CD79B (IgΞ²) is a type I transmembrane signaling subunit of the B-cell antigen receptor. It forms a disulfide-linked heterodimer with CD79A that associates with membrane immunoglobulin, supports receptor assembly and surface expression, and couples antigen recognition to intracellular signaling through immunoreceptor tyrosine-based activation motifs. The paired CD79 chains also support receptor-directed antigen trafficking to late endosomal processing compartments, facilitating MHC class II presentation. Ig-beta enhances Ig-alpha phosphorylation in chimeric-receptor experiments, although the underlying recruitment or protection mechanism is unresolved. Biallelic CD79B defects cause autosomal recessive agammaglobulinemia 6; the hypomorphic G137S allele impairs heterodimer assembly and receptor surface expression, with a leaky block in B-cell development.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0002376 immune system process | IEA GO_REF:0000117 | MODIFY | Summary: Specify the B-cell receptor signaling pathway. Reason: The broad electronic immune-system term is compatible with CD79B biology but can be made more informative. CD79B is an integral signaling chain of the BCR; human receptor structure and receptor-loss/rescue experiments support the named pathway. Proposed replacements: B cell receptor signaling pathway |
| GO:0004888 transmembrane signaling receptor activity | IBA GO_REF:0000033 | ACCEPT | Summary: CD79B contributes to the signaling activity of the assembled BCR. Reason: CD79B is an integral signal-transducing component of the antigen receptor: the human receptor structure directly places it in the membrane-immunoglobulin/CD79 heterodimer assembly, and CD79B loss/rescue affects surface assembly and signaling. The receptor contribution therefore remains biologically valid. This judgment concerns activity in the assembled receptor, not autonomous antigen recognition by an isolated chain. Ordinary source relationship metadata is not used to change the action, and no unverified source-defect correction is asserted. The core uses contributes_to_molecular_function to describe the complex role. A separate human CD79B-specific adaptor MF is not added merely by extrapolating the CD79A/SYK phosphopeptide or non-ITAM BLNK experiments. Supporting Evidence: PMID:35981043 IgM-BCR comprises two heavy chains, two light chains, and the IgΞ±/IgΞ² heterodimer. PMID:36426942 Rescue experiments with CD79B wild-type restored surface expression of CD79A and IgM with mature glycosylation |
| GO:0004888 transmembrane signaling receptor activity | IEA GO_REF:0000120 | ACCEPT | Summary: CD79B contributes to the signaling activity of the assembled BCR. Reason: CD79B is an integral signal-transducing component of the antigen receptor: the human receptor structure directly places it in the membrane-immunoglobulin/CD79 heterodimer assembly, and CD79B loss/rescue affects surface assembly and signaling. The receptor contribution therefore remains biologically valid. This judgment concerns activity in the assembled receptor, not autonomous antigen recognition by an isolated chain. Ordinary source relationship metadata is not used to change the action, and no unverified source-defect correction is asserted. The core uses contributes_to_molecular_function to describe the complex role. A separate human CD79B-specific adaptor MF is not added merely by extrapolating the CD79A/SYK phosphopeptide or non-ITAM BLNK experiments. Supporting Evidence: PMID:35981043 IgM-BCR comprises two heavy chains, two light chains, and the IgΞ±/IgΞ² heterodimer. PMID:36426942 Rescue experiments with CD79B wild-type restored surface expression of CD79A and IgM with mature glycosylation |
| GO:0004888 transmembrane signaling receptor activity | ISS GO_REF:0000024 | ACCEPT | Summary: CD79B contributes to the signaling activity of the assembled BCR. Reason: CD79B is an integral signal-transducing component of the antigen receptor: the human receptor structure directly places it in the membrane-immunoglobulin/CD79 heterodimer assembly, and CD79B loss/rescue affects surface assembly and signaling. The receptor contribution therefore remains biologically valid. This judgment concerns activity in the assembled receptor, not autonomous antigen recognition by an isolated chain. Ordinary source relationship metadata is not used to change the action, and no unverified source-defect correction is asserted. The core uses contributes_to_molecular_function to describe the complex role. A separate human CD79B-specific adaptor MF is not added merely by extrapolating the CD79A/SYK phosphopeptide or non-ITAM BLNK experiments. Supporting Evidence: PMID:35981043 IgM-BCR comprises two heavy chains, two light chains, and the IgΞ±/IgΞ² heterodimer. PMID:36426942 Rescue experiments with CD79B wild-type restored surface expression of CD79A and IgM with mature glycosylation |
