The nucleoporin ALADIN regulates Aurora A localization to ensure robust mitotic spindle formation

The formation of the mitotic spindle is a complex process that requires massive cellular reorganization. Regulation by mitotic kinases controls this entire process. One of these mitotic controllers is Aurora A kinase, which is itself highly regulated. In this study we show that the nuclear pore protein 2 ALADIN is a novel spatial regulator of Aurora A. Without ALADIN, we observe Aurora A spreading from centrosomes onto spindle microtubules, which affects the distribution of a subset of microtubule regulators and slows spindle assembly and chromosome alignment. ALADIN interacts with inactive Aurora A and is recruited to the spindle pole after Aurora A inhibition. Curiously, mutations in ALADIN cause triple A syndrome. We find some of the mitotic phenotypes that we observe after ALADIN depletion also occur in cells from triple A syndrome patients, which raises the possibility that mitotic errors may underlie the etiology of this syndrome