title: Protein tyrosine phosphatase-dependent proteolysis of focal adhesion complexes in endothelial cell apoptosis.
abstract: Adenosine and/or homocysteine causes endothelial cell apoptosis, a mechanism requiring protein tyrosine phosphatase (PTPase) activity. We investigated the role of focal adhesion contact disruption in adenosine-homocysteine endothelial cell apoptosis. Analysis of focal adhesion kinase (FAK), paxillin, and vinculin demonstrated disruption of focal adhesion complexes after 4 h of treatment with adenosine-homocysteine followed by caspase-induced proteolysis of FAK, paxillin, and p130(CAS). No significant changes were noted in tyrosine phosphorylation of FAK or paxillin. Pretreatment with the caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone prevented adenosine-homocysteine-induced DNA fragmentation and FAK, paxillin, and p130(CAS) proteolysis. Asp-Glu-Val-Asp-ase activity was detectable in endothelial cells after 4 h of treatment with adenosine-homocysteine. The PTPase inhibitor sodium orthovanadate did not prevent endothelial cell retraction or FAK, paxillin, or vinculin redistribution. Sodium orthovanadate did block adenosine-homocysteine-induced FAK, paxillin, and p130(CAS) proteolysis and Asp-Glu-Val-Asp-ase activity. Thus disruption of focal adhesion contacts and caspase-induced degradation of focal adhesion contact proteins occurs in adenosine-homocysteine endothelial cell apoptosis. Focal adhesion contact disruption induced by adenosine-homocysteine is independent of PTPase or caspase activation. These studies demonstrate that disruption of focal adhesion contacts is an early, but not an irrevocable, event in endothelial cell apoptosis.
authors.affiliation: Pulmonary/Critical Care Medicine Section, Providence Veterans Affairs Medical Center, and Department of Medicine, Brown University School of Medicine, Providence, Rhode Island 02908, USA.
authors.forename: E O
authors.initials: EO
authors.lastname: Harrington
authors.forename: A
authors.initials: A
authors.lastname: Smeglin
authors.forename: J
authors.initials: J
authors.lastname: Newton
authors.forename: G
authors.initials: G
authors.lastname: Ballard
authors.forename: S
authors.initials: S
authors.lastname: Rounds
mesh_terms: D000241:Adenosine / Q000633:toxicity; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002417:Cattle; D050719:Crk-Associated Substrate Protein; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D005455:Fluorescent Antibody Technique; D051416:Focal Adhesion Protein-Tyrosine Kinases; D022001:Focal Adhesions / Q000378:metabolism*; D006710:Homocysteine / Q000633:toxicity; D006868:Hydrolysis; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors; D010766:Phosphorylation / Q000187:drug effects; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D014443:Tyrosine; D014638:Vanadates / Q000494:pharmacology; D016596:Vinculin / Q000378:metabolism
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D050719:Crk-Associated Substrate Protein; D015853:Cysteine Proteinase Inhibitors; D003598:Cytoskeletal Proteins; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D006710:Homocysteine; D016596:Vinculin; D014638:Vanadates; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases; D020169:Caspases; D000241:Adenosine