MPK3 (AtMPK3, At3g45640) is a TEY-motif, group A mitogen-activated protein kinase of the CMGC family and the closest paralog of MPK6, with which it is largely functionally redundant. It is activated by dual phosphorylation of its activation loop by the MAP kinase kinases MKK4 and MKK5 (and also MKK7/MKK9), downstream of MAPKKKs such as MAPKKK3/5, MEKK1 and YODA. Upon activation it phosphorylates proline-directed Ser/Thr-Pro motifs on substrates and moves from the cytoplasm into the nucleus. In pattern-triggered immunity MPK3 acts downstream of pattern recognition receptors including the flagellin receptor FLS2 and the chitin receptor CERK1 (via RLCKs such as PBL27); it phosphorylates the transcription factor WRKY33, which drives expression of camalexin biosynthetic genes, together with ERF6/ERF104, VQ-motif proteins, VIP1 and LIP5, and with MPK6 contributes to stabilization of the ethylene biosynthetic enzymes ACS2/ACS6 (direct phosphorylation of which is best documented for MPK6). The YODA-MKK4/MKK5-MPK3/MPK6 module restricts stomatal lineage entry by phosphorylating SPEECHLESS and is recruited to the cell cortex by BASL; the same module downstream of ERECTA shapes inflorescence architecture, and MPK3/MPK6 are needed for ovule integument development, pollen tube funicular guidance and stigma receptivity. MPK3 is also activated by abiotic stresses (H2O2/ozone, osmotic stress, cold, UV-B) and phosphorylates ICE1 to reduce freezing tolerance. MPK3 activity is turned off by MAPK phosphatases such as MKP1 and MKP2.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000165 MAPK cascade | IEA GO_REF:0000108 | ACCEPT | Summary: MPK3 is the terminal MAP kinase of several MAPK cascades (MEKK1/MAPKKK3/5-MKK4/MKK5-MPK3/MPK6 in pattern-triggered immunity; YDA-MKK4/MKK5-MPK3/MPK6 in stomatal and inflorescence development; MKK9-MPK3/MPK6 in ethylene signalling). Reason: Core process; MPK3 performs the final phosphorylation step of these cascades. Mapping from MAP kinase activity is appropriate. Supporting Evidence: PMID:11875555 Here we identify a complete plant MAP kinase cascade (MEKK1, MKK4/MKK5 and MPK3/MPK6) and WRKY22/WRKY29 transcription factors that function downstream of the flagellin receptor FLS2 PMID:17259259 Loss of function of MKK4/MKK5 or MPK3/MPK6 disrupts the coordinated cell fate specification of stomata versus pavement cells, resulting in the formation of clustered stomata. |
| GO:0004672 protein kinase activity | IDA PMID:22631074 Determination of primary sequence specificity of Arabidopsis... | ACCEPT | Summary: Positional peptide library and in vitro kinase assays with recombinant MPK3 and native Arabidopsis substrate proteins define a proline-directed consensus (L/P-P/X-S-P-R/K) and confirm direct substrate phosphorylation. Reason: Direct biochemical evidence for MPK3 protein kinase activity; parent of the more specific MAP kinase activity term. Supporting Evidence: PMID:22631074 a preference towards the sequence L/P-P/X-S-P-R/K for both kinases PMID:22631074 MPK3 and MPK6 phosphorylated all proteins tested more efficiently than did another MAPK, MPK4 |
| GO:0004672 protein kinase activity | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro-based protein kinase activity from the kinase domain (IPR000719/IPR008271). Reason: Correct, if general; MPK3 is a catalytically active Ser/Thr MAP kinase (EC 2.7.11.24). Supporting Evidence: file:ARATH/MPK3/MPK3-deep-research-falcon.md MPK3 is an intracellular, ATP-dependent protein kinase that transfers phosphate from ATP to hydroxyl groups on target-protein serine or threonine residues |
| GO:0004672 protein kinase activity | IMP PMID:21276203 The Arabidopsis protein kinase Pto-interacting 1-4 is a comm... | ACCEPT | Summary: MPK3 phosphorylates the protein kinases OXI1 and PTI1-4/CARK3 in vitro. Reason: Experimental support for protein kinase activity with identified substrates; correct parent-level MF. Supporting Evidence: PMID:21276203 OXI1 and PTI1-4 were substrates of MPK3 and MPK6 in vitro |
| GO:0004672 protein kinase activity | TAS PMID:12434021 Mitogen-activated protein kinase signaling in postgerminatio... | ACCEPT | Summary: Traceable author statement for protein kinase activity from a study of MAPK signalling in ABA-mediated postgermination arrest. Reason: Kinase activity is extensively established for MPK3 by direct assays; the TAS row is consistent with this. Supporting Evidence: PMID:22631074 MPK3 and MPK6 phosphorylated all proteins tested more efficiently than did another MAPK, MPK4 |
