| Structural highlights
Function
MPK6_ARATH Involved in oxidative stress-mediated signaling cascade (such as ozone). Involved in the innate immune MAP kinase signaling cascade (MEKK1, MKK4/MKK5 and MPK3/MPK6) downstream of bacterial flagellin receptor FLS2. May be involved in hypersensitive response (HR)-mediated signaling cascade by modulating LIP5 phosphorylation and subsequent multivesicular bodies (MVBs) trafficking. May phosphorylate regulators of WRKY transcription factors. Phosphorylates 1-aminocyclopropane-1-carboxylic acid synthases (ACS2 and ACS6) and may be involved in the regulation of bacterial elicitor flagellin-induced ethylene production. Regulates locally gene-mediated and basal resistance response to certain pathogens. May be involved in the cold and salinity stress-mediated MAP kinase signaling cascade (MEKK1, MKK1/MKK2 and MPK4/MPK6). MKK1-MPK6 module mediates abscisic acid (ABA)-dependent CAT1 expression with H(2)O(2) production and response to drought and salt stress. MKK1-MPK6 module is also involved in sugar signaling during the process of seed germination. MKK3-MPK6 module plays an important role in the jasmonate signal transduction pathway through the negative regulation of MYC2/JIN1 expression. MKK9-MPK3/MPK6 module phosphorylates and activates EIN3, leading to the promotion of EIN3-mediated transcription in ethylene signaling. MPK3/MPK6 cascade regulates camalexin synthesis through transcriptional regulation of the biosynthetic genes after pathogen infection. MKK9-MPK6 module positively regulates leaf senescence. YDA-MKK4/MKK5-MPK3/MPK6 module regulates stomatal cell fate before the guard mother cell (GMC) is specified. This MAPK cascade also functions downstream of the ER receptor in regulating coordinated local cell proliferation, which shapes the morphology of plant organs.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
Publication Abstract from PubMed
Mitogen-activated protein kinase (MAPK) cascades, which are the highly conserved signalling modules in eukaryotic organisms, have been shown to play important roles in regulating growth, development, and stress responses. The structures of various MAPKs from yeast and animal have been solved, and structure-based mutants were generated for their function analyses, however, the structures of plant MAPKs remain unsolved. Here, we report the crystal structure of Arabidopsis MPK6 at a 3.0 A resolution. Although MPK6 is topologically similar to ERK2 and p38, the structures of the glycine-rich loop, MAPK insert, substrate binding sites, and L16 loop in MPK6 show notable differences from those of ERK2 and p38. Based on the structural comparison, we constructed MPK6 mutants and analyzed their kinase activity both in vitro and in planta. MPK6(F364L) and MPK6(F368L) mutants, in which Phe364 and Phe368 in the L16 loop were changed to Leu, respectively, acquired higher intrinsic kinase activity and retained the normal MAPKK activation property. The expression of MPK6 mutants with basal activity is sufficient to induce camalexin biosynthesis; however, to induce ethylene and leaf senescence, the expression of MPK6 mutants with higher activity is required. The results suggest that these mutants can be used to analyze the specific biological functions of MPK6.
Analysis of crystal structure of Arabidopsis MPK6 and generation of its mutants with higher activity.,Wang B, Qin X, Wu J, Deng H, Li Y, Yang H, Chen Z, Liu G, Ren D Sci Rep. 2016 May 10;6:25646. doi: 10.1038/srep25646. PMID:27160427[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Menke FL, van Pelt JA, Pieterse CM, Klessig DF. Silencing of the mitogen-activated protein kinase MPK6 compromises disease resistance in Arabidopsis. Plant Cell. 2004 Apr;16(4):897-907. Epub 2004 Mar 12. PMID:15020743 doi:https://dx.doi.org/10.1105/tpc.015552
