Fibronectin binding sites on cultured human fibroblasts were localized by high voltage electron microscopy using either 5- or 18-nm colloidal gold beads (Au5 or Au18) bound to intact fibronectin, the 70-kD amino-terminal fragment of fibronectin that blocks incorporation of exogenous fibronectin into extracellular matrix, or 160-180-kD fragments of fibronectin with cell adhesion and heparin-binding activities. Binding sites for Au18-fibronectin on the cell surface were localized to specific regions along the edge of the fibroblast and on retraction fibers. Au18-fibronectin complexes at these sites were initially localized in clusters that co-aligned with intracellular microfilament bundles. With longer incubations, Au18-fibronectin complexes were arranged into long fibrillar networks on the cell surface and in the extracellular space. The appearance of Au18-fibronectin in these fibrillar networks and disappearance of clusters of Au18-fibronectin suggest that Au18-fibronectin complexes are arranged into matrix at specific regions of the cell surface. Au18-70-kD fragment complexes initially had a similar distribution to Au18-fibronectin complexes. With longer incubations, Au18-70-kD fragment complexes were found in long linear arrangements on the cell surface. Double labeling experiments using Au18-70-kD fragment and Au5-160-180-kD fragments showed that the 70-kD fragment and the 160-180-kD fragments bind to different regions of the cell.
Article| January 01 1987
Localization of cell surface sites involved in fibronectin fibrillogenesis.
D M Peters
D F Mosher
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1987) 104 (1): 121–130.
D M Peters, D F Mosher; Localization of cell surface sites involved in fibronectin fibrillogenesis.. J Cell Biol 1 January 1987; 104 (1): 121–130. doi: https://doi.org/10.1083/jcb.104.1.121
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