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 (PubMed:24954417, PubMed:19465911). Promotes maturation of the iron-sulfur protein subunit SDHB of the SDH catalytic dimer, protecting it from the deleterious effects of oxidants (PubMed:24954417). May act together with SDHAF3 (PubMed:24954417). Contributes to iron-sulfur cluster incorporation into SDHB by binding to SDHB and recruiting the iron-sulfur transfer complex formed by HSC20, HSPA9 and ISCU through direct binding to HSC20 (PubMed:26749241). Interacts with SDHB within an SDHA-SDHB subcomplex (PubMed:19465911, PubMed:26749241). Also interacts with the iron-sulfur transfer complex formed by HSC20, HSPA9 and ISCU through direct binding to HSC20 (PubMed:26749241). Binding of SDHAF1 to SDHB precedes and is necessary for recruitment of the iron-sulfur transfer complex by SDHAF1 (PubMed:26749241). Ubiquitously expressed. The disease is caused by variants affecting the gene represented in this entry. Riboflavin supplementation, which is used as a treatment in SDHAF1-deficient patients, enhances SDHA flavinylation and activity and reduces levels of HIF1A, HIF2A and succinate. Belongs to the complex I LYR family. SDHAF1 subfamily.