title: G-protein-coupled receptor-2-interacting protein-1 is required for endothelial cell directional migration and tumor angiogenesis via cortactin-dependent lamellipodia formation.
abstract: OBJECTIVE
  Recent evidence suggests G-protein-coupled receptor-2-interacting protein-1 (GIT1) overexpression in several human metastatic tumors, including breast, lung, and prostate. Tumor metastasis is associated with an increase in angiogenesis. We have showed previously that GIT1 is required for postnatal angiogenesis during lung development. However, the functional role of GIT1 in pathological angiogenesis during tumor growth is unknown.
  
  
  RESULTS
  In the present study, we show inhibition of angiogenesis in matrigel implants as well as reduced tumor angiogenesis and melanoma tumor growth in GIT1-knockout mice. We demonstrate that this is a result of impaired directional migration of GIT1-depleted endothelial cells toward a vascular endothelial growth factor gradient. Cortactin-mediated lamellipodia formation in the leading edge is critical for directional migration. We observed a significant reduction in cortactin localization and lamellipodia formation in the leading edge of GIT1-depleted endothelial cells. We specifically identified that the Spa homology domain (aa 250-420) of GIT1 is required for GIT1-cortactin complex localization to the leading edge. The mechanisms involved extracellular signal-regulated kinases 1 and 2-mediated Cortactin-S405 phosphorylation and activation of Rac1/Cdc42. Finally, using gain of function studies, we show that a constitutively active mutant of cortactin restored directional migration of GIT1-depleted cells.
  
  
  CONCLUSIONS
  Our data demonstrated that a GIT1-cortactin association through GIT1-Spa homology domain is required for cortactin localization to the leading edge and is essential for endothelial cell directional migration and tumor angiogenesis.
authors.affiliation: From the Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY (S.M., M.P.S., T.T., C.K.C., A.M. G.Y., B.C.B., J.P.); and Department of Microbiology & Immunology, University of Rochester Medical Center, Rochester, NY (S.A.G., E.M.L.).
authors.forename: Syamantak
authors.initials: S
authors.lastname: Majumder
authors.forename: Mark P
authors.initials: MP
authors.lastname: Sowden
authors.forename: Scott A
authors.initials: SA
authors.lastname: Gerber
authors.forename: Tamlyn
authors.initials: T
authors.lastname: Thomas
authors.forename: Christine K
authors.initials: CK
authors.lastname: Christie
authors.forename: Amy
authors.initials: A
authors.lastname: Mohan
authors.forename: Guoyong
authors.initials: G
authors.lastname: Yin
authors.forename: Edith M
authors.initials: EM
authors.lastname: Lord
authors.forename: Bradford C
authors.initials: BC
authors.lastname: Berk
authors.forename: Jinjiang
authors.initials: J
authors.lastname: Pang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D018797:Cell Cycle Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement; D051356:Cortactin / Q000235:genetics / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008546:Melanoma, Experimental / Q000098:blood supply / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; 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; D009389:Neovascularization, Pathologic; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D011554:Pseudopodia / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction; D012983:Soft Tissue Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors; D014162:Transfection; D047368:Tumor Burden; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C495868:CTTN protein, human; D018797:Cell Cycle Proteins; D051356:Cortactin; C495869:Cttn protein, mouse; C485647:GIT1 protein, human; D020690:GTPase-Activating Proteins; C120766:Git1 protein, mouse; D042461:Vascular Endothelial Growth Factor A; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein
keywords: G-protein–coupled receptor kinase; cortactin; endothelial cells; interacting protein-1; tumor angiogenesis