Fig. 6: Cys127 S-glutathionylation of FABP5 potentiates its nuclear translocation and fatty acid binding in response to ROS.

a Model structure of FABP5 and its 6 cysteines, generated by Pymol and based on the crystal structure of Homo sapiens FABP5 (PDB ID,4LKT). b Mass spectra of a peptide from FABP5 including glutathionylated cysteine 120 and cysteine127. c Immunofluorescence staining (with FABP5) and confocal microscopy imaging of COS-7 cells with overexpression of FABP5 WT, C67S, C87S, C120S, and C127S after exposure to H₂O₂ (200 μM) for 1 h (green, FABP5; blue, DAPI; scale bars, 10 μm). d Immunoblot analysis of cytoplasmic and nuclear FABP5 in COS-7 cells transfected with FABP5 WT or C127S after exposure to H₂O₂ (200 μM) for 1 h. Lamin B1 (nuclear fraction) and GAPDH (cytoplasmic fraction) are loading controls. e Model structure of FABP5 interaction with an FA (Fatty Acid, Linoleic Acid), generated by Pymol and based on the crystal structure of FABP5 (PDB ID, 4LKT). f Docking structure of FABP5 in complex with S-glutathionylated Cys127 interacting with an FA (Fatty Acid, Linoleic Acid). g Docking structure of dimer FABP5 (PDB ID, 4AZM, Homo sapiens) in complex with reduced glutathione (GSH) on Cys127. h Co-IP for S-glutathionylation of FABP5 in COS-7 cells overexpressing pXJ40-3xFlag-FABP5 WT or C127S and exposed to H₂O₂ (200 μM) for 15 min (IP, GSH; IB, FABP5). Whole-cell lysates confirm the expression of FABP5 and β-actin (DTT, negative control). i Immunoblot analysis of FABP5 fatty acid binding. Purified recombinant FABP5 WT or C127S protein (1 μg) was incubated with GSSG (1 mM) for 15 min, then mixed with Biotin-linoleic acid in the absence or presence of BMS309403 (5 mM) for 30 min. FABP5 that associated with the Biotin-linoleic acid was captured using streptavidin magnetic beads. Source data are provided as a Source Data file.