Processing and Subcellular Trafficking of ER-Tethered EIN2 Control Response to Ethylene Gas

• Published in: Science (American Association for the Advancement of Science) Vol. 338; no. 6105; pp. 390 - 393
• Main Authors: Qiao, Hong, Shen, Zhouxin, Huang, Shao-shan Carol, Schmitz, Robert J., Urich, Mark A., Briggs, Steven P., Ecker, Joseph R.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 19-10-2012; The American Association for the Advancement of Science
• Subjects: Active Transport, Cell Nucleus; Antibodies; Arabidopsis - drug effects; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biological and medical sciences; Cell nucleus; Cell Nucleus - metabolism; Endoplasmic reticulum; Endoplasmic Reticulum - metabolism; Ethylene; Ethylenes - metabolism; Ethylenes - pharmacology; Feedback (Response); Fundamental and applied biological sciences. Psychology; Gases; Gases - metabolism; Gases - pharmacology; Gene expression; Genes; Hormones; Maintenance; Metabolism; Mutation; Nuclear Localization Signals - genetics; Nuclear Localization Signals - metabolism; Nuclei; Perception; Phenotypes; Phosphorylation; Plant physiology and development; Protein Kinases - metabolism; Proteins; Proteolysis; Receptors; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Seedlings; Transgenic plants; Western blotting; Phosphorylation; Membrane protein; Ethylene; Activation; Dephosphorylation; Fragmentation; Arabidopsis thaliana; Cruciferae; Proteolysis; Dicotyledones; Angiospermae; Development; Cleavage; Transcription factor; Translocation; Intracellular transport; Enzyme; Transferases; Stress; Kinase; Spermatophyta; Phytohormone; Mutation; Experimental plant; Endoplasmic reticulum
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1225974

Ethylene gas is essential for many developmental processes and stress responses in plants. ETHYLENE INSENSITIVE2 (EIN2), an NRAMP-like integral membrane protein, plays an essential role in ethylene signaling, but its function remains enigmatic. Here we report that phosphorylation-regulated proteolytic processing of EIN2 triggers its endoplasmic reticulum (ER)–to–nucleus translocation. ER-tethered EIN2 shows CONSTITUTIVE TRIPLE RESP0NSE1 (CTR1) kinase-dependent phosphorylation. Ethylene triggers dephosphorylation at several sites and proteolytic cleavage at one of these sites, resulting in nuclear translocation of a carboxyl-terminal EIN2 fragment (EIN2-C'). Mutations that mimic EIN2 dephosphorylation, or inactivate CTR1, show constitutive cleavage and nuclear localization of EIN2-C' and EIN3 and EIN3-LIKE1-dependent activation of ethylene responses. These findings uncover a mechanism of subcellular communication whereby ethylene stimulates phosphorylation-dependent cleavage and nuclear movement of the EIN2-C' peptide, linking hormone perception and signaling components in the ER with nuclear-localized transcriptional regulators.