A Protein Scaffold Plays Matchmaker for Chordin

In this issue, report that the scaffold protein Olfactomedin 1 (ONT1) recruits the Tolloid proteases to their substrate Chordin, an antagonist of bone morphogenetic proteins (BMPs), during development of the frog embryo. Consequently, ONT1 expression in the organizer of the late gastrula stabilizes the gradient of BMP signaling that is essential for dorsoventral patterning.