4EZA

Crystal structure of the atypical phosphoinositide (aPI) binding domain of IQGAP2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.210 
  • R-Value Observed: 0.210 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

IQGAP Proteins Reveal an Atypical Phosphoinositide (aPI) Binding Domain with a Pseudo C2 Domain Fold.

Dixon, M.J.Gray, A.Schenning, M.Agacan, M.Tempel, W.Tong, Y.Nedyalkova, L.Park, H.W.Leslie, N.R.van Aalten, D.M.Downes, C.P.Batty, I.H.

(2012) J Biol Chem 287: 22483-22496

  • DOI: 10.1074/jbc.M112.352773
  • Primary Citation of Related Structures:  
    4EZA

  • PubMed Abstract: 
  • Class I phosphoinositide (PI) 3-kinases act through effector proteins whose 3-PI selectivity is mediated by a limited repertoire of structurally defined, lipid recognition domains. We describe here the lipid preferences and crystal structure of a new cla ...

    Class I phosphoinositide (PI) 3-kinases act through effector proteins whose 3-PI selectivity is mediated by a limited repertoire of structurally defined, lipid recognition domains. We describe here the lipid preferences and crystal structure of a new class of PI binding modules exemplified by select IQGAPs (IQ motif containing GTPase-activating proteins) known to coordinate cellular signaling events and cytoskeletal dynamics. This module is defined by a C-terminal 105-107 amino acid region of which IQGAP1 and -2, but not IQGAP3, binds preferentially to phosphatidylinositol 3,4,5-trisphosphate (PtdInsP(3)). The binding affinity for PtdInsP(3), together with other, secondary target-recognition characteristics, are comparable with those of the pleckstrin homology domain of cytohesin-3 (general receptor for phosphoinositides 1), an established PtdInsP(3) effector protein. Importantly, the IQGAP1 C-terminal domain and the cytohesin-3 pleckstrin homology domain, each tagged with enhanced green fluorescent protein, were both re-localized from the cytosol to the cell periphery following the activation of PI 3-kinase in Swiss 3T3 fibroblasts, consistent with their common, selective recognition of endogenous 3-PI(s). The crystal structure of the C-terminal IQGAP2 PI binding module reveals unexpected topological similarity to an integral fold of C2 domains, including a putative basic binding pocket. We propose that this module integrates select IQGAP proteins with PI 3-kinase signaling and constitutes a novel, atypical phosphoinositide binding domain that may represent the first of a larger group, each perhaps structurally unique but collectively dissimilar from the known PI recognition modules.


    Organizational Affiliation

    Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dow St., Dundee DD1 5EH, Scotland, United Kingdom.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Ras GTPase-activating-like protein IQGAP2 AB114Homo sapiensMutation(s): 0 
Gene Names: IQGAP2
Find proteins for Q13576 (Homo sapiens)
Explore Q13576 
Go to UniProtKB:  Q13576
NIH Common Fund Data Resources
PHAROS:  Q13576
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.210 
  • R-Value Observed: 0.210 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.067α = 90
b = 47.234β = 95.51
c = 46.631γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SHELXphasing
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report



Entry History 

Revision History 

  • Version 1.0: 2012-05-16
    Type: Initial release
  • Version 1.1: 2012-07-18
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description