Jiraiya inhibits bone morphogenetic protein (BMP) signaling during embryogenesis [1]. The human member of this family is TMEM221.

1: Jiraiya attenuates BMP signaling by interfering with type II BMP receptors in neuroectodermal patterning. Aramaki T, Sasai N, Yakura R, Sasai Y; Dev Cell. 2010;19:547-561. PMID:20951346