During mitosis in higher eukaryotes, nuclear pore complexes (NPCs) disassemble in prophase and are rebuilt in anaphase and telophase. NPC formation is hypothesized to occur by the interaction of mitotically stable subcomplexes that form defined structural intermediates. To determine the sequence of events that lead to breakdown and reformation of functional NPCs during mitosis, we present here our quantitative assay based on confocal time-lapse microscopy of single dividing cells. We use this assay to systematically investigate the kinetics of dis- and reassembly for eight nucleoporin subcomplexes relative to nuclear transport in NRK cells, linking the assembly state of the NPC with its function. Our data establish that NPC assembly is an ordered stepwise process that leads to import function already in a partially assembled state. We furthermore find that nucleoporin dissociation does not occur in the reverse order from binding during assembly, which may indicate a distinct mechanism.

Nup133 links CENP-F, NudE/EL, and the dynein/dynactin complex to anchor centrosomes to the nuclear membrane.

The organization and biophysical properties of the cytosol implicitly govern molecular interactions within cells. However, little is known about mechanisms by which cells regulate cytosolic properties and intracellular diffusion rates. Here, we demonstrate that the intracellular environment of budding yeast undertakes a startling transition upon glucose starvation in which macromolecular mobility is dramatically restricted, reducing the movement of both chromatin in the nucleus and mRNPs in the cytoplasm. This confinement cannot be explained by an ATP decrease or the physiological drop in intracellular pH. Rather, our results suggest that the regulation of diffusional mobility is induced by a reduction in cell volume and subsequent increase in molecular crowding which severely alters the biophysical properties of the intracellular environment. A similar response can be observed in fission yeast and bacteria. This reveals a novel mechanism by which cells globally alter their properties to establish a unique homeostasis during starvation.DOI: http://dx.doi.org/10.7554/eLife.09376.001

Recruitment of nuclear pore complex (NPC) components during interphase occurs in a different order and with slower kinetics than during postmitotic NPC assembly, suggesting the two processes are regulated by distinct mechanisms.

In eukaryotes, all macromolecules traffic between the nucleus and the cytoplasm through nuclear pore complexes (NPCs), which are among the largest supramolecular assemblies in cells. Although their composition in yeast and metazoa is well characterized, understanding how NPCs are assembled and form the pore through the double membrane of the nuclear envelope and how both processes are controlled still remains a challenge. Here, we summarize what is known about the biogenesis of NPCs throughout the cell cycle with special focus on the membrane reorganization and the regulation that go along with NPC assembly.