Emerging complexity of ethylene signal transduction

The plant hormone ethylene modulates growth and development and mediates diverse stresses and pathogens. Genetic studies with a laboratory reference plant, Arabidopsis, enabled researchers first to identify and place several key signaling components in a linear pathway for hormone signaling. Biochemical and cellular investigations have now led us to integrate functionally these genetically identified factors within a signaling context. Multi-step regulation of protein stability that accompanies phosphorylation/de-phosphorylation appears to be a central and underlying molecular mechanism. Here, we briefly summarize recent findings in such post-translational regulation of ethylene signaling factors. Based on this, we can postulate a new framework and formulate specific questions to unravel the emerging dynamics and complexity of ethylene signaling.