hydrogen bonding. Overall, these hydrogen bonds and ion interactions work to maintain the association of the α-β chains. |
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==Function== | ==Function== | ||
| - | + | Once bound to an antigen, BCRs undergo a conformational change in their extracellular region. While the exact conformational change is still not known, it initiates several signal transduction pathways. These pathways are responsible for processing the antigen and initiating the appropriate immune responses. More specifically, the α-β subunit is connected to the phosphorylation of an immunoreceptor tyrosine-based activation motif (ITAM) upon binding. This in turn triggers the activation of kinases downstream that aid in the immune response. BCRs can be oligomeric prior to antigen binding, but once bound become an active monomer. | |
==Medical Relevancy== | ==Medical Relevancy== | ||
===B-cell Formation=== | ===B-cell Formation=== | ||
| + | The formation of B-cells occurs in the bone marrow. BCRs are attached to B-cells through the aid of membrane-bound proteins in bone marrow cells. During this process, gene recombination occurs, which allows unique BCRs to become highly specific to different antigens. | ||
===Diseases=== | ===Diseases=== | ||
Revision as of 15:08, 27 March 2023
| This Sandbox is Reserved from February 27 through August 31, 2023 for use in the course CH462 Biochemistry II taught by R. Jeremy Johnson at the Butler University, Indianapolis, USA. This reservation includes Sandbox Reserved 1765 through Sandbox Reserved 1795. |
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Contents |
IgM B-cell Receptor
Introduction
The human B-cell receptor(BCR) is a complex protein made up of three domains: extracellular, transmembrane, and intracellular. While the extracellular region makes up most of the protein, perhaps the most interesting interactions can be found in the transmembrane domain. Unlike other BCRs, the IgM BCR has a specific heavy chain interaction with the α-β subunit of the protein. BCRs are found on the surface of B-cells as membrane bound proteins (ref). In general the role of BCRs is to bind to foreign antigens and initiate the appropriate immune response.
Structure
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Function
Once bound to an antigen, BCRs undergo a conformational change in their extracellular region. While the exact conformational change is still not known, it initiates several signal transduction pathways. These pathways are responsible for processing the antigen and initiating the appropriate immune responses. More specifically, the α-β subunit is connected to the phosphorylation of an immunoreceptor tyrosine-based activation motif (ITAM) upon binding. This in turn triggers the activation of kinases downstream that aid in the immune response. BCRs can be oligomeric prior to antigen binding, but once bound become an active monomer.
Medical Relevancy
B-cell Formation
The formation of B-cells occurs in the bone marrow. BCRs are attached to B-cells through the aid of membrane-bound proteins in bone marrow cells. During this process, gene recombination occurs, which allows unique BCRs to become highly specific to different antigens.
