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 (By similarity). Confers resistance to soil-born pathogens (e.g. the root-penetrating fungus Fusarium oxysporum) by regulating membrane trafficking, specifically mediating ABCG36/PEN3 exit from the endoplasmic reticulum and subsequent relocalization at the host-pathogen interface of the plasma membrane (PubMed:29085068). Protein modification; protein ubiquitination. Expressed at very low levels. The BTB/POZ domain mediates the interaction with some component of ubiquitin ligase complexes. ABCG36/PEN3 retention and accumulation in the endoplasmic reticulum associated with an increased sensitivity to the root-penetrating pathogenic fungus Fusarium oxysporum. Truncated C-terminus.