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Tiki homology domain antagonizes Wnt function via cleavage of amino-terminal residues Tiki is a membrane-associated metalloprotease that inhibits Wnt via the cleavage of its amino terminus, diminishing Wnt's binding to receptors. Wnt is essential in animal development and homeostasis. In xenopus, tiki is critical in head development. In human cells, TIKI inhibits Wnt-signaling, which is important in embryogenesis, homeostasis, and regeneration. Deregulation of WNT contributes to birth defects, cancer and various diseases. TIKI homology domains are part of the TraB family and are related to the Erythromycin esterase, GumN plant pathogens, RtxA toxins, and Campylobacter Jejuni heme-binding, Chan-like proteins. TraB/PrgY are identified in gut bacterium Enterococcus faecalis, but its function has not been well characterized. Plasmid-borne, TraB has been implicated in the regulation of pheromone sensitivity and specificity. Based on homology to TIKI activity, it has been proposed that TraB acts as a metalloprotease in the inactivation of mating pheromone. The TIKI/TraB family has 2 conserved GxxH motifs and conserved glutamate and arginine residues that may be catalytic. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",