Mediates responses to the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D). Not involved in the response to indole-3-acetic acid (IAA). May interact with RUB modification-related components and may regulate the culling-ring ubiquitin E3 ligase complex (CRL) activity. Expressed in siliques and anthers. It is uncertain whether Met-1 or Met-10 is the initiator. Truncated N-terminus.