Ferroptosis suppressor protein 1 (FSP1), also known as apoptosis-inducing factor mitochondria-associated 2 (AIFM2), is a flavoprotein and NAD(P)H-dependent oxidoreductase that inhibits ferroptosis in a glutathione peroxidase 4 (GPX4) and glutathione-independent manner.{50700,50699,45864} It is encoded by AIFM2 in humans and is composed of a short N-terminal hydrophobic region followed by a flavin adenine dinucleotide-dependent oxidoreductase domain.{50699} FSP1 localizes to the plasma membrane in a myristoylation-dependent manner, where it reduces coenzyme Q10 (CoQ10; Item No. 11506) to CoQ10H2. Reduced CoQ10 functions as a radical-trapping antioxidant and inhibits lipid peroxidation. AIFM2 expression positively correlates with resistance to GPX4 inhibitors, including (1S,3R)-RSL3 (Item No. 19288), ML-210 (Item No. 23282), and ML-162 (Item No. 20455), in cancer cell lines. Withdrawal of the ferroptosis inhibitor ferrostatin-1 (Item No. 17729) reduces tumor growth in an Fsp1/Gpx4 double knockout, but not a GPX4 single knockout, H460 lung cancer mouse xenograft model, indicating that FSP1 confers resistance to ferroptotic cell death. Cayman’s FSP1 Polyclonal Antibody can be used for ELISA and Western blot (WB) applications. The antibody recognizes FSP1 at 41 kDa from human and mouse samples.