Actin-Associated Proteins in Ameloblast Differentiation

Abstract

Focal contacts are systems of adherens junctions of the cell-extracellular matrix type, which allow the transfer of fundamental signals from the extracellular matrix to nuclear compartments, capable of regulating adhesion, proliferation, migration and differentiation of cells. Recently, many authors have concentrated their attention on epitheliomesenchymal interactions which guide organogenesis of dental germ, identifying numerous growth and differentiation factors and having the inner enamel epithelial cells of the enamel organ as a target. Given that the two cellular compartments in their tooth germ are separated by a basal membrane and by an extracellular matrix, which touches it, we wanted to evaluate the presence of focal contacts through the identification of talin and vinculin, proteins of the actin-associated protein complex. In this study we utilized the hemimandibles of young Wistar rats and we extracted the related odontogenic tooth organs present at their apical end. Specimens are processed with antibody against vinculin and talin. Results show that these junctional system proteins are present at the apical poles of both cellular compartments suggesting that putative epithelial-mesenchymal interactions, other than marker molecules, may use focal contacts as a system for transmission of signals.

Epithelial‐specific knockout of the Rac1 gene leads to enamel defects

“…On the other hand, attachment of cells to the extracellular matrix results in the clustering of integrins and the formation of focal complexes, which are associated with a variety of dynamic changes in cytoplasmic proteins and the organization of the actin cytoskeleton for maintaining cell growth, survival, and directing cell migration (13). It has been suggested that the cytoskeletal organization in ameloblasts may determine the formation of distal terminal junction complexes and the cyclic activity of ameloblast secretory end‐pieces known as Tomes’ processes and be involved in pattern formation of the enamel matrix (14–17).…”