Potent circulating inhibitor of angiogenesis. Signals through the type I activin receptor ACVRL1 but not other Alks. Signaling through SMAD1 in endothelial cells requires TGF-beta coreceptor endoglin/ENG. Homodimer; disulfide-linked (PubMed:25237187, PubMed:28564608). Detected in extracellular fluid as mature homodimer, and in complex with its propeptide (PubMed:21710321, PubMed:25237187). Interacts with ACVRL1, BMPR2 and ACVR2B with high affinity (in vitro) (PubMed:22799562, PubMed:22347366, PubMed:25237187, PubMed:25751889). Identified in a complex with ACVRL1 and ACVR2B (PubMed:22718755). Has ten times lower affinity for ACVR2A (in vitro) (PubMed:25751889). Interacts with ENG, forming a heterotetramer with a 2:2 stoichiometry (PubMed:21737454, PubMed:28564608). Can form a heteromeric complex with ENG and ACVRL1 (PubMed:28564608). Interacts with type I receptor ACVR1 (PubMed:20628059). Detected in blood plasma (at protein level). A reversible disulfide bond can be formed between the two subunits in the homodimer; this has no effect on GDF2 activity. The disease is caused by variants affecting the gene represented in this entry. Belongs to the TGF-beta family. Can promote osteogenic differentiation in vitro (PubMed:25237187, PubMed:25751889). This is probably not physiologically relevant. GDF2 entry