G-protein-coupled receptor kinase interacting protein-1 is required for pulmonary vascular development.
BACKGROUND
The G-protein-coupled receptor kinase interacting protein-1 (GIT1) is a multidomain scaffold protein that participates in many cellular functions including receptor internalization, focal adhesion remodeling, and signaling by both G-protein-coupled receptors and tyrosine kinase receptors. However, there have been no in vivo studies of GIT1 function to date.


RESULTS
To determine essential functions of GIT1 in vivo, we generated a traditional GIT1 knockout mouse. GIT1 knockout mice exhibited approximately 60% perinatal mortality. Pathological examination showed that the major abnormality in GIT1 knockout mice was impaired lung development characterized by markedly reduced numbers of pulmonary blood vessels and increased alveolar spaces. Given that vascular endothelial growth factor (VEGF) is essential for pulmonary vascular development, we investigated the role of GIT1 in VEGF signaling in the lung and cultured endothelial cells. Because activation of phospholipase-Cgamma (PLCgamma) and extracellular signal-regulated kinases 1/2 (ERK1/2) by angiotensin II requires GIT1, we hypothesized that GIT1 mediates VEGF-dependent pulmonary angiogenesis by modulating PLCgamma and ERK1/2 activity in endothelial cells. In cultured endothelial cells, knockdown of GIT1 decreased VEGF-mediated phosphorylation of PLCgamma and ERK1/2. PLCgamma and ERK1/2 activity in lungs from GIT1 knockout mice was reduced postnatally.


CONCLUSIONS
Our data support a critical role for GIT1 in pulmonary vascular development by regulating VEGF-induced PLCgamma and ERK1/2 activation.
Pang
Jinjiang
J
Aab Cardiovascular Research Institute and the Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
Hoefen
Ryan
R
Pryhuber
Gloria S
GS
Wang
Jing
J
Yin
Guoyong
G
White
R James
RJ
Xu
Xiangbin
X
O'Dell
Michael R
MR
Mohan
Amy
A
Michaloski
Heidi
H
Massett
Michael P
MP
Yan
Chen
C
Berk
Bradford C
BC
D000818:Animals; D000831:Animals, Newborn; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051966:Phospholipase C gamma / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D011650:Pulmonary Alveoli / Q000002:abnormalities* / Q000098:blood supply / Q000502:physiology; D011651:Pulmonary Artery / Q000002:abnormalities* / Q000502:physiology; D011652:Pulmonary Circulation; D011667:Pulmonary Veins / Q000002:abnormalities* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D015996:Survival Rate; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D018797:Cell Cycle Proteins; D020690:GTPase-Activating Proteins; C120766:Git1 protein, mouse; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D004247:DNA; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D051966:Phospholipase C gamma