Model of the mechanism of NPC transmission to daughter cells. (A) In wild-type cells, a diffusion barrier at the bud neck is established (orange). (B) We envision that the delivery of Nsp1_CYT (green triangles) to the daughter through a mechanism that requires Myo2 and an association with ER (blue, which bind the daughter cortex through the exocyst complex [grey box]) licenses NPC passage by disrupting the diffusion barrier. (C) Forces applied to the mother NE through NP and/or spindle elongation result in the transmission of NPCs (red ovals). Under conditions in which Nsp1_CYT is inhibited or Myo2 function is impaired, the barrier remains intact and restricts the passage of NPCs, leading to the specific loss of viability of daughter cells. De novo NPC assembly continues as indicated by the white ovals.