Interaction between hex and GATA transcription factors in vascular endothelial cells inhibits flk-1/KDR-mediated vascular endothelial growth factor signaling.
Recent evidence supports a role for GATA transcription factors as important signal intermediates in differentiated endothelial cells. The goal of this study was to identify proteins that interact with endothelial-derived GATA transcription factors. Using yeast two-hybrid screening, we identified hematopoietically expressed homeobox (Hex) as a GATA-binding partner in endothelial cells. The physical association between Hex and GATA was confirmed with immunoprecipitation in cultured cells. Hex overexpression resulted in decreased flk-1/KDR expression, both at the level of the promoter and the endogenous gene, and attenuated vascular endothelial growth factor-mediated tube formation in primary endothelial cell cultures. In electrophoretic mobility shift assays, Hex inhibited the binding of GATA-2 to the flk-1/KDR 5'-untranslated region GATA motif. Finally, in RNase protection assays, transforming growth factor beta1, which has been previously shown to decrease flk-1 expression by interfering with GATA binding activity, was shown to increase Hex expression in endothelial cells. Taken together, the present study provides evidence for a novel association between Hex and GATA and suggests that transforming growth factor beta-mediated repression of flk-1/KDR and vascular endothelial growth factor signaling involves the inducible formation of inhibitory Hex-GATA complexes.
Minami
Takashi
T
Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan. minami@med.rcast.u-tokyo.ac.jp
Murakami
Takeshi
T
Horiuchi
Keiko
K
Miura
Mai
M
Noguchi
Tamio
T
Miyazaki
Jun-ichi
J
Hamakubo
Takao
T
Aird
William C
WC
Kodama
Tatsuhiko
T
D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D050991:GATA4 Transcription Factor; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism*; D014471:Umbilical Veins; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors* / Q000502:physiology*
D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; C484170:GATA4 protein, human; C078492:HHEX protein, human; D018398:Homeodomain Proteins; D014157:Transcription Factors; D040301:Vascular Endothelial Growth Factor Receptor-2