Substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3 ubiquitin ligase complex. The BCR(KLHL7) complex acts by mediating ubiquitination and subsequent degradation of substrate proteins. Probably mediates 'Lys-48'-linked ubiquitination (By similarity). Protein modification; protein ubiquitination. Homodimer. Component of the BCR(KLHL7) E3 ubiquitin ligase complex, at least composed of CUL3 and KLHL7 and RBX1 (By similarity). Colocalizes with CUL3 in punctate structures at the perinuclear region of the cytoplasm.