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).
Nucleoporins may be involved in both binding and translocation of the proteins during nucleocytoplasmic transport. In S.pombe it is required for the nuclear localization of retrotransposon tf1. {Experimental EvidencePubMed:10409764}.
National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory