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The carboxyl‐terminal fragment of osteopontin suppresses arginine‐glycine‐asparatic acid‐dependent cell adhesion
Author(s) -
Takahashi Kazuhisa,
Takahashi Fumiyuki,
Tanabe Kenneth K.,
Takahashi Hideki,
Fukuchi Yoshinosuke
Publication year - 1998
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549800204632
Subject(s) - osteopontin , cell adhesion , cleavage (geology) , chemistry , thrombin , microbiology and biotechnology , biochemistry , glycoprotein , cell adhesion molecule , cell , biology , immunology , platelet , paleontology , fracture (geology)
Osteopontin (OPN) is a secreted glycoprotein implicated in cell adhesion. It contains the arginine‐glycine‐asparatic acid (RGD) cell adhesive domain and the thrombin cleavage sequence. Although thrombin cleavage of OPN has been shown to be of physiological importance, the function of C‐terminal OPN fragment cleaved by thrombin remains unknown. To determine its role, we performed cell adhesion assays using glutathione S‐transferase‐OPN fusion protein fragments and full‐length OPN fusion protein. The N‐terminal fragment containing RGD motif promoted enhanced adhesion of mouse and human fibroblasts by 2.9 and 2.8 folds in comparison with full‐length OPN, respectively. The enhanced adhesion of both cells mediated by N‐terminal fragment was significantly suppressed by addition of C‐terminal fragment lacking RGD motif that has less cell adhesive property than full‐length OPN. These results suggest that the C‐terminal domain may play a pivotal role in regulating OPN functions by suppressing the RGD‐dependent cell adhesion.