The function of CIAO3 (cytosolic iron-sulfur assembly component 3, ENSG00000103245) is as follows. Component of the cytosolic iron-sulfur protein assembly (CIA) complex, a multiprotein complex that mediates the incorporation of iron-sulfur cluster into extramitochondrial Fe/S proteins. Seems to negatively regulate the level of HIF1A expression, although this effect could be indirect. {ECO:0000269|PubMed:16956324, ECO:0000269|PubMed:18270200}.