Association of fibronectin and vinculin with focal contacts and stress fibers in stationary hamster fibroblasts.

Singer, Irwin

doi:10.1083/jcb.92.2.398

Cited by 139 publications

(79 citation statements)

References 49 publications

(67 reference statements)

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“…The results also agree with a recent report showing that u-PA mRNA is increased in quiescent cultured fibroblasts and keratinocytes upon growth stimulation (21). The elongation of the vinculin plaques in quiescent WI-38 fibroblasts is consistent with earlier findings (43), also describing the induction of fibronexus contact sites under similar conditions. The well-spread phenotype is thought to be maintained by tensile forces mediated by the actincontaining microfilaments (20).…”

Section: Discussionsupporting

confidence: 93%

See 1 more Smart Citation

Ultrastructural localization of plasma membrane-associated urokinase-type plasminogen activator at focal contacts.

Pöllänen

Hedman

Nielsen

et al. 1988

The Journal of Cell Biology

297

117

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Abstract.We have recently shown that urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor type 1 are both found extracellularly beneath cultured human skin fibroblasts and HT-1080 sarcoma cells, but in distinct localizations. Here, the ultrastructural distribution of u-PA was studied using immunoferritin electron microscopy. In HT-1080 cells, u-PA on the extracellular aspect of the plasma membrane was detected at sites of direct contact of the cell with the growth substratum beneath all parts of the ventral cell surface. The ferritin-labeled adhesion plaques, which were enriched in submembraneous microfilaments, were frequently seen at the leading lamellae of the cells as well as in lamellipodia and microspikes. Besides the cell-substratum adhesion plaques, ferritin label was detected at cell-cell contact sites. Double-label immunofluorescence showed a striking colocalization of u-PA and vinculin in both HT-1080 cells and WI-38 lung fibroblasts, which is consistent with u-PA being a focal contact component. The u-PAcontaining focal contacts of WI-38 cells had no direct codistribution with fibronectin fibrils. In WI-38 cells made stationary by cultivation in a medium containing 0.5 % FCS, vinculin plaques became highly elongated and more centrally located, whereas u-PA immunolabel disappeared from such focal adhesions. These findings show that plasma membrane-associated u-PA is an intrinsic component of focal contacts, where, we propose, it enables directional proteolysis for cell migration and invasion. rIESIVE interactions of cells with the extracellular matrix and their reversal are critical events for morphogenetic movements during embryonic development and for cancer cell invasion during metastasis (30, 49). The molecular structures at the sites where cultured cells contact each other and the growth substratum are thus of great interest. Focal contacts, the sites of closest cell-substratum apposition, can be visualized either by electron microscopy (1) or by interference reflection microscopy (23). Focal contacts are localized at the termini of actin-containing microfilament bundles, and contain vinculin (7, 19) and talin (6) on the cytoplasmic side, but apparently do not have fibronectin on the extracellular side (9). The so-called close contacts exhibit a greater substrate separation distance, do not contain vinculin, and probably represent a more labile type of contact (23). A third kind of substrate adhesion site termed the fibronexus (42) or extracellular matrix contact site (9) is characteristic of well-spread and stationary fibroblasts. It features a codistribution of fibronectin, its plasma membrane receptor, actin, vinculin, and alpha-actinin throughout the entire contact site and is located at central regions of the cell rather than at its margins (11,15). Fibronexuses show very close transmembrane associations of actin microfilaments and fibronectin fibrils (42,43).

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Section: Discussionsupporting

confidence: 93%

“…It features a codistribution of fibronectin, its plasma membrane receptor, actin, vinculin, and alpha-actinin throughout the entire contact site and is located at central regions of the cell rather than at its margins (11,15). Fibronexuses show very close transmembrane associations of actin microfilaments and fibronectin fibrils (42,43). …”

mentioning

confidence: 99%

Ultrastructural localization of plasma membrane-associated urokinase-type plasminogen activator at focal contacts.

Pöllänen

Hedman

Nielsen

et al. 1988

The Journal of Cell Biology

297

117

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“…7G) was observed in the lamellipodia structures (yellow). After 4 h of attachment to FN, lamellipodia structures had disappeared, and focal adhesion contacts were well organized as defined by immunostaining with anti-vinculin antibodies, a marker for focal adhesions (43) (Fig. 7E).…”

Section: Fig 5 14-3-3 Proteins and Cas Associate In A Phosphoserinementioning

confidence: 92%

Cell Adhesion Regulates the Interaction between the Docking Protein p130Cas and the 14-3-3 Proteins

