May act as a substrate-specific adapter of an E3 ubiquitin-protein ligase complex (CUL3-RBX1-BTB) which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Also targeted for degradation by the 26S proteasome pathway. May be involved in gametophyte development. Protein modification; protein ubiquitination. Interacts with CUL3A. Interacts with GTE9/BET9 and GTE11/BET10 through the BTB domain. Preferentially expressed in young leaves, roots and stems. Up-regulated by auxin (IAA). Down-regulated by salicylic acid (SA) and hydrogen peroxide. The BTB/POZ domain mediates the interaction with some component of ubiquitin ligase complexes.