Curtabbi, AndreaGuaras, AdelaCabrera-Alarcón, José LuisRivero, MaribelCalvo, EnriqueRosa-Moreno, MarinaVazquez, JesusMedina, MilagrosEnriquez, Jose Antonio2024-03-212024-03-212024-02Redox Biol. 2024 Feb:69:103001.http://hdl.handle.net/20.500.12105/19037Respiratory complex I plays a crucial role in the mitochondrial electron transport chain and shows promise as a therapeutic target for various human diseases. While most studies focus on inhibiting complex I at the Q-site, little is known about inhibitors targeting other sites within the complex. In this study, we demonstrate that diphenyleneiodonium (DPI), a N-site inhibitor, uniquely affects the stability of complex I by reacting with its flavin cofactor FMN. Treatment with DPI blocks the final stage of complex I assembly, leading to the complete and reversible degradation of complex I in different cellular models. Growing cells in medium lacking the FMN precursor riboflavin or knocking out the mitochondrial flavin carrier gene SLC25A32 results in a similar complex I degradation. Overall, our findings establish a direct connection between mitochondrial flavin homeostasis and complex I stability and assembly, paving the way for novel pharmacological strategies to regulate respiratory complex I.engVoRhttp://creativecommons.org/licenses/by-nc-nd/4.0/Electron Transport Complex IRiboflavinHumansMitochondriaAttribution-NonCommercial-NoDerivatives 4.0 Internacional381455896910300110.1016/j.redox.2023.1030012213-2317Redox biologyopen access