Nuclear pore complexes (NPCs) fuse the two membranes of the nuclear envelope 
(NE) to a pore, connecting cytoplasm and nucleoplasm and allowing exchange of 
macromolecules between these compartments. Most NPC proteins do not contain 
integral membrane domains and thus it is largely unclear how NPCs are embedded 
and anchored in the NE. Here, we show that the evolutionary conserved nuclear 
pore protein Nup53 binds independently of other proteins to membranes, a 
property that is crucial for NPC assembly and conserved between yeast and 
vertebrates. The vertebrate protein comprises two membrane binding sites, of 
which the C-terminal domain has membrane deforming capabilities, and is 
specifically required for de novo NPC assembly and insertion into the intact NE 
during interphase. Dimerization of Nup53 contributes to its membrane interaction 
and is crucial for its function in NPC assembly.