Enhanced osteoblast adhesion on transglutaminase 2-crosslinked fibronectin

• Published in: Amino acids Vol. 36; no. 4; pp. 747 - 753
• Main Authors: Forsprecher, J., Wang, Z., Nelea, V., Kaartinen, M. T.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.04.2009; Springer Nature B.V
• Subjects: 3T3 Cells; Analytical Chemistry; Animals; Biochemical Engineering; Biochemistry; Biomedical and Life Sciences; Cattle; Cell Adhesion; Cell adhesion & migration; Fibronectins - chemistry; Fibronectins - metabolism; GTP-Binding Proteins - chemistry; GTP-Binding Proteins - metabolism; Guinea Pigs; Integrin beta1 - metabolism; Life Sciences; Mice; Microscopy, Fluorescence; Neurobiology; Original Article; Osteoblasts - cytology; Osteoblasts - enzymology; Osteoblasts - metabolism; Polymers - chemistry; Proteins; Proteomics; Surface Properties; Transglutaminases - chemistry; Transglutaminases - metabolism; Integrin clustering; Osteoblast adhesion; Transglutaminase 2; Fibronectin; Protein crosslinking
• ISSN: 0939-4451; 1438-2199
• DOI: 10.1007/s00726-008-0125-7

Fibronectin (FN) is a cell adhesion protein that binds integrins in a process also involving the protein-crosslinking enzyme transglutaminase 2 (TG2) as a co-receptor. The cell-adhesive property of TG2 has been linked to a complex formation with FN and to its ability to crosslink and polymerize FN on the cell surface. We tested here the effects of extracellular FN, before and after in vitro crosslinking and polymerization by TG2, on MC3T3-E1 osteoblast adhesion. We show that TG2-mediated crosslinking creates large, compacted chain-like protein clusters that include both TG2 and FN molecules as analyzed by Western blotting and atomic force microscopy. Crosslinking of FN significantly promotes osteoblast adhesion as measured by crystal violet staining, and enhances β 1 -integrin clustering on the cell surface as visualized by immunofluorescence microscopy. We hypothesize that TG2-mediated crosslinking enhances the cell-adhesive properties of FN by increasing the molecular rigidity of FN in the extracellular matrix.