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The adhesion molecule PECAM-1 enhances the TGF-β-mediated inhibition of T cell function. Sci Signal 2016 Mar 08;9(418):ra27



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Pubmed Central ID




Scopus ID

2-s2.0-84960380725   7 Citations


Transforming growth factor-β (TGF-β) is an immunosuppressive cytokine that inhibits the proinflammatory functions of T cells, and it is a major factor in abrogating T cell activity against tumors. Canonical TGF-β signaling results in the activation of Smad proteins, which are transcription factors that regulate target gene expression. We found that the cell surface molecule platelet endothelial cell adhesion molecule-1 (PECAM-1) facilitated noncanonical (Smad-independent) TGF-β signaling in T cells. Subcutaneously injected tumor cells that are dependent on TGF-β-mediated suppression of immunity for growth grew more slowly in PECAM-1(-/-) mice than in their wild-type counterparts. T cells isolated from PECAM-1(-/-) mice demonstrated relative insensitivity to the TGF-β-dependent inhibition of interferon-γ (IFN-γ) production, granzyme B synthesis, and cellular proliferation. Similarly, human T cells lacking PECAM-1 demonstrated decreased sensitivity to TGF-β in a manner that was partially restored by reexpression of PECAM-1. Co-incubation of T cells with TGF-β and a T cell-activating antibody resulted in PECAM-1 phosphorylation on an immunoreceptor tyrosine-based inhibitory motif (ITIM) and the recruitment of the inhibitory Src homology 2 (SH2) domain-containing tyrosine phosphatase-2 (SHP-2). Such conditions also induced the colocalization of PECAM-1 with the TGF-β receptor complex as identified by coimmunoprecipitation, confocal microscopy, and proximity ligation assays. These studies indicate a role for PECAM-1 in enhancing the inhibitory functions of TGF-β in T cells and suggest that therapeutic targeting of the PECAM-1-TGF-β inhibitory axis represents a means to overcome TGF-β-dependent immunosuppression within the tumor microenvironment.

Author List

Newman DK, Fu G, Adams T, Cui W, Arumugam V, Bluemn T, Riese MJ


Weiguo Cui PhD Associate Professor in the Microbiology and Immunology department at Medical College of Wisconsin
Debra K. Newman PhD Investigator in the Blood Research Institute department at BloodCenter of Wisconsin
Debra K. Newman PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Matthew J. Riese MD, PhD Associate Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Motifs
Mice, Knockout
Platelet Endothelial Cell Adhesion Molecule-1
Protein Tyrosine Phosphatase, Non-Receptor Type 11
Receptors, Transforming Growth Factor beta
Smad Proteins
Transforming Growth Factor beta
jenkins-FCD Prod-411 e00897e83867fcfa48419861683711f8d99adb75