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Kegulian NC, Visakan G, Bapat RA, Moradian-Oldak J. Ameloblastin and its multifunctionality in amelogenesis: A review. Matrix Biol 2024; 131:62-76. [PMID: 38815936 DOI: 10.1016/j.matbio.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/16/2024] [Accepted: 05/24/2024] [Indexed: 06/01/2024]
Abstract
Extracellular matrix proteins play crucial roles in the formation of mineralized tissues like bone and teeth via multifunctional mechanisms. In tooth enamel, ameloblastin (Ambn) is one such multifunctional extracellular matrix protein implicated in cell signaling and polarity, cell adhesion to the developing enamel matrix, and stabilization of prismatic enamel morphology. To provide a perspective for Ambn structure and function, we begin this review by describing dental enamel and enamel formation (amelogenesis) followed by a description of enamel extracellular matrix. We then summarize the established domains and motifs in Ambn protein, human amelogenesis imperfecta cases, and genetically engineered mouse models involving mutated or null Ambn. We subsequently delineate in silico, in vitro, and in vivo evidence for the amphipathic helix in Ambn as a proposed cell-matrix adhesive and then more recent in vitro evidence for the multitargeting domain as the basis for dynamic interactions of Ambn with itself, amelogenin, and membranes. The multitargeting domain facilitates tuning between Ambn-membrane interactions and self/co-assembly and supports a likely overall role for Ambn as a matricellular protein. We anticipate that this review will enhance the understanding of multifunctional matrix proteins by consolidating diverse mechanisms through which Ambn contributes to enamel extracellular matrix mineralization.
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Affiliation(s)
- Natalie C Kegulian
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar St., CSA 148, Los Angeles, CA 90033, USA
| | - Gayathri Visakan
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar St., CSA 148, Los Angeles, CA 90033, USA
| | - Rucha Arun Bapat
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar St., CSA 148, Los Angeles, CA 90033, USA
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar St., CSA 148, Los Angeles, CA 90033, USA.
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2
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Costa CRR, Chalgoumi R, Baker A, Guillou C, Yamaguti PM, Simancas Escorcia V, Abbad L, Amorin BR, de Lima CL, Cannaya V, Benassarou M, Berdal A, Chatziantoniou C, Cases O, Cosette P, Kozyraki R, Acevedo AC. Gingival proteomics reveals the role of TGF beta and YAP/TAZ signaling in Raine syndrome fibrosis. Sci Rep 2024; 14:9497. [PMID: 38664418 PMCID: PMC11045870 DOI: 10.1038/s41598-024-59713-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Raine syndrome (RNS) is a rare autosomal recessive osteosclerotic dysplasia. RNS is caused by loss-of-function disease-causative variants of the FAM20C gene that encodes a kinase that phosphorylates most of the secreted proteins found in the body fluids and extracellular matrix. The most common RNS clinical features are generalized osteosclerosis, facial dysmorphism, intracerebral calcifications and respiratory defects. In non-lethal RNS forms, oral traits include a well-studied hypoplastic amelogenesis imperfecta (AI) and a much less characterized gingival phenotype. We used immunomorphological, biochemical, and siRNA approaches to analyze gingival tissues and primary cultures of gingival fibroblasts of two unrelated, previously reported RNS patients. We showed that fibrosis, pathological gingival calcifications and increased expression of various profibrotic and pro-osteogenic proteins such as POSTN, SPARC and VIM were common findings. Proteomic analysis of differentially expressed proteins demonstrated that proteins involved in extracellular matrix (ECM) regulation and related to the TGFβ/SMAD signaling pathway were increased. Functional analyses confirmed the upregulation of TGFβ/SMAD signaling and subsequently uncovered the involvement of two closely related transcription cofactors important in fibrogenesis, Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ). Knocking down of FAM20C confirmed the TGFβ-YAP/TAZ interplay indicating that a profibrotic loop enabled gingival fibrosis in RNS patients. In summary, our in vivo and in vitro data provide a detailed description of the RNS gingival phenotype. They show that gingival fibrosis and calcifications are associated with, and most likely caused by excessed ECM production and disorganization. They furthermore uncover the contribution of increased TGFβ-YAP/TAZ signaling in the pathogenesis of the gingival fibrosis.
