Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex that acts as a regulator of ion transport in the distal nephron. The BCR(KLHL3) complex acts by mediating ubiquitination of WNK4, an inhibitor of potassium channel KCNJ1, leading to WNK4 degradation (By similarity). The BCR(KLHL3) complex also mediates ubiquitination and degradation of CLDN8, a tight-junction protein required for paracellular chloride transport in the kidney (By similarity). Protein modification; protein ubiquitination. Homodimer. Component of the BCR(KLHL3) E3 ubiquitin ligase complex, at least composed of CUL3 and KLHL3 and RBX1 (By similarity). Interacts with SLC12A3 (By similarity). Interacts with WNK1 and WNK4 (By similarity). Interacts with CLDN8 (By similarity). Phosphorylation at Ser-433 by PKA decreases the interaction with WNK4, Leading to inhibit WNK4 degradation by the BCR(KLHL3) complex. Phosphorylation at Ser-433 is increased by insulin.