Importin-11, a nuclear import receptor for the ubiquitin-conjugating enzyme, UbcM2.

Importins are members of a family of transport receptors (karyopherins) that mediate the nucleocytoplasmic transport of protein and RNA cargoes. We identified importin-11 as a potential new human member of this family, on the basis of limited similarity to the Saccharomyces cerevisiae protein, Lph2p, and cloned the complete open reading ...
frame. Importin-11 interacts with the Ran GTPase, and constitutively shuttles between the nuclear and cytoplasmic compartments. A yeast dihybrid screen identified UbcM2, an E2-type ubiquitin-conjugating enzyme, as a binding partner and potential transport cargo for importin-11. Importin-11 and UbcM2 interact directly, and the complex is disassembled by Ran:GTP but not by Ran:GDP. UbcM2 is constitutively nuclear and shuttles between the nuclear and cytoplasmic compartments. Nuclear import of UbcM2 requires Ran and importin-11, and is inhibited by wheatgerm agglutinin, energy depletion or dominant interfering mutants of Ran and importin-beta. These data establish importin-11 as a new member of the karyopherin family of transport receptors, and identify UbcM2 as a nuclear member of the E2 ubiquitin-conjugating enzyme family.
Mesh Terms:
Active Transport, Cell Nucleus, Amino Acid Sequence, Animals, Carrier Proteins, Cell Line, Cell Membrane Permeability, Cell Nucleus, Cloning, Molecular, Cytoplasm, Fluorescent Antibody Technique, Guanosine Triphosphate, Humans, Karyopherins, Ligases, Mice, Molecular Sequence Data, Mutation, Nuclear Proteins, Phylogeny, Protein Binding, RNA, Messenger, Ubiquitins, ran GTP-Binding Protein
EMBO J.
Date: Oct. 16, 2000
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