CORYNE (CRN; also SUPPRESSOR OF LLP1 2, SOL2) is a plasma membrane protein with a short extracellular region, a single transmembrane helix and a cytoplasmic kinase-like domain. The kinase-like domain is a pseudokinase: it has an HYN instead of an HRD catalytic loop and a degenerate glycine-rich loop, shows no autophosphorylation in vitro, and a kinase-dead variant fully complements crn-1. CRN associates with the receptor-like protein CLAVATA2 (CLV2) through transmembrane and juxtamembrane contacts, and the two proteins require each other to leave the endoplasmic reticulum and reach the plasma membrane. The CLV2/CRN complex acts in parallel with, and can associate with, CLV1/BAM receptor kinases and CIK co-receptor kinases to transmit the CLV3 peptide signal that restricts WUSCHEL expression and stem cell number in shoot and floral meristems. In roots, CRN is required in the protophloem for responses to root-active CLE peptides, partly by stabilizing the CLE45 receptor BAM3. Its kinase-like domain contributes to shoot but not root signalling. CRN is also needed for floral organ development and for perception of nematode CLE-like effectors.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0001653 peptide receptor activity | IMP PMID:28607033 Perception of root-active CLE peptides requires CORYNE funct... | MODIFY | Summary: crn mutants are resistant to root-active CLE peptides, and protophloem-specific CRN restores sensitivity. CRN has essentially no ectodomain and is not thought to bind the peptide. It contributes by forming the CLV2/CRN complex, by trafficking CLV2 to the plasma membrane and by stabilizing BAM3. Reason: The IMP shows that CRN is required for CLE perception, not that it binds peptide. A receptor-complex scaffold activity describes the pseudokinase role better. Proposed replacements: signaling receptor complex adaptor activity Supporting Evidence: PMID:28607033 the receptor-like protein CLAVATA 2 (CLV2) and the pseudokinase CORYNE (CRN) are necessary to fully sense root-active CLE peptides PMID:28607033 CRN stabilizes BAM3 expression and thus is required for BAM3-mediated CLE45 signaling PMID:21398569 The additive nature of crn and clv1 alleles suggests that CRN may play a scaffolding role, perhaps to aid export of CLV2 to the plasma membrane file:ARATH/CRN/CRN-deep-research-falcon.md short extracellular segment rather than an extracellular leucine-rich-repeat binding domain |
| GO:0004672 protein kinase activity | IDA NOT PMID:21398569 An evolutionarily conserved pseudokinase mediates stem cell ... | ACCEPT | Summary: Purified CRN kinase domain shows no autophosphorylation, while CLV1 does under the same conditions. A CRN K146E variant fully complements crn-1. CRN lacks the catalytic Asp of the HRD motif. Reason: The NOT annotation is well supported by biochemistry, sequence and in vivo complementation. Supporting Evidence: PMID:21398569 No activity was seen for either CRN protein, suggesting that wild-type CRN lacks autokinase activity under standard conditions. PMID:21398569 indicating that CRN does not require kinase activity for wild-type function PMID:21398569 CRN contains a His-Tyr-Asn (HYN) motif in the presumed catalytic loop instead of the His-Arg-Asp (HRD) motif typical of functional kinases and therefore lacks the critical active-site Asp |
| GO:0005102 signaling receptor binding | IPI PMID:19843317 Analysis of interactions among the CLAVATA3 receptors reveal... | ACCEPT | Summary: CRN interacts directly with the receptor-like protein CLV2, which forms the CLV2/CRN heteromeric receptor complex. Reason: This binding to the receptor CLV2 is central to CRN function. Supporting Evidence: PMID:19843317 CLV2 can directly interact with CRN in the absence of CLV3 PMID:20626648 Transgenic Arabidopsis plants stably expressing CLV2-MYC and CRN-GFP were used to assess interactions in vivo. Here we also observed robust co-IP between the two proteins PMID:19933383 CRN readily forms homomers and interacts with CLV2 through the transmembrane domain and adjacent juxtamembrane sequences. |
| GO:0005102 signaling receptor binding | IPI PMID:20626648 CLAVATA2 forms a distinct CLE-binding receptor complex regul... | ACCEPT | Summary: CRN interacts directly with the receptor-like protein CLV2, which forms the CLV2/CRN heteromeric receptor complex. Reason: This binding to the receptor CLV2 is central to CRN function. Supporting Evidence: PMID:19843317 CLV2 can directly interact with CRN in the absence of CLV3 PMID:20626648 Transgenic Arabidopsis plants stably expressing CLV2-MYC and CRN-GFP were used to assess interactions in vivo. Here we also observed robust co-IP between the two proteins PMID:19933383 CRN readily forms homomers and interacts with CLV2 through the transmembrane domain and adjacent juxtamembrane sequences. |
| GO:0005515 protein binding | IPI PMID:20626648 CLAVATA2 forms a distinct CLE-binding receptor complex regul... | MODIFY | Summary: CRN co-immunoprecipitates with CLV2 in transient and stable Arabidopsis expression. Reason: Generic protein binding is better captured as signaling receptor binding (CLV2). Proposed replacements: signaling receptor binding Supporting Evidence: PMID:20626648 Transgenic Arabidopsis plants stably expressing CLV2-MYC and CRN-GFP were used to assess interactions in vivo. Here we also observed robust co-IP between the two proteins |
| GO:0005515 protein binding | IPI PMID:27229734 Shared and distinct functions of the pseudokinase CORYNE (CR... | MODIFY | Summary: CRN co-immunoprecipitates with CLV2 in transient and stable Arabidopsis expression. Reason: Generic protein binding is better captured as signaling receptor binding (CLV2). Proposed replacements: signaling receptor binding Supporting Evidence: PMID:20626648 Transgenic Arabidopsis plants stably expressing CLV2-MYC and CRN-GFP were used to assess interactions in vivo. Here we also observed robust co-IP between the two proteins |
| GO:0005515 protein binding | IPI PMID:29581511 A group of receptor kinases are essential for CLAVATA signal... | MODIFY | Summary: CRN associates at the plasma membrane with the CIK LRR receptor kinases (CIK1-4), which act as co-receptors of CLV1, CLV2/CRN and RPK2 in CLV3 signalling. Reason: The CIKs are transmembrane receptor Ser/Thr kinases, so receptor serine/threonine kinase binding is the informative term. Proposed replacements: receptor serine/threonine kinase binding Supporting Evidence: PMID:29581511 CIKs function as co-receptors of CLV1, CLV2/CRN and RPK2 to mediate CLV3 signalling through phosphorylation. |
| GO:0005515 protein binding | IPI PMID:29581511 A group of receptor kinases are essential for CLAVATA signal... | MODIFY | Summary: CRN associates at the plasma membrane with the CIK LRR receptor kinases (CIK1-4), which act as co-receptors of CLV1, CLV2/CRN and RPK2 in CLV3 signalling. Reason: The CIKs are transmembrane receptor Ser/Thr kinases, so receptor serine/threonine kinase binding is the informative term. Proposed replacements: receptor serine/threonine kinase binding Supporting Evidence: PMID:29581511 CIKs function as co-receptors of CLV1, CLV2/CRN and RPK2 to mediate CLV3 signalling through phosphorylation. |
| GO:0005515 protein binding | IPI PMID:29581511 A group of receptor kinases are essential for CLAVATA signal... | MODIFY | Summary: CRN associates at the plasma membrane with the CIK LRR receptor kinases (CIK1-4), which act as co-receptors of CLV1, CLV2/CRN and RPK2 in CLV3 signalling. Reason: The CIKs are transmembrane receptor Ser/Thr kinases, so receptor serine/threonine kinase binding is the informative term. Proposed replacements: receptor serine/threonine kinase binding Supporting Evidence: PMID:29581511 CIKs function as co-receptors of CLV1, CLV2/CRN and RPK2 to mediate CLV3 signalling through phosphorylation. |
| GO:0005515 protein binding | IPI PMID:29581511 A group of receptor kinases are essential for CLAVATA signal... | MODIFY | Summary: CRN associates at the plasma membrane with the CIK LRR receptor kinases (CIK1-4), which act as co-receptors of CLV1, CLV2/CRN and RPK2 in CLV3 signalling. Reason: The CIKs are transmembrane receptor Ser/Thr kinases, so receptor serine/threonine kinase binding is the informative term. Proposed replacements: receptor serine/threonine kinase binding Supporting Evidence: PMID:29581511 CIKs function as co-receptors of CLV1, CLV2/CRN and RPK2 to mediate CLV3 signalling through phosphorylation. |
