Cytokine that may play an important role during carcinogenesis and metanephric kidney organogenesis, as BMP a antagonist required for early limb outgrowth and patterning in maintaining the FGF4-SHH feedback loop (PubMed:12808456, PubMed:15201225). Down-regulates the BMP4 signaling in a dose-dependent manner (PubMed:15133038). Antagonist of BMP2; inhibits BMP2-mediated differentiation of osteoblasts (in vitro) (By similarity). Acts as inhibitor of monocyte chemotaxis (By similarity). Homodimer; can also form homooligomers. Interacts with BMP2; can form higher oligomers with BMP2 (By similarity). Interacts with SLIT1 and SLIT2 in a glycosylation-dependent manner (By similarity). Highly expressed in spleen and to a lesser extent in lung, skeletal muscle and kidney. Expressed only in non-transformed cells or primary fibroblasts in culture but not in established transformed or tumor derived cell lines. Broadly expressed in limb bud mesenchyme but restricted to the distal limb bud mesenchyme and concentrated posteriorly. Expressed in ovary especially in granulosa cells of follicles of type 4. Up-regulated by GDF9 dose-dependent manner and BMP4 in granulosa cells. Highly regulated during folliculogenesis. Belongs to the DAN family.