Functions as a component of the nuclear pore complex (NPC). NPC components, collectively referred to as nucleoporins (NUPs), can play the role of both NPC structural components and of docking or interaction partners for transiently associated nuclear transport factors. NUP170 probably plays an important role in NPC assembly and organization. In addition it is required for chromosome transmission fidelity. Component of the nuclear pore complex (NPC). NPC constitutes the exclusive means of nucleocytoplasmic transport. NPCs allow the passive diffusion of ions and small molecules and the active, nuclear transport receptor-mediated bidirectional transport of macromolecules such as proteins, RNAs, ribonucleoparticles (RNPs), and ribosomal subunits across the nuclear envelope. Due to its 8-fold rotational symmetry, all subunits are present with 8 copies or multiples thereof. During mitosis NUP53 changes its binding partner within the NPC from NUP170 to NIC96, exposing a high affinity binding site for the karyopherin PSE1, and retaining it in the NPC. Symmetric distribution. Present with 1560 molecules/cell in log phase SD medium. Belongs to the non-repetitive/WGA-negative nucleoporin family.