Ubiquitination of basal VEGFR2 regulates signal transduction and endothelial function

• Published in: Biology open Vol. 6; no. 10; pp. 1404 - 1415
• Main Authors: Smith, Gina A, Fearnley, Gareth W, Abdul-Zani, Izma, Wheatcroft, Stephen B, Tomlinson, Darren C, Harrison, Michael A, Ponnambalam, Sreenivasan
• Format: Journal Article
• Language: English
• Published: England The Company of Biologists Ltd 15-10-2017; The Company of Biologists
• Subjects: Activation; Angiogenesis; Availability; Cell adhesion & migration; Cell migration; Cell proliferation; Cell surface; Decision making; Degradation; Depletion; Endosomes; Endothelial; Endothelial cells; Extracellular signal-regulated kinase; Growth factors; Kinases; Membrane trafficking; Membranes; Protein turnover; Protein-tyrosine kinase receptors; Proteolysis; Receptor mechanisms; Receptors; Signal transduction; Signaling; Tyrosine; UBA1; Ubiquitin; Ubiquitination; Vascular endothelial growth factor; Vascular endothelial growth factor receptor 2; VEGF-A; VEGFR2; VEGFR2; Angiogenesis; Signal transduction; Ubiquitination; Endothelial; UBA1; VEGF-A
• ISSN: 2046-6390; 2046-6390
• DOI: 10.1242/bio.027896

Cell surface receptors can undergo recycling or proteolysis but the cellular decision-making events that sort between these pathways remain poorly defined. Vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor receptor 2 (VEGFR2) regulate signal transduction and angiogenesis, but how signaling and proteolysis is regulated is not well understood. Here, we provide evidence that a pathway requiring the E1 ubiquitin-activating enzyme UBA1 controls basal VEGFR2 levels, hence metering plasma membrane receptor availability for the VEGF-A-regulated endothelial cell response. VEGFR2 undergoes VEGF-A-independent constitutive degradation via a UBA1-dependent ubiquitin-linked pathway. Depletion of UBA1 increased VEGFR2 recycling from endosome-to-plasma membrane and decreased proteolysis. Increased membrane receptor availability after UBA1 depletion elevated VEGF-A-stimulated activation of key signaling enzymes such as PLCγ1 and ERK1/2. Although UBA1 depletion caused an overall decrease in endothelial cell proliferation, surviving cells showed greater VEGF-A-stimulated responses such as cell migration and tubulogenesis. Our study now suggests that a ubiquitin-linked pathway regulates the balance between receptor recycling and degradation which in turn impacts on the intensity and duration of VEGF-A-stimulated signal transduction and the endothelial response.