Age-dependent deterioration of nuclear pore assembly in mitotic cells decreases transport dynamics

Nuclear transport is facilitated by the Nuclear Pore Complex (NPC) and is essential for life in eukaryotes. The NPC is a long-lived and exceptionally large structure. We asked whether NPC function is compromised in ageing mitotic cells. By imaging of single yeast cells during ageing, we show that the abundance of several NPC components and NPC assembly factors decreases while signs of misassembled NPCs appear. Consequently, nuclear permeability decreases, resulting in decreased dynamics of transcription factor shuttling and increased nuclear compartmentalisation. In support that declining NPC quality control is important in mitotic ageing, we find that the transport kinetics observed in ageing is mimicked in an NPC assembly mutant. Additionally, the single cell life histories reveal that cells that better maintain NPC function are longer lived. We conclude that assembly and quality control of NPCs are major challenges for ageing mitotic cells.