The GTP-binding protein Ran/TC4 is required for protein import into the nucleus.
Two cytosolic fractions (A and B) from Xenopus oocytes are sufficient to support protein import into the nuclei of digitonin-permeabilized cells. Fraction A recognizes the nuclear localization sequence (NLS) and binds the import substrate to the nuclear envelope, whereas fraction B mediates the subsequent passage of the bound substrate into the nucleus. Here we report that two interacting components are required for full fraction-B activity, purify one of these components to homogeneity, and show that it is the highly abundant GTP-binding protein Ran (Ras-related nuclear protein)/TC4.
Moore
M S
MS
Laboratory of Cell Biology, Howard Hughes Medical Institute, Rockefeller University, New York, New York 10021.
Blobel
G
G
D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D009865:Oocytes; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011915:Rats, Inbred BUF; D011994:Recombinant Proteins / Q000378:metabolism; D014981:Xenopus; D020931:ran GTP-Binding Protein
D006150:Guanine Nucleotides; D009687:Nuclear Proteins; D011506:Proteins; D011994:Recombinant Proteins; D019204:GTP-Binding Proteins; D020931:ran GTP-Binding Protein