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ETHYLENE INSENSITIVE2 (EIN2) is a key component of ethylene signaling and its activity is inhibited on the phosphorylation of Ser645 and Ser924 by the Raf-like CONSTITUTIVE TRIPLE RESPOPNSE1 (CTR1) in the absence of ethylene. Ethylene prevents CTR1 activity and thus the EIN2~(Ser645/Ser924) phosphorylation, and subcellular trafficking of a proteolytically cleaved EIN2 C-terminus (EIN2-C) from the endoplasmic reticulum to the nucleus and processing bodies triggers ethylene signaling. Here we report activation of EIN2-mediated ethylene signaling in the absence of CTR1 in part requiring ethylene, and the signaling is unexpectedly complex. Transgenes encoding EIN2, EIN2 variants with mutations that respectively prevent and mimic Ser~(645)/Ser~(924) phosphorylation, and EIN2-C complemented ein2, and these transgenic lines responded to ethylene. The subcellular distribution pattern of fluorescence protein-tagged EIN2 and its variants was similar, and the distribution was affected little in response to ethylene. Interestingly, the subcellular distribution of YELLOW FLUORESCENCE PROTEIN (YFP)-EIN2 and EIN2-YFP was similar: particles or aggregates in the cytosol and speckles in the nucleus. EIN2-C-YFP was primarily observed in the cytosol and not in the nucleus. Western blots and mass-spectrum analyses suggested a high complexity of EIN2, and EIN2 is likely proteolytically cleaved into multiple fragments. Our results suggested a possible nuclear localization of the full-length EIN2, weak association of the EIN2 Ser~(645)/Ser~(924) status and ethylene signaling, and complexity of ethylene signaling by EIN2 and its …