Summary
Understanding how the nuclear pore complex (NPC) assembles is of fundamental importance to grasp the mechanisms behind its essential function and understand its role during evolution of eukaryotes1–4. While we know that at least two NPC assembly pathways exist, one during exit from mitosis and one during nuclear growth in interphase, we currently lack a quantitative map of their molecular events. Here, we use fluorescence correlation spectroscopy (FCS) calibrated live imaging of endogenously fluorescently-tagged nucleoporins to map the changes in composition and stoichiometry of seven major modules of the human NPC during its assembly in single dividing cells. This systematic quantitative map reveals that the two assembly pathways employ strikingly different molecular mechanisms, inverting the order of addition of two large structural components, the central ring complex and nuclear filaments. Our dynamic stoichiometry data allows us to perform the first computational simulation that predicts the structure of postmitotic NPC assembly intermediates.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Results strengthened by new experiments with 3D-STED (new Fig. 4) and live imaging of a newly-generated Nup cell lines (Extended Figs. 7, 8). Variance of integrative models highlighted more clearly (Extended Fig. 6). Clarified points in the discussion. Author list updated.
