Shohei UedaShigeru KitaniTakushi NambaMasayoshi AraiHaruo IkedaTakuya NihiraOsaka UniversityKochi UniversityMahidol UniversityKitasato University2019-08-282019-08-282018-10-01Journal of Antibiotics. Vol.71, No.10 (2018), 854-86118811469002188202-s2.0-85049596403https://repository.li.mahidol.ac.th/handle/20.500.14594/47295© 2018, The Author(s) under exclusive licence to the Japan Antibiotics Research Association. β-Carboline alkaloids and related compounds show a broad spectrum of biological activities. We previously identified new members of the β-carboline alkaloid family by using an engineered Kitasatospora setae strain and a heterologous Streptomyces host expressing the plausible biosynthetic genes, including the hypothetical gene kse_70640 (kslB). Here, we elucidated the chemical structure of a new tetrahydro-β-carboline compound (named kitasetalic acid) that appeared in a heterologous Streptomyces host expressing the kslB gene alone. Kitasetalic acid suppressed the expression of glucose-regulated protein 78 (GRP78) without inducing cell death. This is the first report to show that a tetrahydro-β-carboline compound regulates the expression of the GRP78 protein in cancer cell lines.Mahidol UniversityPharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1038/s41429-018-0074-7