NPC-MEM · The Nuclear Pore Complex: Bridging Membrane Remodelling and Lipid Metabolism

The nuclear pore complex (NPC) is a defining component of eukaryotic cells. Its role as a selective transport channel is well-documented, but NPCs also remodel the nuclear envelope, bending and fusing the inner and outer nuclear membranes to form a pore without rupturing the cell nucleus. The underlying mechanism of this process is poorly understood, despite its profound implications for cellular function. My proposal addresses how nuclear pore complexes function as membrane remodelling machines, which remains a fundamental question in eukaryotic biology. Despite its significance, this question has been scarcely explored, primarily due to technical challenges. These include the need for detailed knowledge of NPC protein structure, which has only recently emerged, the lack of tools for NPC membrane biochemistry, and the requirement for a deeper understanding of the inner nuclear membrane (INM), where NPC biogenesis begins during interphase. The process by which NPCs sculpt membrane pores is tied to lipid chemistry, which is the output of lipid metabolism. Therefore, the core strategy of this proposal is to study the nexus between nucleoporins, lipids, and lipid metabolism in an integrated manner, through biochemical reconstitution and system-wide approaches. Using newly developed tools, we will reconstitute and structurally characterize the largest NPC assembly on a membrane to date, revealing how stepwise NPC assembly drives progressive membrane remodelling. This will enable us to reveal the principles of pore membrane formation. Concurrently, we will identify every lipid metabolism enzyme at the INM and use new technology to catalogue all INM lipids. This will provide a foundational reference for nuclear envelope biology and enable us to test how specific lipids impact NPCs and the cell nucleus. This proposal aims to offer pioneering insights into NPC biogenesis and how nuclear lipid metabolism affects NPC function.