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Affiliation(s)
- Cláudio Rodrigues Rezende Costa
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
- Oral Center for Inherited Diseases, University Hospital of Brasília, Oral Histopathology Laboratory, Department of Dentistry, Health Sciences Faculty, University of Brasília (UnB), Brasília, Brazil
- Department of Dentistry, Health Group of Natal (GSAU-NT), Brazilian Air Force, Natal, Parnamirim, Brazil
| | - Rym Chalgoumi
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
| | - Amina Baker
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
| | - Clément Guillou
- Rouen University, INSA Rouen Normandie, CNRS, Normandie Univ, PBS UMR 6270, 76000, Rouen, France
- Rouen University, INSERM US51, CNRS UAR 2026, HeRacles PISSARO, 76000, Rouen, France
| | - Paulo Marcio Yamaguti
- Oral Center for Inherited Diseases, University Hospital of Brasília, Oral Histopathology Laboratory, Department of Dentistry, Health Sciences Faculty, University of Brasília (UnB), Brasília, Brazil
| | - Victor Simancas Escorcia
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
- Grupo de Investigación GENOMA, Universidad del Sinú, Cartagena, Colombia
| | - Lilia Abbad
- MRS1155, INSERM, Sorbonne Université, 75020, Paris, France
| | - Bruna Rabelo Amorin
- Oral Center for Inherited Diseases, University Hospital of Brasília, Oral Histopathology Laboratory, Department of Dentistry, Health Sciences Faculty, University of Brasília (UnB), Brasília, Brazil
| | - Caroline Lourenço de Lima
- Oral Center for Inherited Diseases, University Hospital of Brasília, Oral Histopathology Laboratory, Department of Dentistry, Health Sciences Faculty, University of Brasília (UnB), Brasília, Brazil
| | - Vidjea Cannaya
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
| | - Mourad Benassarou
- Service de Chirurgie Maxillo-Faciale et Stomatologie, Hôpital de La Pitié Salpétrière, Sorbonne Université, 75006, Paris, France
| | - Ariane Berdal
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
- CRMR O-RARES, Hôpital Rothshild, UFR d'Odontologie-Garancière, Université de Paris Cité, 75012, Paris, France
| | | | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
| | - Pascal Cosette
- Rouen University, INSA Rouen Normandie, CNRS, Normandie Univ, PBS UMR 6270, 76000, Rouen, France
- Rouen University, INSERM US51, CNRS UAR 2026, HeRacles PISSARO, 76000, Rouen, France
| | - Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France.
- CRMR O-RARES, Hôpital Rothshild, UFR d'Odontologie-Garancière, Université de Paris Cité, 75012, Paris, France.
- Rouen University, UFR SANTE ROUEN NORMANDIE, Inserm 1096, 76000, Rouen, France.
| | - Ana Carolina Acevedo
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Oral Molecular Pathophysiology, 75006, Paris, France
- Oral Center for Inherited Diseases, University Hospital of Brasília, Oral Histopathology Laboratory, Department of Dentistry, Health Sciences Faculty, University of Brasília (UnB), Brasília, Brazil
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Shao C, Bapat RA, Su J, Moradian-Oldak J. Regulation of Hydroxyapatite Nucleation In Vitro through Ameloblastin-Amelogenin Interactions. ACS Biomater Sci Eng 2023; 9:1834-1842. [PMID: 35068157 PMCID: PMC9308824 DOI: 10.1021/acsbiomaterials.1c01113] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Amelogenin (Amel) and ameloblastin (Ambn) are two primary extracellular enamel matrix proteins that play crucial roles for proper thickness, prismatic structure, and robust mechanical properties. Previous studies have shown that Amel and Ambn bind to each other, but the effect of their coassembly on the nucleation of hydroxyapatite (HAP) is unclear. Here, we systematically investigated the coassembly of recombinant mouse Amel and Ambn in various ratios using in situ atomic force microscopy, dynamic light scattering, and transmission electron microscopy. The size of protein particles decreased as the Ambn:Amel ratio increased. To define the coassembly domain on Ambn, we used Ambn-derived peptides and Ambn variants to examine their effects on the amelogenin particle size distribution. We found that the peptide sequence encoded by exon 5 of Ambn affected Amel self-assembly but the variant lacking this sequence did not have any effect on Amel self-assembly. Furthermore, through monitoring the pH change in bulk mineralization solution, we tracked the nucleation behavior of HAP in the presence of Ambn and Amel and found that their coassemblies at different ratios showed varying abilities to stabilize amorphous calcium phosphate. These results demonstrated that Ambn and Amel coassemble with each other via a motif within the sequence encoded by exon 5 of Ambn and cooperate in regulating the nucleation of HAP crystals, enhancing our understanding of the important role of enamel matrix proteins in amelogenesis.
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Affiliation(s)
- Changyu Shao
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, Los Angeles, California 90033, United States
| | - Rucha Arun Bapat
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, Los Angeles, California 90033, United States
| | - Jingtan Su
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, Los Angeles, California 90033, United States
| | - Janet Moradian-Oldak
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, 2250 Alcazar Street, Los Angeles, California 90033, United States
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4
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Desoutter A, Cases O, Collart Dutilleul PY, Simancas Escorcia V, Cannaya V, Cuisinier F, Kozyraki R. Enamel and dentin in Enamel renal syndrome: A confocal Raman microscopy view. Front Physiol 2022; 13:957110. [PMID: 36091358 PMCID: PMC9453029 DOI: 10.3389/fphys.2022.957110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Enamel Renal Syndrome (ERS) is a rare genetic disorder caused by biallelic mutations in Family with sequence similarity 20A (FAM20A) gene encoding the secretory pathway pseudokinase FAM20A. ERS is characterized by hypoplastic amelogenesis imperfecta (AI), impaired tooth eruption, intra-pulpal calcifications, gingival fibromatosis and nephrocalcinosis of various severity. Previous studies showed that the hypoplastic enamel was also hypomineralized but its chemical composition has not been extensively studied. Furthermore it is currently unclear whether dentinal defects are associated with AI in ERS patients. The objective of the study was to provide a structural and chemical analysis of enamel, dentin and dentin enamel junction (DEJ) in ERS patients carrying four, previously reported, distinct mutations in FAM20A. Chemical cartography obtained with Raman microscopy showed that compared to control samples, ERS enamel composition was severely altered and a cementum-like structure was observed in some cases. Chemical composition of peripulpal dentin was also affected and usual gradient of phosphate intensity, shown in DEJ profile, was absent in ERS samples. DEJ and dentinal anomalies were further confirmed by scanning electron microscopy analysis. In conclusion, our study shows that enamel formation is severely compromised in ERS patients and provides evidence that dentinal defects are an additional feature of the ERS dental phenotype.
