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Thermodynamic and structural description of allosterically regulated VEGFR-2 dimerization.
Brozzo, Maurice S; Bjelic, Sasa; Kisko, Kaisa; Schleier, Thomas; Leppänen, Veli-Matti; Alitalo, Kari; Winkler, Fritz K; Ballmer-Hofer, Kurt.
Afiliação
  • Brozzo MS; Biomolecular Research, Molecular Cell Biology Paul Scherrer Institut, Villigen, Switzerland.
Blood ; 119(7): 1781-8, 2012 Feb 16.
Article em En | MEDLINE | ID: mdl-22207738
VEGFs activate 3 receptor tyrosine kinases, VEGFR-1, VEGFR-2, and VEGFR-3, promoting angiogenic and lymphangiogenic signaling. The extracellular receptor domain (ECD) consists of 7 Ig-homology domains; domains 2 and 3 (D23) represent the ligand-binding domain, whereas the function of D4-7 is unclear. Ligand binding promotes receptor dimerization and instigates transmembrane signaling and receptor kinase activation. In the present study, isothermal titration calorimetry showed that the Gibbs free energy of VEGF-A, VEGF-C, or VEGF-E binding to D23 or the full-length ECD of VEGFR-2 is dominated by favorable entropic contribution with enthalpic penalty. The free energy of VEGF binding to the ECD is 1.0-1.7 kcal/mol less favorable than for binding to D23. A model of the VEGF-E/VEGFR-2 ECD complex derived from small-angle scattering data provided evidence for homotypic interactions in D4-7. We also solved the crystal structures of complexes between VEGF-A or VEGF-E with D23, which revealed comparable binding surfaces and similar interactions between the ligands and the receptor, but showed variation in D23 twist angles. The energetically unfavorable homotypic interactions in D4-7 may be required for re-orientation of receptor monomers, and this mechanism might prevent ligand-independent activation of VEGFR-2 to evade the deleterious consequences for blood and lymph vessel homeostasis arising from inappropriate receptor activation.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Termodinâmica / Receptor 2 de Fatores de Crescimento do Endotélio Vascular / Multimerização Proteica Tipo de estudo: Prognostic_studies Limite: Animals / Humans Idioma: En Ano de publicação: 2012 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Termodinâmica / Receptor 2 de Fatores de Crescimento do Endotélio Vascular / Multimerização Proteica Tipo de estudo: Prognostic_studies Limite: Animals / Humans Idioma: En Ano de publicação: 2012 Tipo de documento: Article