The nuclear envelope is a membrane system which surrounds the nucleoplasm of eukaryotic cells. It is composed of the nuclear lamina, nuclear pore complexes and two nuclear membranes. The space between the two membranes is called the nuclear intermembrane space.
The nuclear pore complex (NPC) constitutes the exclusive means of nucleocytoplasmic transport. NPCs allow the passive diffusion of ions and small molecules and the active bidirectional transport of macromolecules such as proteins, RNAs etc across the double-membrane nuclear envelope.The NPC is composed of at least 30 distinct subunits known as Nucleoporins (NUPs).
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 (PubMed:15116432). Nup189 is autocatalytically cleaved in vivo in 2 polypeptides which assume different functions in the NPC (PubMed:26137436). Nup98 as one of the FG repeat nucleoporins participates in karyopherin interactions and contains part of the autocatalytic cleavage activity. Nup96 as part of the NUP84 complex is involved in nuclear poly(A)+ RNA and tRNA export (By similarity). {By
SimilarityUniProtKB:P49687, Experimental EvidencePubMed:15116432, Experimental EvidencePubMed:26137436}.
National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory