title: Two functional forms of vascular endothelial growth factor receptor-2/Flk-1 mRNA are expressed in normal rat retina.
abstract: Vascular endothelial growth factor (VEGF) is an important mediator of ocular neovascularization by exerting its endothelial specific mitogenic effects through high affinity tyrosine kinase receptors. By screening a rat retina cDNA library, we have isolated a clone encoding the full-length prototypic form of the rat VEGF receptor-2/Flk-1, as well as a short form of the mRNA that encodes the complete seven N-terminal immunoglobulin-like extracellular ligand-binding domains, transmembrane region, NH2-terminal half of the intracellular kinase domain, and kinase insert domain but does not encode the COOH-terminal half of the intracellular kinase domain and carboxyl-terminal region. Both forms of mRNA are detected in rat retina, although the short form is expressed at a lower level. VEGF induced a biphasic increase of cytoplasmic calcium with both forms in HK 293 transfected cells, indicating that both forms of the VEGF receptor-2/Flk-1 are functional and that the COOH-terminal half of the intracellular kinase domain and carboxyl region of VEGF receptor-2/Flk-1 are not strictly necessary for either ligand binding or this biological activity.
authors.affiliation: Department of Medicine, West Los Angeles VA Medical Center, California, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Wen
authors.forename: J L
authors.initials: JL
authors.lastname: Edelman
authors.forename: T
authors.initials: T
authors.lastname: Kang
authors.forename: N
authors.initials: N
authors.lastname: Zeng
authors.forename: G
authors.initials: G
authors.lastname: Sachs
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D017978:Receptors, Growth Factor / Q000235:genetics*; D011975:Receptors, Mitogen / Q000235:genetics*; D040262:Receptors, Vascular Endothelial Growth Factor; D012160:Retina / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D011975:Receptors, Mitogen; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D002118:Calcium