Cytokine that may play an important role during carcinogenesis and metanephric kidney organogenesis, as a BMP antagonist required for early limb outgrowth and patterning in maintaining the FGF4-SHH feedback loop. Down-regulates the BMP4 signaling in a dose-dependent manner (By similarity). Antagonist of BMP2; inhibits BMP2-mediated differentiation of osteoblasts (in vitro) (By similarity). Acts as inhibitor of monocyte chemotaxis (PubMed:15528323). Can inhibit the growth or viability of normal cells but not transformed cells when is overexpressed. 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 (PubMed:15528323). Highly expressed in the brain, kidney, spleen, and testis and weakly expressed in the lung and liver. Predominantly expressed in differentiated cells as neurons in brain, type I cells in lung and globlet cells in intestine. Down-regulated in cells transformed by oncogenes. Belongs to the DAN family.