Identification of Rapaglutin E as an Isoform-Specific Inhibitor of Glucose Transporter 1

ACS Chem Biol. 2025 May 16;20(5):1004-1009. doi: 10.1021/acschembio.5c00152. Epub 2025 Apr 14.

Abstract

Natural products rapamycin and FK506 are macrocyclic compounds with therapeutic benefits whose unique scaffold inspired the generation and exploration of hybrid macrocycle rapafucins. From this library, a potent inhibitor of the facilitative glucose transporter (GLUT), rapaglutin A (RgA), was previously identified. RgA is a pan-GLUT inhibitor of Class I isoforms GLUT1, GLUT3, and GLUT4. Herein, we report the discovery of rapaglutin E (RgE). Unlike RgA, RgE is highly specific for GLUT1. Further characterization revealed that RgE and RgA likely bound to distinct sites on GLUT1 despite their shared FKBP-binding domain, suggesting that the distinct effector domains of RgE and RgA play key roles in the recognition of GLUTs.

MeSH terms

  • Glucose Transporter Type 1* / antagonists & inhibitors
  • Glucose Transporter Type 1* / metabolism
  • Humans
  • Protein Isoforms / antagonists & inhibitors
  • Protein Isoforms / metabolism

Substances

  • Glucose Transporter Type 1
  • Protein Isoforms