Probable cytoskeletal component that directly or indirectly plays an important role in neurofilament architecture. May act as a substrate-specific adapter of an E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Controls degradation of TBCB (By similarity). Controls degradation of MAP1B and MAP1S, and is critical for neuronal maintenance and survival. Protein modification; protein ubiquitination. Interacts with TBCB. Interacts with CUL3. Part of a complex that contains CUL3, RBX1 and GAN. Interacts (via BTB domain) with UBA1 (By similarity). Interacts (via Kelch domains) with MAP1B (via C-terminus) and MAP1S (via C-terminus). Expressed in brain, heart and muscle (at protein level). Ubiquitinated by E3 ubiquitin ligase complex formed by CUL3 and RBX1 and probably targeted for proteasome-independent degradation. Mice have a relatively normal life span. However, they display deterioration in motor function with onset varying from 6 to 10 months as well as abnormalities in non-neuronal tissues. The prominent pathological features include limb weakness, muscular atrophy, axonal degeneration, neurofilament accumulation, an abnormal microtubule network, mitochondrial swelling and thinned myelin sheaths.