Figure 2. Effects of Dia1 and ROCK signaling on endothelial junctions and their underlying actin cytoskeleton. Junctionally localized RhoGEFs selectively activate Dia1 (blue arrows) or ROCK (red arrows) via RhoA. Dia1 promotes actin polymerization while ROCK induces actomyosin-induced contractility. Furthermore, Dia1 and ROCK promote junction integrity independently by inhibiting VE-cadherin endocytosis and promoting VE-cadherin clustering, respectively, at sites of cell-cell contact.