Nuclear targeting signal recognition: a key control point in nuclear transport?
Recent progress indicates that there are multiple pathways of nucleocytoplasmic transport which involve specific targeting sequences, such as nuclear localization sequences (NLSs), and cytosolic receptor molecules of the importin/karyopherin superfamily which recognise and dock the NLS-containing proteins at the nuclear pore. This first step of nuclear import/export is of central importance, with the affinity of the importin-targeting sequence interaction a critical parameter in determining transport efficiency. Different importins possess distinct NLS-binding specificities, which allows the system to be modulated through differential expression of the importins themselves, as well as through competition between different importins for the same protein, and between different proteins for the same importin. The targeting sequence-importin interaction can also be influenced directly by phosphorylation increasing the affinity of the interaction with importins or by targeting sequence masking through phosphorylation or specific protein binding. Targeting sequence recognition thus appears to represent a key control point in the regulation of nuclear transport. BioEssays 22:532-544, 2000.
Jans
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Nuclear Signalling Lab., Division for Biochem. and Mol. Biol., John Curtin School of Medical Research, Australian National University, Canberra, Australia. David.Jans@anu.edu.au
Xiao
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Lam
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D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D001693:Biological Transport, Active; D002467:Cell Nucleus / Q000378:metabolism*; D006801:Humans; D028884:Karyopherins; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation
D028884:Karyopherins; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins