Analysis of co-assembly and co-localization of ameloblastin and amelogenin

Mazumder, Parichita; Prajapati, Saumya; Lokappa, Sowmya Bekshe; Gallon, Victoria A.; Moradian‐Oldak, Janet

doi:10.3389/fphys.2014.00274

Cited by 23 publications

(37 citation statements)

References 49 publications

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“…S7A). This process, resulting in the formation of regular bundles of crystallites within prisms and the IPM, might occur via a direct interaction between AMEL and AMBN (21)(22)(23). Moreover, the N-terminal moiety of AMBN was found to concentrate along the prism/IPM boundary and to form a protein sheath around growing prisms (39,41).…”

Section: Discussionmentioning

confidence: 98%

Intrinsically disordered proteins drive enamel formation via an evolutionarily conserved self-assembly motif

Wald

Špoutil

Osičková

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The formation of mineralized tissues is governed by extracellular matrix proteins that assemble into a 3D organic matrix directing the deposition of hydroxyapatite. Although the formation of bones and dentin depends on the self-assembly of type I collagen via the Gly-X-Y motif, the molecular mechanism by which enamel matrix proteins (EMPs) assemble into the organic matrix remains poorly understood. Here we identified a Y/F-x-x-Y/L/F-x-Y/F motif, evolutionarily conserved from the first tetrapods to man, that is crucial for higher order structure self-assembly of the key intrinsically disordered EMPs, ameloblastin and amelogenin. Using targeted mutations in mice and high-resolution imaging, we show that impairment of ameloblastin self-assembly causes disorganization of the enamel organic matrix and yields enamel with disordered hydroxyapatite crystallites. These findings define a paradigm for the molecular mechanism by which the EMPs self-assemble into supramolecular structures and demonstrate that this process is crucial for organization of the organic matrix and formation of properly structured enamel.

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Section: Discussionmentioning

confidence: 98%

Intrinsically disordered proteins drive enamel formation via an evolutionarily conserved self-assembly motif

Wald

Špoutil

Osičková

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…These mice also have reduced expression of amelogenin with no apparent change in the levels of several other ameloblast-produced proteins [52,53] indicating that there must be some interaction between amelogenin and ameloblastin during the mineralization process. Studying mouse ameloblasts at different stages of development, Moradian Oldak [54] reported amelogenin and ameloblastin co-localized near the secretory face of ameloblasts at the earliest stages of their formation; with maturation, ameloblastin was lost from the enamel surface. Additionally, they found using circular dichroism, that amelogenin and ameloblastin could form stable complexes.…”

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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“…These coefficients quantified the colocalized fraction of each molecular species in the same spatial regions of a microscopic image, as previously described (Gallon et al 2013;Mazumder et al 2014). …”

Section: In Vivo Quantitative Co-localization Analysismentioning

confidence: 99%

Amelogenin-Ameloblastin Spatial Interaction around Maturing Enamel Rods

et al. 2016

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Amelogenin and ameloblastin are 2 extracellular matrix proteins that are essential for the proper development of enamel. We recently reported that amelogenin and ameloblastin colocalized during the secretory stage of enamel formation when nucleation of enamel crystallites occurs. Direct interactions between the 2 proteins have been also demonstrated in our in vitro studies. Here, we explore interactions between their fragments during enamel maturation. We applied in vivo immunofluorescence imaging, quantitative colocalization analysis, and a new FRET (fluorescence resonance energy transfer) technique to demonstrate ameloblastin and amelogenin interaction in the maturing mouse enamel. Using immunochemical analysis of protein samples extracted from 8-d-old (P8) first molars from mice as a model for maturation-stage enamel, we identified the ~17-kDa ameloblastin (Ambn-N) and the TRAP (tyrosine-rich amelogenin peptide) fragments. We used Ambn-N18 and Ambn-M300 antibodies raised against the N-terminal and C-terminal segments of ameloblastin, as well as Amel-FL and Amel-C19 antibodies against full-length recombinant mouse amelogenin (rM179) and C-terminal amelogenin, respectively. In transverse sections, co-localization images of N-terminal fragments of amelogenin and ameloblastin around the prism boundary revealed the "fish net" pattern of the enamel matrix. Using in vivo FRET microscopy, we further demonstrated spatial interactions between amelogenin and ameloblastin N-terminal fragments. In the maturing mouse enamel, the association of these residual protein fragments created a discontinuity between enamel rods, which we suggest is important for support and maintenance of enamel rods and eventual contribution to unique enamel mechanical properties. We present data that support cooperative functions of enamel matrix proteins in mediating the structural hierarchy of enamel and that contribute to our efforts to design and develop enamel biomimetic material.

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Analysis of co-assembly and co-localization of ameloblastin and amelogenin

Cited by 23 publications

References 49 publications

Intrinsically disordered proteins drive enamel formation via an evolutionarily conserved self-assembly motif

Intrinsically disordered proteins drive enamel formation via an evolutionarily conserved self-assembly motif

Intrinsically disordered proteins and biomineralization

Amelogenin-Ameloblastin Spatial Interaction around Maturing Enamel Rods

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