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Affiliation(s)
- Alban Desoutter
- Laboratoire Bioingénierie et Nanosciences LBN, Université de Montpellier, Montpellier, France
- *Correspondence: Alban Desoutter,
| | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
| | | | - Victor Simancas Escorcia
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
- Facultad de Odontología, Universidad de Cartagena, Grupo Interdisciplinario de Investigaciones y Tratamientos Odontológicos Universidad de Cartagena (GITOUC), Cartagena, Colombia
| | - Vidjea Cannaya
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
| | - Frédéric Cuisinier
- Laboratoire Bioingénierie et Nanosciences LBN, Université de Montpellier, Montpellier, France
| | - Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris Cité, Laboratory of Oral Molecular Pathophysiology, Paris, France
- CRMR O-RARES, Hôpital Rothshild, UFR d’Odontologie-Garancière, Université de Paris Cité, Paris, France
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5
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Dong C, Lamichhane B, Yamazaki H, Vasquez B, Wang J, Zhang Y, Feng JQ, Margolis HC, Beniash E, Wang X. The phosphorylation of serine 55 in enamelin is essential for murine amelogenesis. Matrix Biol 2022; 111:245-263. [PMID: 35820561 DOI: 10.1016/j.matbio.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 06/02/2022] [Accepted: 07/07/2022] [Indexed: 10/17/2022]
Abstract
Amelogenesis imperfecta (AI) is an inherited developmental enamel defect affecting tooth masticatory function, esthetic appearance, and the well-being of patients. As one of the major enamel matrix proteins (EMPs), enamelin (ENAM) has three serines located in Ser-x-Glu (S-x-E) motifs, which are potential phosphorylation sites for the Golgi casein kinase FAM20C. Defects in FAM20C have similarly been associated with AI. In our previous study of EnamRgsc514 mice, the Glu57 in the S55-X56-E57 motif was mutated into Gly, which was expected to cause a phosphorylation failure of Ser55 because Ser55 cannot be recognized by FAM20C. The severe enamel defects in ENAMRgsc514 mice reminiscent of Enam-knockout mouse enamel suggested a potentially important role of Ser55 phosphorylation in ENAM function. However, the enamel defects and ENAM dysfunction may also be attributed to distinct physicochemical differences between Glu57 and Gly57. To clarify the significance of Ser55 phosphorylation to ENAM function, we generated two lines of Enam knock-in mice using CRISPR-Cas9 method to eliminate or mimic the phosphorylation state of Ser55 by substituting it with Ala55 or Asp55 (designated as S55A or S55D), respectively. The teeth of 6-day or 4-week-old mice were subjected to histology, micro-CT, SEM, TEM, immunohistochemistry, and mass spectrometry analyses to characterize the morphological, microstructural and proteomic changes in ameloblasts, enamel matrix and enamel rods. Our results showed that the enamel formation and EMP expression in S55D heterozygotes (Het) were less disturbed than those in S55A heterozygotes, while both homozygotes (Homo) had no mature enamel formation. Proteomic analysis revealed alterations of enamel matrix biosynthetic and mineralization processes in S55A Hets. Our present findings indicate that Asp55 substitution partially mimics the phosphorylation state of Ser55 in ENAM. Ser55 phosphorylation is essential for ENAM function during amelogenesis.
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Affiliation(s)
- Changchun Dong
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Bikash Lamichhane
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Hajime Yamazaki
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Brent Vasquez
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jingya Wang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Yongxu Zhang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Jian Q Feng
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States
| | - Henry C Margolis
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States; Department of Periodontics and Preventive Dentistry, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Elia Beniash
- Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xiaofang Wang
- Department of Biomedical Sciences, Texas A&M University School of Dentistry, 3302 Gaston Ave, Dallas, TX 75246, United States.
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Govitvattana N, Kaku M, Ohyama Y, Jaha H, Lin IP, Mochida H, Pavasant P, Mochida Y. Molecular Cloning of Mouse Homologue of Enamel Protein C4orf26 and Its Phosphorylation by FAM20C. Calcif Tissue Int 2021; 109:445-454. [PMID: 33884476 PMCID: PMC8429244 DOI: 10.1007/s00223-021-00847-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/26/2021] [Indexed: 10/21/2022]
Abstract
It is widely accepted that cellular processes are controlled by protein phosphorylation and has become increasingly clear that protein degradation, localization and conformation as well as protein-protein interaction are the examples of subsequent cellular events modulated by protein phosphorylation. Enamel matrix proteins belong to members of the secretory calcium binding phosphoprotein (SCPP) family clustered on chromosome 4q21, and most of the SCPP phosphoproteins have at least one S-X-E motifs (S; serine, X; any amino acid, E; glutamic acid). It has been reported that mutations in C4orf26 gene, located on chromosome 4q21, are associated with autosomal recessive type of Amelogenesis Imperfecta (AI), a hereditary condition that affects enamel formation/mineralization. The enamel phenotype observed in patients with C4orf26 mutations is hypomineralized and partially hypoplastic, indicating that C4orf26 protein may function at both secretory and maturation stages of amelogenesis. The previous in vitro study showed that the synthetic phosphorylated peptide based on C4orf26 protein sequence accelerates hydroxyapatite nucleation. Here we show the molecular cloning of Gm1045, mouse homologue of C4orf26, which has 2 splicing isoforms. Immunohistochemical analysis demonstrated that the immunolocalization of Gm1045 is mainly observed in enamel matrix in vivo. Our report is the first to show that FAM20C, the Golgi casein kinase, phosphorylates C4orf26 and Gm1045 in cell cultures. The extracellular localization of C4orf26/Gm1045 was regulated by FAM20C kinase activity. Thus, our data point out the biological importance of enamel matrix-kinase control of SCPP phosphoproteins and may have a broad impact on the regulation of amelogenesis and AI.
