NADPH-dependent reductase which is a central component of the cytosolic iron-sulfur (Fe-S) protein assembly (CIA) machinery. Transfers electrons from NADPH via its FAD and FMN prosthetic groups to the [2Fe-2S] cluster of ciapin1, another key component of the CIA machinery. In turn, this reduced cluster provides electrons for assembly of cytosolic iron-sulfur cluster proteins. It can also reduce the [2Fe-2S] cluster of cisd1 and activate this protein implicated in Fe/S cluster repair. {Sequence AnalysisHAMAP-Rule:MF_03178}.