TY - JOUR
T1 - Focal adhesion sites and the removal of substratum-bound fibronectin
AU - Grinnell, F.
PY - 1986/12/1
Y1 - 1986/12/1
N2 - Fibronectin was not removed from the substratum beneath focal adhesion sites when fibroblasts spread in serum-free medium on adsorbed fibronectin substrata, or when fibroblasts spread in serumcontaining medium on covalently cross-linked fibronectin substrata. Under these conditions, there was colocalization between 140-kD fibroneetin receptors and focal adhesion sites. It was concluded that removal of adsorbed fibronectin from beneath focal adhesion sites was a mechanical process that required serum. The effect of serum was nonspecific since serum could be replaced by equivalent concentrations of serum albumin, ovalbumin, or gamma globulins. Quantitative measurements indicated that the presence of proteins in the incubation medium weakens the interaction of fibronectin with the substratum, thereby allowing the adsorbed protein to be removed from the substratum at sites of high stress. After removing fibronectin from the substratum, cells reorganized this material into patches and fibrils beneath cells, and the reorganized fibronectin colocalized with fibronectin receptors. Some of the patches of fibronectin were phagocytosed. The fibronectin fibrils were observed to be in register with actin filament bundles and sometimes translocated to the upper cell surfaces. It is proposed that removal of fibronectin from beneath focal adhesion sites is an example of how cells can modify their extracellular matrices through contractile activity.
AB - Fibronectin was not removed from the substratum beneath focal adhesion sites when fibroblasts spread in serum-free medium on adsorbed fibronectin substrata, or when fibroblasts spread in serumcontaining medium on covalently cross-linked fibronectin substrata. Under these conditions, there was colocalization between 140-kD fibroneetin receptors and focal adhesion sites. It was concluded that removal of adsorbed fibronectin from beneath focal adhesion sites was a mechanical process that required serum. The effect of serum was nonspecific since serum could be replaced by equivalent concentrations of serum albumin, ovalbumin, or gamma globulins. Quantitative measurements indicated that the presence of proteins in the incubation medium weakens the interaction of fibronectin with the substratum, thereby allowing the adsorbed protein to be removed from the substratum at sites of high stress. After removing fibronectin from the substratum, cells reorganized this material into patches and fibrils beneath cells, and the reorganized fibronectin colocalized with fibronectin receptors. Some of the patches of fibronectin were phagocytosed. The fibronectin fibrils were observed to be in register with actin filament bundles and sometimes translocated to the upper cell surfaces. It is proposed that removal of fibronectin from beneath focal adhesion sites is an example of how cells can modify their extracellular matrices through contractile activity.
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U2 - 10.1083/jcb.103.6.2697
DO - 10.1083/jcb.103.6.2697
M3 - Article
C2 - 2947902
AN - SCOPUS:0022896245
SN - 0021-9525
VL - 103
SP - 2697
EP - 2706
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 6
ER -