Abstract
TAP-p15 heterodimers have been implicated in the export of mRNAs through nuclear pore complexes (NPCs). We report a structural analysis of the interaction domains of TAP and p15 in a ternary complex with a Phe-Gly (FG) repeat of an NPC component. The TAP-p15 heterodimer is structurally similar to the homodimeric transport factor NTF2, but unlike NTF2, it is incompatible with either homodimerization or Ran binding. The NTF2-like heterodimer functions as a single structural unit in recognizing an FG repeat at a hydrophobic pocket present only on TAP and not on p15. This FG binding site interacts synergistically with a second site at the C terminus of TAP to mediate mRNA transport through the pore. In general, our findings suggest that FG repeats bind with a similar conformation to different classes of transport factors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP Binding Cassette Transporter, Subfamily B, Member 2
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ATP-Binding Cassette Transporters / chemistry*
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ATP-Binding Cassette Transporters / metabolism
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Active Transport, Cell Nucleus / physiology*
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Amino Acid Sequence
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Animals
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Binding Sites
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Carrier Proteins / chemistry*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Crystallography, X-Ray
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Dimerization
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Humans
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Models, Molecular
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Molecular Sequence Data
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Mutagenesis, Site-Directed
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Nuclear Pore / chemistry*
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Nuclear Pore / metabolism
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Nuclear Proteins / chemistry*
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Nucleocytoplasmic Transport Proteins*
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Protein Binding
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Protein Structure, Tertiary
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RNA, Messenger / genetics
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RNA, Messenger / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Sequence Alignment
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ran GTP-Binding Protein / metabolism
Substances
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ATP Binding Cassette Transporter, Subfamily B, Member 2
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ATP-Binding Cassette Transporters
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Carrier Proteins
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NXT1 protein, human
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Nuclear Proteins
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Nucleocytoplasmic Transport Proteins
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RNA, Messenger
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Recombinant Fusion Proteins
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TAP1 protein, human
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ran GTP-Binding Protein