CR1 encodes complement receptor type 1/CD35, a large single-pass membrane receptor composed of complement-control protein repeat domains and expressed on erythrocytes, monocytes/macrophages, granulocytes, B cells, subsets of T cells, follicular dendritic cells, and other immune-associated cells. CR1 binds complement-opsonized ligands, especially C3b and C4b, allowing immune adherence and clearance of immune complexes and particles from the circulation. CR1 also regulates complement by accelerating decay of classical and alternative pathway convertases and acting as a factor I cofactor for cleavage of C3b and C4b. In specific immune-cell contexts, CR1 engagement can modulate T-cell, B-cell, and regulatory T-cell responses, while complement-pathway interactions with C1q, MBL, ficolins, and microbial ligands broaden its immune-recognition roles.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005576 extracellular region | IBA GO_REF:0000033 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0045959 negative regulation of complement activation, classical pathway | IBA GO_REF:0000033 | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0002456 T cell mediated immunity | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0001848 complement binding | IEA GO_REF:0000117 | ACCEPT | Summary: CR1 directly binds complement ligands, especially C3b and C4b, and functions as their cell-surface receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0004875 complement receptor activity | IEA GO_REF:0000117 | ACCEPT | Summary: CR1 directly binds complement ligands, especially C3b and C4b, and functions as their cell-surface receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0005886 plasma membrane | IEA GO_REF:0000117 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0006957 complement activation, alternative pathway | IEA GO_REF:0000117 | ACCEPT | Summary: This complement activation/MAC annotation is supported in specific B-cell complement deposition contexts while remaining part of CR1 complement receptor biology. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0016020 membrane | IEA GO_REF:0000044 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0030449 regulation of complement activation | IEA GO_REF:0000117 | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:1903659 regulation of complement-dependent cytotoxicity | IEA GO_REF:0000117 | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0005515 protein binding | IPI PMID:23460739 Deciphering complement receptor type 1 interactions with rec... | MODIFY | Summary: The MBL/ficolin/C1q interaction evidence supports complement-recognition ligand binding, but generic protein binding is too broad. Reason: Replace generic protein binding with complement binding for CR1 interactions with recognition proteins of the lectin/classical complement pathways. Proposed replacements: complement binding |
| GO:0005515 protein binding | IPI PMID:29563915 C1q and Mannose-Binding Lectin Interact with CR1 in the Same... | MODIFY | Summary: The MBL/ficolin/C1q interaction evidence supports complement-recognition ligand binding, but generic protein binding is too broad. Reason: Replace generic protein binding with complement binding for CR1 interactions with recognition proteins of the lectin/classical complement pathways. Proposed replacements: complement binding |
| GO:0005886 plasma membrane | IDA GO_REF:0000052 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0002251 organ or tissue specific immune response | IGI PMID:20702729 Abnormal immune complex processing and spontaneous glomerulo... | KEEP AS NON CORE | Summary: This mouse disease/model annotation reflects complement-dependent immune-complex pathology and glomerular consequences rather than the primary molecular function of CR1. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0002434 immune complex clearance | IGI PMID:20702729 Abnormal immune complex processing and spontaneous glomerulo... | ACCEPT | Summary: CR1 on erythrocytes and immune cells mediates immune adherence and clearance of complement-opsonized immune complexes/particles. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0006956 complement activation | IGI PMID:20702729 Abnormal immune complex processing and spontaneous glomerulo... | KEEP AS NON CORE | Summary: This mouse disease/model annotation reflects complement-dependent immune-complex pathology and glomerular consequences rather than the primary molecular function of CR1. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0032835 glomerulus development | IGI PMID:20702729 Abnormal immune complex processing and spontaneous glomerulo... | KEEP AS NON CORE | Summary: This mouse disease/model annotation reflects complement-dependent immune-complex pathology and glomerular consequences rather than the primary molecular function of CR1. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0016020 membrane | EXP PMID:1385479 Expression and localization of proteins of the complement sy... | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:1903660 negative regulation of complement-dependent cytotoxicity | IDA PMID:31862673 Complement Receptor 1 (CR1/CD35)-expressing retinal pigment ... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0001970 positive regulation of activation of membrane attack complex | IMP PMID:11981823 The role of complement receptors type 1 (CR1, CD35) and 2 (C... | ACCEPT | Summary: This complement activation/MAC annotation is supported in specific B-cell complement deposition contexts while remaining part of CR1 complement receptor biology. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0005515 protein binding | IPI PMID:18684861 Ligation of erythrocyte CR1 induces its clustering in comple... | MARK AS OVER ANNOTATED | Summary: The FAP-1/scaffold interaction may be real in erythrocyte CR1 clustering, but generic protein binding does not define CR1 molecular function. Reason: This annotation is less informative than specific CR1 complement-binding, complement receptor, immune-complex clearance, or complement-regulatory terms. |
