XB-ART-43038ACS Chem Biol July 15, 2011; 6 (7): 700-8.
Importazole, a small molecule inhibitor of the transport receptor importin-β.
During interphase, the transport receptor importin-β carries cargoes into the nucleus, where RanGTP releases them. A similar mechanism operates in mitosis to generate a gradient of active spindle assembly factors around mitotic chromosomes. Importin-β and RanGTP have been implicated in additional cellular processes, but the precise roles of the Ran/importin-β pathway throughout the cell cycle remain poorly understood. We implemented a FRET-based, high-throughput small molecule screen for compounds that interfere with the interaction between RanGTP and importin-β and identified importazole, a 2,4-diaminoquinazoline. Importazole specifically blocks importin-β-mediated nuclear import both in Xenopus egg extracts and cultured cells, without disrupting transportin-mediated nuclear import or CRM1-mediated nuclear export. When added during mitosis, importazole impairs the release of an importin-β cargo FRET probe and causes both predicted and novel defects in spindle assembly. Together, these results indicate that importazole specifically inhibits the function of importin-β, likely by altering its interaction with RanGTP. Importazole is a valuable tool to evaluate the function of the importin-β/RanGTP pathway at specific stages during the cell cycle.
PubMed ID: 21469738
PMC ID: PMC3137676
Article link: ACS Chem Biol
Grant support: R01 GM065232-04 NIGMS NIH HHS , R01 GM065232-07 NIGMS NIH HHS , R01 GM065232-08 NIGMS NIH HHS , R01GM065232 NIGMS NIH HHS , R21 NS53592 NINDS NIH HHS , R01 GM065232 NIGMS NIH HHS , R21 NS053592 NINDS NIH HHS
Genes referenced: ran xpo1