5TBK

Crystal structure of human importin a3 bound to RCC1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.45 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.278 
  • R-Value Observed: 0.278 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Three-dimensional context rather than NLS amino acid sequence determines importin alpha subtype specificity for RCC1.

Sankhala, R.S.Lokareddy, R.K.Begum, S.Pumroy, R.A.Gillilan, R.E.Cingolani, G.

(2017) Nat Commun 8: 979-979

  • DOI: 10.1038/s41467-017-01057-7
  • Primary Citation of Related Structures:  
    5T94, 5TBK

  • PubMed Abstract: 
  • Active nuclear import of Ran exchange factor RCC1 is mediated by importin α3. This pathway is essential to generate a gradient of RanGTP on chromatin that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. Here we identify the mechanisms of importin α3 selectivity for RCC1 ...

    Active nuclear import of Ran exchange factor RCC1 is mediated by importin α3. This pathway is essential to generate a gradient of RanGTP on chromatin that directs nucleocytoplasmic transport, mitotic spindle assembly and nuclear envelope formation. Here we identify the mechanisms of importin α3 selectivity for RCC1. We find this isoform binds RCC1 with one order of magnitude higher affinity than the generic importin α1, although the two isoforms share an identical NLS-binding groove. Importin α3 uses its greater conformational flexibility to wedge the RCC1 β-propeller flanking the NLS against its lateral surface, preventing steric clashes with its Armadillo-core. Removing the β-propeller, or inserting a linker between NLS and β-propeller, disrupts specificity for importin α3, demonstrating the structural context rather than NLS sequence determines selectivity for isoform 3. We propose importin α3 evolved to recognize topologically complex NLSs that lie next to bulky domains or are masked by quaternary structures.Importin α3 facilitates the nuclear transport of the Ran guanine nucleotide exchange factor RCC1. Here the authors reveal the molecular basis for the selectivity of RCC1 for importin α3 vs the generic importin α1 and discuss the evolution of importin α isoforms.


    Organizational Affiliation

    Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, Bari, 70126, Italy. gino.cingolani@jefferson.edu.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Importin subunit alpha-3A, B, C, D, E, F, G, H521Homo sapiensMutation(s): 0 
Gene Names: KPNA4QIP1
Find proteins for O00629 (Homo sapiens)
Explore O00629 
Go to UniProtKB:  O00629
NIH Common Fund Data Resources
PHAROS:  O00629
Protein Feature View
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Regulator of chromosome condensationI, P [auth J], J [auth K], K [auth L], L [auth M], M [auth N], N [auth O], O [auth P]421Homo sapiensMutation(s): 0 
Gene Names: RCC1CHC1
Find proteins for P18754 (Homo sapiens)
Explore P18754 
Go to UniProtKB:  P18754
NIH Common Fund Data Resources
PHAROS:  P18754
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.45 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.278 
  • R-Value Observed: 0.278 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.403α = 75.65
b = 162.494β = 85.63
c = 161.592γ = 72.17
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM074846
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM100888

Revision History  (Full details and data files)

  • Version 1.0: 2017-09-13
    Type: Initial release
  • Version 1.1: 2017-10-04
    Changes: Author supporting evidence
  • Version 1.2: 2017-11-01
    Changes: Author supporting evidence, Database references
  • Version 1.3: 2019-12-25
    Changes: Author supporting evidence