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Li M, Zheng J, Luo D, Xu K, Sheng R, MacDonald BT, He X, Zhang X. Frizzled receptors facilitate Tiki inhibition of Wnt signaling at the cell surface. EMBO Rep 2023; 24:e55873. [PMID: 36994853 PMCID: PMC10240186 DOI: 10.15252/embr.202255873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 02/28/2023] [Accepted: 03/17/2023] [Indexed: 03/31/2023] Open
Abstract
The membrane-tethered protease Tiki antagonizes Wnt3a signaling by cleaving and inactivating Wnt3a in Wnt-producing cells. Tiki also functions in Wnt-receiving cells to antagonize Wnt signaling by an unknown mechanism. Here, we demonstrate that Tiki inhibition of Wnt signaling at the cell surface requires Frizzled (FZD) receptors. Tiki associates with the Wnt-FZD complex and cleaves the N-terminus of Wnt3a or Wnt5a, preventing the Wnt-FZD complex from recruiting and activating the coreceptor LRP6 or ROR1/2 without affecting Wnt-FZD complex stability. Intriguingly, we demonstrate that the N-terminus of Wnt3a is required for Wnt3a binding to LRP6 and activating β-catenin signaling, while the N-terminus of Wnt5a is dispensable for recruiting and phosphorylating ROR1/2. Both Tiki enzymatic activity and its association with the Wnt-FZD complex contribute to its inhibitory function on Wnt5a. Our study uncovers the mechanism by which Tiki antagonizes Wnt signaling at the cell surface and reveals a negative role of FZDs in Wnt signaling by acting as Tiki cofactors. Our findings also reveal an unexpected role of the Wnt3a N-terminus in the engagement of the coreceptor LRP6.
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Affiliation(s)
- Mingyi Li
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and the Department of Laboratory Medicine, Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengduChina
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Jing Zheng
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and the Department of Laboratory Medicine, Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengduChina
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Dong Luo
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and the Department of Laboratory Medicine, Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengduChina
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Kai Xu
- Department of Orthopedics, Tongji Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Ren Sheng
- College of Life and Health ScienceNortheastern UniversityShenyangChina
| | | | - Xi He
- Department of Neurology, Harvard Medical School, The F. M. Kirby Neurobiology CenterBoston Children's HospitalBostonMAUSA
| | - Xinjun Zhang
- The Key Laboratory for Human Disease Gene Study of Sichuan Province and the Department of Laboratory Medicine, Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengduChina
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
- Research Unit for Blindness Prevention of the Chinese Academy of Medical Sciences (2019RU026)Sichuan Academy of Medical Sciences and Sichuan Provincial People's HospitalChengduChina
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Li M, Zheng J, Luo D, Xu K, Zhang X. Tiki proteins are substrates of membrane-type matrix metalloproteinases. FEBS Lett 2022; 596:1851-1859. [PMID: 35689492 DOI: 10.1002/1873-3468.14423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/16/2022] [Accepted: 05/23/2022] [Indexed: 11/11/2022]
Abstract
Tiki proteins represent a new family of Wnt-specific proteases that inhibit Wnt signalling by cleaving and inactivating Wnt proteins. Tiki proteins are glycosylphosphatidylinositol (GPI)-anchored proteases and function in both Wnt-producing and Wnt-responsive cells. However, how Tiki proteins are regulated remains elusive. In this study, we demonstrate that matrix metalloproteinase 15 (MMP15) interacts with TIKI2 and degrades TIKI2 on the cell surface. Functionally, MMP15 relieves the inhibitory effect of TIKI2 on Wnt signalling in Wnt-responsive cells. We further show that Tiki proteins are substrates of MMP14, MMP15 and MMP16 but not MMP3 or MMP13. Our study provides insights into the potential regulation of Tiki family proteins by other proteases.
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Affiliation(s)
- Mingyi Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Zheng
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Dong Luo
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Kai Xu
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinjun Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Li M, Zheng J, He X, Zhang X. Tiki proteins are glycosylphosphatidylinositol-anchored proteases. FEBS Lett 2022; 596:1037-1046. [PMID: 35182431 PMCID: PMC9038680 DOI: 10.1002/1873-3468.14320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/10/2022] [Accepted: 02/07/2022] [Indexed: 11/07/2022]
Abstract
Wnt signalling pathways play pivotal roles in development, homeostasis and human diseases, and are tightly regulated. We previously identified Tiki as a novel family of Wnt inhibitory proteases. Tiki proteins were predicted as type I transmembrane proteins and can act in both Wnt-producing and Wnt-responsive cells. Here, we characterize Tiki proteins as glycosylphosphatidylinositol (GPI)-anchored proteases. TIKI1/2 proteins are enriched on the detergent-resistant membrane microdomains and can be released from the plasma membrane by GPI-specific glycerophosphodiesterases GDE3 and GDE6, but not by GDE2. The GPI anchor determines the cellular localization of Tiki proteins and their regulation by GDEs, but not their inhibitory activity on Wnt signalling. Our study uncovered novel characteristics and potential regulations of the Tiki family proteases.
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Affiliation(s)
- Mingyi Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Zheng
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xi He
- The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, MA USA
| | - Xinjun Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
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Abstract
Wnt proteins are modified and inactivated by two extracellular enzymatic antagonists, Tiki and Notum. Tiki proteins act as membrane-tethered metalloproteases to cleave a fragment from the amino terminus of Wnt proteins. Notum is a Wnt deacylase that removes the lipid modification that is essential for Wnt activities. Here, we provide detailed procedures for preparing enzymatic active Tiki and Notum proteins and the in vitro enzymatic reactions. We also describe a metabolic labeling and click chemistry method for detection of Wnt protein acylation.
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Affiliation(s)
- Xinjun Zhang
- The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, CLS 12064, 3 Blackfan Circle, Boston, MA, 02115, USA.
| | - Xi He
- The F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, CLS 12064, 3 Blackfan Circle, Boston, MA, 02115, USA.
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Zhang X, MacDonald BT, Gao H, Shamashkin M, Coyle AJ, Martinez RV, He X. Characterization of Tiki, a New Family of Wnt-specific Metalloproteases. J Biol Chem 2015; 291:2435-43. [PMID: 26631728 DOI: 10.1074/jbc.m115.677807] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Indexed: 11/06/2022] Open
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 β-sheet within an α+β-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 β-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.
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Affiliation(s)
- Xinjun Zhang
- From the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Bryan T MacDonald
- From the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Huilan Gao
- the Centers for Therapeutic Innovation, Pfizer, Boston, Massachusetts 02115
| | - Michael Shamashkin
- the Centers for Therapeutic Innovation, Pfizer, Boston, Massachusetts 02115
| | - Anthony J Coyle
- the Centers for Therapeutic Innovation, Pfizer, Boston, Massachusetts 02115
| | - Robert V Martinez
- the Centers for Therapeutic Innovation, Pfizer, Boston, Massachusetts 02115
| | - Xi He
- From the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115 and
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