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Affiliation(s)
- Nattanan Govitvattana
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, 02118, USA
- Department of Pediatric Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Masaru Kaku
- Division of Bio-Prosthodontics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata, 951-8514, Japan
| | - Yoshio Ohyama
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, 02118, USA
| | - Haytham Jaha
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, 02118, USA
| | - I-Ping Lin
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, 02118, USA
- Graduate Institute of Clinical Dentistry, School of Dentistry, College of Medicine, National Taiwan University, Taipei, 10048, Taiwan
| | - Hanna Mochida
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, 02118, USA
| | - Prasit Pavasant
- Center of Excellence in Regenerative Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand.
| | - Yoshiyuki Mochida
- Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, MA, 02118, USA.
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The ABCs of the atypical Fam20 secretory pathway kinases. J Biol Chem 2021; 296:100267. [PMID: 33759783 PMCID: PMC7948968 DOI: 10.1016/j.jbc.2021.100267] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/12/2022] Open
Abstract
The study of extracellular phosphorylation was initiated in late 19th century when the secreted milk protein, casein, and egg-yolk protein, phosvitin, were shown to be phosphorylated. However, it took more than a century to identify Fam20C, which phosphorylates both casein and phosvitin under physiological conditions. This kinase, along with its family members Fam20A and Fam20B, defined a new family with altered amino acid sequences highly atypical from the canonical 540 kinases comprising the kinome. Fam20B is a glycan kinase that phosphorylates xylose residues and triggers peptidoglycan biosynthesis, a role conserved from sponges to human. The protein kinase, Fam20C, conserved from nematodes to humans, phosphorylates well over 100 substrates in the secretory pathway with overall functions postulated to encompass endoplasmic reticulum homeostasis, nutrition, cardiac function, coagulation, and biomineralization. The preferred phosphorylation motif of Fam20C is SxE/pS, and structural studies revealed that related member Fam20A allosterically activates Fam20C by forming a heterodimeric/tetrameric complex. Fam20A, a pseudokinase, is observed only in vertebrates. Loss-of-function genetic alterations in the Fam20 family lead to human diseases such as amelogenesis imperfecta, nephrocalcinosis, lethal and nonlethal forms of Raine syndrome with major skeletal defects, and altered phosphate homeostasis. Together, these three members of the Fam20 family modulate a diverse network of secretory pathway components playing crucial roles in health and disease. The overarching theme of this review is to highlight the progress that has been made in the emerging field of extracellular phosphorylation and the key roles secretory pathway kinases play in an ever-expanding number of cellular processes.
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8
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Yoshioka H, Wang YY, Suzuki A, Shayegh M, Gajera MV, Zhao Z, Iwata J. Overexpression of miR-1306-5p, miR-3195, and miR-3914 Inhibits Ameloblast Differentiation through Suppression of Genes Associated with Human Amelogenesis Imperfecta. Int J Mol Sci 2021; 22:ijms22042202. [PMID: 33672174 PMCID: PMC7926528 DOI: 10.3390/ijms22042202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 02/06/2023] Open
Abstract
Amelogenesis imperfecta is a congenital form of enamel hypoplasia. Although a number of genetic mutations have been reported in humans, the regulatory network of these genes remains mostly unclear. To identify signatures of biological pathways in amelogenesis imperfecta, we conducted bioinformatic analyses on genes associated with the condition in humans. Through an extensive search of the main biomedical databases, we found 56 genes in which mutations and/or association/linkage were reported in individuals with amelogenesis imperfecta. These candidate genes were further grouped by function, pathway, protein–protein interaction, and tissue-specific expression patterns using various bioinformatic tools. The bioinformatic analyses highlighted a group of genes essential for extracellular matrix formation. Furthermore, advanced bioinformatic analyses for microRNAs (miRNAs), which are short non-coding RNAs that suppress target genes at the post-transcriptional level, predicted 37 candidates that may be involved in amelogenesis imperfecta. To validate the miRNA–gene regulation association, we analyzed the target gene expression of the top seven candidate miRNAs: miR-3195, miR-382-5p, miR-1306-5p, miR-4683, miR-6716-3p, miR-3914, and miR-3935. Among them, miR-1306-5p, miR-3195, and miR-3914 were confirmed to regulate ameloblast differentiation through the regulation of genes associated with amelogenesis imperfecta in AM-1 cells, a human ameloblastoma cell line. Taken together, our study suggests a potential role for miRNAs in amelogenesis imperfecta.
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Affiliation(s)
- Hiroki Yoshioka
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA; (H.Y.); (A.S.); (M.S.); (M.V.G.)
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Yin-Ying Wang
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
| | - Akiko Suzuki
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA; (H.Y.); (A.S.); (M.S.); (M.V.G.)
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Meysam Shayegh
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA; (H.Y.); (A.S.); (M.S.); (M.V.G.)
| | - Mona V. Gajera
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA; (H.Y.); (A.S.); (M.S.); (M.V.G.)
