Fibronectin Regulates Assembly of Actin Filaments and Focal Contacts in Cultured Cells via the Heparin-binding Site in Repeat III<sub>13</sub>

Bloom, Laird; Ingham, Kenneth C.; Hynes, Richard O.

doi:10.1091/mbc.10.5.1521

Cited by 128 publications

(134 citation statements)

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“…Integrin ␣5␤1 binding to the FN cell-binding domain together with HS side chains of syndecan-4 interacting with heparin-binding sites on FN are essential for cells to spread and organize their cytoskeleton (Bloom et al, 1999;Saoncella et al, 1999;Echtermeyer et al, 2001). Of the multiple heparin domains in FN, binds to the FNIII13 module in the HepII domain (Huang et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…These molecules, which consist of a protein core modified with glycosaminoglycan (GAG) side chains, are found at the cell surface, inside the cell, or incorporated into the ECM (Lander, 1998). Transmembrane heparan sulfate proteoglycans (HSPGs) of the syndecan family bind to ECM proteins and cooperate with heterodimeric integrin receptors to regulate cell adhesive activities (Bloom et al, 1999;Kusano et al, 2000;. One member of this family, syndecan-4, is up-regulated during tissue repair (Gallo et al, 1996) and syndecan-4 -null mice show defects in wound healing (Echtermeyer et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

Midwood

Valenick

Hsia

et al. 2004

MBoC

132

139

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Syndecan-4 is a ubiquitously expressed heparan sulfate proteoglycan that modulates cell interactions with the extracellular matrix. It is transiently up-regulated during tissue repair by cells that mediate wound healing. Here, we report that syndecan-4 is essential for optimal fibroblast response to the three-dimensional fibrin-fibronectin provisional matrix that is deposited upon tissue injury. Interference with syndecan-4 function inhibits matrix contraction by preventing cell spreading, actin stress fiber formation, and activation of focal adhesion kinase and RhoA mediated-intracellular signaling pathways. Tenascin-C is an extracellular matrix protein that regulates cell response to fibronectin within the provisional matrix. Syndecan-4 is also required for tenascin-C action. Inhibition of syndecan-4 function suppresses tenascin-C activity and overexpression of syndecan-4 circumvents the effects of tenascin-C. In this way, tenascin-C and syndecan-4 work together to control fibroblast morphology and signaling and regulate events such as matrix contraction that are essential for efficient tissue repair. INTRODUCTIONTissue architecture is defined by the three-dimensional (3D) organization of the proteins and proteoglycans that comprise the extracellular matrix (ECM). Individual ECM components influence cell arrangements and activities through binding to transmembrane receptors, thus initiating intracellular signaling and altering gene expression and other downstream events. Tissues undergo continual maintenance and remodeling through controlled deposition and removal of specific ECM components. These changes in ECM composition and organization modulate cell behaviors and serve important roles throughout development and in the adult during both physiological and pathological processes (Lukashev and Werb, 1998).The provisional matrix that forms at sites of tissue injury undergoes extensive remodeling and turnover during wound repair. Composed predominantly of covalently cross-linked fibrin and plasma fibronectin (FN), this fibrin-FN provisional matrix coordinates the activities of cells involved in wound repair. It is remodeled over time to recapitulate normal tissue and this remodeling involves cellmediated contraction and deposition of new FN-rich matrix (Clark, 1996;Midwood et al., 2004). FN, a major component of the matrix, is a ubiquitously expressed, multifunctional extracellular glycoprotein that promotes cell adhesion. It controls many intracellular pathways and influences a wide range of cell functions (Hynes, 1990). For example, FN within a 3D fibrin-FN provisional matrix initiates signaling via focal adhesion kinase (FAK) and RhoA in order to promote fibroblast spreading, stress fiber formation, and focal adhesion assembly (Wenk et al., 2000;.The provisional matrix contacts many other ECM proteins that are induced at different stages of tissue repair, including thrombospondins, SPARC, and tenascin-C. These proteins are specifically up-regulated at wound sites where they modulate cell-ECM interactions (re...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

Midwood

Valenick

Hsia

et al. 2004

MBoC

132

139

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“…Several proteins, including p130Cas, Crk, FAK, paxillin, Rho, and Shc, have been identified in pathways leading to integrinmediated ERK2 activation (3,5,7,15). Furthermore, because Fn possesses other signal-generating domains, such as the heparin-binding domain (31), integrin binding to Fn may initiate an ERK2 response by exposing cryptic sites on Fn that interact with a secondary receptor that directly activates ERK2. Despite the complex involvement of several pathways and molecules leading to ERK2 activation, the observed rate of increase in ERK2 activity was simply proportional to both integrin and Fn levels at low Fn density (Fig.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Relationship among Integrin-Ligand Binding, Adhesion, and Signaling via Focal Adhesion Kinase and Extracellular Signal-regulated Kinase 2