| GO:0004674 protein serine/threonine kinase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA assignment of protein serine/threonine kinase activity from the PANTHER MAPK node (PTN000622075), shared with MPK6, MPK4 and fungal/animal ERK-type kinases. Reason: Sound phylogenetic inference; MPK3 phosphorylates Ser/Thr-Pro motifs and sits squarely in the ERK-like MAPK clade. Supporting Evidence: PMID:22631074 a preference towards the sequence L/P-P/X-S-P-R/K for both kinases |
| GO:0004707 MAP kinase activity | IEA GO_REF:0000120 | ACCEPT | Summary: MAP kinase activity (EC 2.7.11.24) from InterPro MAP kinase conserved site/EC mapping. MPK3 is a TEY-type group A MAPK activated by MKK4/MKK5/MKK7/MKK9 dual phosphorylation. Reason: Defining core molecular function of MPK3. Supporting Evidence: file:ARATH/MPK3/MPK3-deep-research-falcon.md MPK3 is an intracellular, ATP-dependent protein kinase that transfers phosphate from ATP to hydroxyl groups on target-protein serine or threonine residues PMID:10717008 a phosphorylation cascade involving two stress MAPKs, AtMPK3 and AtMPK6 |
| GO:0005515 protein binding | IPI PMID:12506203 NDP kinase 2 interacts with two oxidative stress-activated M... | REMOVE | Summary: IPI with NDPK2 (AT5G63310); yeast two-hybrid and pull-down show NDPK2 interacts with MPK3 and MPK6 in H2O2 signalling. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. NDPK2 is a regulator/partner in oxidative-stress signalling; no specific MF is established for MPK3 from this interaction. Supporting Evidence: PMID:12506203 Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6 |
| GO:0005515 protein binding | IPI PMID:12506203 NDP kinase 2 interacts with two oxidative stress-activated M... | REMOVE | Summary: IPI with NDPK2 (O64903), same study as above. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:12506203 Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6 |
| GO:0005515 protein binding | IPI PMID:17947581 Trojan horse strategy in Agrobacterium transformation: abusi... | REMOVE | Summary: IPI with the bZIP transcription factor VIP1 (Q9MA75), a direct MPK3 substrate phosphorylated in response to Agrobacterium. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. VIP1 is a substrate; the relevant function is captured by kinase activity terms. Supporting Evidence: PMID:17947581 VIP1 is a transcription factor that is a direct target of the Agrobacterium-induced mitogen-activated protein kinase (MAPK) MPK3 |
| GO:0005515 protein binding | IPI PMID:19513235 Comprehensive analysis of protein-protein interactions betwe... | REMOVE | Summary: IPI with MKK4 (O80397), the upstream MAP kinase kinase that activates MPK3. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. The MKK4-MPK3 relationship is captured by MAPK cascade. Supporting Evidence: PMID:19513235 Comprehensive analysis of protein-protein interactions between Arabidopsis MAPKs and MAPK kinases helps define potential MAPK signalling modules |
| GO:0005515 protein binding | IPI PMID:20626661 MAPK phosphatase MKP2 mediates disease responses in Arabidop... | MODIFY | Summary: IPI with the dual-specificity MAPK phosphatase MKP2/DSPTP1B (Q9M8K7), which dephosphorylates and inactivates MPK3; BiFC shows in vivo association. Reason: Generic protein binding should be replaced by the more informative phosphatase binding, as done for the paralog MPK6 (PTP1/MKP binding). MKP2 is a negative regulator that binds and inactivates MPK3. Proposed replacements: phosphatase binding Supporting Evidence: PMID:20626661 MKP2 associates with MPK3 and MPK6 in vivo |
| GO:0005515 protein binding | IPI PMID:21276203 The Arabidopsis protein kinase Pto-interacting 1-4 is a comm... | REMOVE | Summary: IPI with PTI1-4/CARK3 (O80719), a protein kinase phosphorylated by MPK3. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. PTI1-4 is a substrate; kinase activity is retained from the same paper. Supporting Evidence: PMID:21276203 OXI1 and PTI1-4 were substrates of MPK3 and MPK6 in vitro |