García-Guzmán¹,

Dolfi²,

Russello

et al. 1999

Journal of Biological Chemistry

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Integrin ligand binding induces a signaling complex formation via the direct association of the docking protein p130Cas (Cas) with diverse molecules. We report here that the 14-3-3 protein interacts with Cas in the yeast two-hybrid assay. We also found that the two proteins associate in mammalian cells and that this interaction takes place in a phosphoserine-dependent manner, because treatment of Cas with a serine phosphatase greatly reduced its ability to bind 14-3-3. Furthermore, the Cas-14-3-3 interaction was found to be regulated by integrin-mediated cell adhesion. Thus, when cells are detached from the extracellular matrix, the binding of Cas to 14-3-3 is greatly diminished, whereas replating the cells onto fibronectin rapidly induces the association. Consistent with these results, we found that the subcellular localization of Cas and 14-3-3 is also regulated by integrin ligand binding and that the two proteins display a significant co-localization during cell attachment to the extracellular matrix. In conclusion, our results demonstrate that 14-3-3 proteins participate in integrin-activated signaling pathways through their interaction with Cas, which, in turn, may contribute to important biological responses regulated by cell adhesion to the extracellular matrix.

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“…Integrin ligation leads to clustering of integrins into focal contacts, areas of the cell that are in close apposition to the substrate (Izzard and Lochner, 1980;Chen and Singer, 1982), and that are rich in signaling and cytoskeletal proteins, including FAK, paxillin, and vinculin (Singer, 1982;Parsons et al, 2000;Turner, 2000). Clustering of integrins can also lead to the coclustering of signaling proteins (Miyamoto et al, 1995).…”

Section: Focal Contact Proteins Are Maintained During Turnover Of Thementioning

confidence: 99%

Fibronectin Polymerization Regulates the Composition and Stability of Extracellular Matrix Fibrils and Cell-Matrix Adhesions

Sottile

Hocking

2002

MBoC

550

510

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Remodeling of extracellular matrices occurs during development, wound healing, and in a variety of pathological processes including atherosclerosis, ischemic injury, and angiogenesis. Thus, identifying factors that control the balance between matrix deposition and degradation during tissue remodeling is essential for understanding mechanisms that regulate a variety of normal and pathological processes. Using fibronectin-null cells, we found that fibronectin polymerization into the extracellular matrix is required for the deposition of collagen-I and thrombospondin-1 and that the maintenance of extracellular matrix fibronectin fibrils requires the continual polymerization of a fibronectin matrix. Further, integrin ligation alone is not sufficient to maintain extracellular matrix fibronectin in the absence of fibronectin deposition. Our data also demonstrate that the retention of thrombospondin-1 and collagen I into fibrillar structures within the extracellular matrix depends on an intact fibronectin matrix. An intact fibronectin matrix is also critical for maintaining the composition of cell-matrix adhesion sites; in the absence of fibronectin and fibronectin polymerization, neither ␣5␤1 integrin nor tensin localize to fibrillar cell-matrix adhesion sites. These data indicate that fibronectin polymerization is a critical regulator of extracellular matrix organization and stability. The ability of fibronectin polymerization to act as a switch that controls the organization and composition of the extracellular matrix and cell-matrix adhesion sites provides cells with a means of precisely controlling cell-extracellular matrix signaling events that regulate many aspects of cell behavior including cell proliferation, migration, and differentiation. INTRODUCTIONExtracellular matrix remodeling plays an important role during development, wound healing, atherosclerosis, ischemic injury, and angiogenesis. Perturbing matrix remodeling by preventing the turnover of collagen I or by altering the levels of matrix-degrading proteases or protease inhibitors has been shown to result in fibrosis, arthritis, reduced angiogenesis, and developmental abnormalities (Liu et al., 1995;Vu et al., 1998;Holmbeck et al., 1999;Ducharme et al., 2000). In normal adult tissue, some extracellular matrix components such as elastin and fibrillar collagen have half lives of months to years (Krane, 1985;Debelle and Tamburro, 1999). Other extracellular matrix components, such as proteoglycans, thrombospondin-1 and -2, and vitronectin, can be endocytosed and degraded in the lysosomes (McKeownLongo et al., 1984;Yanagishita and Hascall, 1984; MurphyUllrich and Mosher, 1987;Hausser et al., 1992;Godyna et al., 1995a;Pijuan-Thompson and Gladson, 1997;Memmo and McKeown-Longo, 1998). Extracellular matrix molecules can also be degraded extracellularly by proteases such as matrix metalloproteinases (MMPs), plasminogen activators, and plasmin (Hynes, 1990;Marchina and Barlati, 1996;Shapiro, 1998).Recent data indicate that polymerized forms of extracellular matri...

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Association of fibronectin and vinculin with focal contacts and stress fibers in stationary hamster fibroblasts.

Cited by 139 publications

References 49 publications

Ultrastructural localization of plasma membrane-associated urokinase-type plasminogen activator at focal contacts.

Ultrastructural localization of plasma membrane-associated urokinase-type plasminogen activator at focal contacts.

Cell Adhesion Regulates the Interaction between the Docking Protein p130Cas and the 14-3-3 Proteins

Fibronectin Polymerization Regulates the Composition and Stability of Extracellular Matrix Fibrils and Cell-Matrix Adhesions

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