VCAM-1 activation of endothelial cell protein tyrosine phosphatase 1B.
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.
Deem
Tracy L
TL
Allergy-Immunology Division, Northwestern University, Feinberg School of Medicine, 240 East Huron, Chicago, IL 60611, USA.
Abdala-Valencia
Hiam
H
Cook-Mills
Joan M
JM
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*
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