As a compartment border, the nuclear envelope (NE) needs to serve as both a protective membrane shell for the genome and a versatile communication interface between the nucleus and the cytoplasm. Despite its important structural role in sheltering the genome, the NE is a dynamic and highly adaptable boundary that changes composition during differentiation, deforms in response to mechanical challenges, can be repaired upon rupture and even rapidly disassembles and reforms during open mitosis. NE remodelling is fundamentally involved in cell growth, division and differentiation, and if perturbed can lead to devastating diseases such as muscular dystrophies or premature ageing.