Dual control of nuclear EIN3 by bifurcate MAPK cascades in C 2H4 signalling

Sang Dong Yoo, Young Hee Cho, Guillaume Tena, Yan Xiong, Jen Sheen

Research output: Contribution to journalArticlepeer-review

370 Citations (Scopus)


A principal question in MAP kinase (MAPK/MPK) cascade signalling is how similar components dictate different specificity in the information-processing machineries from yeast to humans and plants. In Arabidopsis, how MPK3/6 modulates distinct outputs in diverse signal transduction pathways remains elusive. By combining systematic cellular and genetic screens, here we uncover a previously unexpected MKK9-MPK3/MPK6 cascade promoting ethylene-insensitive 3 (EIN3)-mediated transcription in ethylene signalling. The mkk9 mutant exhibits a broad spectrum of moderate ethylene-insensitive phenotypes, and translocated MKK9 governs nuclear signalling downstream of receptors. Breaking a linear model and conventional MAPK signalling, ethylene inactivates the negative regulator constitutive triple response 1 (CTR1, a Raf-like MAPK kinase kinase (MAPKKK)) to activate the positive MKK9-MPK3/6 cascade. The bifurcate and antagonistic CTR1 and MKK9 pathways are both critical in determining ethylene-signalling specificity through two MAPK phosphorylation sites with opposite effects on EIN3 stability. The results suggest a new paradigm for linking intertwined MAPK cascades to control quantitative responses and specificity in signalling networks.

Original languageEnglish
Pages (from-to)789-795
Number of pages7
Issue number7180
Publication statusPublished - 2008 Feb 14

ASJC Scopus subject areas

  • General


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