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Human Genetics Center, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Correspondence: (Z.Z.); (J.I.)
| | - Junichi Iwata
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA; (H.Y.); (A.S.); (M.S.); (M.V.G.)
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Correspondence: (Z.Z.); (J.I.)
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Odontogenesis-associated phosphoprotein truncation blocks ameloblast transition into maturation in Odaph C41*/C41* mice. Sci Rep 2021; 11:1132. [PMID: 33441959 PMCID: PMC7807025 DOI: 10.1038/s41598-020-80912-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/21/2020] [Indexed: 01/29/2023] Open
Abstract
Mutations of Odontogenesis-Associated Phosphoprotein (ODAPH, OMIM *614829) cause autosomal recessive amelogenesis imperfecta, however, the function of ODAPH during amelogenesis is unknown. Here we characterized normal Odaph expression by in situ hybridization, generated Odaph truncation mice using CRISPR/Cas9 to replace the TGC codon encoding Cys41 into a TGA translation termination codon, and characterized and compared molar and incisor tooth formation in Odaph+/+, Odaph+/C41*, and OdaphC41*/C41* mice. We also searched genomes to determine when Odaph first appeared phylogenetically. We determined that tooth development in Odaph+/+ and Odaph+/C41* mice was indistinguishable in all respects, so the condition in mice is inherited in a recessive pattern, as it is in humans. Odaph is specifically expressed by ameloblasts starting with the onset of post-secretory transition and continues until mid-maturation. Based upon histological and ultrastructural analyses, we determined that the secretory stage of amelogenesis is not affected in OdaphC41*/C41* mice. The enamel layer achieves a normal shape and contour, normal thickness, and normal rod decussation. The fundamental problem in OdaphC41*/C41* mice starts during post-secretory transition, which fails to generate maturation stage ameloblasts. At the onset of what should be enamel maturation, a cyst forms that separates flattened ameloblasts from the enamel surface. The maturation stage fails completely.
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10
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Shin NY, Yamazaki H, Beniash E, Yang X, Margolis SS, Pugach MK, Simmer JP, Margolis HC. Amelogenin phosphorylation regulates tooth enamel formation by stabilizing a transient amorphous mineral precursor. J Biol Chem 2020; 295:1943-1959. [PMID: 31919099 DOI: 10.1074/jbc.ra119.010506] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/30/2019] [Indexed: 11/06/2022] Open
Abstract
Dental enamel comprises interwoven arrays of extremely long and narrow crystals of carbonated hydroxyapatite called enamel rods. Amelogenin (AMELX) is the predominant extracellular enamel matrix protein and plays an essential role in enamel formation (amelogenesis). Previously, we have demonstrated that full-length AMELX forms higher-order supramolecular assemblies that regulate ordered mineralization in vitro, as observed in enamel rods. Phosphorylation of the sole AMELX phosphorylation site (Ser-16) in vitro greatly enhances its capacity to stabilize amorphous calcium phosphate (ACP), the first mineral phase formed in developing enamel, and prevents apatitic crystal formation. To test our hypothesis that AMELX phosphorylation is critical for amelogenesis, we generated and characterized a hemizygous knockin (KI) mouse model with a phosphorylation-defective Ser-16 to Ala-16 substitution in AMELX. Using EM analysis, we demonstrate that in the absence of phosphorylated AMELX, KI enamel lacks enamel rods, the hallmark component of mammalian enamel, and, unlike WT enamel, appears to be composed of less organized arrays of shorter crystals oriented normal to the dentinoenamel junction. KI enamel also exhibited hypoplasia and numerous surface defects, whereas heterozygous enamel displayed highly variable mosaic structures with both KI and WT features. Importantly, ACP-to-apatitic crystal transformation occurred significantly faster in KI enamel. Secretory KI ameloblasts also lacked Tomes' processes, consistent with the absence of enamel rods, and underwent progressive cell pathology throughout enamel development. In conclusion, AMELX phosphorylation plays critical mechanistic roles in regulating ACP-phase transformation and enamel crystal growth, and in maintaining ameloblast integrity and function during amelogenesis.
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Affiliation(s)
- Nah-Young Shin
- The Forsyth Institute, Cambridge, Massachusetts 02142; Department of Developmental Biology, Harvard School of Dental Medicine, Boston, Massachusetts 02115
| | - Hajime Yamazaki
- The Forsyth Institute, Cambridge, Massachusetts 02142; Department of Developmental Biology, Harvard School of Dental Medicine, Boston, Massachusetts 02115; Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh, School of Dental Medicine, Pittsburgh, Pennsylvania 15213
| | - Elia Beniash
- Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh, School of Dental Medicine, Pittsburgh, Pennsylvania 15213
| | - Xu Yang
- Department of Oral Biology, Center for Craniofacial Regeneration, University of Pittsburgh, School of Dental Medicine, Pittsburgh, Pennsylvania 15213
| | - Seth S Margolis
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Megan K Pugach
- The Forsyth Institute, Cambridge, Massachusetts 02142; Department of Developmental Biology, Harvard School of Dental Medicine, Boston, Massachusetts 02115
| | - James P Simmer
- Department of Biologic and Material Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48108
| | - Henry C Margolis
- The Forsyth Institute, Cambridge, Massachusetts 02142; Department of Developmental Biology, Harvard School of Dental Medicine, Boston, Massachusetts 02115; Department of Periodontics and Preventive Dentistry, Center for Craniofacial Regeneration, University of Pittsburgh, School of Dental Medicine, Pittsburgh, Pennsylvania 15213.
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11
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Green DR, Schulte F, Lee KH, Pugach MK, Hardt M, Bidlack FB. Mapping the Tooth Enamel Proteome and Amelogenin Phosphorylation Onto Mineralizing Porcine Tooth Crowns. Front Physiol 2019; 10:925. [PMID: 31417410 PMCID: PMC6682599 DOI: 10.3389/fphys.2019.00925] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/09/2019] [Indexed: 01/13/2023] Open
Abstract
Tooth enamel forms in an ephemeral protein matrix where changes in protein abundance, composition and posttranslational modifications are critical to achieve healthy enamel properties. Amelogenin (AMELX) with its splice variants is the most abundant enamel matrix protein, with only one known phosphorylation site at serine 16 shown in vitro to be critical for regulating mineralization. The phosphorylated form of AMELX stabilizes amorphous calcium phosphate, while crystalline hydroxyapatite forms in the presence of the unphosphorylated protein. While AMELX regulates mineral transitions over space and time, it is unknown whether and when un-phosphorylated amelogenin occurs during enamel mineralization. This study aims to reveal the spatiotemporal distribution of the cleavage products of the most abundant AMLEX splice variants including the full length P173, the shorter leucine-rich amelogenin protein (LRAP), and the exon 4-containing P190 in forming enamel, all within the context of the changing enamel matrix proteome during mineralization. We microsampled permanent pig molars, capturing known stages of enamel formation from both crown surface and inner enamel. Nano-LC-MS/MS proteomic analyses after tryptic digestion rendered more than 500 unique protein identifications in enamel, dentin, and bone. We mapped collagens, keratins, and proteolytic enzymes (CTSL, MMP2, MMP10) and determined distributions of P173, LRAP, and P190 products, the enamel proteins enamelin (ENAM) and ameloblastin (AMBN), and matrix-metalloprotease-20 (MMP20) and kallikrein-4 (KLK4). All enamel proteins and KLK4 were near-exclusive to enamel and in excellent agreement with published abundance levels. Phosphorylated P173 and LRAP products decreased in abundance from recently deposited matrix toward older enamel, mirrored by increasing abundances of testicular acid phosphatase (ACPT). Our results showed that hierarchical clustering analysis of secretory enamel links closely matching distributions of unphosphorylated P173 and LRAP products with ACPT and non-traditional amelogenesis proteins, many associated with enamel defects. We report higher protein diversity than previously published and Gene Ontology (GO)-defined protein functions related to the regulation of mineral formation in secretory enamel (e.g., casein α-S1, CSN1S1), immune response in erupted enamel (e.g., peptidoglycan recognition protein, PGRP), and phosphorylation. This study presents a novel approach to characterize and study functional relationships through spatiotemporal mapping of the ephemeral extracellular matrix proteome.
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Affiliation(s)
- Daniel R Green
- The Forsyth Institute, Cambridge, MA, United States.,Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, United States
| | | | - Kyu-Ha Lee
- The Forsyth Institute, Cambridge, MA, United States.,Department of Oral Health Policy and Epidemiology, Harvard School of Dental Medicine, Boston, MA, United States
| | - Megan K Pugach
- The Forsyth Institute, Cambridge, MA, United States.,Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, United States
| | - Markus Hardt
- The Forsyth Institute, Cambridge, MA, United States.,Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, United States
| | - Felicitas B Bidlack
- The Forsyth Institute, Cambridge, MA, United States.,Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, United States
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12
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Abstract
Ameloblastin is the second most abundant enamel matrix protein, and is thought to be essential for ameloblast cell polarization, cell adhesion, and enamel mineralization. However, studies of ameloblastin's function and its molecular mechanism have been limited due to difficulty in obtaining recombinant ameloblastin in vitro. Here, we present a protocol for successful ameloblastin expression and purification in E. coli.
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13
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Lu T, Li M, Xu X, Xiong J, Huang C, Zhang X, Hu A, Peng L, Cai D, Zhang L, Wu B, Xiong F. Whole exome sequencing identifies an AMBN missense mutation causing severe autosomal-dominant amelogenesis imperfecta and dentin disorders. Int J Oral Sci 2018; 10:26. [PMID: 30174330 PMCID: PMC6119682 DOI: 10.1038/s41368-018-0027-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 11/25/2022] Open
Abstract
Tooth development is a complex process that involves precise and time-dependent orchestration of multiple genetic, molecular, and cellular interactions. Ameloblastin (AMBN, also named “amelin” or “sheathlin”) is the second most abundant enamel matrix protein known to have a key role in amelogenesis. Amelogenesis imperfecta (AI [MIM: 104500]) refers to a genetically and phenotypically heterogeneous group of conditions characterized by inherited developmental enamel defects. The hereditary dentin disorders comprise a variety of autosomal-dominant genetic symptoms characterized by abnormal dentin structure affecting either the primary or both the primary and secondary teeth. The vital role of Ambn in amelogenesis has been confirmed experimentally using mouse models. Only two cases have been reported of mutations of AMBN associated with non-syndromic human AI. However, no AMBN missense mutations have been reported to be associated with both human AI and dentin disorders. We recruited one kindred with autosomal-dominant amelogenesis imperfecta (ADAI) and dentinogenesis imperfecta/dysplasia characterized by generalized severe enamel and dentin defects. Whole exome sequencing of the proband identified a novel heterozygous C-T point mutation at nucleotide position 1069 of the AMBN gene, causing a Pro to Ser mutation at the conserved amino acid position 357 of the protein. Exfoliated third molar teeth from the affected family members were found to have enamel and dentin of lower mineral density than control teeth, with thinner and easily fractured enamel, short and thick roots, and pulp obliteration. This study demonstrates, for the first time, that an AMBN missense mutation causes non-syndromic human AI and dentin disorders. A mutation on a gene involved in healthy tooth development may cause both enamel and dentin disorders. The ameloblastin enamel protein, and its associated gene, AMBN, play vital roles in enamel formation and tooth remodelling. Mutations on AMBN can cause amelogenesis imperfecta (AI), a genetic and hereditory condition resulting in enamel defects and severe tooth decay. Now, Fu Xiong and Bu-Ling Wu at Southern Medical University in Guangzhou, China, and co-workers have identified an AMBN mutation found in both enamel and dentin defect disorders. The researchers analyzed extracted teeth from a Chinese patient with both AI and a severe dentin disorder, along with teeth from affected and non-affected members of the same family, and compared the results with a control group. They identified a rare mutation on AMBN common to all affected individuals.
