Loss of nuclear envelope integrity? No probLEM-BAF has it covered

Abstract

Ruptures of the nuclear envelope can drive a catastrophic loss of nucleocytoplasmic compartmentalization. In this issue, Halfmann et al. (2019. J. Cell Biol. https://doi.org/10.1083/jcb.201901116) describe a mechanism for surveilling the integrity of the nuclear barrier and coupling the sensing of nuclear ruptures to the recruitment of the nuclear envelope repair machinery.

Figure 1.

Nuclear envelope repair requires two phases, surveillance and nuclear envelope sealing. Loss of nuclear integrity is surveilled by BAF, which is only exposed to chromatin in its dephosphorylated form at sites of nuclear envelope rupture. BAF also promotes nuclear envelope sealing by locally recruiting LEM proteins, including LEMD2, which is an adapter for engaging CHMP7 and additional ESCRT components.