This entry includes Tiki1/2 from humans, TraB/PrgY from the gut flora Enterococcusfaecalis and gumN from the plant pathogen Xanthomonas. Tiki1 is homologous to TraB/PrgY. They have a pair of widely spaced GX2H motifs and a conserved glutamate. From the structural study, this group of proteins have been identified as an ancient metalloprotease clan with a common protein architecture (cobbled from the folds of the EreA/ChaN/PMT group) that mediates proteolytic activities [2]. Tiki1 is a membrane-associated protease that inhibits Wnt via the cleavage of its amino terminus, diminishing Wnt's binding to receptors [1,3]. TraB/PrgY is an inhibitor peptide that may act as a protease to inactivate the mating pheromone [2].

1: The TIKI/TraB/PrgY family: a common protease fold for cell signaling from bacteria to metazoa?. Bazan JF, Macdonald BT, He X; Dev Cell. 2013;25:225-227. PMID:23673329

2: Tiki1 is required for head formation via Wnt cleavage-oxidation and inactivation. Zhang X, Abreu JG, Yokota C, MacDonald BT, Singh S, Coburn KL, Cheong SM, Zhang MM, Ye QZ, Hang HC, Steen H, He X; Cell. 2012;149:1565-1577. PMID:22726442