Required for nuclear pore complex assembly, maintenance and function (PubMed:20547758, PubMed:22718353). Required for nuclear import of phosphorylated Mad via importin msk (PubMed:20547758). Has no role in classical nuclear localization signal (cNLS)-dependent nuclear import via importin-beta (PubMed:20547758). Mediates the association between the nuclear pore complex and a subclass of silenced regions bound by Polycomb group (PcG) proteins, enables long-range interactions between Polycomb loci and contributes to repression of polycomb targets (PubMed:31784359). Together with Nup62 and Nup154, contributes to karyosome morphology and chromatin organization including attachment to the nuclear envelope in oocytes and nurse cells (PubMed:26341556). Part of the nuclear pore complex (NPC) (By similarity). Interacts with msk (via C-terminus); this association might be facilitated by Nup75 (PubMed:20547758). Interacts with Mad (preferentially when phosphorylated) (PubMed:20547758). Interacts with Nup154 (via N-terminus) (PubMed:22718353). Interacts with the Polycomb group (PcG) proteins Pc and E(z) (PubMed:31784359). When not in the nuclear pore complex, can localize to the nuclear lumen proximal to the inner nuclear membrane. RNAi-mediated knockdown in oocytes and nurse cells results in irregular distribution of chromatin to the nuclear periphery, leading to disrupted karyosome morphology (PubMed:26341556). RNAi-mediated knockdown in the wing disk results in de-repression of genes silenced by the Polycomb group proteins complexes such Abd-B (PubMed:31784359). Belongs to the nucleoporin interacting component (NIC) family.