Key maternal determinant of the dorsal organizer and body axis formation in vertebrates that acts by promoting stabilization of beta-catenin (ctnnb1) (PubMed:30467143). Localizes on the plasma membrane of the future dorsal blastomeres in early blastulas and binds to and promotes the tankyrase-mediated degradation of axin (axin1 and axin2). Axin degradation results in stabilization and nuclear translocation of beta-catenin (ctnnb1) for activating organizer-specific target gene expression (By similarity). Interacts with axin1; leading to promote the tankyrase-mediated degradation of axin. Interacts with axin2; leading to promote the tankyrase-mediated degradation of axin. Enriched on the plasma membrane of blastomeres only in a small region in which the dorsal organizer will form. Transcripts are present in granules at the vegetal cortex of oocytes andmove dorsally along with cortical rotation after fertilization. Morpholino knockdown of the protein results in embryos lacking the body axis and dorsal tissues (PubMed:30467143). Reduced dorsal marker expression but enhanced ventral marker expression (PubMed:30467143). Belongs to the huluwa family.