| GO:0005515 protein binding | IPI PMID:21798944 Evidence for network evolution in an Arabidopsis interactome... | REMOVE | Summary: IPI with NDPK2 (O64903) from the Arabidopsis Interactome high-throughput Y2H map. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:21798944 Evidence for network evolution in an Arabidopsis interactome map |
| GO:0005515 protein binding | IPI PMID:21798944 Evidence for network evolution in an Arabidopsis interactome... | REMOVE | Summary: IPI with MKK4 (O80397) from the Arabidopsis Interactome high-throughput Y2H map. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:21798944 Evidence for network evolution in an Arabidopsis interactome map |
| GO:0005515 protein binding | IPI PMID:21798944 Evidence for network evolution in an Arabidopsis interactome... | REMOVE | Summary: IPI with Q8LGS1 from the Arabidopsis Interactome high-throughput Y2H map. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:21798944 Evidence for network evolution in an Arabidopsis interactome map |
| GO:0005515 protein binding | IPI PMID:24750137 The Arabidopsis thaliana mitogen-activated protein kinases M... | REMOVE | Summary: IPI with VQ4 (Q5M750), one of a subclass of VQ-motif proteins that are MPK3/MPK6 substrates in immunity. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. VQ4 is a substrate. Supporting Evidence: PMID:24750137 The Arabidopsis thaliana mitogen-activated protein kinases MPK3 and MPK6 target a subclass of |
| GO:0005515 protein binding | IPI PMID:25010425 Arabidopsis LIP5, a positive regulator of multivesicular bod... | REMOVE | Summary: IPI with LIP5 (Q9SZ15), an MVB-biogenesis regulator that is an MPK6/MPK3 substrate in basal resistance. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. LIP5 is a substrate. Supporting Evidence: PMID:25010425 as an interacting protein and a substrate of pathogen-responsive MPK6/MPK3 |
| GO:0005515 protein binding | IPI PMID:27913741 AIK1, A Mitogen-Activated Protein Kinase, Modulates Abscisic... | REMOVE | Summary: IPI with MKK5 (Q8RXG3), an upstream activating MAP kinase kinase. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Captured by MAPK cascade. Supporting Evidence: PMID:27913741 AIK1, A Mitogen-Activated Protein Kinase, Modulates Abscisic Acid Responses through the MKK5-MPK6 Kinase Cascade |
| GO:0005515 protein binding | IPI PMID:29056553 MPK3- and MPK6-Mediated ICE1 Phosphorylation Negatively Regu... | REMOVE | Summary: IPI with ICE1 (AT3G26744), which MPK3 phosphorylates to reduce ICE1 stability. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. ICE1 is a substrate; captured by protein phosphorylation and kinase terms. Supporting Evidence: PMID:29056553 mitogen-activated protein kinase 3 (MPK3) and MPK6 interact with and phosphorylate ICE1, which reduces its stability and transcriptional activity |
| GO:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | REMOVE | Summary: IPI with O24408 from a large-scale phytohormone protein-interaction network screen. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:32612234 Extensive signal integration by the phytohormone protein network |
| GO:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | REMOVE | Summary: IPI with O80397 from a large-scale phytohormone protein-interaction network screen. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:32612234 Extensive signal integration by the phytohormone protein network |
| GO:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | REMOVE | Summary: IPI with Q8LGS1 from a large-scale phytohormone protein-interaction network screen. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:32612234 Extensive signal integration by the phytohormone protein network |
| GO:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | REMOVE | Summary: IPI with Q9LQF0 from a large-scale phytohormone protein-interaction network screen. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:32612234 Extensive signal integration by the phytohormone protein network |
| GO:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | REMOVE | Summary: IPI with Q9ZR37 from a large-scale phytohormone protein-interaction network screen. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. Supporting Evidence: PMID:32612234 Extensive signal integration by the phytohormone protein network |
