Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 278, Issue 51, Pages 51267-51276Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M310678200
Keywords
-
Categories
Funding
- NHLBI NIH HHS [1R01HL65978-01] Funding Source: Medline
Ask authors/readers for more resources
Tumor necrosis factor (TNF), via its receptor 2 (TNFR2), induces Etk (or Bmx) activation and Etk-dependent endothelial cell (EC) migration and tube formation. Because TNF receptor 2 lacks an intrinsic kinase activity, we examined the kinase(s) mediating TNF-induced Etk activation. TNF induces a coordinated phosphorylation of vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) and Etk, which is blocked by VEGFR2-specific inhibitors. In response to TNF, Etk and VEGFR2 form a complex resulting in a reciprocal activation between the two kinases. Subsequently, the downstream phosphatidylinositol 3-kinase (PI3K)-Akt signaling (but not signaling through phospholipase C-gamma) was initiated and directly led to TNF-induced EC migration, which was significantly inhibited by VEGFR2-, PI3K-, or Akt-specific inhibitors. Phosphorylation of VEGFR2 at Tyr-801 and Tyr-1175, the critical sites for VEGF-induced PI3K-Akt signaling, was not involved in TNF-mediated Akt activation. However, TNF induces phosphorylation of Etk at Tyr-566, directly mediating the recruitment of the p85 subunit of PI3K. Furthermore, TNF- but not VEGF-induced activation of VEGFR2, Akt, and EC migration are blunted in EC genetically deficient with Etk. Taken together, our data demonstrated that TNF induces transactivation between Etk and VEGFR2, and Etk directly activates PI3K- Akt angiogenic signaling independent of VEGF-induced VEGFR2- PI3K- Akt signaling pathway.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available