Plays an essential role in the assembly of succinate dehydrogenase (SDH), an enzyme complex (also referred to as respiratory complex II) that is a component of both the tricarboxylic acid (TCA) cycle and the mitochondrial electron transport chain, and which couples the oxidation of succinate to fumarate with the reduction of ubiquinone (coenzyme Q) to ubiquinol. Binds to the flavoprotein subunit SdhA in its FAD-bound form, blocking the generation of excess reactive oxigen species (ROS) and facilitating its assembly with the iron-sulfur protein subunit SdhB into the SDH catalytic dimer. Interacts with SdhA in its FAD-bound form. Belongs to the SDHAF4 family.