| GO:0005515 protein binding | IPI PMID:33419940 Chromatin phosphoproteomics unravels a function for AT-hook ... | REMOVE | Summary: IPI with AHL13 (AT4G17950), an AT-hook nuclear protein phosphorylated by MAPKs in PAMP-triggered immunity. Reason: Bare protein binding is uninformative about molecular function; removal does not dispute the reported interaction. AHL13 is a MAPK target. Supporting Evidence: PMID:33419940 Chromatin phosphoproteomics unravels a function for AT-hook motif nuclear localized protein AHL13 in PAMP-triggered immunity |
| GO:0005524 ATP binding | IEA GO_REF:0000002 | ACCEPT | Summary: ATP binding from the kinase ATP-binding site signatures (IPR017441). Reason: Required for catalysis; structurally certain for an active protein kinase. Supporting Evidence: file:ARATH/MPK3/MPK3-deep-research-falcon.md MPK3 is an intracellular, ATP-dependent protein kinase that transfers phosphate from ATP to hydroxyl groups on target-protein serine or threonine residues |
| GO:0005634 nucleus | EXP PMID:15500467 Stress hormone-independent activation and nuclear translocat... | ACCEPT | Summary: Activated MPK3 translocates into the nucleus during ozone exposure. Reason: Direct in planta evidence; nucleus is a principal site of MPK3 action on transcription factor substrates (WRKY33, VIP1, SPCH). Supporting Evidence: PMID:15500467 activated AtMPK3 and AtMPK6 are translocated to the nucleus during the early stages of O3 treatment |
| GO:0005634 nucleus | EXP PMID:31235876 Bipartite anchoring of SCREAM enforces stomatal initiation b... | ACCEPT | Summary: BiFC places MPK3-SCRM (ICE1) complexes in the nucleus in the stomatal lineage. Reason: Supports nuclear localization of MPK3 when engaging SCRM/SPCH. Supporting Evidence: PMID:31235876 Strong YFP signals were reconstituted in the nuclei of leaves co-expressing SCRM-YFPn with MPK3 or MPK6 fused with a complementary YFPc. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: IBA nuclear localization from the MAPK PANTHER node. Reason: Concordant with experimental nuclear localization. Supporting Evidence: PMID:15500467 activated AtMPK3 and AtMPK6 are translocated to the nucleus during the early stages of O3 treatment file:ARATH/MPK3/MPK3-deep-research-falcon.md The principal experimentally supported sites are the cytoplasm and nucleus. |
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular-location mapping to nucleus. Reason: Concordant with experimental evidence. Supporting Evidence: PMID:15500467 activated AtMPK3 and AtMPK6 are translocated to the nucleus during the early stages of O3 treatment |
| GO:0005634 nucleus | ISM GO_REF:0000122 | ACCEPT | Summary: Sequence-based (AtSubP) prediction of nuclear localization. Reason: Concordant with experimental evidence. Supporting Evidence: file:ARATH/MPK3/MPK3-deep-research-falcon.md The principal experimentally supported sites are the cytoplasm and nucleus. |
| GO:0005737 cytoplasm | EXP PMID:15500467 Stress hormone-independent activation and nuclear translocat... | ACCEPT | Summary: MPK3 is cytoplasmic before activation and moves to the nucleus on ozone treatment. Reason: Resting-state location of MPK3. Supporting Evidence: PMID:15500467 activated AtMPK3 and AtMPK6 are translocated to the nucleus during the early stages of O3 treatment file:ARATH/MPK3/MPK3-deep-research-falcon.md The principal experimentally supported sites are the cytoplasm and nucleus. |
| GO:0005737 cytoplasm | IBA GO_REF:0000033 | ACCEPT | Summary: IBA cytoplasm localization from the MAPK PANTHER node. Reason: Concordant with experimental evidence. Supporting Evidence: file:ARATH/MPK3/MPK3-deep-research-falcon.md The principal experimentally supported sites are the cytoplasm and nucleus. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular-location mapping to cytoplasm. Reason: Concordant with experimental evidence. Supporting Evidence: file:ARATH/MPK3/MPK3-deep-research-falcon.md The principal experimentally supported sites are the cytoplasm and nucleus. |
| GO:0005938 cell cortex | IDA PMID:25843888 The BASL polarity protein controls a MAPK signaling feedback... | KEEP AS NON CORE | Summary: BASL recruits YODA and MPK3/MPK6 to the polar cortical crescent of stomatal-lineage cells. Reason: Experimentally supported but a specialized, cell-type-specific pool rather than the main site of MPK3 activity. Supporting Evidence: PMID:25843888 Phosphorylated BASL functions as a scaffold and recruits the MAPKKK YODA and MPK3/6 to spatially concentrate signaling at the cortex |
