IWR1

IWR1 is a designation used in biology to refer to more than one distinct entity, depending on the context. The most commonly encountered uses are as follows.

Inhibitors of Wnt response 1 (IWR-1) are small-molecule compounds that suppress the Wnt/β-catenin signaling pathway. They were identified in chemical biology screens as molecules that reduce Wnt reporter activity. IWR-1 and its derivatives, such as IWR-1-endo, are thought to act by stabilizing the destruction complex that targets β-catenin for degradation, thereby decreasing the transcription of Wnt target genes. Because Wnt signaling plays a key role in development and cancer, IWR-1 compounds are used as tools to study pathway dynamics and to probe potential therapeutic strategies.

Iwr1 refers to a yeast protein involved in nuclear import of RNA polymerase II. In Saccharomyces cerevisiae, Iwr1p is associated with the nuclear pore complex and is required for efficient import of RNA polymerase II into the nucleus, enabling transcription. The protein is considered part of the cellular machinery that coordinates large-scale transport between the cytoplasm and nucleus, and its function has been linked to transcriptional competence. Orthologs or functionally related proteins are recognized in other eukaryotes, though specific roles can vary by organism.

Overall, IWR1 can denote either a set of Wnt signaling inhibitors or a yeast nuclear transport factor, reflecting the diverse naming conventions used across molecular biology.