@article {442,
	title = {Structural and mechanistic insights into VEGF receptor 3 ligand binding and activation},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {110},
	year = {2013},
	month = {08/2013},
	pages = {12960 - 12965},
	abstract = {Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key drivers of blood and lymph vessel formation in development, but also in several pathological processes. VEGF-C signaling through VEGFR-3 promotes lymphangiogenesis, which is a clinically relevant target for treating lymphatic insufficiency and for blocking tumor angiogenesis and metastasis. The extracellular domain of VEGFRs consists of seven Ig homology domains; domains 1-3 (D1-3) are responsible for ligand binding, and the membrane-proximal domains 4-7 (D4-7) are involved in structural rearrangements essential for receptor dimerization and activation. Here we analyzed the crystal structures of VEGF-C in complex with VEGFR-3 domains D1-2 and of the VEGFR-3 D4-5 homodimer. The structures revealed a conserved ligand-binding interface in D2 and a unique mechanism for VEGFR dimerization and activation, with homotypic interactions in D5. Mutation of the conserved residues mediating the D5 interaction (Thr446 and Lys516) and the D7 interaction (Arg737) compromised VEGF-C induced VEGFR-3 activation. A thermodynamic analysis of VEGFR-3 deletion mutants showed that D3, D4-5, and D6-7 all contribute to ligand binding. A structural model of the VEGF-C/VEGFR-3 D1-7 complex derived from small-angle X-ray scattering data is consistent with the homotypic interactions in D5 and D7. Taken together, our data show that ligand-dependent homotypic interactions in D5 and D7 are essential for VEGFR activation, opening promising possibilities for the design of VEGFR-specific drugs.},
	isbn = {1091-6490},
	doi = {10.1073/pnas.1301415110},
	url = {http://www.pnas.org/content/110/32/12960.long}
}
@article {45,
	title = {Structural determinants of vascular endothelial growth factor-D receptor binding and specificity},
	journal = {Blood},
	volume = {117},
	year = {2011},
	month = {2011/Feb/},
	pages = {1507 - 15},
	abstract = {Vascular endothelial growth factors (VEGFs) and their tyrosine kinase receptors (VEGFR-1-3) are central mediators of angiogenesis and lymphangiogenesis. VEGFR-3 ligands VEGF-C and VEGF-D are produced as precursor proteins with long N- and C-terminal propeptides and show enhanced VEGFR-2 and VEGFR-3 binding on proteolytic removal of the propeptides. Two different proteolytic cleavage sites have been reported in the VEGF-D N-terminus. We report here the crystal structure of the human VEGF-D Cys117Ala mutant at 2.9 {\r A} resolution. Comparison of the VEGF-D and VEGF-C structures shows similar extended N-terminal helices, conserved overall folds, and VEGFR-2 interacting residues. Consistent with this, the affinity and the thermodynamic parameters for VEGFR-2 binding are very similar. In comparison with VEGF-C structures, however, the VEGF-D N-terminal helix was extended by 2 more turns because of a better resolution. Both receptor binding and functional assays of N-terminally truncated VEGF-D polypeptides indicated that the residues between the reported proteolytic cleavage sites are important for VEGF-D binding and activation of VEGFR-3, but not of VEGFR-2. Thus, we define here a VEGFR-2-specific form of VEGF-D that is angiogenic but not lymphangiogenic. These results provide important new insights into VEGF-D structure and function.},
	url = {http://view.ncbi.nlm.nih.gov/pubmed/21148085},
	author = {Lepp{\"a}nen, Veli-Matti and Jeltsch, Michael and Anisimov, Andrey and Tvorogov, Denis and Aho, Kukka and Kalkkinen, Nisse and Toivanen, Pyry and Yl{\"a}-Herttuala, Seppo and Ballmer-Hofer, Kurt and Alitalo, Kari}
}
