3KND

TPX2:importin-alpha complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.185 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Novel binding of the mitotic regulator TPX2 (target protein for Xenopus kinesin-like protein 2) to importin-alpha.

Giesecke, A.Stewart, M.

(2010) J Biol Chem 285: 17628-17635

  • DOI: 10.1074/jbc.M110.102343
  • Primary Citation of Related Structures:  
    3KND

  • PubMed Abstract: 
  • Several aspects of mitotic spindle assembly are orchestrated by the Ran GTPase through its modulation of the interaction between spindle assembly factors and importin-alpha. One such factor is TPX2 that promotes microtubule assembly in the vicinity of chromosomes ...

    Several aspects of mitotic spindle assembly are orchestrated by the Ran GTPase through its modulation of the interaction between spindle assembly factors and importin-alpha. One such factor is TPX2 that promotes microtubule assembly in the vicinity of chromosomes. TPX2 is inhibited when bound to importin-alpha, which occurs when the latter is bound to importin-beta. The importin-alpha:beta interaction is disrupted by the high RanGTP concentration near the chromosomes, releasing TPX2. In more distal regions, where Ran is predominantly GDP-bound, TPX2 remains bound to importin-alpha and so is inhibited. Here we use a combination of structural and biochemical methods to define the basis for TPX2 binding to importin-alpha. A 2.2 A resolution crystal structure shows that the primary nuclear localization signal ((284)KRKH(287)) of TPX2, which has been shown to be crucial for inhibition, binds to the minor NLS-binding site on importin-alpha. This atypical interaction pattern was confirmed using complementary binding studies that employed importin-alpha variants in which binding to either the major or minor NLS-binding site was impaired, together with competition assays using the SV40 monopartite NLS that binds primarily to the major site. The different way in which TPX2 binds to importin-alpha could account for much of the selectivity necessary during mitosis because this would reduce the competition for binding to importin-alpha from other NLS-containing proteins.


    Organizational Affiliation

    Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Importin subunit alpha-2A460Mus musculusMutation(s): 0 
Gene Names: importin alpha 2Kpna2Rch1
UniProt & NIH Common Fund Data Resources
Find proteins for P52293 (Mus musculus)
Explore P52293 
Go to UniProtKB:  P52293
IMPC:  MGI:103561
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Targeting protein for Xklp2B81Xenopus laevisMutation(s): 0 
Gene Names: TPX2tpx2-a
UniProt
Find proteins for Q6NUF4 (Xenopus laevis)
Explore Q6NUF4 
Go to UniProtKB:  Q6NUF4
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.185 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78.527α = 90
b = 89.317β = 90
c = 99.273γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 2009-11-12 
  • Released Date: 2010-03-23 
  • Deposition Author(s): Stewart, M.

Revision History  (Full details and data files)

  • Version 1.0: 2010-03-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2012-12-26
    Changes: Database references
  • Version 1.3: 2017-11-01
    Changes: Refinement description