Core component of the 3M complex, a complex required to regulate microtubule dynamics and genome integrity. It is unclear how the 3M complex regulates microtubules, it could act by controlling the level of a microtubule stabilizer (PubMed:24793695, PubMed:24793696). Acts as a regulator of the Cul7-RING(FBXW8) ubiquitin-protein ligase, playing a critical role in the ubiquitin ligase pathway that regulates Golgi morphogenesis and dendrite patterning in brain. Required to localize CUL7 to the Golgi apparatus in neurons. Component of the 3M complex, composed of core components CUL7, CCDC8 and OBSL1. Interacts with CCDC8. Interacts with CUL7; the interaction is direct. Interacts with FBXW8. Interacts (via N-terminal Ig-like domain) with TTN/titin (via C-terminal Ig-like domain); the interaction is direct. Colocalizes with CUL7 at the Golgi apparatus in neurons (PubMed:21572988). Widely expressed, with predominant levels found in the heart. The disease is caused by variants affecting the gene represented in this entry. Extended N-terminus.