Matrix-specific Activation of Src and Rho Initiates Capillary Morphogenesis of Endothelial Cells

FASEB J. 2004 Mar;18(3):457-68. doi: 10.1096/fj.03-0948com.


Interstitial collagen I stimulates microvascular endothelial cells to form solid cords that imitate precapillary structures found during angiogenesis. Time-lapse microscopy identified cell retraction and disruption of cell-cell contacts as early critical steps in collagen I-induced capillary morphogenesis. These early stages paralleled collagen I activation of Src kinase and GTPase Rho through beta1 integrins. The Src inhibitor PP2, dominant-negative Src, and Rho inhibitor exoenzyme C3 transferase each inhibited collagen I induction of actin stress fibers that mediate cell retraction and each inhibited capillary morphogenesis. Collagen I also disrupted VE-cadherin from intercellular junctions through a Src-dependent mechanism; both the Src inhibitor PP2 and dominant-negative Src preserved VE-cadherin localization to regions of cell-cell contact. An active Src mutant disrupted VE-cadherin and cell-cell contacts similarly to collagen I. In sharp contrast, laminin-1 did not induce capillary morphogenesis, and laminin-1 did not induce activation of Src or Rho. Rather, laminin-1 induced persistent activation of the GTPase Rac. Thus, these studies identify activation of Src and Rho as key mechanisms by which collagen I provokes capillary morphogenesis of microvascular endothelial cells, and they define marked differences between the functions of collagen I and laminin-1 in regulating endothelial cell morphogenesis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ADP Ribose Transferases / pharmacology
  • Amino Acid Substitution
  • Animals
  • Antigens, CD
  • Botulinum Toxins / pharmacology
  • Cadherins / metabolism
  • Capillaries / cytology*
  • Chickens
  • Collagen Type I / physiology*
  • Endothelial Cells / drug effects
  • Endothelial Cells / ultrastructure
  • Endothelium, Vascular / cytology*
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Intercellular Junctions / drug effects
  • Laminin / pharmacology
  • Microscopy, Video
  • Morphogenesis / physiology
  • Mutation, Missense
  • Point Mutation
  • Proto-Oncogene Proteins pp60(c-src) / antagonists & inhibitors
  • Proto-Oncogene Proteins pp60(c-src) / genetics
  • Proto-Oncogene Proteins pp60(c-src) / physiology*
  • Pyrimidines / pharmacology
  • Stress Fibers / ultrastructure
  • rhoA GTP-Binding Protein / antagonists & inhibitors
  • rhoA GTP-Binding Protein / physiology*


  • AG 1879
  • Antigens, CD
  • Cadherins
  • Collagen Type I
  • Enzyme Inhibitors
  • Laminin
  • Pyrimidines
  • cadherin 5
  • laminin 1
  • ADP Ribose Transferases
  • exoenzyme C3, Clostridium botulinum
  • Proto-Oncogene Proteins pp60(c-src)
  • Botulinum Toxins
  • rhoA GTP-Binding Protein