| GO:0005515 protein binding | IPI PMID:25416956 A proteome-scale map of the human interactome network. | REMOVE | Summary: CD79B interaction reported by PMID:25416956; generic binding is uninformative as a functional annotation. Reason: The publication-linked interaction involving CD79B is retained as an assay observation, but bare protein binding does not identify its biological activity. This row is removed under the current protein-binding policy, not because the interaction is false or because another row duplicates it. The screen or affinity experiment alone does not justify transferring the partner's function or assigning an endogenous B-cell complex. Supporting Evidence: |
| GO:0005515 protein binding | IPI PMID:25910212 Widespread macromolecular interaction perturbations in human... | REMOVE | Summary: CD79B interaction reported by PMID:25910212; generic binding is uninformative as a functional annotation. Reason: The publication-linked interaction involving CD79B is retained as an assay observation, but bare protein binding does not identify its biological activity. This row is removed under the current protein-binding policy, not because the interaction is false or because another row duplicates it. The screen or affinity experiment alone does not justify transferring the partner's function or assigning an endogenous B-cell complex. |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | REMOVE | Summary: CD79B interaction reported by PMID:32296183; generic binding is uninformative as a functional annotation. Reason: The publication-linked interaction involving CD79B is retained as an assay observation, but bare protein binding does not identify its biological activity. This row is removed under the current protein-binding policy, not because the interaction is false or because another row duplicates it. The screen or affinity experiment alone does not justify transferring the partner's function or assigning an endogenous B-cell complex. Supporting Evidence: |
| GO:0005515 protein binding | IPI PMID:35512704 Systematic discovery of mutation-directed neo-protein-protei... | REMOVE | Summary: CD79B interaction reported by PMID:35512704; generic binding is uninformative as a functional annotation. Reason: The publication-linked interaction involving CD79B is retained as an assay observation, but bare protein binding does not identify its biological activity. This row is removed under the current protein-binding policy, not because the interaction is false or because another row duplicates it. The screen or affinity experiment alone does not justify transferring the partner's function or assigning an endogenous B-cell complex. Supporting Evidence: |
| GO:0005886 plasma membrane | IDA GO_REF:0000052 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral membrane component of the BCR. Human receptor structure and CD79B knockout/rescue experiments support its presence and activity at the B-cell surface. The curated antibody-localization assertion agrees with the independent human functional evidence; the individual antibody-image experiment was not independently reconstructed. |
| GO:0005886 plasma membrane | IDA PMID:36426942 Mechanism of CD79A and CD79B Support for IgM+ B Cell Fitness... | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral membrane component of the BCR. Human receptor structure and CD79B knockout/rescue experiments support its presence and activity at the B-cell surface. |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral membrane component of the BCR. Human receptor structure and CD79B knockout/rescue experiments support its presence and activity at the B-cell surface. |
| GO:0005886 plasma membrane | TAS PMID:8486355 Isolation and chromosomal mapping of the human immunoglobuli... | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral membrane component of the BCR. Human receptor structure and CD79B knockout/rescue experiments support its presence and activity at the B-cell surface. The human B29 cloning abstract identifies the membrane protein in the immunoglobulin receptor complex. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-1112666 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-5690701 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-5690702 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-5690740 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-9606151 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-9691421 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-983696 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-983700 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-983703 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-983707 | ACCEPT | Summary: CD79B is present at the plasma membrane as part of the BCR. Reason: CD79B is an integral component of the BCR at the B-cell surface. The cached Reactome reaction places its receptor complex at the plasma membrane, consistent with human receptor structure and CD79B knockout/rescue experiments. |
| GO:0006955 immune response | TAS PMID:8486355 Isolation and chromosomal mapping of the human immunoglobuli... | MODIFY | Summary: Specify B-cell receptor signaling rather than the broader process. Reason: The original immune-response or signal-transduction annotation describes the correct general biology. The directly supported role is the signaling contribution of CD79B within the BCR complex, for which a specific existing process term is available. This does not assign antigen binding or intrinsic kinase catalysis to CD79B. Proposed replacements: B cell receptor signaling pathway |
