Saccharocarcin B is an unusual tetronic acid structurally related to kijanimicin, chlorothricin, tetrocarcins and versipelostatin which has pronounced activity against Gram positive bacteria and Chlamydia trachomatis. Several members of this class have received considerable literature focus. Versipelostatin was shown to inhibit transcription from the promoter of GRP78, a gene that is activated as part of a stress signaling pathway under glucose deprivation resulting in unfolded protein response (UPR). The UPR-inhibitory action was seen only in conditions of glucose deprivation and caused selective and massive killing of the glucose-deprived cells. Tetrocarcin A appears to target the phosphatidylinositide-3'-kinase/Akt signaling pathway.