title: Functional interaction of VEGF-C and VEGF-D with neuropilin receptors.
abstract: Lymphatic vascular development is regulated by vascular endothelial growth factor receptor-3 (VEGFR-3), which is activated by its ligands VEGF-C and VEGF-D. Neuropilin-2 (NP2), known to be involved in neuronal development, has also been implicated to play a role in lymphangiogenesis. We aimed to elucidate the mechanism by which NP2 is involved in lymphatic endothelial cell signaling. By in vitro binding studies we found that both VEGF-C and VEGF-D interact with NP2, VEGF-C in a heparin-independent and VEGF-D in a heparin-dependent manner. We also mapped the domains of VEGF-C and NP2 required for their binding. The functional importance of the interaction of NP2 with the lymphangiogenic growth factors was demonstrated by cointernalization of NP2 along with VEGFR-3 in endocytic vesicles of lymphatic endothelial cells upon stimulation with VEGF-C or VEGF-D. NP2 also interacted with VEGFR-3 in coprecipitation studies. Our results show that NP2 is directly involved in an active signaling complex with the key regulators of lymphangiogenesis and thus suggest a mechanism by which NP2 functions in the development of the lymphatic vasculature.
authors.affiliation: Molecular/Cancer Biology Laboratory and Ludwig Institute for Cancer Research, Biomedicum Helsinki, P.O.B. 63, FI-00014 University of Helsinki, Helsinki, Finland.
authors.forename: Terhi
authors.initials: T
authors.lastname: Kärpänen
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Heckman
authors.forename: Salla
authors.initials: S
authors.lastname: Keskitalo
authors.forename: Michael
authors.initials: M
authors.lastname: Jeltsch
authors.forename: Hanna
authors.initials: H
authors.lastname: Ollila
authors.forename: Gera
authors.initials: G
authors.lastname: Neufeld
authors.forename: Luca
authors.initials: L
authors.lastname: Tamagnone
authors.forename: Kari
authors.initials: K
authors.lastname: Alitalo
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D004330:Drosophila; D004730:Endothelium, Vascular / Q000502:physiology; D006493:Heparin / Q000502:physiology; D006801:Humans; D007668:Kidney; D008208:Lymphatic System / Q000502:physiology; D008969:Molecular Sequence Data; D018919:Neovascularization, Physiologic; D039943:Neuropilin-2 / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D042582:Vascular Endothelial Growth Factor C / Q000235:genetics / Q000378:metabolism*; D042643:Vascular Endothelial Growth Factor D / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D039943:Neuropilin-2; D011994:Recombinant Proteins; D042582:Vascular Endothelial Growth Factor C; D042643:Vascular Endothelial Growth Factor D; D006493:Heparin