Importazole, a small molecule inhibitor of the transport receptor importin-?.

ABSTRACT: During interphase, the transport receptor importin-? 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-? and RanGTP have been implicated in additional cellular processes, but the precise roles of the Ran/importin-? 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-? and identified importazole, a 2,4-diaminoquinazoline. Importazole specifically blocks importin-?-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-? 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-?, likely by altering its interaction with RanGTP. Importazole is a valuable tool to evaluate the function of the importin-?/RanGTP pathway at specific stages during the cell cycle.

SUBMITTER: Soderholm JF 

PROVIDER: S-EPMC3137676 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature