The nucleocytoplasmic transport of macromolecules is dependent on specific targeting signals that are recognised by members of the importin (IMP) superfamily of transport molecules that mediate translocation through the nuclear envelope‑localised nuclear pore complex. Recent evidence implicates...

Steroid hormone receptors are ligand‑regulated transcription factors that undergo translation in the cytoplasm and translocation into the nucleus. Nuclear import of steroid hormone receptors depends on a bipartite nuclear localization signal (NLS) encoded within the DNA binding domain (DBD) and...

In human cells, the majority of nucleocytoplasmic transport is mediated by 19 members of the Karyopherinβ (Kapβs/Importins/Exportins) protein family. Thus, Kapβs are critically involved in cellular processes such as gene expression, signal transduction, immune response, oncogenesis and viral...

Ribosomes are some of the bulkiest and most abundant ribonucleoprotein complexes (RNPs) in cells. They are assembled within the nucleus but function in translation in the cytoplasm and thus must be exported out of the nucleus through the nuclear pore complexes (NPCs). This chapter will present...

MRNA export is an indispensable step during the complex process of eukaryotic gene expression: the mRNA, created by RNA polymerase II in the nucleus, has to be transported to the cytoplasm, where the ribosomes are responsible for the synthesis of the encoded protein. This transport process is not...

The biogenesis of spliceosomal UsnRNPs in higher eukaryotes requires a cytoplasmic maturation step. After transcription and initial processing in the nucleus, the snRNAs U1, U2, U4 and U5 are exported to the cytoplasm in an m7G‑Cap dependent manner utilising the PHAX/CRM1 dependent pathway. In...

Transport of proteins and ribonucleoprotein particles between the nucleus and the cytoplasm occurs via nuclear pore complexes (NPCs) that are embedded in the double membrane of the nuclear envelope (NE). Major advances have been made in recent years to improve the structural resolution of the...

TRNA trafficking between the nucleus and cytoplasm is a complex process that plays an essential role in protein synthesis, regulation of cell division, nutrient‑related regulation of gene expression, replication of the HIV genome and neuronal development. In eukaryotes tRNAs are made as...

Imaging of single fluorescent proteins or ribonucleoprotein particles within cells is a showcase of vital functions at the molecular level. Single‑molecule detection within live cells can be performed with a spatial precision in the nanometer range and a time resolution in the millisecond...

Nuclear transport receptors (NTRs) ferry signal‑bearing cargos to and fro between the nucleus and cytoplasm. Translocation occurs through the central channel of the nuclear pore complex (NPC), which is guarded by scores of FG‑nups. A major unresolved conceptual problem in the nuclear...

Compared to the extremely large volume of work that has been done on the structure of the nuclear pore complex and transport through its central channel, the question of how integral membrane proteins get to the inner nuclear membrane has been largely ignored. Three distinct mechanisms have been...

The existence of a membrane barrier between the nucleus and the cytoplasm in eukaryotic cells necessitates an efficient transport system for macromolecules between the two compartments. Transported molecules carry signals that mediate interaction with a large variety of receptor proteins. These...