Growth factor of the TGF-beta superfamily that plays essential roles in many developmental processes including cartilage and bone formation (PubMed:31019025). Also plays an important role in the regulation of HAMP/hepcidin expression and iron metabolism by acting as a ligand for hemojuvelin/HJV (PubMed:26582087). Also acts to promote expression of HAMP, potentially via the interaction with its receptor BMPR1A/ALK3 (PubMed:30097509, PubMed:31800957). Initiates the canonical BMP signaling cascade by associating with type I receptor ACVR1 and type II receptor ACVR2B (PubMed:18070108). In turn, ACVR1 propagates signal by phosphorylating SMAD1/5/8 that travel to the nucleus and act as activators and repressors of transcription of target. Can also signal through non-canonical pathway such as TAZ-Hippo signaling cascade to modulate VEGF signaling by regulating VEGFR2 expression (PubMed:33021694). {ECO:0000269|PubMed:18070108, ECO:0000269|PubMed:26582087, ECO:0000269|PubMed:30097509, ECO:0000269|PubMed:31019025, ECO:0000269|PubMed:31800957, ECO:0000269|PubMed:33021694}. This is the function of ENSG00000153162 (BMP6, bone morphogenetic protein 6).