N-ethylmaleimide-sensitive factor is associated with the nuclear envelope

N-Ethylmaleimide-sensitive factor (NSF) is an ATPase involved in many membr ane fusion events within the exocytic and endocytotic pathways. In the pres ent study we showed that NSF is associated with the nuclear envelope. Golgi -associated NSF was released from membranes upon incubation with Mg2+-ATP, reflecting the disassembly of a complex consisting of NSF, soluble NSF atta chment proteins (SNAPs), and SNAP receptors (SNAREs), In contrast nuclear e nvelope-associated NSF in interphase cells was not released by the same tre atment. During mitosis, however, it was released from nuclear membranes by Mg2+-ATP. These results suggest that the binding mode of nuclear membrane-a ssociated NSF changes during the cell cycle, (C) 2000 Academic Press.