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Affiliation(s)
- Ting Lu
- Department of Stomatology, Nanfang Hospital, College of Stomatology, Southern Medical University, Guangzhou, Guangdong, China.,Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Meiyi Li
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiangmin Xu
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China.,Guangdong Key Laboratory of Biological Chip, Guangzhou, Guangdong, China
| | - Jun Xiong
- Department of Laboratory Medicine, ZhuJiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Cheng Huang
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Xuelian Zhang
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Aiqin Hu
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Ling Peng
- Department of Stomatology, Nanfang Hospital, College of Stomatology, Southern Medical University, Guangzhou, Guangdong, China
| | - Decheng Cai
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Leitao Zhang
- Department of Stomatology, Nanfang Hospital, College of Stomatology, Southern Medical University, Guangzhou, Guangdong, China
| | - Buling Wu
- Department of Stomatology, Nanfang Hospital, College of Stomatology, Southern Medical University, Guangzhou, Guangdong, China.
| | - Fu Xiong
- Department of Medical Genetics, School of Basic Medicine Sciences, Southern Medical University, Guangzhou, Guangdong, China. .,Guangdong Key Laboratory of Biological Chip, Guangzhou, Guangdong, China.
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14
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Chaweewannakorn W, Ariyoshi W, Okinaga T, Fujita Y, Maki K, Nishihara T. Ameloblastin attenuates RANKL-mediated osteoclastogenesis by suppressing activation of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1). J Cell Physiol 2018; 234:1745-1757. [PMID: 30105896 DOI: 10.1002/jcp.27045] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/25/2018] [Indexed: 01/03/2023]
Abstract
Ameloblastin (Ambn) is an extracellular matrix protein and member of the family of enamel-related gene products. Like amelogenin, Ambn is mainly associated with tooth development, especially biomineralization of enamel. Previous studies have shown reductions in the skeletal dimensions of Ambn-deficient mice, suggesting that the protein also has effects on the differentiation of osteoblasts and/or osteoclasts. However, the specific pathways used by Ambn to influence osteoclast differentiation have yet to be identified. In the present study, two cellular models, one based on bone marrow cells and another on RAW264.7 cells, were used to examine the effects of Ambn on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis. The results showed that Ambn suppresses osteoclast differentiation, cytoskeletal organization, and osteoclast function by the downregulation of the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts, actin ring formation, and areas of pit resorption. The expression of the osteoclast-specific genes TRAP, MMP9, cathepsin K, and osteoclast stimulatory transmembrane protein (OC-STAMP) was abolished in the presence of Ambn, while that of nuclear factor of activated T cells cytoplasmic 1 (NFATc1), the master regulatory factor of osteoclastogenesis, was also attenuated by the downregulation of c-Fos expression. In Ambn-induced RAW264.7 cells, phosphorylation of cAMP-response element-binding protein (CREB), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK), but not extracellular signal-regulated kinase 1/2 (ERK1/2), was reduced. Calcium oscillation was also decreased in the presence of Ambn, suggesting its involvement in both RANKL-induced osteoclastogenesis and costimulatory signaling. B-lymphocyte-induced maturation protein-1 (Blimp1), a transcriptional repressor of negative regulators of osteoclastogenesis, was also downregulated by Ambn, resulting in the elevated expression of v-maf musculoaponeurotic fibrosarcoma oncogene family, protein B (MafB), B-cell lymphoma 6 (Bcl6), and interferon regulatory factor-8 (Irf8). Taken together, these findings suggest that Ambn suppresses RANKL-induced osteoclastogenesis by modulating the NFATc1 axis.
