Toyocamycin is a natural adenosine analog first isolated from Streptomyces and shown in early studies to be cytotoxic to bacteria, fungi, and cancer cells and to have antiviral activities. Toyocamycin prevents IRE1α-induced mRNA cleavage (IC50 = 80 nM) and inhibits constitutive activation of XBP1 in multiple myeloma cell lines. It is used to study IRE1α action in the endoplasmic reticulum stress response, particularly in the context of cancer. It also inhibits phosphatidylinositol kinase in vitro (IC50 = 3.3 μg/ml), but not in cells, and blocks the ribosomal RNA-processing kinase Rio1 (IC50 = ~30 nM).
![4-AMINO-5-CYANO-7-(BETA-D-RIBOFURANOSYL)PYRROLO[2,3-D]PYRIMIDINE](https://www.chemicalbook.com/CAS/GIF/606-58-6.gif)