| GO:0007165 signal transduction | IEA GO_REF:0000117 | MODIFY | Summary: Specify B-cell receptor signaling rather than the broader process. Reason: The original immune-response or signal-transduction annotation describes the correct general biology. The directly supported role is the signaling contribution of CD79B within the BCR complex, for which a specific existing process term is available. This does not assign antigen binding or intrinsic kinase catalysis to CD79B. Proposed replacements: B cell receptor signaling pathway |
| GO:0007165 signal transduction | TAS PMID:8486355 Isolation and chromosomal mapping of the human immunoglobuli... | MODIFY | Summary: Specify B-cell receptor signaling rather than the broader process. Reason: The original immune-response or signal-transduction annotation describes the correct general biology. The directly supported role is the signaling contribution of CD79B within the BCR complex, for which a specific existing process term is available. This does not assign antigen binding or intrinsic kinase catalysis to CD79B. Proposed replacements: B cell receptor signaling pathway |
| GO:0007166 cell surface receptor signaling pathway | IEA GO_REF:0000002 | MODIFY | Summary: Specify B-cell receptor signaling rather than the broader process. Reason: The original immune-response or signal-transduction annotation describes the correct general biology. The directly supported role is the signaling contribution of CD79B within the BCR complex, for which a specific existing process term is available. This does not assign antigen binding or intrinsic kinase catalysis to CD79B. Proposed replacements: B cell receptor signaling pathway |
| GO:0009897 external side of plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: The extracellular portion of CD79B is associated with the external face of the plasma membrane. Reason: The extracellular immunoglobulin-like region of CD79B is exposed outside the plasma membrane and contacts membrane immunoglobulin in the receptor assembly. Its ITAM remains cytoplasmic. Human structural evidence supports the exposed domain's location and assembly contribution without assigning extracellular kinase docking or autonomous antigen recognition. The original phylogenetic/orthology assertion is retained; no independent reconstruction of its ancestral node is claimed. Supporting Evidence: |
| GO:0009897 external side of plasma membrane | IEA GO_REF:0000107 | ACCEPT | Summary: The extracellular portion of CD79B is associated with the external face of the plasma membrane. Reason: The extracellular immunoglobulin-like region of CD79B is exposed outside the plasma membrane and contacts membrane immunoglobulin in the receptor assembly. Its ITAM remains cytoplasmic. Human structural evidence supports the exposed domain's location and assembly contribution without assigning extracellular kinase docking or autonomous antigen recognition. The original phylogenetic/orthology assertion is retained; no independent reconstruction of its ancestral node is claimed. Supporting Evidence: |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: Refine membrane localization to the established cell-surface receptor location. Reason: The single-pass CD79 chain is part of the plasma-membrane BCR; the more informative supported location is already represented in this review. Intracellular trafficking does not negate this refinement. Proposed replacements: plasma membrane |
| GO:0019815 B cell receptor complex | IBA GO_REF:0000033 | ACCEPT | Summary: CD79B is an integral signaling component of the B-cell receptor complex. Reason: The human IgM-BCR structural study directly describes membrane immunoglobulin together with the Ig-alpha/Ig-beta heterodimer; human CD79B loss and WT rescue support its assembly role. The source PAINT assertion includes human CD79A and CD79B among descendant evidence; target self-evidence is expected and not circular. |
| GO:0019815 B cell receptor complex | IDA PMID:35981043 Cryo-EM structure of the human IgM B cell receptor. | ACCEPT | Summary: CD79B is an integral signaling component of the B-cell receptor complex. Reason: The human IgM-BCR structural study directly describes membrane immunoglobulin together with the Ig-alpha/Ig-beta heterodimer; human CD79B loss and WT rescue support its assembly role. |
| GO:0019815 B cell receptor complex | IEA GO_REF:0000120 | ACCEPT | Summary: CD79B is an integral signaling component of the B-cell receptor complex. Reason: The human IgM-BCR structural study directly describes membrane immunoglobulin together with the Ig-alpha/Ig-beta heterodimer; human CD79B loss and WT rescue support its assembly role. |
| GO:0030183 B cell differentiation | IBA GO_REF:0000033 | ACCEPT | Summary: CD79B-dependent receptor function contributes to B-cell differentiation. Reason: CD79B participates through its receptor-assembly and ITAM-signaling contribution in the developmental checkpoints of B cells. Human disease and receptor-assembly evidence (PMID17675462), together with mouse single- and double-deficiency results (PMID12097390), support this central physiological role. Preserved V(D)J recombination distinguishes signaling-dependent maturation from recombinase catalysis. The inherited PAINT judgment is corroborated, not rejected on donor count. |
