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. Required for flavinylation (covalent attachment of FAD) of the flavoprotein subunit SDH1 of the SDH catalytic dimer. It is unclear whether it participates in the chemistry of FAD attachment (enzymatic function) or acts as a chaperone that maintains SDH1 in a conformation that is susceptible to autocatalytic FAD attachment (PubMed:19628817). Does not bind FAD or FADH(2) in vitro (PubMed:23062074). Involved in sporulation (PubMed:12432101). Required for the full activation of the early meiotic inducer IME1 (PubMed:12586695). Interacts with SDH1 within the SDH catalytic dimer. Respiratory deficient phenotype: viable on glucose medium, but is inviable on non-fermentable carbon sources such as glycerol. Cells lack SDH activity due to a complete loss of FAD cofactor attachment of SDH1. Present with 1080 molecules/cell in log phase SD medium. Belongs to the SDHAF2 family.