The cysteine-rich domain (CRD) is an essential part of the crescent protein, a member of the secreted frizzled-related protein (SFRP) family, which regulates convergent extension movements (CEMs) during gastrulation and neurulation. Xenopus laevis crescent efficiently forms inhibitory complexes with Wnt5a and Wnt11, but this effect is cancelled in the presence of another member of the SFRP family, Frzb1. A potential role for Crescent in head formation is to regulate a non-canonical Wnt pathway positively in the adjacent posterior mesoderm, and negatively in the overlying anterior neuroectoderm.
Jiyao W et al.(2023). "The conserved domain database in 2023.",