Figure 4. Nuclear envelope repair.

Under unperturbed conditions, the inner nuclear membrane protein LEMD2 and the endoplasmic reticulum‐associated protein CHMP7 are spatially separated because CHMP7 is actively exported out of the nucleus through nuclear pore complexes (NPCs). Following rupture, unphosphorylated cytosolic BAF coats the exposed chromatin. Interaction of BAF with integral membrane LEM‐domain proteins facilitates recruitment of nuclear membrane and decreases the size of the rupture. Subsequently, the CHMP7 and LEMD2 interaction promotes nucleation and polymerization of ESCRT‐III, which together with the regulatory ATPase VPS4 further constricts the rupture and promotes sealing.