Proteins (axin-1, 862 aa; axin-2, 843 aa) that control dorsoventral patterning by down-regulating β-*catenin to inhibit the Wnt signalling pathway, ventralizing the embryo, and activating a Wnt-independent JNK signalling pathway that dorsalizes. Mutations in axin-1 are associated with hepatocellular carcinoma, and greater methylation of the promoter is reported in a case of a caudal duplication anomaly. Defects in axin-2 cause oligodontia–colorectal cancer syndrome in which there is severe tooth agenesis and colorectal cancer. Axin interaction partner and dorsalization antagonist (AIDA, 306 aa) inhibits the axin-mediated JNK activation by disrupting the axin homodimerization that is required.
Subjects: Medicine and health