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 membrane surrounding the nucleus. This term is used when it is not known if the protein is found in or associated with the inner or outer nuclear membrane.
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 (GSP1 and GSP2 GTPases associated predominantly with GTP in the nucleus, with GDP in the cytoplasm). As one of the FG repeat nucleoporins NUP1 is involved in interactions with and guidance of nuclear transport receptors such as SRP1-KAP95 (importin alpha and beta) through the NPC. Like the closely related NUP2 it also plays an important role in disassembling and recycling SRP1-KAP95 to the cytoplasm after nuclear import. Upon entry of the heterotrimeric SRP1- KAP95-cargo complex in the nucleus, NUP1 binds through its C-terminus to KAP95, thus accelerating the release of KAP95 and, indirectly, of the nuclear localization signal (NLS)-containing cargo from the SRP1- KAP95-cargo complex. {Experimental EvidencePubMed:10684247, Experimental EvidencePubMed:11046143, Experimental EvidencePubMed:11387327, Experimental EvidencePubMed:11535617, Experimental EvidencePubMed:11867631, Experimental EvidencePubMed:12372823, Experimental EvidencePubMed:12543930, Experimental EvidencePubMed:12604785, Experimental EvidencePubMed:12917401, Experimental EvidencePubMed:15039779}.
DNA-directed RNA polymerases I, II, and III subunit RPABC2 (RNA polymerases I, II, and III subunit ABC2) (ABC23) (DNA-directed RNA polymerases I, II, and III 23 kDa polypeptide)
National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory