Nucleoporins, core structural components of the nuclear pore complex, are implicated in a number of functions beyond their canonical role in nucleocytoplasmic transport. The Nup107 complex forms a structural scaffold in the nuclear pore. The nucleoporin Seh1 is a member of the Nup107 complex and of the unrelated GATOR2 complex, possibly linking the nutrient-sensing role of the mTOR signalling pathway with mitosis. To characterise the roles of Seh1 in interphase and mitosis, Melpomeni Platani, William Earnshaw and colleagues (Platani et al., 2018) combined a chemical genetics approach with quantitative proteomics to finely tune Seh1 levels and analyse its function in mitosis separately from its roles in interphase. Their results confirm that, in mitosis, Seh1 regulates the centromeric localisation of Aurora B kinase, therefore modulating faithful chromosome segregation and alignment. Interestingly, the authors also show that Seh1 itself is essential for the association of the GATOR2 complex with mitotic chromosomes. Taken together, the results of this study better define the role of Seh1 in mitosis and provide a strong basis for further investigation of the mitotic role of the mTORC1 activator GATOR2.