| GO:0005515 protein binding | IPI PMID:33909893 Receptor-like cytoplasmic kinase MAZZA mediates developmenta... | MODIFY | Summary: The receptor-like cytoplasmic kinase MAZZA (CARK5/PTI1-3) associates with CLV1-family receptors and with CRN in the presence of CLV2. Reason: The partner is a protein kinase, so protein kinase binding is more informative than protein binding. This is non-core. Proposed replacements: protein kinase binding Supporting Evidence: PMID:33909893 the membrane-associated receptor-like cytoplasmic kinase (RLCK) MAZZA (MAZ) and additional members of the Pti1-like protein family interact in vivo with CLV1f receptors. |
| GO:0005524 ATP binding | IEA GO_REF:0000002 | REMOVE | Summary: This IEA comes from the generic protein kinase domain signature. In CRN the glycine-rich loop that positions ATP has diverged from GXGXXG to GXDXXG, and the catalytic loop lacks the active-site Asp. CRN shows no kinase activity. Reason: The domain-based ATP binding inference is contradicted by the pseudokinase features of CRN. No ATP binding has been shown, and its kinase-like function is catalysis-independent. Supporting Evidence: PMID:21398569 The G-loop, GXGXXG, which binds and positions ATP, has diverged in CRN to GXDXXG. PMID:21398569 CRN contains a His-Tyr-Asn (HYN) motif in the presumed catalytic loop instead of the His-Arg-Asp (HRD) motif typical of functional kinases and therefore lacks the critical active-site Asp PMID:21398569 No activity was seen for either CRN protein, suggesting that wild-type CRN lacks autokinase activity under standard conditions. |
| GO:0005739 mitochondrion | ISM GO_REF:0000122 | REMOVE | Summary: This is a sequence-based prediction of mitochondrial targeting. CRN is a single-pass plasma membrane protein that passes through the ER. Reason: It is contradicted by many experimental localization studies (plasma membrane and ER). Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005789 endoplasmic reticulum membrane | EXP PMID:19933383 Stem cell signaling in Arabidopsis requires CRN to localize ... | KEEP AS NON CORE | Summary: CRN is found in the ER when CLV2 is absent or with the crn-1 transmembrane mutation, because CLV2 and CRN must assemble before ER export. Reason: The ER is a transit and quality-control location, not the signalling site. Supporting Evidence: PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005789 endoplasmic reticulum membrane | IDA PMID:27229734 Shared and distinct functions of the pseudokinase CORYNE (CR... | KEEP AS NON CORE | Summary: CRN is found in the ER when CLV2 is absent or with the crn-1 transmembrane mutation, because CLV2 and CRN must assemble before ER export. Reason: The ER is a transit and quality-control location, not the signalling site. Supporting Evidence: PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005789 endoplasmic reticulum membrane | IDA PMID:28607033 Perception of root-active CLE peptides requires CORYNE funct... | KEEP AS NON CORE | Summary: CRN is found in the ER when CLV2 is absent or with the crn-1 transmembrane mutation, because CLV2 and CRN must assemble before ER export. Reason: The ER is a transit and quality-control location, not the signalling site. Supporting Evidence: PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005789 endoplasmic reticulum membrane | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: CRN is found in the ER when CLV2 is absent or with the crn-1 transmembrane mutation, because CLV2 and CRN must assemble before ER export. Reason: The ER is a transit and quality-control location, not the signalling site. Supporting Evidence: PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | EXP PMID:19933383 Stem cell signaling in Arabidopsis requires CRN to localize ... | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | HDA PMID:14506206 Large-scale analysis of in vivo phosphorylated membrane prot... | ACCEPT | Summary: CRN was identified among plasma membrane phosphoproteins in a large-scale proteomic survey. Reason: This is consistent with the directed localization studies. Supporting Evidence: PMID:14506206 plasma membrane phosphoproteins of Arabidopsis PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | IDA PMID:19843317 Analysis of interactions among the CLAVATA3 receptors reveal... | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | IDA PMID:21051944 Membrane distributions of two ligand-binding receptor comple... | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | IDA PMID:27229734 Shared and distinct functions of the pseudokinase CORYNE (CR... | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | IDA PMID:28607033 Perception of root-active CLE peptides requires CORYNE funct... | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | IDA PMID:29581511 A group of receptor kinases are essential for CLAVATA signal... | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: CRN localizes to the plasma membrane, which depends on CLV2. The plasma membrane is where the CLV2/CRN complex acts. Reason: This is the functional location and is supported by several experimental studies. Supporting Evidence: PMID:19843317 Fluorescence targeting showed that CRN was localized to the plasma membrane. PMID:19933383 We found that CLV2 and CRN require each other for export from the endoplasmic reticulum and localization to the plasma membrane (PM). |
| GO:0009909 regulation of flower development | IMP PMID:12932329 Root-specific CLE19 overexpression and the sol1/2 suppressor... | KEEP AS NON CORE | Summary: sol2 (crn) plants show floral phenotypes similar to weak clv alleles, such as extra carpels, which result from enlarged floral meristems. Reason: This is a downstream developmental phenotype of loss of CLE signalling. Supporting Evidence: PMID:12932329 sol2 plants display floral phenotypes reminiscent of clv weak alleles |
| GO:0010075 regulation of meristem growth | IDA PMID:20697738 CLE14/CLE20 peptides may interact with CLAVATA2/CORYNE recep... | ACCEPT | Summary: crn mutants accumulate stem cells, like clv mutants, and CRN acts with CLV2 to restrict WUS and meristem size. In the root, CLV2/CRN mediate CLE14/CLE20-triggered root meristem reduction. Reason: This is the central physiological output of CLV2/CRN signalling. Supporting Evidence: PMID:18381924 Mutations in CRN cause stem cell proliferation, similar to clv1, clv2, and clv3 mutants. PMID:21705761 The CLAVATA1 (CLV1), CLV2, and CORYNE (CRN) receptors in Arabidopsis thaliana maintain cell proliferation in shoot apical meristems by restricting expression of the transcription factor WUSCHEL (WUS). PMID:20697738 synthetic 12-amino-acid CLE14 and CLE20 peptides inhibit, irreversibly, root growth by reducing cell division rates in the root apical meristem |
| GO:0010075 regulation of meristem growth | IDA PMID:28586647 Phosphate Starvation-Dependent Iron Mobilization Induces CLE... | ACCEPT | Summary: crn mutants accumulate stem cells, like clv mutants, and CRN acts with CLV2 to restrict WUS and meristem size. In the root, CLV2/CRN mediate CLE14/CLE20-triggered root meristem reduction. Reason: This is the central physiological output of CLV2/CRN signalling. Supporting Evidence: PMID:18381924 Mutations in CRN cause stem cell proliferation, similar to clv1, clv2, and clv3 mutants. PMID:21705761 The CLAVATA1 (CLV1), CLV2, and CORYNE (CRN) receptors in Arabidopsis thaliana maintain cell proliferation in shoot apical meristems by restricting expression of the transcription factor WUSCHEL (WUS). PMID:20697738 synthetic 12-amino-acid CLE14 and CLE20 peptides inhibit, irreversibly, root growth by reducing cell division rates in the root apical meristem |
| GO:0010075 regulation of meristem growth | IMP PMID:18381924 The receptor kinase CORYNE of Arabidopsis transmits the stem... | ACCEPT | Summary: crn mutants accumulate stem cells, like clv mutants, and CRN acts with CLV2 to restrict WUS and meristem size. In the root, CLV2/CRN mediate CLE14/CLE20-triggered root meristem reduction. Reason: This is the central physiological output of CLV2/CRN signalling. Supporting Evidence: PMID:18381924 Mutations in CRN cause stem cell proliferation, similar to clv1, clv2, and clv3 mutants. PMID:21705761 The CLAVATA1 (CLV1), CLV2, and CORYNE (CRN) receptors in Arabidopsis thaliana maintain cell proliferation in shoot apical meristems by restricting expression of the transcription factor WUSCHEL (WUS). PMID:20697738 synthetic 12-amino-acid CLE14 and CLE20 peptides inhibit, irreversibly, root growth by reducing cell division rates in the root apical meristem |
