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 (By similarity).