VCAM-1 activation of endothelial cell protein tyrosine phosphatase 1B

Tracy L. Deem, Hiam Abdala-Valencia, Joan M. Cook-Mills*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


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)α 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 PKCα 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 PKCα and then serine phosphorylation of PTP1B. This PTP1B activity is necessary for VCAM-1-dependent trans-endothelial lymphocyte migration. These data show, for the first time, a function for PTP1B in VCAM-1-dependent lymphocyte migration.

Original languageEnglish (US)
Pages (from-to)3865-3873
Number of pages9
JournalJournal of Immunology
Issue number6
StatePublished - Mar 15 2007

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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