Secreted scaffold protein that plays an essential role in dorsoventral patterning during early development. Stabilizes axial formation by restricting chordin (CHRD) activity on the dorsal side. Acts by facilitating the association between the tolloid protease BMP1 and its substrate chordin (CHRD), leading to enhance chordin (CHRD) degradation by BMP1. Interacts (via coiled coil domain) with BMP1 and (via olfactomedin-like domain) CHRD. Belongs to the OLFML3 family.