Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin-protein ligase complex required for mitotic progression and cytokinesis. The BCR(KLHL9-KLHL13) E3 ubiquitin ligase complex mediates the ubiquitination of AURKB and controls the dynamic behavior of AURKB on mitotic chromosomes and thereby coordinates faithful mitotic progression and completion of cytokinesis (By similarity). Protein modification; protein ubiquitination. Component of the BCR(KLHL9-KLHL13) E3 ubiquitin ligase complex, at least composed of CUL3, KLHL9, KLHL13 and RBX1. Interacts with AURKB (By similarity).