The function of SCUBE3 (signal peptide, CUB domain and EGF like domain containing 3, ENSG00000146197) is as follows. Is a positive regulator of the BMP signaling pathway, required for proper chondrogenesis, osteogenesis and skeletal development. It acts as a coreceptor for BMP ligands, particularly BMP2 and BMP4, facilitating their interactions with BMP type I receptors (PubMed:33308444). It is required for ligand-induced recruitment of BMP receptors to lipid rafts (By similarity). Binds to TGFBR2 and activates TGFB signaling. In lung cancer cells, could serve as an endogenous autocrine and paracrine ligand of TGFBR2, which could regulate TGFBR2 signaling and hence modulate epithelial-mesenchymal transition and cancer progression. {ECO:0000250|UniProtKB:Q6NZL8, ECO:0000269|PubMed:21441952, ECO:0000269|PubMed:33308444}.