Adapter protein for the cul3 E3 ubiquitin-protein ligase complex (By similarity). Involved in late neuronal development and muscle formation (PubMed:18855900). Homodimer and heterodimer. Interacts with cul3 via the BTB domain. Found in punctated bodies in the cytoplasm. Highly expressed in the developing nervous system. Embryos show strong defects in late neuronal markers and strongly reduced and disorganized axons while early neural development is unaffected. Muscle development is also affected.