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. Active directional transport is assured by both, a Phe-Gly (FG) repeat affinity gradient for these transport factors across the NPC and a transport cofactor concentration gradient across the nuclear envelope (GSP1 and GSP2 GTPases associated predominantly with GTP in the nucleus, with GDP in the cytoplasm). NSP1 plays an important role in several nuclear transport pathways including poly(A)+ RNA, tRNA, pre-ribosome, signal recognition particle (SRP), and protein transport. 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. NSP1 interacts alternatively with NUP82 or NUP57 through its C-terminal coiled coil in two distinct NPC subcomplexes, the NUP82 subcomplex and the NUP57 subcomplex (NIC96, NSP1, NUP49, NUP57). The NUP82 subcomplex is the base for interactions with NUP116 and GLE2 and with NUP42 and GLE1. Interacts through its FG repeats with karyopherins, such as KAP95, KAP123, PSE1, LOS1, NTF2, the heterodimeric mRNA transport factor MEX67/MTR2, and GSP1. Symmetric distribution. Contains FG repeats. FG repeats are interaction sites for karyopherins (importins, exportins) and form probably an affinity gradient, guiding the transport proteins unidirectionally with their cargo through the NPC. FG repeat regions are highly flexible and lack ordered secondary structure. The overall conservation of FG repeats regarding exact sequence, spacing, and repeat unit length is limited. FG repeat types and their physico-chemical environment change across the NPC from the nucleoplasmic to the cytoplasmic side. Present with 2400 molecules/cell in log phase SD medium. Belongs to the nucleoporin NSP1/NUP62 family.