| GO:0005938 cell cortex | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: UniProt subcellular-location mapping to cell cortex, derived from the BASL study. Reason: As for the IDA row: real but specialized localization. Supporting Evidence: PMID:25843888 Phosphorylated BASL functions as a scaffold and recruits the MAPKKK YODA and MPK3/6 to spatially concentrate signaling at the cortex |
| GO:0006468 protein phosphorylation | IDA PMID:29056553 MPK3- and MPK6-Mediated ICE1 Phosphorylation Negatively Regu... | ACCEPT | Summary: MPK3 phosphorylates ICE1 in vitro and in vivo. Reason: Direct demonstration of MPK3 substrate phosphorylation; protein phosphorylation is the catalytic process MPK3 executes. Supporting Evidence: PMID:29056553 mitogen-activated protein kinase 3 (MPK3) and MPK6 interact with and phosphorylate ICE1, which reduces its stability and transcriptional activity |
| GO:0006970 response to osmotic stress | IDA PMID:12220631 Different protein kinase families are activated by osmotic s... | KEEP AS NON CORE | Summary: MPK3 (and MPK6) are activated within minutes by hypo-osmotic stress in cell suspensions. Reason: Activation by osmotic stress is documented, but this is one of many stress inputs to a pleiotropic MAPK. Supporting Evidence: PMID:12220631 two of the MAP kinases were identified as AtMPK6 and AtMPK3 |
| GO:0006979 response to oxidative stress | IEP PMID:10717008 Functional analysis of oxidative stress-activated mitogen-ac... | KEEP AS NON CORE | Summary: H2O2 activates an ANP1-initiated cascade involving MPK3 and MPK6. Reason: Well supported (oxidative stress-activated cascade, also ozone); a peripheral stress output for a pleiotropic MAPK. Supporting Evidence: PMID:10717008 a phosphorylation cascade involving two stress MAPKs, AtMPK3 and AtMPK6 |
| GO:0006979 response to oxidative stress | TAS PMID:12119167 Mitogen-activated protein kinase cascades in plants: a new n... | KEEP AS NON CORE | Summary: TAS oxidative-stress response from the plant MAPK nomenclature review. Reason: Consistent with primary data on H2O2/ozone activation of MPK3. Supporting Evidence: PMID:12119167 These protein phosphorylation cascades link extracellular stimuli to a wide range of cellular responses PMID:10717008 a phosphorylation cascade involving two stress MAPKs, AtMPK3 and AtMPK6 |
| GO:0007165 signal transduction | IC PMID:12119167 Mitogen-activated protein kinase cascades in plants: a new n... | ACCEPT | Summary: IC signal transduction inferred from MAP kinase activity (nomenclature review). Reason: Correct, general; MAPK cascade is the informative child term and is also annotated. Supporting Evidence: PMID:12119167 Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules in eukaryotes, including yeasts, animals and plants. |
| GO:0007165 signal transduction | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA signal transduction. Reason: Correct, general parent of MAPK cascade. Supporting Evidence: PMID:12119167 These protein phosphorylation cascades link extracellular stimuli to a wide range of cellular responses |
| GO:0009409 response to cold | IEP PMID:8570631 A gene encoding a mitogen-activated protein kinase kinase ki... | KEEP AS NON CORE | Summary: MPK3 transcripts accumulate after touch, cold and salinity stress (Northern blot). Reason: Expression evidence only, but MPK3 activity is also functionally linked to cold/freezing via ICE1 phosphorylation; peripheral process. Supporting Evidence: PMID:8570631 The mRNA levels of these three protein kinases increased markedly and simultaneously in response to touch, cold, and salinity stress. |
