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Transport Into and Out of the Nucleus
The nuclear envelope contains numerous nuclear pore complexes (NPCs), which are large, complex structures composed of multiple copies of 30 different proteins called nucleoporins (see Figure 13-33). FG-
Transport of macromolecules larger than 40 kDa through nuclear pores requires the assistance of nuclear transport receptors that interact with both the transported molecule and FG-
Proteins imported into or exported from the nucleus contain a specific amino acid sequence that functions as a nuclear-
Several different types of NESs and NLSs have been identified. Each type of nuclear-
A cargo protein bearing an NES or NLS translocates through nuclear pores bound to its cognate nuclear transport receptor. The transient interactions between nuclear transport receptors and FG-
The unidirectional nature of protein export and import through nuclear pores results from the participation of Ran, a monomeric G protein that exists in different conformations when bound to GTP or GDP. Localization of the Ran guanine nucleotide exchange factor (Ran-
Most mRNPs are exported from the nucleus by binding to a heterodimeric mRNP exporter in the nucleoplasm that interacts with FG-