This entry includes Dickkopf-related proteins 1-4 (DKK1-4) and Dickkopf-like protein 1 (DKKL1). The Dickkopf (Dkk) proteins are cysteine-rich secretory proteins and highly conserved inhibitors of the canonical Wnt signaling pathway, which play key roles in many essential biological processes []. DKKL1 is a acrosomal protein that affects in vitro fertilization, but the effect is attenuated in vivo [].
