Structure and Interactions of the Endogenous Human Commander Complex

Summary The Commander complex, a 16-protein subunit assembly, plays multiple roles in various intracellular events, including regulation of cell homeostasis, cell cycle, and immune response. The complex is composed of COMMD1-10, CCDC22, CCDC93, DENND10, VPS26C, VPS29, and VPS35L. These proteins are expressed ubiquitously in the human body and have been linked to diseases including Wilson’s disease, atherosclerosis, and several cancers. Despite its importance, the structure and molecular functions of the Commander complex are poorly understood. Here, we report the structure and key interactions of the endogenous human Commander complex by cryogenic electron microscopy (cryo-EM) and mass spectrometry-based proteomics. Our results show that the complex is asymmetric, consisting of a stable core of a pseudo-symmetric ring of COMMD proteins 1–10 and a mobile effector consisting of DENND10 and the Retriever sub-complex, constituted by VPS35L, VPS29 and VPS26C. The two halves are scaffolded together by CCDC22 and CCDC93. This study directly confirms the cellular composition of Commander and identifies major interaction interfaces, defining the structure and interaction landscape of the complex. These findings offer new insights into its known roles in endosomal processes and intracellular transport, and uncovers a strong association with cilium assembly, and centrosome and centriole functions. Highlights High-resolution structure of the Commander complex determined by cryo-EM shows a rigid COMMD1–10 core decorated by mobile effectors DENND10 and the Retriever sub-complex. Comprehensive interactome analysis uncovers a plethora of novel interactions, implicating the Commander complex in previously unidentified processes, such as cilium assembly, cell cycle, and organelle biogenesis. Structural organization and identified interaction partners of the Commander complex provide a basis for further research into its molecular functions, related diseases, and potential therapeutic targets. eTOC blurb We provide a comprehensive structural analysis of the endogenous human Commander complex, revealing its functional organization and novel interactions involved in diverse cellular processes. These findings uncover new interaction surfaces and pave the way for further research into the molecular mechanisms of the Commander complex.