EGFL7 affected angiogenic sprouting in dependence of integrin α5β1 EGFL7 affected angiogenic sprouting in dependence of integrin α5β1 AStructural analysis of recombinant EGFL7 by transmission electron microscopy (TEM) showed aggregates with a fibrillar structure of varying sizes. Black scale bar left represents 50 nm. Higher magnifications depict rodlike EGFL7 particles. Black scale bar right represents 15 nm. White scale bar represents 5 nm.B, CPositively charged amino acid residues at the C‐terminus and negative charges at the N‐terminus make EGFL7 a polar molecule with a preference toward oligomerization.DAngiogenic sprouting of primary human umbilical vein endothelial cell (HUVEC) spheroids embedded in a collagen‐based matrix was induced by the application of EGFL7 (E7), fibronectin (Fn), or a combination of both (upper row). Co‐application of an integrin α5β1‐blocking antibody (anti‐α5β1) reduced sprouting in all cases but control (lower row). Scale bar represents 100 μm.EE7, Fn, and a combination of both significantly increased the mean cumulative sprout length per spheroid, an effect blocked by anti‐α5β1 (n = 3; one‐way ANOVA (intergroup differences) and Mann–Whitney U‐test (intra‐group differences); mean ± SEM).F–IMeasurement of Rho GTPase signaling downstream of integrins (F). Quantification of (G) Cdc42, (H) Rac1, and (I) RhoA activation by immunoblotting subsequent to seeding HUVECs on E7, Fn, or a combination of both. Preferentially, E7 activated Cdc42 and Fn activated Rac1, but both proteins antagonized each other. None of the treatments affected RhoA signaling (n = 3; one‐way ANOVA; mean ± SEM). IP, immunoprecipitation; AU, arbitrary units. Source data are available online for this figure. Nevenka Dudvarski Stanković et al. EMBO Mol Med. 2018;10:e8420 © as stated in the article, figure or figure legend