Metastasis-suppressor 1 (MTSS1) is a membrane-interacting scaffolding protein that regulates the integrity of epithelial cell–cell junctions and functions as a tumor suppressor in a wide range of carcinomas. MTSS1 binds phosphoinositide-rich membranes through its I-BAR domain and is capable of sensing and generating negative membrane curvature in vitro. However, the mechanisms…