Fig. 3

Model of the core ethylene-signaling pathway as described in the text. Top: in the absence of the ethylene signal, the ethylene receptors (represented by the isoform ETR1) activate the CTR1 protein kinase, which represses EIN2 function. In the nucleus, the master transcription factors EIN3/EIL1 are degraded. Bottom: when ethylene is detected, the ethylene receptors no longer activate CTR1, resulting in the proteolytic release of the EIN2 C-END, which inhibits protein translation of the F-box proteins EBF1/2. EIN3/EIL1 are consequently stabilized and regulate an extensive transcriptional cascade involving the ERF1 transcription factor. Other elements that regulate the pathway can be found in [37]