TY - JOUR
T1 - p68RacGAP is a novel GTPase-activating protein that interacts with vascular endothelial zinc finger-1 and modulates endothelial cell capillary formation
AU - Aitsebaomo, Julius
AU - Wennerberg, Krister
AU - Der, Channing J
AU - Zhang, Chunlian
AU - Kedar, Vishram
AU - Moser, Martin
AU - Kingsley-Kallesen, Michelle L
AU - Zeng, Guo-Qing
AU - Patterson, Cam
PY - 2004/4/23
Y1 - 2004/4/23
N2 - The endothelium is required for maintenance of vascular integrity and homeostasis during vascular development and in adulthood. However, little is known about the coordinated interplay between transcription factors and signaling molecules that regulate endothelial cell-dependent transcriptional events. Vascular endothelial zinc finger-1 (Vezf1) is a zinc finger-containing transcription factor that is specifically expressed within the endothelium during vascular development. We have previously shown that Vezf1 potently activates transcription of the endothelin-1 promoter. We now report the identification of p68RacGAP, a novel Vezf1-interacting 68-kDa RhoGAP domain-containing protein. p68RacGAP mRNA is highly expressed in vascular endothelial cells by Northern blot analysis, and immunohistochemical staining of adult mouse tissues identified p68RacGAP in endothelial cells, vascular smooth muscle cells, and epithelial cells in vivo. Rac1 and Vezf1 both bind avidly to p68RacGAP, suggesting that p68RacGAP is not only a GTPase-activating protein for Rac1 but that p68RacGAP may also be part of the protein complex that binds to and modulates Vezf1 transcriptional activity. Functionally p68RacGAP specifically activates the GTPase activity of Rac1 in vivo but not Cdc42 or RhoA. In addition, p68RacGAP potently inhibits Vezf1/DB1-mediated transcriptional activation of the human endothelin-1 promoter and modulates endothelial cell capillary tube formation. Taken together, these data suggest that p68RacGAP is a multifunctional regulatory protein that has a Rac1-specific GTPase-activating activity, regulates transcriptional activity of the endothelin-1 promoter, and is involved in the signal transduction pathway that regulates endothelial cell capillary tube formation during angiogenesis.
AB - The endothelium is required for maintenance of vascular integrity and homeostasis during vascular development and in adulthood. However, little is known about the coordinated interplay between transcription factors and signaling molecules that regulate endothelial cell-dependent transcriptional events. Vascular endothelial zinc finger-1 (Vezf1) is a zinc finger-containing transcription factor that is specifically expressed within the endothelium during vascular development. We have previously shown that Vezf1 potently activates transcription of the endothelin-1 promoter. We now report the identification of p68RacGAP, a novel Vezf1-interacting 68-kDa RhoGAP domain-containing protein. p68RacGAP mRNA is highly expressed in vascular endothelial cells by Northern blot analysis, and immunohistochemical staining of adult mouse tissues identified p68RacGAP in endothelial cells, vascular smooth muscle cells, and epithelial cells in vivo. Rac1 and Vezf1 both bind avidly to p68RacGAP, suggesting that p68RacGAP is not only a GTPase-activating protein for Rac1 but that p68RacGAP may also be part of the protein complex that binds to and modulates Vezf1 transcriptional activity. Functionally p68RacGAP specifically activates the GTPase activity of Rac1 in vivo but not Cdc42 or RhoA. In addition, p68RacGAP potently inhibits Vezf1/DB1-mediated transcriptional activation of the human endothelin-1 promoter and modulates endothelial cell capillary tube formation. Taken together, these data suggest that p68RacGAP is a multifunctional regulatory protein that has a Rac1-specific GTPase-activating activity, regulates transcriptional activity of the endothelin-1 promoter, and is involved in the signal transduction pathway that regulates endothelial cell capillary tube formation during angiogenesis.
KW - Amino Acid Sequence
KW - Animals
KW - Base Sequence
KW - Blotting, Northern
KW - Bradykinin/metabolism
KW - COS Cells
KW - Capillaries/metabolism
KW - Cell Line
KW - Endothelial Cells/cytology
KW - Endothelin-1/genetics
KW - Endothelium, Vascular/metabolism
KW - GTPase-Activating Proteins/chemistry
KW - Green Fluorescent Proteins
KW - Immunohistochemistry
KW - Kruppel-Like Transcription Factors
KW - Luciferases/metabolism
KW - Luminescent Proteins/metabolism
KW - Lysophospholipids/metabolism
KW - Mice
KW - Models, Genetic
KW - Molecular Sequence Data
KW - Mutagenesis, Site-Directed
KW - NIH 3T3 Cells
KW - Neovascularization, Pathologic
KW - Phylogeny
KW - Plasmids/metabolism
KW - Platelet-Derived Growth Factor/metabolism
KW - Precipitin Tests
KW - Promoter Regions, Genetic
KW - Protein Binding
KW - Protein Structure, Tertiary
KW - RNA/metabolism
KW - RNA, Messenger/metabolism
KW - Signal Transduction
KW - Tissue Distribution
KW - Transcription Factors/metabolism
KW - Transcription, Genetic
KW - Transfection
KW - Two-Hybrid System Techniques
U2 - 10.1074/jbc.M311721200
DO - 10.1074/jbc.M311721200
M3 - Journal article
C2 - 14966113
SN - 0021-9258
VL - 279
SP - 17963
EP - 17972
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 17
ER -