KCNRG (potassium channel regulatory protein) is an ER-associated protein that negatively regulates voltage-gated potassium channels of the Kv1 family. It contains an N-terminal T1 (tetramerization) domain homologous to those found in Kv alpha-subunits, which allows KCNRG to interact with the cytoplasmic N-terminal domains of Kv1 channels (specifically KCNA1/Kv1.1 and KCNA4/Kv1.4). By associating with these channels in the ER, KCNRG retains a fraction of channels in endomembranes, thereby reducing their surface expression and attenuating K+ currents. KCNRG forms homooligomers and is located in the 13q14.3 chromosomal region frequently deleted in B-cell malignancies, suggesting a possible tumor suppressor role. KCNRG is also recognized as a pulmonary autoantigen in APS-1 (autoimmune polyendocrine syndrome type 1).
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005783 endoplasmic reticulum | IBA GO_REF:0000033 | ACCEPT | Summary: KCNRG localization to the endoplasmic reticulum is well-supported by experimental data. PMID:19968958 demonstrates that "KCNRG is an ER-associated protein" and proposes it "regulates Kv1 family channel proteins by retaining a fraction of channels in endomembranes." The phylogenetic inference (IBA) is consistent with the experimental evidence. Reason: The ER localization is central to KCNRG's mechanism of action. By residing in the ER, KCNRG can interact with newly synthesized Kv channels during their biosynthetic pathway and prevent their trafficking to the plasma membrane. This is a core aspect of KCNRG function. Supporting Evidence: PMID:19968958 Our data indicates that KCNRG is an ER-associated protein, which we propose regulates Kv1 family channel proteins by retaining a fraction of channels in endomembranes. file:human/KCNRG/KCNRG-deep-research-falcon.md model: Edison Scientific Literature |
| GO:0005783 endoplasmic reticulum | IEA GO_REF:0000044 | ACCEPT | Summary: Computational inference of ER localization based on UniProt subcellular location vocabulary. This is supported by the experimental IDA evidence from PMID:19968958. Reason: While this is an electronic annotation, it correctly captures the experimentally validated ER localization. The mapping from UniProt vocabulary is accurate. Supporting Evidence: PMID:19968958 Our data indicates that KCNRG is an ER-associated protein |
| GO:0042802 identical protein binding | IEA GO_REF:0000117 | ACCEPT | Summary: KCNRG self-association/homooligomerization is supported by UniProt annotation which states "Can form homooligomers" based on PMID:19968958. The ARBA-derived annotation is consistent with known biology. Reason: Homooligomerization is relevant to KCNRG function. The T1 domain that KCNRG possesses is homologous to the tetramerization domain of Kv channels, suggesting oligomerization is an inherent property of this domain. This is supported by protein-protein interaction data. Supporting Evidence: PMID:19968958 Current attenuation requires the presence of the N-terminal T1 Domain |
| GO:0051260 protein homooligomerization | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based inference of homooligomerization. KCNRG contains a T1-type BTB domain (IPR003131) which mediates tetramerization in Kv channel alpha-subunits. UniProt confirms KCNRG "Can form homooligomers" (PMID:19968958). Reason: The T1/BTB domain in KCNRG is structurally related to the tetramerization domains of Kv channels. Homooligomerization is consistent with the domain architecture and is experimentally supported. Supporting Evidence: PMID:19968958 Current attenuation requires the presence of the N-terminal T1 Domain |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | REMOVE | Summary: High-throughput protein interaction study. "Protein binding" is uninformative for GO annotation purposes. KCNRG has specific, functionally relevant binding partners (KCNA1, KCNA4) that should be annotated with more informative terms. Reason: GO:0005515 "protein binding" is too general and does not provide meaningful functional information. The core molecular function of KCNRG is potassium channel regulation, not generic protein binding. More specific terms should be used instead. Supporting Evidence: PMID:32296183 Apr 8. A reference map of the human binary protein interactome. |
| GO:0042802 identical protein binding | IPI PMID:16189514 Towards a proteome-scale map of the human protein-protein in... | ACCEPT | Summary: High-throughput yeast two-hybrid study detecting KCNRG self-interaction. The homooligomerization of KCNRG is consistent with its T1 domain architecture. Reason: Self-association is supported by domain architecture (T1 domain mediates tetramerization) and UniProt annotation. This is a legitimate molecular function annotation. Supporting Evidence: PMID:19968958 Current attenuation requires the presence of the N-terminal T1 Domain PMID:16189514 Towards a proteome-scale map of the human protein-protein interaction network. |
