Fig. 5
A Sdc2 conserved N-terminal region is required for specific association with VEGFR2. a Multi-alignment of Sdc2 sequences (human, mouse, and rat) unveiled that Sdc2 extracellular domain present a 59 aminoacid region with high-homology (D1) and a low-homology region (D2). Transmembrane domain (Tm) and intracellular domain (ICD) are also indicated. Black stripes identify sites that are not conserved among the three sequences. b Alignment of human Sdc2 with Sdc4 revealed little conservation in extracellular domain (colored aminoacid are conserved). Furthermore, Sdc4 does not present homology differences between D1 and D2 (see panel d); however, these regions were defined following alignment with Sdc2. c Schematic representation of D1/D2 regions in extracellular domain and relation with HS chains. d Percentual identity between various domain of Sdc2 and Sdc4. Identity is calculated by alignment of human sequence with mouse and rat (second and third column) or by alignment of human Sdc2 vs human Sdc4 (fourth column). e, f Mouse ECs (e) or HUVEC (f) were transduced for 16 h with adenovirus expressing the indicated construct (MOI = 1–2), starved for 8 h and then stimulated with VEGFA165 (50 ng/ml). e A chimera construct swapping Sdc4 D1 region with Sdc2 D1 (Sdc2D1/Sdc4D2) showed association with VEGFR2 at the same extent of full length Sdc2. Conversely, replacement of Sdc2 D1 with Sdc4 D1 (Sdc2D1/Sdc4D2) abolished Sdc2 ability to form a complex with VEGFR2. f A mutant expressing only Sdc2 D1 region (Sdc2D1) formed complex with VEGFR2 upon VEGFA165 stimulation while Sdc4 D1 did not associate with VEGFR2
