Transport across the nuclear envelope: enigmas and explanations.
The transport of molecules across the nuclear envelope plays a central role in the metabolism of the cell. Significant advances in three major areas highlight the limits of our current knowledge and point to the prospect of exciting future developments. Firstly, findings that ions and small proteins do not diffuse freely into the nucleus call into question the current views of nuclear envelope permeability. Secondly, indications that nuclear protein import can be regulated in conjunction with the cell cycle and development have been confirmed by the clear demonstration of regulated nuclear entry of specific transcription factors and morphogens. Thirdly, identification and characterisation of candidate receptor proteins indicates that the recognition of the nuclear targeting sequence occurs in the cytoplasm, suggesting that a different recognition event occurs at the nuclear pore.
Dingwall
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MRC Laboratory of Molecular Biology, Cambridge, UK.
D000818:Animals; D001692:Biological Transport; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000378:metabolism; D002463:Cell Membrane Permeability; D003593:Cytoplasm / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism; D006801:Humans; D007477:Ions; D008099:Liver / Q000378:metabolism; D051379:Mice; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism
D002352:Carrier Proteins; D006657:Histones; D007477:Ions; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface