3KND

TPX2:importin-alpha complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.151 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.182 

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

  • 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 o ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Importin subunit alpha-2
A
460Mus musculusMutation(s): 0 
Gene Names: Kpna2 (Rch1)
Find proteins for P52293 (Mus musculus)
Go to UniProtKB:  P52293
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Targeting protein for Xklp2
B
81Xenopus laevisMutation(s): 0 
Gene Names: tpx2-a
Find proteins for Q6NUF4 (Xenopus laevis)
Go to UniProtKB:  Q6NUF4
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.151 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.182 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 78.527α = 90.00
b = 89.317β = 90.00
c = 99.273γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
SCALAdata scaling
MOSFLMdata reduction
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

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

Revision History 

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