- ↑ Teige M, Scheikl E, Eulgem T, Doczi R, Ichimura K, Shinozaki K, Dangl JL, Hirt H. The MKK2 pathway mediates cold and salt stress signaling in Arabidopsis. Mol Cell. 2004 Jul 2;15(1):141-52. PMID:15225555 doi:https://dx.doi.org/10.1016/j.molcel.2004.06.023
- ↑ Liu Y, Zhang S. Phosphorylation of 1-aminocyclopropane-1-carboxylic acid synthase by MPK6, a stress-responsive mitogen-activated protein kinase, induces ethylene biosynthesis in Arabidopsis. Plant Cell. 2004 Dec;16(12):3386-99. Epub 2004 Nov 11. PMID:15539472 doi:https://dx.doi.org/tpc.104.026609
- ↑ Miles GP, Samuel MA, Zhang Y, Ellis BE. RNA interference-based (RNAi) suppression of AtMPK6, an Arabidopsis mitogen-activated protein kinase, results in hypersensitivity to ozone and misregulation of AtMPK3. Environ Pollut. 2005 Nov;138(2):230-7. PMID:15964670 doi:https://dx.doi.org/S0269-7491(05)00226-5
- ↑ Wang H, Ngwenyama N, Liu Y, Walker JC, Zhang S. Stomatal development and patterning are regulated by environmentally responsive mitogen-activated protein kinases in Arabidopsis. Plant Cell. 2007 Jan;19(1):63-73. Epub 2007 Jan 26. PMID:17259259 doi:https://dx.doi.org/10.1105/tpc.106.048298
- ↑ Takahashi F, Yoshida R, Ichimura K, Mizoguchi T, Seo S, Yonezawa M, Maruyama K, Yamaguchi-Shinozaki K, Shinozaki K. The mitogen-activated protein kinase cascade MKK3-MPK6 is an important part of the jasmonate signal transduction pathway in Arabidopsis. Plant Cell. 2007 Mar;19(3):805-18. Epub 2007 Mar 16. PMID:17369371 doi:https://dx.doi.org/10.1105/tpc.106.046581
- ↑ Xing Y, Jia W, Zhang J. AtMKK1 mediates ABA-induced CAT1 expression and H2O2 production via AtMPK6-coupled signaling in Arabidopsis. Plant J. 2008 May;54(3):440-51. doi: 10.1111/j.1365-313X.2008.03433.x. Epub 2008 , Jan 31. PMID:18248592 doi:https://dx.doi.org/10.1111/j.1365-313X.2008.03433.x
- ↑ Yoo SD, Cho YH, Tena G, Xiong Y, Sheen J. Dual control of nuclear EIN3 by bifurcate MAPK cascades in C2H4 signalling. Nature. 2008 Feb 14;451(7180):789-95. doi: 10.1038/nature06543. PMID:18273012 doi:https://dx.doi.org/10.1038/nature06543
- ↑ Ren D, Liu Y, Yang KY, Han L, Mao G, Glazebrook J, Zhang S. A fungal-responsive MAPK cascade regulates phytoalexin biosynthesis in Arabidopsis. Proc Natl Acad Sci U S A. 2008 Apr 8;105(14):5638-43. doi:, 10.1073/pnas.0711301105. Epub 2008 Mar 31. PMID:18378893 doi:https://dx.doi.org/10.1073/pnas.0711301105
- ↑ Zhou C, Cai Z, Guo Y, Gan S. An arabidopsis mitogen-activated protein kinase cascade, MKK9-MPK6, plays a role in leaf senescence. Plant Physiol. 2009 May;150(1):167-77. doi: 10.1104/pp.108.133439. Epub 2009 Feb , 27. PMID:19251906 doi:https://dx.doi.org/10.1104/pp.108.133439
- ↑ Xing Y, Jia W, Zhang J. AtMKK1 and AtMPK6 are involved in abscisic acid and sugar signaling in Arabidopsis seed germination. Plant Mol Biol. 2009 Aug;70(6):725-36. doi: 10.1007/s11103-009-9503-0. Epub 2009 , May 31. PMID:19484493 doi:https://dx.doi.org/10.1007/s11103-009-9503-0
- ↑ Meng X, Wang H, He Y, Liu Y, Walker JC, Torii KU, Zhang S. A MAPK cascade downstream of ERECTA receptor-like protein kinase regulates Arabidopsis inflorescence architecture by promoting localized cell proliferation. Plant Cell. 2012 Dec;24(12):4948-60. doi: 10.1105/tpc.112.104695. Epub 2012 Dec, 21. PMID:23263767 doi:https://dx.doi.org/10.1105/tpc.112.104695
- ↑ Wang F, Shang Y, Fan B, Yu JQ, Chen Z. Arabidopsis LIP5, a positive regulator of multivesicular body biogenesis, is a critical target of pathogen-responsive MAPK cascade in plant basal defense. PLoS Pathog. 2014 Jul 10;10(7):e1004243. doi: 10.1371/journal.ppat.1004243., eCollection 2014 Jul. PMID:25010425 doi:https://dx.doi.org/10.1371/journal.ppat.1004243
- ↑ Wang B, Qin X, Wu J, Deng H, Li Y, Yang H, Chen Z, Liu G, Ren D. Analysis of crystal structure of Arabidopsis MPK6 and generation of its mutants with higher activity. Sci Rep. 2016 May 10;6:25646. doi: 10.1038/srep25646. PMID:27160427 doi:https://dx.doi.org/10.1038/srep25646
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