Assembly and alignment of fibronectin-coated gold beads into fibrils by human skin fibroblasts.
The assembly of fibronectin into fibrils was monitored by high voltage electron microscopy using 18 nm colloidal gold beads bound to fibronectin (Au18-fibronectin) or an amino terminal 70 kd fragment of fibronectin (Au18-70 kd) that blocks the incorporation of fibronectin into disulfide bonded fibrils. Subconfluent cultures of human skin fibroblasts were incubated with the colloidal gold complexes for 0.25, 0.5, 1.5 and 5 h. In fibroblast cultures incubated with Au18-fibronectin and Au18-70 kd fragments for 0.25 and 0.5 h, the complexes of Au18-fibronectin and Au18-70 kd fragment were observed bound to the cell surface in clusters near bundles of intracellular microfilaments, usually along the lateral edges of the fibroblasts. Fibroblast cultures incubated with Au18-fibronectin and Au18-70 kd fragment for 1.5 and 5 h showed a more linear arrangement of the Au18-fibronectin and Au18-70 kd fragment along the lateral and retracting edges and on filopodia. This alignment of Au18-fibronectin into linear arrangements on the fibroblast cell surface suggests that the assembly of fibronectin fibrils occurs on specific regions of the fibroblast.
D008841:Actin Cytoskeleton / Q000648:ultrastructure*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000648:ultrastructure*; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000648:ultrastructure; D005353:Fibronectins / Q000378:metabolism*; D006046:Gold; D006801:Humans; D007231:Infant, Newborn; D008854:Microscopy, Electron; D012867:Skin / Q000378:metabolism / Q000648:ultrastructure*
D005353:Fibronectins; D006046:Gold