Pathological angiogenesis is an essential component of tumor growth, development, and metastasis for which few therapeutic options exist. Although a great deal about angiogenesis has been learned over the past several decades, it remains unclear how integral membrane receptors cooperate with one another to influence cellular signaling in response to extracellular cues. Two important families of receptors in angiogenesis, the Ties and Integrins, respond to the extracellular environment via outside-in and, in the case of Integrins, inside- out signaling. Recently, it was reported that the endothelial specific tyrosine kinase receptor, Tie2, forms complexes with two of the endothelial Integrins heterodimers, ?5?1 and ?v?3, providing a convenient clarification for the integration of extracellular stimuli. However, our preliminary studies suggest that Integrins bind to both Tie1 and Tie2 on the cellular membrane, and that binding occurs strictly through the extracellular domains. To elucidate the biological role of these interactions, biochemical and biophysical methods including co-immunoprecipitation, confocal microscopy, and FRET will be used to follow receptor/Integrin association in response to the Tie2 ligands Angiopoietin-1 and -2 as well as the Integrin ligands fibronectin, and vitronectin. Furthermore, structural determination either through x-ray crystallography or cryo-electron microscopy of an Integrin/Tie complex will identify the basis for growth factor receptor-integrin signal transduction.

Public Health Relevance

It is important to understand the complex process of angiogenesis for its multifaceted role in human afflictions, most importantly tumor growth and metastasis. Many anti-angiogenic chemotherapeutics have been pursued targeting the VEGF receptor family and the angiopoietin ligands without great success. Our goal is to characterize the interactions between endothelial specific Tie receptors and integrins as a potential therapeutic target of the tumor angiogenic switch.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
3F31CA165673-02S1
Application #
8919553
Study Section
Special Emphasis Panel (ZRG1-F04-D (20))
Program Officer
Korczak, Jeannette F
Project Start
2012-09-01
Project End
2015-05-31
Budget Start
2014-09-01
Budget End
2015-05-31
Support Year
2
Fiscal Year
2014
Total Cost
$25,074
Indirect Cost
Name
Virginia Commonwealth University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
105300446
City
Richmond
State
VA
Country
United States
Zip Code
23298
Dalton, Annamarie C; Barton, William A (2014) Over-expression of secreted proteins from mammalian cell lines. Protein Sci 23:517-25
Barton, William A; Dalton, Annamarie C; Seegar, Tom C M et al. (2014) Tie2 and Eph receptor tyrosine kinase activation and signaling. Cold Spring Harb Perspect Biol 6: