Possible regulator of the ethylene pathway, which acts by regulating the stability of 1-aminocyclopropane-1-carboxylate synthase (ACS) enzymes. May act as a substrate-specific adapter that connects ACS enzymes, such as ACS5, to ubiquitin ligase complexes, leading to proteasomal degradation of ACS enzymes (By similarity). Protein modification; protein ubiquitination. Interacts with the C-terminal domain of ACS4, ACS5 AND ACS9. Predominantly expressed in flowers. The BTB/POZ-like domain may mediate the interaction with some component of ubiquitin ligase complexes. Belongs to the ETO1 family.