Biological Assembly 1  

 3D View: Structure | 1D-3D View | Validation Report | Predict Membrane 

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 14.83 kDa 
• Atom Count: 1045 
• Modelled Residue Count: 133 
• Deposited Residue Count: 133 
• Unique protein chains: 2

2KNC

Platelet integrin ALFAIIB-BETA3 transmembrane-cytoplasmic heterocomplex

• PDB DOI: 10.2210/pdb2KNC/pdb
• BMRB: 16496

• Classification: CELL ADHESION
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 
• Membrane Protein: Yes  OPMPDBTMMemProtMDmpstruc


• Deposited: 2009-08-20 Released: 2009-09-29 
• Deposition Author(s): Yang, J., Ma, Y., Page, R.C., Misra, S., Plow, E.F., Qin, J.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 98 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 

Literature

Structure of an integrin alphaIIb beta3 transmembrane-cytoplasmic heterocomplex provides insight into integrin activation.

Yang, J., Ma, Y.Q., Page, R.C., Misra, S., Plow, E.F., Qin, J.

(2009) Proc Natl Acad Sci U S A 106: 17729-17734

• PubMed: 19805198 
• DOI: 10.1073/pnas.0909589106
• Primary Citation of Related Structures:  
  2KNC


• PubMed Abstract: 
  

Heterodimeric integrin adhesion receptors regulate diverse biological processes including angiogenesis, thrombosis and wound healing. The transmembrane-cytoplasmic domains (TMCDs) of integrins play a critical role in controlling activation of these receptors via an inside-out signaling mechanism, but the precise structural basis remains elusive. Here, we present the solution structure of integrin alphaIIb beta3 TMCD heterodimer, which reveals a right-handed coiled-coil conformation with 2 helices intertwined throughout the transmembrane region. The helices extend into the cytoplasm and form a clasp that differs significantly from a recently published alphaIIb beta3 TMCD structure. We show that while a point mutation in the clasp interface modestly activates alphaIIb beta3, additional mutations in the transmembrane interface have a synergistic effect, leading to extensive integrin activation. Detailed analyses and structural comparison with previous studies suggest that extensive integrin activation is a highly concerted conformational transition process, which involves transmembrane coiled-coil unwinding that is triggered by the membrane-mediated alteration and disengagement of the membrane-proximal clasp. Our results provide atomic insight into a type I transmembrane receptor heterocomplex and the mechanism of integrin inside-out transmembrane signaling.

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Organizational Affiliation: 

Department of Molecular Cardiology NB20, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Integrin alpha-IIb	A	54	Homo sapiens	Mutation(s): 0  Gene Names: ITGA2B, GP2B, ITGAB Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for P08514 (Homo sapiens) Explore P08514  Go to UniProtKB:  P08514
PHAROS:  P08514 GTEx:  ENSG00000005961

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Integrin beta-3	B	79	Homo sapiens	Mutation(s): 0  Gene Names: ITGB3, GP3A Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for P05106 (Homo sapiens) Explore P05106  Go to UniProtKB:  P05106
PHAROS:  P05106 GTEx:  ENSG00000259207

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 98 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 
• OLDERADO: 2KNC Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2009-08-20 
• Released Date: 2009-09-29 
Deposition Author(s): Yang, J., Ma, Y., Page, R.C., Misra, S., Plow, E.F., Qin, J.

Revision History  

• Version 1.0: 2009-09-29
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2011-08-10
  Changes: Database references
• Version 1.3: 2020-02-26
  Changes: Data collection, Database references, Other
• Version 1.4: 2021-08-18
  Changes: Data collection, Database references, Experimental preparation, Structure summary