title: VCAM-1 activation of endothelial cell protein tyrosine phosphatase 1B.
abstract: Lymphocytes migrate from the blood into tissue by binding to and migrating across endothelial cells. One of the endothelial cell adhesion molecules that mediate lymphocyte binding is VCAM-1. We have reported that binding to VCAM-1 activates endothelial cell NADPH oxidase for the generation of reactive oxygen species (ROS). The ROS oxidize and stimulate an increase in protein kinase C (PKC)alpha activity. Furthermore, these signals are required for VCAM-1-dependent lymphocyte migration. In this report, we identify a role for protein tyrosine phosphatase 1B (PTP1B) in the VCAM-1 signaling pathway. In primary cultures of endothelial cells and endothelial cell lines, Ab cross-linking of VCAM-1 stimulated an increase in serine phosphorylation of PTP1B, the active form of PTP1B. Ab cross-linking of VCAM-1 also increased activity of PTP1B. This activation of PTP1B was downstream of NADPH oxidase and PKCalpha in the VCAM-1 signaling pathway as determined with pharmacological inhibitors and antisense approaches. In addition, during VCAM-1 signaling, ROS did not oxidize endothelial cell PTP1B. Instead PTP1B was activated by serine phosphorylation. Importantly, inhibition of PTP1B activity blocked VCAM-1-dependent lymphocyte migration across endothelial cells. In summary, VCAM-1 activates endothelial cell NADPH oxidase to generate ROS, resulting in oxidative activation of PKCalpha and then serine phosphorylation of PTP1B. This PTP1B activity is necessary for VCAM-1-dependent transendothelial lymphocyte migration. These data show, for the first time, a function for PTP1B in VCAM-1-dependent lymphocyte migration.
authors.affiliation: Allergy-Immunology Division, Northwestern University, Feinberg School of Medicine, 240 East Huron, Chicago, IL 60611, USA.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Deem
authors.forename: Hiam
authors.initials: H
authors.lastname: Abdala-Valencia
authors.forename: Joan M
authors.initials: JM
authors.lastname: Cook-Mills
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology* / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009097:Multienzyme Complexes / Q000276:immunology / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000276:immunology / Q000378:metabolism; D010084:Oxidation-Reduction; D051571:Protein Kinase C-alpha / Q000276:immunology / Q000378:metabolism; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000276:immunology / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000276:immunology / Q000378:metabolism*
chemical_list: D009097:Multienzyme Complexes; D017382:Reactive Oxygen Species; D019010:Vascular Cell Adhesion Molecule-1; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D051571:Protein Kinase C-alpha; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; C516609:Ptpn1 protein, mouse