Intrinsically Disordered Enamel Matrix Protein Ameloblastin Forms Ribbon-like Supramolecular Structures via an N-terminal Segment Encoded by Exon 5

Wald, Tomáš; Osičková, Adriana; Šulc, Miroslav; Benada, Oldřich; Semerádtová, Alena; Rezabkova, Lenka; Veverka, Václav; Bednářová, Lucie; Malý, Jan; Macek, Pavel; Šebo, Peter; Slaby, Ivan; Vondrášek, Jiřı́; Osička, Radim

doi:10.1074/jbc.m113.456012

Cited by 37 publications

(77 citation statements)

References 65 publications

(96 reference statements)

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“…Janet Moradian-Oldak and her collaborators John Evans and Wendy Shaw investigated the secondary structure of amelogenin and ameloblastin, two major enamel proteins. Both were shown to be IDPs [43,44], their binding partners were other IDPs (enamelin and tuftelin) and HA. Enamel formation does not occur on a collagen matrix; rather it forms under the direction of the previously mentioned IDPs.…”

Section: Intrinsically Disordered Proteins (Idps)mentioning

confidence: 99%

Intrinsically disordered proteins and biomineralization

2016

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In vertebrates and invertebrates biomineralization is controlled by the cell and the proteins they produce. A large number of these proteins are intrinsically disordered, gaining some secondary structure when they interact with their binding partners. These partners include the component ions of the mineral being deposited, the crystals themselves, the template on which the initial crystals form, and other intrinsically disordered proteins and peptides. This review speculates why intrinsically disordered proteins are so important for biomineralization, providing illustrations from the SIBLING (small integrin binding N-glycosylated) proteins and their peptides. It is concluded that the flexible structure, and the ability of the intrinsically disordered proteins to bind to a multitude of surfaces is crucial, but details on the precise-interactions, energetics and kinetics of binding remain to be determined.

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Section: Intrinsically Disordered Proteins (Idps)mentioning

confidence: 99%

Intrinsically disordered proteins and biomineralization

2016

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“…Enamel formation, or amelogenesis, is initiated when the ectoderm-derived inner enamel epithelial cells (IEE) exchange signals with neural ectomesenchyme-derived cells resulting in IEE cell elongation, polarization and differentiation to ameloblasts cells that synthesize and secrete the enamel matrix proteins. The two most abundant proteins in the enamel matrix, amelogenin [6, 7] and ameloblastin [8], are intrinsically disordered proteins that undergo self-assembly to form a matrix that is guides formation of the carbonated hydroxyapatite (HAP) mineral phase [9–11]. Simultaneously with enamel matrix formation, the ameloblasts also direct enamel protein degradation and resorption resulting in almost complete replacement of the matrix by mineral.…”

Section: 0 Introductionmentioning

confidence: 99%

Bioactive nanofibers enable the identification of thrombospondin 2 as a key player in enamel regeneration

et al. 2015

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Tissue regeneration and development involves highly synchronized signals both between cells and with the extracellular environment. Biomaterials can be tuned to mimic specific biological signals and control cell response(s). As a result, these materials can be used as tools to elucidate cell signaling pathways and candidate molecules involved with cellular processes. In this work, we explore enamel-forming cells, ameloblasts, which have a limited regenerative capacity. By exposing undifferentiated cells to a self-assembling matrix bearing RGDS epitopes, we elicited a regenerative signal at will that subsequently led to the identification of thrombospondin 2 (TSP2), an extracellular matrix protein that has not been previously recognized as a key player in enamel development and regeneration. Targeted disruption of the thrombospondin 2 gene (Thbs2) resulted in enamel formation with a disordered architecture that was highly susceptible to wear compared to their wild-type counterparts. To test the regenerative capacity, we injected the bioactive matrix into the enamel organ and discovered that the enamel organic epithelial cells in TSP-null mice failed to polarize on the surface of the artificial matrix, greatly reducing integrin β1 and Notch1 expression levels, which represent signaling pathways known to be associated with TSP2. These results suggest TSP2 plays an important role in regulating cell-matrix interactions during enamel formation. Exploiting the signaling pathways activated by biomaterials can provide insight into native signaling mechanisms crucial for tooth development and cell-based strategies for enamel regeneration.

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“…In this respect they are like many other unfolded proteins including their evolutionary ancestor ODAM (Murphy, et al 2008). Another SCPP, ameloblastin, when expressed recombinantly in an unphosphorylated form, forms twisted, ribbon-like, structures with an average width and thickness of 18 and 0.34 nm (Wald, et al 2013). …”

Section: Caseins Can Form Amyloid Fibrilsmentioning

confidence: 99%

Casein structures in the context of unfolded proteins

Thorn

Ecroyd

Carver

et al. 2015

International Dairy Journal

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Caseins were among the first proteins to be recognised as functional but unfolded. Many others are now known, providing better models of casein behaviour than either detergents or folded proteins. Caseins are members of a paralogous group of unfolded phosphoproteins, some of which share the ability to sequester amorphous calcium phosphate through phosphate centres. Non-covalent interactions of caseins can be through Pro-and Gln-rich sequences. Similar sequences in other unfolded proteins can also form open and highly hydrated structures such as gels, mucus and slimes. Many unfolded proteins, including κ-and αS2-caseins, can form amyloid fibrils under physiological conditions. The sequence-specific interactions that lead to fibrils can be reduced or eliminated by low specificity interactions among a mixture of caseins to yield, instead, amorphous aggregates. The size of amorphous whole casein aggregates is limited by the C-terminal half of κ-casein whose sequence resembles that of a soluble mucin. Disciplines Medicine and Health Sciences | Social and Behavioral Sciences

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Intrinsically Disordered Enamel Matrix Protein Ameloblastin Forms Ribbon-like Supramolecular Structures via an N-terminal Segment Encoded by Exon 5

Cited by 37 publications

References 65 publications

Intrinsically disordered proteins and biomineralization

Intrinsically disordered proteins and biomineralization

Bioactive nanofibers enable the identification of thrombospondin 2 as a key player in enamel regeneration

Casein structures in the context of unfolded proteins

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