| GO:0010075 regulation of meristem growth | IMP PMID:21705761 CLAVATA signaling pathway receptors of Arabidopsis regulate ... | ACCEPT | Summary: crn mutants accumulate stem cells, like clv mutants, and CRN acts with CLV2 to restrict WUS and meristem size. In the root, CLV2/CRN mediate CLE14/CLE20-triggered root meristem reduction. Reason: This is the central physiological output of CLV2/CRN signalling. Supporting Evidence: PMID:18381924 Mutations in CRN cause stem cell proliferation, similar to clv1, clv2, and clv3 mutants. PMID:21705761 The CLAVATA1 (CLV1), CLV2, and CORYNE (CRN) receptors in Arabidopsis thaliana maintain cell proliferation in shoot apical meristems by restricting expression of the transcription factor WUSCHEL (WUS). PMID:20697738 synthetic 12-amino-acid CLE14 and CLE20 peptides inhibit, irreversibly, root growth by reducing cell division rates in the root apical meristem |
| GO:0010078 maintenance of root meristem identity | IMP PMID:28607033 Perception of root-active CLE peptides requires CORYNE funct... | KEEP AS NON CORE | Summary: CRN is required for full sensitivity of the proximal root meristem to root-active CLE peptides. Its kinase domain is dispensable for this. Reason: This is a root-context output of CLE perception, based mainly on peptide-resistance assays. Supporting Evidence: PMID:28607033 the receptor-like protein CLAVATA 2 (CLV2) and the pseudokinase CORYNE (CRN) are necessary to fully sense root-active CLE peptides PMID:27229734 we show that the kinase domain of CRN is actively involved in CLV3 signal transduction in the shoot apical meristem of Arabidopsis, but it is dispensable for CRN protein function in root meristem maintenance. |
| GO:0010088 phloem development | IMP PMID:28607033 Perception of root-active CLE peptides requires CORYNE funct... | KEEP AS NON CORE | Summary: CRN acts in the protophloem to mediate the response to root-active CLE peptides that suppress protophloem differentiation. Reason: This is a context-specific developmental output. Supporting Evidence: PMID:28607033 protophloem-specific CRN expression complements resistance of the crn mutant to root-active CLE peptides |
| GO:0033612 receptor serine/threonine kinase binding | IPI PMID:19843317 Analysis of interactions among the CLAVATA3 receptors reveal... | KEEP AS NON CORE | Summary: In luciferase complementation assays, CRN interacts weakly with the receptor kinase CLV1, and CLV1 can associate with CLV2/CRN heterodimers. Reason: The interaction is real but weak and secondary, linking the two parallel receptor complexes. Supporting Evidence: PMID:19843317 CLV1 did not interact with CLV2, but can interact weakly with CRN |
| GO:0045595 regulation of cell differentiation | IMP PMID:28607033 Perception of root-active CLE peptides requires CORYNE funct... | KEEP AS NON CORE | Summary: Through CLE perception, CRN regulates protophloem and root meristem cell differentiation. Reason: This is a downstream developmental output. Supporting Evidence: PMID:28607033 the receptor-like protein CLAVATA 2 (CLV2) and the pseudokinase CORYNE (CRN) are necessary to fully sense root-active CLE peptides |
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Download this section (compressed HTML)Q: The CRN kinase-like domain is required for CLV3 signalling in the shoot but not in the root, even though it lacks catalytic activity. Does it act as an allosteric activator of a partner kinase (for example a CIK or CLV1) or as a docking site for RLCKs such as MAZZA?
Experiment: Map CRN pseudokinase-domain interactors in shoot apex cells by TurboID proximity labelling with and without CLV3 peptide. Then test whether CRN pseudokinase-domain mutants that do not complement in the shoot lose specific interactors or reduce CIK/PBL phosphorylation.
Hypothesis: The CRN pseudokinase domain allosterically activates or recruits a catalytically active partner kinase during CLV3 signalling in the shoot.
Type: proximity labeling proteomics
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