Tyrosine phosphorylation of paxillin/pp125FAK and microvascular endothelial barrier function.
The transendothelial movement of solutes is a dynamic process controlled by a complex interaction between the cytoskeleton and adhesion proteins. The aim of this study was to examine whether protein tyrosine phosphorylation is involved in the regulation of endothelial barrier function. The apparent permeability coefficient of albumin (Pa) was measured in isolated and perfused coronary venules. Tyrosine phosphatase inhibitors, including phenylarsine oxide and sodium orthovanadate, dose and time dependently increased basal Pa. Western blot analysis of cultured coronary venular endothelial cells revealed that inhibition of tyrosine phosphatase induced an increase in phosphotyrosine content in a number of proteins, including bands at 65-70 and 120-130 kDa, which were identified as paxillin and focal adhesion kinase (pp125FAK), respectively. The time course and dose responsiveness of protein tyrosine phosphorylation were tightly correlated with those of increases in Pa. Furthermore, stimulation of endothelial cells with histamine or phorbol myristate acetate (PMA) enhanced tyrosine phosphorylation of paxillin and pp125FAK, which was blocked by the tyrosine kinase inhibitor damnacanthal. Correspondingly, the increases in venular permeability elicited by histamine and PMA were abolished in damnacanthal-treated venules. Taken together, the data suggest a possible involvement of protein tyrosine phosphorylation in the control of endothelial barrier function. Paxillin and its associated focal adhesion proteins may play a specific role in agonist-induced hyperpermeability responses in the endothelium of exchange vessels.
Yuan
Y
Y
Department of Surgery, Texas A & M University Health Science Center, Temple, Texas 76504, USA.
Meng
F Y
FY
Huang
Q
Q
Hawker
J
J
Wu
H M
HM
D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D002199:Capillary Permeability / Q000187:drug effects; D002417:Cattle; D015815:Cell Adhesion Molecules / Q000302:isolation & purification / Q000378:metabolism*; D003326:Coronary Circulation / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D051419:Paxillin; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism; D013552:Swine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014699:Venules / Q000502:physiology*
D001152:Arsenicals; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D004791:Enzyme Inhibitors; D051419:Paxillin; D010750:Phosphoproteins; C029341:oxophenylarsine; D019000:Phosphotyrosine; D006632:Histamine; D011505:Protein-Tyrosine Kinases; D011972:Receptor, Insulin; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases; D013755:Tetradecanoylphorbol Acetate