Questiomycin A (Phx-3) is a GRP78 (cytoprotective endoplasmic reticulum chaperone) degrader and enhances the anticancer activity of Sorafenib. Questiomycin A is also an antimicrobial/antibiotic that can be obtained from the metabolite of Pseudomonas chlororaphis HT66. Questiomycin A can be used in research on biological control of cancer and plant diseases[1][2].