Tenascin-X: beyond the architectural function
Résumé
Tenascin-X is the largest member of the tenascin (TN) family of evolutionary conserved extracellular matrix glycoproteins, which also comprises TN-C, TN-R and TN-W. Among this family, TN-X is the only member described so far to exert a crucial architectural function as evidenced by a connective tissue disorder (a recessive form of Ehlers-Danlos syndrome) resulting from a loss-of-function of this glycoprotein in humans and mice. However, TN-X is more than an architectural protein, as it displays features of a matricellular protein by modulating cell adhesion. However, the cellular functions associated with the anti-adhesive properties of TN-X have not yet been revealed. Recent findings indicate that TN-X is also an extracellular regulator of signaling pathways. Indeed, TN-X has been shown to regulate the bioavailability of the Transforming Growth Factor (TGF)-β and to modulate epithelial cell plasticity. The next challenges will be to unravel whether the signaling functions of TN-X are functionally linked to its matricellular properties.
Mots clés
ECM
extracellular matrix
EDS
Ehlers-Danlos syndrome
EGF
epidermal growth factor
EMT
epithelial-to-mesenchymal transition
Ehlers-Danlos syndrome (EDS)
FAK
focal adhesion kinase
FBG
fibrinogen-like domain
FNIII
fibronectin type III module
LAP
latency associated peptide
MMP
matrix metalloproteinase
SLC
small latent complex
TGF-β
TGF-β activation
TN
tenascin
TSP-1
thrombospondin-1
VEGF
vascular endothelial growth factor
cell signaling
epithelial-to-mesenchymal transition (EMT)
integrin α11β1
matricellular protein
tenascin-X
transforming growth factor-β
integrin a11b1
matricellu- lar protein
TGF-b activation Abbreviations: ECM
epithelial-to-mesen- chymal transition
latency associ- ated peptide
TGF-b
transforming growth factor-b
TSP- 1