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Affiliation(s)
- Wichida Chaweewannakorn
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan.,Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Wataru Ariyoshi
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Toshinori Okinaga
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Yuko Fujita
- Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Kenshi Maki
- Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Tatsuji Nishihara
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
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15
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Stakkestad Ø, Lyngstadaas SP, Thiede B, Vondrasek J, Skålhegg BS, Reseland JE. Phosphorylation Modulates Ameloblastin Self-assembly and Ca 2+ Binding. Front Physiol 2017; 8:531. [PMID: 28798693 PMCID: PMC5529409 DOI: 10.3389/fphys.2017.00531] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/10/2017] [Indexed: 01/10/2023] Open
Abstract
Ameloblastin (AMBN), an important component of the self-assembled enamel extra cellular matrix, contains several in silico predicted phosphorylation sites. However, to what extent these sites actually are phosphorylated and the possible effects of such post-translational modifications are still largely unknown. Here we report on in vitro experiments aimed at investigating what sites in AMBN are phosphorylated by casein kinase 2 (CK2) and protein kinase A (PKA) and the impact such phosphorylation has on self-assembly and calcium binding. All predicted sites in AMBN can be phosphorylated by CK2 and/or PKA. The experiments show that phosphorylation, especially in the exon 5 derived part of the molecule, is inversely correlated with AMBN self-assembly. These results support earlier findings suggesting that AMBN self-assembly is mostly dependent on the exon 5 encoded region of the AMBN gene. Phosphorylation was significantly more efficient when the AMBN molecules were in solution and not present as supramolecular assemblies, suggesting that post-translational modification of AMBN must take place before the enamel matrix molecules self-assemble inside the ameloblast cell. Moreover, phosphorylation of exon 5, and the consequent reduction in self-assembly, seem to reduce the calcium binding capacity of AMBN suggesting that post-translational modification of AMBN also can be involved in control of free Ca2+ during enamel extra cellular matrix biomineralization. Finally, it is speculated that phosphorylation can provide a functional crossroad for AMBN either to be phosphorylated and act as monomeric signal molecule during early odontogenesis and bone formation, or escape phosphorylation to be subsequently secreted as supramolecular assemblies that partake in enamel matrix structure and mineralization.
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Affiliation(s)
- Øystein Stakkestad
- Department of Biomaterials, Institute of Clinical Dentistry, University of OsloOslo, Norway
| | - Ståle P Lyngstadaas
- Department of Biomaterials, Institute of Clinical Dentistry, University of OsloOslo, Norway
| | - Bernd Thiede
- Section for Biochemistry and Molecular Biology, Department of Biosciences, University of OsloOslo, Norway
| | - Jiri Vondrasek
- Department of Bioinformatics, Institute of Organic Chemistry and Biochemistry, Czech Academy of SciencesPrague, Czechia
| | - Bjørn S Skålhegg
- Division of Molecular Nutrition, Department of Nutrition, University of OsloOslo, Norway
| | - Janne E Reseland
- Department of Biomaterials, Institute of Clinical Dentistry, University of OsloOslo, Norway
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16
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Lignon G, Beres F, Quentric M, Rouzière S, Weil R, De La Dure-Molla M, Naveau A, Kozyraki R, Dessombz A, Berdal A. FAM20A Gene Mutation: Amelogenesis or Ectopic Mineralization? Front Physiol 2017; 8:267. [PMID: 28515694 PMCID: PMC5413562 DOI: 10.3389/fphys.2017.00267] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/11/2017] [Indexed: 12/12/2022] Open
Abstract
Background and objective:FAM20A gene mutations result in enamel renal syndrome (ERS) associated with amelogenesis imperfecta (AI), nephrocalcinosis, gingival fibromatosis, and impaired tooth eruption. FAM20A would control the phosphorylation of enamel peptides and thus enamel mineralization. Here, we characterized the structure and chemical composition of unerupted tooth enamel from ERS patients and healthy subjects. Methods: Tooth sections were analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF). Results: SEM revealed that prisms were restricted to the inner-most enamel zones. The bulk of the mineralized matter covering the crown was formed by layers with varying electron-densities organized into lamellae and micronodules. Tissue porosity progressively increased at the periphery, ending with loose and unfused nanonodules also observed in the adjoining soft tissues. Thus, the enamel layer covering the dentin in all ERS patients (except a limited layer of enamel at the dentino-enamel junction) displayed an ultrastructural globular pattern similar to one observed in ectopic mineralization of soft tissue, notably in the gingiva of Fam20a knockout mice. XRD analysis confirmed the existence of alterations in crystallinity and composition (vs. sound enamel). XRF identified lower levels of calcium and phosphorus in ERS enamel. Finally, EDS confirmed the reduced amount of calcium in ERS enamel, which appeared similar to dentin. Conclusion: This study suggests that, after an initial normal start to amelogenesis, the bulk of the tissue covering coronal dentin would be formed by different mechanisms based on nano- to micro-nodule aggregation. This evocated ectopic mineralization process is known to intervene in several soft tissues in FAM20A gene mutant.
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Affiliation(s)
- Guilhem Lignon
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France
| | - Fleur Beres
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France
| | - Mickael Quentric
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France
| | - Stephan Rouzière
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique, Univ. Paris-Sud, Université Paris-SaclayOrsay Cedex, France
| | - Raphael Weil
- Laboratoire de Physique des Solides, Centre National de la Recherche Scientifique, Univ. Paris-Sud, Université Paris-SaclayOrsay Cedex, France
| | - Muriel De La Dure-Molla
- Reference Center of Rare Buccal and Facial Malformations MAFACE-Rothschild Hospital, APHPParis, France
| | - Adrien Naveau
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France
| | - Renata Kozyraki
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France
| | - Arnaud Dessombz
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France
| | - Ariane Berdal
- Molecular Oral Pathophysiology, Cordeliers Research Center, UMRS 1138 Institut National de la Santé et de la Recherche Médicale, Paris-Descartes, Pierre-et-Marie-Curie, Paris-Diderot UniversitiesParis, France.,Reference Center of Rare Buccal and Facial Malformations MAFACE-Rothschild Hospital, APHPParis, France
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