| GO:0009555 pollen development | IGI PMID:24717717 Two Mitogen-Activated Protein Kinases, MPK3 and MPK6, Are Re... | MARK AS OVER ANNOTATED | Summary: IGI with MPK6 in a pollen tube guidance study. The cited paper states that mpk3 mpk6 pollen has no developmental defect; the phenotype is in funicular guidance of pollen tubes. Reason: The paper reports normal pollen development and normal pollen tube growth; only guidance is affected, which is captured by the pollen tube guidance row. Pollen development overstates the finding. Supporting Evidence: PMID:24717717 Our previous study using mpk3 + / – mpk6 – / – plants in the quartet1 background demonstrated that mpk3 mpk6 pollen has no developmental defect PMID:24717717 the mpk3 mpk6 mutant pollen had normal pollen tube growth but impaired pollen tube guidance |
| GO:0009611 response to wounding | IEP PMID:17953483 Mechanical stress induces biotic and abiotic stress response... | KEEP AS NON CORE | Summary: MPK3 is a rapid, transient mechanical-stress (touch/wounding)-responsive transcript. Reason: Expression-only evidence; MPK3 is genuinely wound/stress-activated but this is peripheral. Supporting Evidence: PMID:17953483 One kinase identified was MPK3, a MAPK signal transduction component, which has been shown to function in innate immunity and stomatal development |
| GO:0009617 response to bacterium | IEP PMID:19318610 Mitogen-activated protein kinases 3 and 6 are required for f... | KEEP AS NON CORE | Summary: MPK3 mRNA and inactive protein accumulate during chemically induced resistance and the kinase is more strongly activated on bacterial challenge in primed plants. Reason: Expression-based; MPK3 does function in antibacterial immunity (FLS2 cascade), but response to bacterium is a broad response term. Supporting Evidence: PMID:19318610 Upon challenge exposure to biotic or abiotic stress, these two enzymes were more strongly activated in primed plants than in nonprimed plants |
| GO:0009738 abscisic acid-activated signaling pathway | TAS PMID:12434021 Mitogen-activated protein kinase signaling in postgerminatio... | KEEP AS NON CORE | Summary: TAS for ABA signalling from a study linking MAPK signalling to ABA-induced postgermination arrest; MPK3 is also implicated in ABA responses through VIP1. Reason: Plausible and supported by later work, but a peripheral hormone-signalling role. Supporting Evidence: PMID:12434021 we show that the ABA signal is transmitted to the transcriptional apparatus through mitogen-activated protein kinase signaling |
| GO:0009875 pollen-pistil interaction | IGI PMID:32890733 Stigma Receptivity Is Controlled by Functionally Redundant M... | KEEP AS NON CORE | Summary: Genetic interaction (mpk4RNAi/mpk3) shows MPK3 with MPK4 downstream of MKK1/2/3/7/9 mediates stigma receptivity to compatible pollen. Reason: Supported genetically; reproductive developmental role, non-core. Supporting Evidence: PMID:32890733 MKK1/2/3/7/9 are required to transmit upstream signals to two MPKs, MPK3/4, to mediate compatible pollination |
| GO:0010120 camalexin biosynthetic process | IMP PMID:18378893 A fungal-responsive MAPK cascade regulates phytoalexin biosy... | MODIFY | Summary: MPK3/MPK6 activation is sufficient to induce camalexin, and camalexin induction by Botrytis cinerea is compromised in mpk3. MPK3 acts by phosphorylating WRKY33, which induces camalexin biosynthetic genes (CYP71A13, PAD3); MPK3 does not catalyse a biosynthetic step. Reason: The paper concludes that the cascade regulates camalexin synthesis through transcriptional regulation of the biosynthetic genes. MPK3 is a regulator, not a participant in the biosynthetic chemistry, so positive regulation of camalexin biosynthetic process is the accurate term. Proposed replacements: positive regulation of camalexin biosynthetic process Supporting Evidence: PMID:18378893 These results indicate that the MPK3/MPK6 cascade regulates camalexin synthesis through transcriptional regulation of the biosynthetic genes after pathogen infection. PMID:18378893 Induction of camalexin by Botrytis cinerea was preceded by MPK3/MPK6 activation, and compromised in mpk3 and mpk6 mutants. PMID:21498677 WRKY33 functions downstream of MPK3/MPK6 in reprogramming the expression of camalexin biosynthetic genes |
| GO:0010183 pollen tube guidance | IGI PMID:24717717 Two Mitogen-Activated Protein Kinases, MPK3 and MPK6, Are Re... | KEEP AS NON CORE | Summary: mpk3 mpk6 double-mutant pollen tubes are defective in the funicular guidance phase. Reason: Well supported genetically; reproductive developmental role, non-core. Supporting Evidence: PMID:24717717 In vivo pollination assays revealed that the mpk3 mpk6 mutant pollen tubes were defective in the funicular guidance phase. |
