| Structural highlights
Function
MYC2_ARATH Transcriptional activator. Common transcription factor of light, abscisic acid (ABA), and jasmonic acid (JA) signaling pathways. With MYC3 and MYC4, controls additively subsets of JA-dependent responses. In cooperation with MYB2 is involved in the regulation of ABA-inducible genes under drought stress conditions. Can form complexes with all known glucosinolate-related MYBs to regulate glucosinolate biosynthesis. Binds to the MYC recognition site (5'-CACATG-3'), and to the G-box (5'-CACNTG-3') and Z-box (5'-ATACGTGT-3') of promoters. Binds directly to the promoters of the transcription factors PLETHORA1 (PLT1) and PLT2 and represses their expression. Negative regulator of blue light-mediated photomorphogenic growth and blue- and far-red-light regulated gene expression. Activates multiple TIFY/JAZ promoters. Positive regulator of lateral root formation. Regulates sesquiterpene biosynthesis. Subjected to proteasome-dependent proteolysis. The presence of the destruction element (DE) involved in turnover is required for the function to regulate gene transcription.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Publication Abstract from PubMed
Jasmonates (JAs) are essential plant hormones that play important roles in the regulation of plant growth and the response to environmental stress. In the JA signaling pathway, the core transcription factors are a class of basic helix-loop-helix (bHLH) proteins, including MYC2, MYC3, and MYC4, that have different regulatory capacities. Here, we report the 2.7 A crystal structure of the MYC2 bHLH domain complexed with G-box DNA, showing a cis-tetrameric structure. Biochemical assays confirmed that full-length MYC2 forms a stable homo-tetramer both in solution and in DNA-bound states, whereas MYC3 forms only a homodimer. Isothermal titration calorimetry (ITC) assays demonstrated that tetramerization enhanced DNA binding affinity, and fluorescence resonance energy transfer (FRET) assay indicated DNA looping potential of tetrameric MYC2. Luciferase assay further confirmed the importance of tetramerization in transcriptional regulation. Our studies provide a mechanistic explanation for the regulatory differences of MYC transcription factors.
Crystal Structure of Tetrameric Arabidopsis MYC2 Reveals the Mechanism of Enhanced Interaction with DNA.,Lian TF, Xu YP, Li LF, Su XD Cell Rep. 2017 May 16;19(7):1334-1342. doi: 10.1016/j.celrep.2017.04.057. PMID:28514654[12]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Abe H, Urao T, Ito T, Seki M, Shinozaki K, Yamaguchi-Shinozaki K. Arabidopsis AtMYC2 (bHLH) and AtMYB2 (MYB) function as transcriptional activators in abscisic acid signaling. Plant Cell. 2003 Jan;15(1):63-78. PMID:12509522
- ↑ Lorenzo O, Chico JM, Sanchez-Serrano JJ, Solano R. JASMONATE-INSENSITIVE1 encodes a MYC transcription factor essential to discriminate between different jasmonate-regulated defense responses in Arabidopsis. Plant Cell. 2004 Jul;16(7):1938-50. Epub 2004 Jun 18. PMID:15208388 doi:http://dx.doi.org/10.1105/tpc.022319