| GO:0005856 cytoskeleton | IDA PMID:18684861 Ligation of erythrocyte CR1 induces its clustering in comple... | KEEP AS NON CORE | Summary: This erythrocyte clustering, membrane organization, raft, ATP-release, or cytoskeletal annotation is relevant to immune-adherence transfer but is secondary to CR1 complement ligand binding. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0006957 complement activation, alternative pathway | IMP PMID:11981823 The role of complement receptors type 1 (CR1, CD35) and 2 (C... | ACCEPT | Summary: This complement activation/MAC annotation is supported in specific B-cell complement deposition contexts while remaining part of CR1 complement receptor biology. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0008284 positive regulation of cell population proliferation | IDA PMID:25742728 Complement receptor type 1 (CR1/CD35) expressed on activated... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0009986 cell surface | IDA PMID:25742728 Complement receptor type 1 (CR1/CD35) expressed on activated... | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0045591 positive regulation of regulatory T cell differentiation | IDA PMID:25742728 Complement receptor type 1 (CR1/CD35) expressed on activated... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0002435 immune complex clearance by erythrocytes | IDA PMID:24022490 CR1-mediated ATP release by human red blood cells promotes C... | ACCEPT | Summary: CR1 on erythrocytes and immune cells mediates immune adherence and clearance of complement-opsonized immune complexes/particles. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0002430 complement receptor mediated signaling pathway | IDA PMID:16360013 The complement receptor 1, CR1 (CD35), mediates inhibitory s... | ACCEPT | Summary: CR1 engagement can signal through complement receptor-mediated pathways in immune cells. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0002430 complement receptor mediated signaling pathway | IDA PMID:22962438 Complement receptor type 1 (CR1, CD35) is a potent inhibitor... | ACCEPT | Summary: CR1 engagement can signal through complement receptor-mediated pathways in immune cells. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0002638 negative regulation of immunoglobulin production | IDA PMID:22962438 Complement receptor type 1 (CR1, CD35) is a potent inhibitor... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0007009 plasma membrane organization | IDA PMID:24022490 CR1-mediated ATP release by human red blood cells promotes C... | KEEP AS NON CORE | Summary: This erythrocyte clustering, membrane organization, raft, ATP-release, or cytoskeletal annotation is relevant to immune-adherence transfer but is secondary to CR1 complement ligand binding. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0032689 negative regulation of type II interferon production | IDA PMID:16360013 The complement receptor 1, CR1 (CD35), mediates inhibitory s... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0032703 negative regulation of interleukin-2 production | IDA PMID:16360013 The complement receptor 1, CR1 (CD35), mediates inhibitory s... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0042130 negative regulation of T cell proliferation | IDA PMID:16360013 The complement receptor 1, CR1 (CD35), mediates inhibitory s... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0044853 plasma membrane raft | IDA PMID:24022490 CR1-mediated ATP release by human red blood cells promotes C... | KEEP AS NON CORE | Summary: This erythrocyte clustering, membrane organization, raft, ATP-release, or cytoskeletal annotation is relevant to immune-adherence transfer but is secondary to CR1 complement ligand binding. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:1900099 negative regulation of plasma cell differentiation | IDA PMID:22962438 Complement receptor type 1 (CR1, CD35) is a potent inhibitor... | KEEP AS NON CORE | Summary: This adaptive immune-cell annotation is supported or plausible but represents T-cell/B-cell regulatory consequences of CR1 engagement rather than the primary C3b/C4b receptor/cofactor role. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:1904669 ATP export | IDA PMID:24022490 CR1-mediated ATP release by human red blood cells promotes C... | KEEP AS NON CORE | Summary: This erythrocyte clustering, membrane organization, raft, ATP-release, or cytoskeletal annotation is relevant to immune-adherence transfer but is secondary to CR1 complement ligand binding. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0001971 negative regulation of activation of membrane attack complex | IDA PMID:31862673 Complement Receptor 1 (CR1/CD35)-expressing retinal pigment ... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0045916 negative regulation of complement activation | IDA PMID:31862673 Complement Receptor 1 (CR1/CD35)-expressing retinal pigment ... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0030667 secretory granule membrane | TAS Reactome:R-HSA-6798743 | KEEP AS NON CORE | Summary: This intracellular/granule localization is compatible with immune-cell trafficking context but is not the main functional site of CR1 complement receptor activity. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0101003 ficolin-1-rich granule membrane | TAS Reactome:R-HSA-6800426 | KEEP AS NON CORE | Summary: This intracellular/granule localization is compatible with immune-cell trafficking context but is not the main functional site of CR1 complement receptor activity. Reason: Retain as non-core because the annotation is supported or plausible but reflects cell-type-specific adaptive immune modulation, disease/model context, erythrocyte clustering mechanics, or intracellular/granule localization rather than the primary C3b/C4b receptor and complement-regulatory function. |
| GO:0070062 extracellular exosome | HDA PMID:23533145 In-depth proteomic analyses of exosomes isolated from expres... | MARK AS OVER ANNOTATED | Summary: High-throughput extracellular exosome localization is not central to CR1 complement receptor biology and is less informative than membrane/cell-surface annotations. Reason: This annotation is less informative than specific CR1 complement-binding, complement receptor, immune-complex clearance, or complement-regulatory terms. |
