Probable E3 ubiquitin-protein ligase that acts as a negative regulator of the Wnt signaling pathway by mediating the ubiquitination, endocytosis and subsequent degradation of Wnt receptor complex components Frizzled (By similarity). Acts on both canonical and non-canonical Wnt signaling pathway (By similarity). Plays a role in the migration and axon guidance of different neuronal cell types including CAN, HSN, AVK and AVG (PubMed:24401370, PubMed:25448694). Promotes the differentiation and regulates the anteroposterior polarity of AVG unpaired interneurons by sequestering the Wnt signaling proteins cfz-2, mig-1 and mom-5 to endosomes which thereby reduces their cell surface expression and negatively regulates Wnt signaling (PubMed:24401370). May also regulate AVG polarity and axon guidance through Wnt-independent mechanisms involving unc-53/Nav2, unc-73/Trio and cytosolic protein vab-8 (PubMed:25448694). Protein modification; protein ubiquitination. Expressed in a subset of head, ventral nerve cord and tail neurons, the excretory canal and tail epidermis. First expressed during the late gastrulation stage of embryogenesis with high expression in the tail region (PubMed:25448694). In the comma stage of embryogenesis, expression is prominent in the body wall muscle cells (PubMed:25448694). In early larval development, expressed in hypodermal cells, muscle, the pharynx, intestine and in anal depressor and stomatointestinal muscle (PubMed:25448694). In the nervous system, transiently expressed in late embryogenesis and early larval development in AVG unpaired interneurons and during larval development, expressed in neurons in the head and tail ganglia and ventral cord motor neurons (PubMed:24401370, PubMed:25448694). In the late stages of larval development, expressed in the distal tip cell, the vulva, uterine muscle cells and the VC4 and VC5 neurons that flank the vulva (PubMed:25448694). The RING finger region is required to block Wnt signaling and is also required for endosomal localization. Autoubiquitinated. Mutants exhibit cell migration and axon guidance defects in HSN, AVK, CAN and AVG neurons, and also display excretory canal elongation defects with premature termination of the canal. Double knockout with either unc-53 or vab-8 results in premature termination of the AVG axon and AVG polarity defects. Belongs to the ZNRF3 family.