Asthagiri¹,

Nelson²,

Horwitz³

et al. 1999

Journal of Biological Chemistry

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Because integrin-mediated signals are transferred through a physical architecture and synergistic biochemical network whose properties are not well defined, quantitative relationships between extracellular integrin-ligand binding events and key intracellular responses are poorly understood. We begin to address this by quantifying integrin-mediated FAK and ERK2 responses in CHO cells for varied ␣ 5 ␤ 1 expression level and substratum fibronectin density. Plating cells on fibronectin-coated surfaces initiated a transient, biphasic ERK2 response, the magnitude and kinetics of which depended on integrin-ligand binding properties. Whereas ERK2 activity initially increased with a rate proportional to integrin-ligand bond number for low fibronectin density, the desensitization rate was independent of integrin and fibronectin amount but proportional to the ERK2 activity level with an exponential decay constant of 0.3 (؎ 0.08) min ؊1. Unlike the ERK2 activation time course, FAK phosphorylation followed a superficially disparate time course. However, analysis of the early kinetics of the two signals revealed them to be correlated. The initial rates of FAK and ERK2 signal generation exhibited similar dependence on fibronectin surface density, with both rates monotonically increasing with fibronectin amount until saturating at high fibronectin density. Because of this similar initial rate dependence on integrin-ligand bond formation, the disparity in their time courses is attributed to differences in feedback regulation of these signals. Whereas FAK phosphorylation increased to a steady-state level as new integrin-ligand bond formation continued during cell spreading, ERK2 activity was decoupled from the integrin-ligand stimulus and decayed back to a basal level. Accordingly, we propose different functional metrics for representing these two disparate dynamic signals: the steady-state tyrosine phosphorylation level for FAK and the integral of the pulse response for ERK2. These measures of FAK and ERK2 activity were found to correlate with short term cell-substratum adhesivity, indicating that signaling via FAK and ERK2 is proportional to the number of integrin-fibronectin bonds.Integrins are adhesion receptors that not only provide the mechanical link between the cell and the extracellular matrix (ECM) 1 that is essential for adhesion, spreading, and migration (1, 2), but also generate intracellular signals that affect multiple cell functions (3-5). Altered cell behavior due to aberrant regulation of these signals results in pathologies, such as cancer, in which loss of integrin signaling-based control of cell cycle progression leads to anchorage-independent cell growth and tumor formation (6). Because of these significant and wideranging regulatory roles, modulating integrin-mediated signals may provide powerful targets for disease therapy. Furthermore, since integrins interface cells to biomaterials, biomimetic surfaces may be designed to instigate appropriate integrin-mediated signals to elicit desired cell behavior on...

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“…Previously, we defined the A3G75 site as a syndecan-2 and -4 binding site in fibroblasts (29) and the AG73 sequence as a syndecan-1 binding site in HSG cells (13,25). In syndecanmediated cell attachment to the heparin binding domain of fibronectin and to the AG73 peptide, actin filament spikes were associated with membrane ruffles, and no focal contacts with vinculin accumulation were observed (40,45). In this study, actin organization and vinculin localization of fibroblasts on EF-2 and EF-4 were similar to that on AG73.…”

Section: Fig 2 Cell Attachment Activity Of the Ef Peptides A-c Cementioning

confidence: 99%

Biological Activities of Homologous Loop Regions in the Laminin α Chain G Domains

Suzuki

Nakatsuka

Mochizuki

et al. 2003

Journal of Biological Chemistry

127

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Laminin ␣ chains (␣ 1 -␣ 5 chains) have diverse chainspecific biological functions. The LG4 modules of laminin ␣ chains consist of a 14-stranded ␤-sheet (A-N) sandwich structure. Several biologically active sequences have been identified in the connecting loop regions. Here, we evaluated the biological activities of the loop regions of the E and F strands in the LG4 modules using five homologous peptides from each of the mouse ␣ chains (EF-1: DYATLQLQEGRLHFMFDLG, ␣ 1 chain 2747-2765; EF-2: DFGTVQLRNGFPFFSYDLG, ␣ 2 chain 2808 -2826; EF-3: RDSFVALYLSEGHVIFALG, ␣ 3 chain 2266 -2284; EF-4: DFMTLFLAHGRLVFMFNVG, ␣ 4 chain 1511-1529; EF-5: SPSLVLFLNHGHFVAQTEGP, ␣ 5 chain 3304 -3323). These homologous peptides showed chainspecific cell attachment and neurite outgrowth activities. Well organized actin stress fibers and focal contacts with vinculin accumulation were observed in fibroblasts attached on EF-1, whereas fibroblasts on EF-2 and EF-4 showed filopodia with ruffling. Fibroblast attachment to EF-2 and EF-4 was mediated by syndecan-2. In contrast, EF-1 promoted ␣ 2 ␤ 1 integrin-mediated fibroblast attachment and inhibited fibroblast attachment to a recombinant laminin ␣ 1 chain LG4-5. The receptors for EF-3 and EF-5 are unknown. Further, when the active core sequence of EF-1 was cyclized, utilizing two additional cysteine residues at both the N and C termini through a disulfide bridge, the cyclic peptide significantly enhanced integrin-mediated cell attachment. These results indicate that integrin-mediated cell attachment to the EF-1 sequence is conformation-dependent and that the loop structure is important for the activity. The homologous peptides, which promote either integrin-or syndecan-mediated cell attachment, may be useful for understanding the cell type-and chain-specific biological activities of the laminins.

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Fibronectin Regulates Assembly of Actin Filaments and Focal Contacts in Cultured Cells via the Heparin-binding Site in Repeat III₁₃

Cited by 128 publications

References 44 publications

Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

Quantitative Relationship among Integrin-Ligand Binding, Adhesion, and Signaling via Focal Adhesion Kinase and Extracellular Signal-regulated Kinase 2

Biological Activities of Homologous Loop Regions in the Laminin α Chain G Domains

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Fibronectin Regulates Assembly of Actin Filaments and Focal Contacts in Cultured Cells via the Heparin-binding Site in Repeat III13

Cited by 128 publications

References 44 publications

Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

Coregulation of Fibronectin Signaling and Matrix Contraction by Tenascin-C and Syndecan-4

Quantitative Relationship among Integrin-Ligand Binding, Adhesion, and Signaling via Focal Adhesion Kinase and Extracellular Signal-regulated Kinase 2

Biological Activities of Homologous Loop Regions in the Laminin α Chain G Domains

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Fibronectin Regulates Assembly of Actin Filaments and Focal Contacts in Cultured Cells via the Heparin-binding Site in Repeat III₁₃