Regulation of fibronectin receptor distribution by transformation, exogenous fibronectin, and synthetic peptides.

Abstract

Abstract. Recent studies have shown that fibronectin and its 140K membrane receptor complex are spatially associated with microfilaments to form cell surface linkage complexes which are thought to mediate adhesive interactions between fibroblasts and their substrata. We examined the regulation of the organization of these cell surface structures in transformed and fibronectin-reconstituted cells as well as in cells treated with a competitive synthetic peptide inhibitor of fibronectin binding to its receptor. Correlative localization experiments with interference reflection microscopy and double-label or triple-label immunofluorescence revealed a concomitant loss of fibronectin, 140K receptor, and alpha-actinin colocalization at cell substratum extracellular matrix contact sites after transformation of chick fibroblasts by wild-type or temperature-sensitive Rous sarcoma viruses (RSV). Western and dot immunoblot analyses established that although similar total quantities of intact 140K molecules were present in the transformed cell cultures, significantly more was released into the culture medium of transformed cells. The 140K molecules on transformed cells were available for interaction with exogenously added fibronectin, which could reconstitute fibronectin-140K linkage complexes. In such fibronectin reconstitution experiments, many cells expressed both fibronectin-140K-actin linkage complexes and RSV pp60 s~, indicating that the morphological reversion could occur even in the continued presence of RSV transformation. The synthetic peptide Gly-ArgGly-Asp-Ser derived from the sequence of the cellbinding region of fibronectin could also prevent the organization of fibronectin-140K linkage complexes. Our results suggest that fibronectin interaction with cells regulates the organization of fibronectin receptor complexes and cytoskeletal components at the cell surface.

Cell to substratum adhesion is involved in v-Src-induced cellular protein tyrosine phosphorylation: implication for the adhesion-regulated protein tyrosine phosphatase activity

“…Our data showed that cell to substratum adhesion, rather paradoxically, accompanies an induction of the v-Src mediated aberrant protein tyrosine phosphorylation in v-Src transformed ®broblasts. Moreover, actin stress ®bers were formed in our v-Src 3Y1 cells upon adhesion of the cells to ®bronectin, as has been shown previously (Yamada et al, 1976;Ali et al, 1977;Chen et al, 1986). Our results thus indicated that elevation in the level of ECM protein could override, to some extents, the disorganization of cytoskeletal architecture in vSrc cells in spite of the induction of high level of aberrant tyrosine phosphorylation.…”

“…The production of ®bronectin-degrading proteases in v-Src transformed cells (Chen et al, 1984;Fairbairn et al, 1985;Chen and Chen, 1987) and reduction in the level of ECM proteins such as ®bronectin or its mRNA expression (Hynes and Wyke, 1975;Olden and Yamada, 1977;Hayman et al, 1981Hayman et al, , 1982Tyagi et al, 1983) are also involved in the reduced adherence of the transformed cell to culture dishes. On the other hand, it has been demonstrated that cell morphology, cytoskeletal architecture and adherence of cells to culture dishes can be restored to some extents to a normal state when the amounts of the ECM proteins are increased (Yamada et al, 1976;Ali et al, 1977;Chen et al, 1986).…”

Regulation of fibronectin receptor distribution [published erratum appears in J Cell Biol 1992 Jul;118(2):491]

“…Similarly the distribution of the fibronectin receptor with plasma membrane-associated fibronectin fibrils requires the interaction of the fibronectin receptor with extracellular fibrils (Chen et al, 1986;Giancotti et al, 1986;Akiyama et al, 1989;Roman et al, 1989) . These previous experiments demonstrated that the regulation of integrin receptor distribution requires the interaction of the receptor with its ligand and that the distribution of ligand determines the distribution of its receptor.…”

Posterior extension of the chick nephric (Wolffian) duct: The role of fibronectin and NCAM polysialic acid

“…After rehydration through a n ethanol series, the specimens were rinsed in PBS and then immersed in rabbit pre-immune serum (diluted 1:20 with PBS) overnight a t 4°C. After washing in PBS they were then treated with the appropriate antibody raised in rabbits against fibronectin (Mills et al, 1990), 61 integrin (Chen et al, 1986), or a monoclonal antibody (5A5) against PSA (Acheson et al, 1991). The number of specimens observed was: anti-fibronectin, 5; anti-pl integrin, 6; and anti-PSA, 10.…”