Cutaneomucosal venous malformations (VMCMs) are rare inherited disorders caused by mutations in the tyrosine receptor kinase TIE-2. Although thought to function in vascular development and stability, exactly how TIE-2 mutations cause VMCMs is unclear, partly because Tie-2−/− mice are embryonic lethal owing to heart defects. Gjini et al. now report that a tie-2 loss-of-function zebrafish mutant is viable into adulthood. Unlike mice, the function of Tie-2 in zebrafish seems to be redundant to that of Tie-1 during early heart development, although both proteins are required for endocardial-myocardial interactions at later stages. In addition, testing of statins in the tie-2 zebrafish mutant suggests that these drugs act by reducing endothelial cell-cell contacts in newly forming brain vessels.
