May have regulatory role in cell division or differentiation in response to extracellular signals. Interacts with CPNE4 (via VWFA domain). Interacts with SMAD2, SMAD3 and RNF111. Interacts with WWP1. Ubiquitinated by RNF111 and RNF165, promoting proteasomal degradation, leading to enhance the BMP-Smad signaling. Belongs to the SKI family.