| GO:0070062 extracellular exosome | HDA PMID:19056867 Large-scale proteomics and phosphoproteomics of urinary exos... | MARK AS OVER ANNOTATED | Summary: High-throughput extracellular exosome localization is not central to CR1 complement receptor biology and is less informative than membrane/cell-surface annotations. Reason: This annotation is less informative than specific CR1 complement-binding, complement receptor, immune-complex clearance, or complement-regulatory terms. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-3266557 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-6798743 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-6800426 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-8939088 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-977375 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-977602 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-977615 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | TAS Reactome:R-HSA-977629 | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0005886 plasma membrane | IDA PMID:6910481 Complement receptor is an inhibitor of the complement cascad... | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0045957 negative regulation of complement activation, alternative pathway | IDA PMID:10531307 Decay accelerating activity of complement receptor type 1 (C... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0045959 negative regulation of complement activation, classical pathway | IDA PMID:10531307 Decay accelerating activity of complement receptor type 1 (C... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0045959 negative regulation of complement activation, classical pathway | IDA PMID:6910481 Complement receptor is an inhibitor of the complement cascad... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:1900004 negative regulation of serine-type endopeptidase activity | IDA PMID:6910481 Complement receptor is an inhibitor of the complement cascad... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0009986 cell surface | IDA PMID:6978375 Complement receptor (CR1) deficiency in erythrocytes from pa... | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:0001851 complement component C3b binding | IDA PMID:2972794 Identification of distinct C3b and C4b recognition sites in ... | ACCEPT | Summary: CR1 directly binds complement ligands, especially C3b and C4b, and functions as their cell-surface receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0001855 complement component C4b binding | IDA PMID:2972794 Identification of distinct C3b and C4b recognition sites in ... | ACCEPT | Summary: CR1 directly binds complement ligands, especially C3b and C4b, and functions as their cell-surface receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0001861 complement component C4b receptor activity | IDA PMID:2972794 Identification of distinct C3b and C4b recognition sites in ... | ACCEPT | Summary: CR1 directly binds complement ligands, especially C3b and C4b, and functions as their cell-surface receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0004877 complement component C3b receptor activity | IDA PMID:2972794 Identification of distinct C3b and C4b recognition sites in ... | ACCEPT | Summary: CR1 directly binds complement ligands, especially C3b and C4b, and functions as their cell-surface receptor. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
| GO:0009986 cell surface | IDA PMID:2972794 Identification of distinct C3b and C4b recognition sites in ... | ACCEPT | Summary: This membrane/extracellular location is consistent with CR1 as a large ectodomain-containing single-pass complement receptor. Reason: This location is consistent with CR1 acting as a single-pass cell-surface/plasma-membrane complement receptor. |
| GO:1900005 positive regulation of serine-type endopeptidase activity | IDA PMID:2972794 Identification of distinct C3b and C4b recognition sites in ... | ACCEPT | Summary: CR1 regulates complement by accelerating convertase decay and serving as a cofactor for factor I-mediated C3b/C4b cleavage, limiting complement activation and cytotoxicity. Reason: This term captures the core CR1/CD35 role as a cell-surface complement receptor that binds C3b/C4b-bearing ligands, supports immune adherence/clearance, and regulates complement convertase and factor I-dependent cleavage reactions. |
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Download this section (compressed HTML)Q: Should CR1 interactions with C1q, MBL, and ficolins be curated with more specific complement-recognition binding terms rather than generic protein binding?
Suggested experts: Complement pathway experts, GO molecular-function curators
Q: Which CR1 immune-cell regulatory annotations should be considered core across species and cell types versus retained as human T-cell/B-cell context?
Suggested experts: CR1 immunology experts, GO immune process curators
Experiment: Use CR1 variants disrupting C3b/C4b sites, CCP24-25 defense-collagen binding, and cytoplasmic FAP-1 interaction in erythrocytes or engineered immune cells, then measure immune-complex binding, transfer to macrophages, factor I cofactor activity, and convertase decay.
Hypothesis: CR1 immune-adherence clearance and complement-regulatory functions can be separated from defense-collagen binding and erythrocyte clustering modules.
Type: domain-resolved complement receptor function assay
Experiment: Compare CR1 engagement on primary human T-cell and B-cell subsets with C3b/C4b ligands versus antibody crosslinking, quantifying cytokines, proliferation, Treg differentiation, plasma-cell differentiation, and complement receptor signaling markers.
Hypothesis: Adaptive immune-cell effects of CR1 are cell-context-specific signaling outcomes of complement ligand engagement rather than the universal core function of CR1.
Type: primary immune-cell receptor signaling assay
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