Angiogenesis relies on endothelial cells properly processing signals from growth factors provided in both an autocrine and
a paracrine manner. These mitogens bind to their cognate receptor tyrosine kinases (RTKs) on the cell surface, thereby activating
a myriad of complex intracellular signaling pathways whose outputs include cell growth, migration, and morphogenesis. Understanding
how these cascades are precisely controlled will provide insight into physiological and pathological angiogenesis. The Sprouty
(Spry) family of proteins is a highly conserved group of negative feedback loop modulators of growth factor-mediated mitogen-activated
protein kinase (MAPK) activation originally described in
Drosophila. There are four mammalian orthologs (Spry1-4) whose modulation of RTK-induced signaling pathways is growth factor- and cell
context-dependant. Endothelial cells are a group of highly differentiated cell types necessary for defining the mammalian
vasculature. These cells respond to a plethora of growth factors and express all four Spry isoforms, thus highlighting the
complexity that is required to form and maintain vessels in mammals. This review describes Spry functions in the context of
endothelial biology and angiogenesis, and provides an update on Spry-interacting proteins and Spry mechanisms of action.
Keywords EGF - Endothelial cell - ERK - FGF - Growth factors - MAPK - Receptor tyrosine kinase - Sprouty - Spred - VEGF