GMDS, also known as SDR3E1, belongs to the GDP-mannose 4,6-dehydratase family. This protein utilizes NADP as a cofactor to catalyze the conversion of GDP-mannose to GDP-4-keto-6-deoxymannose. Mutations in the gene encoding GMDS are involved in resistance to TRAIL (tumor necrosis factor-related apoptosis-inducing ligand)-induced apoptosis.