| GO:0010200 response to chitin | IEP PMID:15923325 Loss-of-function mutations in chitin responsive genes show i... | KEEP AS NON CORE | Summary: MPK3 transcript is up-regulated by crab-shell chitin and chito-octamer in microarray experiments. Reason: Expression evidence; functionally, MPK3 is activated downstream of the CERK1-PBL27 chitin receptor complex, so a chitin response role is real but is better represented by a signalling pathway term. Supporting Evidence: PMID:15923325 four genes up-regulated by CSC and chito-octamer: AtMPK3 PMID:24750441 Knockout of PBL27 resulted in the suppression of several chitin-induced defense responses, including the activation of MPK3/6 |
| GO:0010224 response to UV-B | IMP PMID:21790814 Arabidopsis MAP kinase phosphatase 1 and its target MAP kina... | KEEP AS NON CORE | Summary: MPK3 is activated by UV-B and hyperactivated in mkp1; mpk3 mutants show elevated UV-B tolerance. Reason: Supported by mutant phenotype; a peripheral abiotic-stress role. Supporting Evidence: PMID:21790814 The MKP1-interacting proteins MPK3 and MPK6 are activated by UV-B stress and are hyperactivated in mkp1. Moreover, mutants mpk3 and mpk6 exhibit elevated UV-B tolerance |
| GO:0010229 inflorescence development | IGI PMID:23263767 A MAPK cascade downstream of ERECTA receptor-like protein ki... | KEEP AS NON CORE | Summary: Loss of MPK3/MPK6 or MKK4/MKK5 gives shortened pedicels and clustered inflorescences; the cascade acts downstream of ERECTA to promote local cell proliferation. Reason: Well supported developmental role; non-core. Supporting Evidence: PMID:23263767 loss of function of MPK3/MPK6 or their upstream MAPK kinases (MAPKKs; or MKKs), MKK4/MKK5, resulted in shortened pedicels and clustered inflorescences |
| GO:0010494 cytoplasmic stress granule | IDA PMID:30664249 Protein and metabolite composition of Arabidopsis stress gra... | KEEP AS NON CORE | Summary: MPK3 was detected in affinity-purified stress-granule proteome (Rbp47b-GFP). The abstract does not name MPK3; the assignment comes from proteomics datasets. Reason: Defer to curator for the proteomic assignment; consistent with later reports that TZF1 recruits MPK3/MPK6 to stress granules. A stress-induced, minor pool. Supporting Evidence: PMID:30664249 the remaining proteins were enriched in key enzymes and regulators, such as cyclin-dependent kinase A (CDKA), that mediate plant responses to stress file:ARATH/MPK3/MPK3-deep-research-falcon.md the Arabidopsis RNA-binding protein TZF1 recruits MPK3/MPK6 and MKK4/5-associated signaling components to cytoplasmic stress granules |
| GO:0035556 intracellular signal transduction | IBA GO_REF:0000033 | ACCEPT | Summary: IBA intracellular signal transduction from the MAPK PANTHER node. Reason: Accurate; MAPK cascade is the more specific term. Supporting Evidence: PMID:12119167 Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules in eukaryotes, including yeasts, animals and plants. |
| GO:0048481 plant ovule development | IGI PMID:18364464 Haplo-insufficiency of MPK3 in MPK6 mutant background uncove... | KEEP AS NON CORE | Summary: In mpk6 background MPK3 is haplo-insufficient, giving female sterility through defective integument development. Reason: Supported genetically; developmental role, non-core. Supporting Evidence: PMID:18364464 MPK3 and MPK6, share a novel function in ovule development: in the MPK6 mutant background, MPK3 is haplo-insufficient, giving female sterility when heterozygous |
| GO:0050826 response to freezing | IMP PMID:29056553 MPK3- and MPK6-Mediated ICE1 Phosphorylation Negatively Regu... | KEEP AS NON CORE | Summary: mpk3 mutants show enhanced freezing tolerance; MPK3 phosphorylates and destabilizes ICE1. Reason: Supported by mutant phenotype and mechanism; a peripheral abiotic-stress role. Supporting Evidence: PMID:29056553 the mpk3 and mpk6 single mutants and the mpk3 mpk6 double mutants show enhanced freezing tolerance, whereas MPK3/MPK6 activation attenuates freezing tolerance |
