The crystal structure of Cellular Repressor of E1A-stimulated Genes (CREG)

Experimental Data Snapshot

  • Resolution: 1.95 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.162 
  • R-Value Observed: 0.163 

wwPDB Validation   3D Report Full Report

This is version 1.2 of the entry. See complete history


The crystal structure of CREG, a secreted glycoprotein involved in cellular growth and differentiation

Sacher, M.Di Bacco, A.Lunin, V.V.Ye, Z.Wagner, J.Gill, G.Cygler, M.

(2005) Proc Natl Acad Sci U S A 102: 18326-18331

  • DOI: https://doi.org/10.1073/pnas.0505071102
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein that inhibits proliferation and enhances differentiation of human embryonal carcinoma cells. CREG binds to the cation-independent mannose 6-phosphate (M6P)/insulin-like growth factor II (IGF2) receptor (IGF2R) (M6P/IGF2R), and this receptor has been shown to be required for CREG-induced growth suppression. To better understand CREG function in cellular growth and differentiation, we solved the 3D crystal structure of this protein to 1.9-A resolution. CREG forms a tight homodimeric complex, and CREG monomers display a beta-barrel fold. The three potential glycosylation sites on CREG map to a confined patch opposite the dimer interface. Thus, dimerization of glycosylated CREG likely presents a bivalent ligand for the M6P/IGF2R. Closely related structural homologs of CREG are FMN-binding split-barrel fold proteins that bind flavin mononucleotide. Our structure shows that the putative flavin mononucleotide-binding pocket in CREG is sterically blocked by a loop and several key bulky residues. A mutant of CREG lacking a part of this loop maintained overall structure and dimerization, as well as M6P/IGF2R binding, but lost the growth suppression activity of WT CREG. Thus, analysis of a structure-based mutant of CREG revealed that binding to M6P/IGF2R, while necessary, is not sufficient for CREG-induced growth suppression. These findings indicate that CREG utilizes a known fold for a previously undescribed function [corrected]

  • Organizational Affiliation

    Montreal Proteomics Network, 740 Doctor Penfield, Montreal, QC, Canada H3A 1A4. michael.sacher@bri.nrc.ca

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cellular Repressor of E1A-stimulated Genes
A, B, C, D
184Homo sapiensMutation(s): 4 
UniProt & NIH Common Fund Data Resources
Find proteins for O75629 (Homo sapiens)
Explore O75629 
Go to UniProtKB:  O75629
PHAROS:  O75629
GTEx:  ENSG00000143162 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO75629
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
A, B, C, D
Experimental Data & Validation

Experimental Data

  • Resolution: 1.95 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.162 
  • R-Value Observed: 0.163 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.13α = 90
b = 121.26β = 90
c = 55.92γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-11-15
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance