Thrombospondin-1 acts as a ligand for CD148 tyrosine phosphatase
| Autor: | Vito Quaranta, Keiko Takahashi, Rebecca Weller, David B. Friedman, Nobuo Tsuboi, Hironobu Yamashita, Takamune Takahashi, Raymond L. Mernaugh |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
medicine.medical_treatment
Protein tyrosine phosphatase Biology Vascular endothelial growth inhibitor Kidney Ligands Thrombospondin 1 Cell surface receptor medicine Human Umbilical Vein Endothelial Cells Humans Cell Proliferation Multidisciplinary Cell growth Growth factor Receptor-Like Protein Tyrosine Phosphatases Class 3 Biological Sciences Cell biology Protein Structure Tertiary Vascular endothelial growth factor A Receptor-Like Protein Tyrosine Phosphatases Biochemistry Ectodomain Gene Knockdown Techniques Microvessels Extracellular Space Protein Binding |
| Popis: | CD148 is a receptor-type protein tyrosine phosphatase that is expressed in several cell types, including vascular endothelial cells and duct epithelial cells. Growing evidence demonstrates a prominent role for CD148 in negative regulation of growth factor signals, suppressing cell proliferation and transformation. However, its extracellular ligand(s) remain unknown. To identify the ligand(s) of CD148, we introduced HA-tagged CD148 into cultured endothelial cells and then isolated its interacting extracellular protein(s) by biotin surface labeling and subsequent affinity purifications. The binding proteins were identified by mass spectrometry. Here we report that soluble thrombospondin-1 (TSP1) binds to the extracellular part of CD148 with high affinity and specificity, and its binding increases CD148 catalytic activity, leading to dephosphorylation of the substrate proteins. Consistent with these findings, introduction of CD148 conferred TSP1-mediated inhibition of cell growth to cells which lack CD148 and TSP1 inhibition of growth. Further, we demonstrate that TSP1-mediated inhibition of endothelial cell growth is antagonized by soluble CD148 ectodomain as well as by CD148 gene silencing. These findings provide evidence that CD148 functions as a receptor for TSP1 and mediates its inhibition of cell growth. |
| Databáze: | OpenAIRE |
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