| GO:0080136 priming of cellular response to stress | IMP PMID:19318610 Mitogen-activated protein kinases 3 and 6 are required for f... | KEEP AS NON CORE | Summary: Priming of defense: MPK3 protein accumulates in an inactive state and is hyperactivated on challenge in primed plants; mpk3 is impaired in priming. Reason: Supported by mutant phenotype; a defense-associated, non-core role. Supporting Evidence: PMID:19318610 Our findings argue that prestress deposition of the signaling components MPK3 and MPK6 is a critical step in priming plants for full induction of defense responses during IR. |
| GO:0106310 protein serine kinase activity | EXP PMID:12220631 Different protein kinase families are activated by osmotic s... | ACCEPT | Summary: Osmotic stress-activated MPK3 kinase activity in cell suspensions (in-gel kinase assays). Reason: Experimental support for Ser/Thr kinase activity (UniProt catalytic activity evidence). Supporting Evidence: PMID:12220631 two of the MAP kinases were identified as AtMPK6 and AtMPK3 |
| GO:0106310 protein serine kinase activity | EXP PMID:15500467 Stress hormone-independent activation and nuclear translocat... | ACCEPT | Summary: Ozone-activated MPK3 kinase activity in planta. Reason: Experimental support for Ser/Thr kinase activity. Supporting Evidence: PMID:15500467 transient activation of 43 and 45 kDa MAPKs. These were identified as AtMPK3 and AtMPK6 |
| GO:0106310 protein serine kinase activity | EXP PMID:21276203 The Arabidopsis protein kinase Pto-interacting 1-4 is a comm... | ACCEPT | Summary: MPK3 phosphorylates OXI1 and PTI1-4 in vitro. Reason: Experimental support for Ser/Thr kinase activity with defined substrates. Supporting Evidence: PMID:21276203 OXI1 and PTI1-4 were substrates of MPK3 and MPK6 in vitro |
| GO:0106310 protein serine kinase activity | IEA GO_REF:0000116 | ACCEPT | Summary: Protein serine kinase activity from the Rhea reaction (RHEA:17989) in the UniProt record. Reason: Correct core catalytic activity. Supporting Evidence: PMID:22631074 a preference towards the sequence L/P-P/X-S-P-R/K for both kinases |
| GO:0160109 plant gross anatomical part developmental process | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA prediction of a very broad plant developmental process term. Reason: MPK3 does act in inflorescence, ovule and stomatal development, so the term is not wrong, but it is very general and these developmental roles are peripheral to the signalling kinase function. Supporting Evidence: PMID:17259259 Loss of function of MKK4/MKK5 or MPK3/MPK6 disrupts the coordinated cell fate specification of stomata versus pavement cells, resulting in the formation of clustered stomata. PMID:23263767 loss of function of MPK3/MPK6 or their upstream MAPK kinases (MAPKKs; or MKKs), MKK4/MKK5, resulted in shortened pedicels and clustered inflorescences |
| GO:1902065 response to L-glutamate | IDA PMID:29344832 Mitogen activated protein kinase 6 and MAP kinase phosphatas... | KEEP AS NON CORE | Summary: MPK3 and MPK6 are rapidly activated in seedlings by L-glutamate. Reason: Experimentally supported but narrow physiological response. Supporting Evidence: PMID:29344832 In-gel phosphorylation assays revealed a rapid and dose-dependent induction of MPK6 and MPK3 activities in wild-type Arabidopsis seedlings in response to L-Glu |
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Download this section (compressed HTML)Q: Is MPK3 itself a direct kinase of ACS2/ACS6 in vivo, or is its contribution to pathogen-induced ethylene mainly via MPK6 and WRKY33-driven ACS transcription?
Q: Should MPK3 carry a regulation of stomatal complex development term (YDA-MKK4/5-MPK3/6 phosphorylation of SPEECHLESS), as it lacks any stomatal development annotation despite strong genetic and biochemical evidence (PMID:17259259)?
Q: Which outputs are non-redundant between MPK3 and MPK6 (e.g. distinct SCRM-binding properties, VIP1, AZI1), and should these be reflected in gene-specific annotations?
Q: Should the MAPK cascade components downstream of pattern recognition receptors (MPK3, MPK6, MKK4, MKK5) carry GO:0002221 pattern recognition receptor signaling pathway, or only MAPK cascade terms? Currently none of them carry it, whereas receptor-proximal RLCKs such as BIK1 do.
Experiment: Analog-sensitive MPK3 (in mpk6 background) with phosphoproteomics after chitin treatment to define MPK3-specific direct substrates downstream of CERK1.
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