Protein modifications during angiogenesis
New blood vessel formation, also known as angiogenesis, is involved in different physiological and pathological processes such as cancer and ischaemia. Protein phosphorylation is implicated in angiogenesis especially at tyrosine residues. Although the role of protein-tyrosine kinases (PTKs) is well established, little is known about protein-tyrosine phosphatases (PTPs) and how they function during angiogenesis. Previous work had indicated changes in PTP expression in endothelial cells upon exposure to angiogenic stimuli. The aim of the EU-funded ‘Role of protein-tyrosine phosphatases in angiogenesis’ (PTPS IN Angiogenesis) project was to further elucidate the biological roles of specific PTPs in endothelial cells in vitro and in vivo. After assessing the expression of specific PTPs in endothelial cells, scientists used specific loss-of-function experiments to test the role of PTPN14 and PTP1B in endothelial cells embedded in three-dimensional (3D) spheroid cultures. Results showed no significant effect of knockdown of these PTPs in vitro or in vivo, suggesting a level of redundancy among PTPs in angiogenesis. Additionally, these findings indicated the need for knocking down more than one PTP in order to determine their function in endothelial cells. PTPS IN Angiogenesis provided useful insight into the role of PTPs in the process of angiogenesis. Project results have the potential to serve as the basis for designing anti-angiogenic strategies to prevent the detrimental effect of post-ischaemic events or cancer metastasis.
