| Title: | "Characterization of Tiki, a New Family of Wnt-specific Metalloproteases" |
| Author(s): | Zhang X; MacDonald BT; Gao H; Shamashkin M; Coyle AJ; Martinez RV; He X; |
| Address: | "From the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115 and. the Centers for Therapeutic Innovation, Pfizer, Boston, Massachusetts 02115. From the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115 and xi.he@childrens.harvard.edu" |
| ISSN/ISBN: | 1083-351X (Electronic) 0021-9258 (Print) 0021-9258 (Linking) |
| Abstract: | "The Wnt family of secreted glycolipoproteins plays pivotal roles in development and human diseases. Tiki family proteins were identified as novel Wnt inhibitors that act by cleaving the Wnt amino-terminal region to inactivate specific Wnt ligands. Tiki represents a new metalloprotease family that is dependent on Mn(2+)/Co(2+) but lacks known metalloprotease motifs. The Tiki extracellular domain shares homology with bacterial TraB/PrgY proteins, known for their roles in the inhibition of mating pheromones. The TIKI/TraB fold is predicted to be distantly related to structures of additional bacterial proteins and may use a core beta-sheet within an alpha+beta-fold to coordinate conserved residues for catalysis. In this study, using assays for Wnt3a cleavage and signaling inhibition, we performed mutagenesis analyses of human TIKI2 to examine the structural prediction and identify the active site residues. We also established an in vitro assay for TIKI2 protease activity using FRET peptide substrates derived from the cleavage motifs of Wnt3a and Xenopus wnt8 (Xwnt8). We further identified two pairs of potential disulfide bonds that reside outside the beta-sheet catalytic core but likely assist the folding of the TIKI domain. Finally, we systematically analyzed TIKI2 cleavage of the 19 human WNT proteins, of which we identified 10 as potential TIKI2 substrates, revealing the hydrophobic nature of Tiki cleavage sites. Our study provides insights into the Tiki family of proteases and its Wnt substrates" |
| Keywords: | "Amino Acid Motifs Animals Catalytic Domain Cysteine/chemistry Disulfides/chemistry Fluorescence Resonance Energy Transfer *Gene Expression Regulation, Enzymologic HEK293 Cells Humans Hydrophobic and Hydrophilic Interactions Ligands Luciferases/metabolism;" |
| Notes: | "MedlineZhang, Xinjun MacDonald, Bryan T Gao, Huilan Shamashkin, Michael Coyle, Anthony J Martinez, Robert V He, Xi eng P30 HD-18655/HD/NICHD NIH HHS/ R01-GM057603/GM/NIGMS NIH HHS/ R01 GM057603/GM/NIGMS NIH HHS/ U54 HD090255/HD/NICHD NIH HHS/ R01-AR060359/AR/NIAMS NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't 2015/12/04 J Biol Chem. 2016 Jan 29; 291(5):2435-43. doi: 10.1074/jbc.M115.677807. Epub 2015 Dec 2" |
