Enables activin receptor binding activity. Involved in nodal signaling pathway. Acts upstream of or within several processes, including animal organ development; digestive tract morphogenesis; and endoderm development. Predicted to be located in plasma membrane. Predicted to be active in cell surface and extracellular region. Is expressed in several structures, including embryo mesoderm; intermediate mesenchyme; neural ectoderm; and primitive streak. Used to study dextro-looped transposition of the great arteries; double outlet right ventricle; right atrial isomerism; and visceral heterotaxy. Human ortholog(s) of this gene implicated in visceral heterotaxy. Orthologous to human CFC1 (cripto, FRL-1, cryptic family 1) and CFC1B (cripto, FRL-1, cryptic family 1B). [provided by Alliance of Genome Resources, Apr 2022]