Enables co-receptor binding activity. Involved in negative regulation of Wnt signaling pathway. Predicted to be located in extracellular region. Predicted to be active in extracellular space. Is expressed in several structures, including alimentary system; central nervous system; embryo mesenchyme; eye; and genitourinary system. Orthologous to human DKK2 (dickkopf WNT signaling pathway inhibitor 2). [provided by Alliance of Genome Resources, Apr 2022]