| GO:0042802 identical protein binding | IPI PMID:19447967 Shifted Transversal Design smart-pooling for high coverage i... | ACCEPT | Summary: Smart-pooling interactome study detecting KCNRG self-interaction. Consistent with T1 domain-mediated homooligomerization. Reason: Multiple independent studies support KCNRG self-association, consistent with domain architecture. Supporting Evidence: PMID:19447967 Shifted Transversal Design smart-pooling for high coverage interactome mapping. |
| GO:0042802 identical protein binding | IPI PMID:25416956 A proteome-scale map of the human interactome network. | ACCEPT | Summary: Proteome-scale human interactome study. KCNRG self-interaction is consistently detected across multiple high-throughput studies. Reason: Reinforces the homooligomerization capacity of KCNRG supported by its T1 domain. Supporting Evidence: PMID:25416956 A proteome-scale map of the human interactome network. |
| GO:0042802 identical protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | ACCEPT | Summary: Binary protein interactome reference map. KCNRG self-interaction detected. Reason: Consistent with T1 domain-mediated homooligomerization observed in multiple studies. Supporting Evidence: PMID:32296183 Apr 8. A reference map of the human binary protein interactome. |
| GO:0005515 protein binding | IPI PMID:19968958 Potassium channel regulator KCNRG regulates surface expressi... | REMOVE | Summary: This annotation likely reflects the interaction between KCNRG and Kv channel alpha-subunits (KCNA1, KCNA4) demonstrated in immunoprecipitation experiments in PMID:19968958. However, "protein binding" is uninformative. Reason: GO:0005515 "protein binding" should not be used when more specific terms are available. KCNRG functions as a potassium channel regulator through direct binding to Kv1 channels. This interaction should be captured with GO:0015459 "potassium channel regulator activity" rather than the generic "protein binding" term. Proposed replacements: potassium channel regulator activity Supporting Evidence: PMID:19968958 Potassium channel regulator KCNRG regulates surface expression of Shaker-type potassium channels. |
| GO:0005783 endoplasmic reticulum | IDA PMID:19968958 Potassium channel regulator KCNRG regulates surface expressi... | ACCEPT | Summary: Direct experimental evidence for ER localization from the key functional study on KCNRG. Usman & Mathew (2010) showed KCNRG is ER-associated using direct assays. Reason: This is the primary experimental evidence for KCNRG subcellular localization. The ER localization is essential for KCNRG's function in retaining Kv channels in endomembranes. Supporting Evidence: PMID:19968958 Our data indicates that KCNRG is an ER-associated protein, which we propose regulates Kv1 family channel proteins by retaining a fraction of channels in endomembranes. |
| GO:1902260 negative regulation of delayed rectifier potassium channel activity | IDA PMID:19968958 Potassium channel regulator KCNRG regulates surface expressi... | ACCEPT | Summary: Core functional annotation supported by direct experimental evidence. PMID:19968958 demonstrates that KCNRG "reduces K+ currents through human K+ channels hKv1.1 and hKv1.4 expressed in Xenopus oocytes." The mechanism involves T1 domain-mediated interaction and retention of channels in the ER. Reason: This is the core molecular/biological function of KCNRG. Kv1.1 and Kv1.4 are delayed rectifier potassium channels, and KCNRG negatively regulates their activity by reducing surface expression. This is well-supported by electrophysiological data showing current attenuation. Supporting Evidence: PMID:19968958 The K(+) channel regulator protein (KCNRG), identified as a putative tumor suppressor, reduces K(+) currents through human K(+) channels hKv1.1 and hKv1.4 expressed in Xenopus oocytes. PMID:19968958 Current attenuation requires the presence of the N-terminal T1 Domain and immunoprecipitation experiments suggest association of KCNRG with the N-terminus of the channel. |
| GO:0015459 potassium channel regulator activity | IDA PMID:19968958 Potassium channel regulator KCNRG regulates surface expressi... | NEW | Summary: NEW ANNOTATION. KCNRG directly binds to and modulates Kv1 potassium channels. The name "potassium channel regulator" directly reflects this molecular function. PMID:19968958 provides direct evidence through immunoprecipitation showing KCNRG association with Kv channel N-terminus and functional data showing current attenuation. Reason: This molecular function term is missing from the current annotation set but is strongly supported by experimental evidence. KCNRG binds Kv1 channels (KCNA1, KCNA4) via T1 domain interactions and modulates their activity by reducing surface expression. This is the core molecular function of the protein. Supporting Evidence: PMID:19968958 The K(+) channel regulator protein (KCNRG), identified as a putative tumor suppressor, reduces K(+) currents through human K(+) channels hKv1.1 and hKv1.4 expressed in Xenopus oocytes. Current attenuation requires the presence of the N-terminal T1 Domain and immunoprecipitation experiments suggest association of KCNRG with the N-terminus of the channel. |
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