- ↑ Yadav V, Mallappa C, Gangappa SN, Bhatia S, Chattopadhyay S. A basic helix-loop-helix transcription factor in Arabidopsis, MYC2, acts as a repressor of blue light-mediated photomorphogenic growth. Plant Cell. 2005 Jul;17(7):1953-66. Epub 2005 May 27. PMID:15923349 doi:http://dx.doi.org/tpc.105.032060
- ↑ Niu Y, Figueroa P, Browse J. Characterization of JAZ-interacting bHLH transcription factors that regulate jasmonate responses in Arabidopsis. J Exp Bot. 2011 Mar;62(6):2143-54. doi: 10.1093/jxb/erq408. Epub 2011 Feb 14. PMID:21321051 doi:http://dx.doi.org/10.1093/jxb/erq408
- ↑ Fernandez-Calvo P, Chini A, Fernandez-Barbero G, Chico JM, Gimenez-Ibanez S, Geerinck J, Eeckhout D, Schweizer F, Godoy M, Franco-Zorrilla JM, Pauwels L, Witters E, Puga MI, Paz-Ares J, Goossens A, Reymond P, De Jaeger G, Solano R. The Arabidopsis bHLH transcription factors MYC3 and MYC4 are targets of JAZ repressors and act additively with MYC2 in the activation of jasmonate responses. Plant Cell. 2011 Feb;23(2):701-15. doi: 10.1105/tpc.110.080788. Epub 2011 Feb 18. PMID:21335373 doi:http://dx.doi.org/10.1105/tpc.110.080788
- ↑ Chen Q, Sun J, Zhai Q, Zhou W, Qi L, Xu L, Wang B, Chen R, Jiang H, Qi J, Li X, Palme K, Li C. The basic helix-loop-helix transcription factor MYC2 directly represses PLETHORA expression during jasmonate-mediated modulation of the root stem cell niche in Arabidopsis. Plant Cell. 2011 Sep;23(9):3335-52. doi: 10.1105/tpc.111.089870. Epub 2011 Sep, 27. PMID:21954460 doi:http://dx.doi.org/10.1105/tpc.111.089870
- ↑ Hong GJ, Xue XY, Mao YB, Wang LJ, Chen XY. Arabidopsis MYC2 interacts with DELLA proteins in regulating sesquiterpene synthase gene expression. Plant Cell. 2012 Jun;24(6):2635-48. doi: 10.1105/tpc.112.098749. Epub 2012 Jun 5. PMID:22669881 doi:http://dx.doi.org/10.1105/tpc.112.098749
- ↑ Kazan K, Manners JM. MYC2: the master in action. Mol Plant. 2013 May;6(3):686-703. doi: 10.1093/mp/sss128. Epub 2012 Nov 9. PMID:23142764 doi:http://dx.doi.org/10.1093/mp/sss128
- ↑ Zhai Q, Yan L, Tan D, Chen R, Sun J, Gao L, Dong MQ, Wang Y, Li C. Phosphorylation-coupled proteolysis of the transcription factor MYC2 is important for jasmonate-signaled plant immunity. PLoS Genet. 2013 Apr;9(4):e1003422. doi: 10.1371/journal.pgen.1003422. Epub 2013 , Apr 4. PMID:23593022 doi:http://dx.doi.org/10.1371/journal.pgen.1003422
- ↑ Schweizer F, Fernandez-Calvo P, Zander M, Diez-Diaz M, Fonseca S, Glauser G, Lewsey MG, Ecker JR, Solano R, Reymond P. Arabidopsis basic helix-loop-helix transcription factors MYC2, MYC3, and MYC4 regulate glucosinolate biosynthesis, insect performance, and feeding behavior. Plant Cell. 2013 Aug;25(8):3117-32. doi: 10.1105/tpc.113.115139. Epub 2013 Aug, 13. PMID:23943862 doi:http://dx.doi.org/10.1105/tpc.113.115139
- ↑ Abe H, Yamaguchi-Shinozaki K, Urao T, Iwasaki T, Hosokawa D, Shinozaki K. Role of arabidopsis MYC and MYB homologs in drought- and abscisic acid-regulated gene expression. Plant Cell. 1997 Oct;9(10):1859-68. PMID:9368419 doi:http://dx.doi.org/10.1105/tpc.9.10.1859
- ↑ Lian TF, Xu YP, Li LF, Su XD. Crystal Structure of Tetrameric Arabidopsis MYC2 Reveals the Mechanism of Enhanced Interaction with DNA. Cell Rep. 2017 May 16;19(7):1334-1342. doi: 10.1016/j.celrep.2017.04.057. PMID:28514654 doi:http://dx.doi.org/10.1016/j.celrep.2017.04.057
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