Mapping of the Sites Involved in Ligand Association and Dissociation at the Extracellular Domain of the Kinase Insert Domain-containing Receptor for Vascular Endothelial Growth Factor

ABSTRACT. Angiogenesis is an essential biological process not only in embryogenesis but also in the progression of a variety of major diseases such as cancer, diabetes and inflammation. Vascular endothelial growth factor (VEGF) family and its receptor system has been shown to be the fundamental regulator in the cell signaling of angiogenesis. Other systems, Angiopoietin-Tie and EphrinB2-Eph4B etc. are also involved in and cooperate with VEGF system to establish the dynamic blood vessel structures. VEGF receptor belongs to PDGF receptor supergene family, and carries seven Ig-domains in the extracellular region and a tyrosine kinase domain in the intracellular region. Three members of VEGF receptor family, Flt-1, KDR/Flk-1 and Flt-4, have unique characteristics in terms of the signal transduction, and regulate angiogenesis, lymphangiongenesis and vascular permeability. Further studies on VEGF-VEGF receptor system may significantly facilitate our understanding on the physiological as well as pathological vascular systems in the body and the development of new strategies to control and suppress the major diseases in humans.

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“…We also showed that the 4th to 7th Ig regions are essential for the receptor dimerization (Tanaka et al, 1997;Shinkai et al, 1998).…”

Section: Structure Of Vegf Receptorsmentioning

confidence: 92%

Structure and Function of VEGF/VEGF-receptor System Involved in Angiogenesis.

Shibuya

2001

Cell Struct. Funct.

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463

343

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“…A previous binding study indicated that both D4 and D5 increase the affinity of VEGFR-2 for VEGF-A. Compared with D1-3, D1-5 showed 86-fold greater affinity and D1-4 showed 16-fold greater affinity (34). Similarly, both D4 and D4-5 of VEGFR-1 have been shown to enhance ligand-induced receptor dimerization in cross-linking experiments (35).…”

Section: Discussionmentioning

confidence: 99%

Structural and mechanistic insights into VEGF receptor 3 ligand binding and activation

Leppänen

Tvorogov

Kisko

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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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.signal transduction | receptor tyrosine kinase V EGFs stimulate angiogenesis and lymphangiogenesis via VEGF receptors (VEGFRs) in endothelial cells. VEGF-A signaling is mediated predominantly through activation of VEGFR-2, resulting in sprouting of blood vessels from preexisting vasculature (1). In contrast, VEGFR-1 seems to have an inhibitory role by sequestering VEGF-A and thereby preventing its interaction with VEGFR-2 (2). On the other hand, VEGFR-3 plays an indispensable role in lymphangiogenesis (3). VEGFRs are involved in various pathological conditions, including solid tumor growth, tumor metastasis, and vascular retinopathies (4, 5).VEGF-C and VEGF-D compose a VEGFR-3-specific subfamily of VEGFs. They are produced with large N-and C-terminal propeptides and gain activity toward VEGFR-3 and VEGFR-2 on proteolytic processing (reviewed in ref. 5). VEGFR-3 maturation involves proteolytic cleavage of the extracellular domain (ECD) in D5 (6-8). Both VEGF-C and VEGFR-3 also interact with the coreceptor neuropilin-2 (9). Loss of the Vegfc gene results in embryonic lethality owing to a lack of lymphatic vessel formation (10), whereas mutations that interfere with VEGFR-3 signaling have been associated with hereditary lymphedema, and mice deficient in Vegfr3 die in utero due to abnormal development of the blood vasculature (11, 12). VEGFR-3 and its heterodimers with VEGFR-2 are also important for sprouting angiogenesis and vascular network formation (13-15).VEGFRs are type V rece...

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“…KDR 7N carrying the N-terminal 1st to 7th Ig-like domains and KDR 5 d 1N carrying the 2nd to 5th Ig-like domains of KDR fused with the Fc portion of an IgG (KDR 7N-Fc and KDR 5 d 1N-Fc, respectively) were obtained as described previously (Shinkai et al, 1998). The production of anti-human Flt-1 mAbs including KM1750 (mouse IgG2b) and anti-human KDR mAbs including KM1992 (mouse IgG1) will be described elsewhere (M Ito et al, in preparation).…”

Section: Anti-vegf Receptors Mabsmentioning

confidence: 99%