| GO:0042802 identical protein binding | IDA PMID:14967045 Homooligomerization of the cytoplasmic domain of the T cell ... | KEEP AS NON CORE | Summary: Purified CD79B cytoplasmic domains have reported homooligomerization capacity. Reason: The PMID14967045 abstract explicitly includes Ig-beta among the recombinant ITAM-containing cytoplasmic domains that oligomerize in solution. This supports the existing identical-protein-binding annotation in its experimental context. It does not replace the native CD79AβCD79B heterodimer with a physiological CD79B homodimer, and no isoform-exclusive or concentration-specific claim is inferred from the abstract. |
| GO:0042802 identical protein binding | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Purified CD79B cytoplasmic domains have reported homooligomerization capacity. Reason: The PMID14967045 abstract explicitly includes Ig-beta among the recombinant ITAM-containing cytoplasmic domains that oligomerize in solution. This supports the existing identical-protein-binding annotation in its experimental context. It does not replace the native CD79AβCD79B heterodimer with a physiological CD79B homodimer, and no isoform-exclusive or concentration-specific claim is inferred from the abstract. |
| GO:0050853 B cell receptor signaling pathway | IBA GO_REF:0000033 | ACCEPT | Summary: CD79B contributes directly to B-cell receptor signaling. Reason: CD79B supplies an ITAM-containing signaling chain within the BCR and is required for its proper surface assembly. The conserved-pathway inference is consistent with human receptor structure and knockout/rescue evidence. It does not imply intrinsic CD79B kinase activity. In murine A20 IIA1.6 cells, PDGFR/Ig-tail heterodimers enhanced Ig-alpha phosphorylation and more closely reproduced endogenous BCR signaling than homodimers (PMID8617796). This supports cooperative signaling without establishing a specific kinase-recruitment mechanism. |
| GO:0050853 B cell receptor signaling pathway | ISS GO_REF:0000024 | ACCEPT | Summary: CD79B contributes directly to B-cell receptor signaling. Reason: CD79B supplies an ITAM-containing signaling chain within the BCR and is required for its proper surface assembly. The conserved-pathway inference is consistent with human receptor structure and knockout/rescue evidence. It does not imply intrinsic CD79B kinase activity. In murine A20 IIA1.6 cells, PDGFR/Ig-tail heterodimers enhanced Ig-alpha phosphorylation and more closely reproduced endogenous BCR signaling than homodimers (PMID8617796). This supports cooperative signaling without establishing a specific kinase-recruitment mechanism. |
| GO:0070062 extracellular exosome | HDA PMID:20458337 MHC class II-associated proteins in B-cell exosomes and pote... | KEEP AS NON CORE | Summary: CD79B has been detected in a B-cell exosome preparation. Reason: The source-linked Vesiclepedia entry for human CD79B identifies mass-spectrometric detection in B-cell exosome experiment80 from PMID20458337. This corroborates the target assignment from the same study, not independent replication. The original supplementary mass-spectrometry row was not independently inspected. Retain the contextual localization without assigning an exosome-biogenesis function or claiming CD79B-specific western validation. Supporting Evidence: |
| GO:0071755 IgM B cell receptor complex | IDA PMID:35981043 Cryo-EM structure of the human IgM B cell receptor. | ACCEPT | Summary: The human IgM BCR contains CD79B. Reason: The structural-study abstract explicitly describes IgM-BCR as two immunoglobulin heavy chains, two light chains and an Ig-alpha/Ig-beta heterodimer. This directly supports membership of the IgM-specific receptor complex. Supporting Evidence: |
| GO:0071755 IgM B cell receptor complex | IDA PMID:36949194 Immunoglobulin M perception by FcΞΌR. | ACCEPT | Summary: Retain CD79B membership of the IgM receptor complex. Reason: The cited Fc-mu-receptor structural abstract examines IgM in the BCR context, but its exact CD79B-containing construct details were not accessible. Independent PMID35981043 directly establishes the human Ig-alpha/Ig-beta-containing IgM BCR, making the component annotation biologically clear. Do not infer wrong-gene attribution from a paper title focused on Fc-mu receptor. |
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Download this section (compressed HTML)Q: Do endogenous human CD79B trafficking studies establish a direct cargo-sorting or adaptor-recruitment step sufficient for GO:0031623 receptor internalization or GO:0019882 antigen processing and presentation, beyond CD79B being receptor cargo and providing permissive signaling? The accessed chimeric-receptor evidence supports cooperative late-endosomal trafficking, but precise native human participation and the appropriate direct-versus-regulatory term remain unresolved.
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