Figure 4.

Steap4 facilitated SLC40A1-mediated iron efflux in cardiomyocytes. (A) A Co-IP experiment demonstrated SLC40A1 and Steap4 interaction. IB, immunoblot; IP immunoprecipitation. (B) Representative images of immunofluorescence staining for Steap4 (green), SLC40A1 (red), and DAPI (blue) in primary neonatal cardiomyocytes. (C) A strong interaction between SLC40A1 and Steap4 was observed through the FRET experiment (n = 3). (D) NMCMs Steap4 and Fth proteins was measured using western blot analysis (n = 3). NMCMs, neonatal mouse cardiomyocytes. (E) Intracellular Fe²⁺ levels were analyzed fluorometrically using FerroOrange staining (n = 4). (F) Total iron levels in the NMCMs were measured (n = 4). The data is presented as the mean value plus or minus the standard error of the mean. Statistical significance is denoted by *p < 0.05 and **p < 0.01.