scholarly journals Fibronectin-stimulated signaling from a focal adhesion kinase-c-Src complex: involvement of the Grb2, p130cas, and Nck adaptor proteins.

1997 ◽  
Vol 17 (3) ◽  
pp. 1702-1713 ◽  
Author(s):  
D D Schlaepfer ◽  
M A Broome ◽  
T Hunter
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Intracellular Signaling ◽  
Protein Tyrosine Kinase ◽  
Adaptor Protein ◽  
Adaptor Proteins ◽  
Sh2 Domain ◽  
Mitogen Activated Protein Kinase

The focal adhesion kinase (FAK), a protein-tyrosine kinase (PTK), associates with integrin receptors and is activated by cell binding to extracellular matrix proteins, such as fibronectin (FN). FAK autophosphorylation at Tyr-397 promotes Src homology 2 (SH2) domain binding of Src family PTKs, and c-Src phosphorylation of FAK at Tyr-925 creates an SH2 binding site for the Grb2 SH2-SH3 adaptor protein. FN-stimulated Grb2 binding to FAK may facilitate intracellular signaling to targets such as ERK2-mitogen-activated protein kinase. We examined FN-stimulated signaling to ERK2 and found that ERK2 activation was reduced 10-fold in Src- fibroblasts, compared to that of Src- fibroblasts stably reexpressing wild-type c-Src. FN-stimulated FAK phosphotyrosine (P.Tyr) and Grb2 binding to FAK were reduced, whereas the tyrosine phosphorylation of another signaling protein, p130cas, was not detected in the Src- cells. Stable expression of residues 1 to 298 of Src (Src 1-298, which encompass the SH3 and SH2 domains of c-Src) in the Src- cells blocked Grb2 binding to FAK; but surprisingly, Src 1-298 expression also resulted in elevated p130cas P.Tyr levels and a two- to threefold increase in FN-stimulated ERK2 activity compared to levels in Src- cells. Src 1-298 bound to both FAK and p130cas and promoted FAK association with p130cas in vivo. FAK was observed to phosphorylate p130cas in vitro and could thus phosphorylate p130cas upon FN stimulation of the Src 1-298-expressing cells. FAK-induced phosphorylation of p130cas in the Src 1-298 cells promoted the SH2 domain-dependent binding of the Nck adaptor protein to p130cas, which may facilitate signaling to ERK2. These results show that there are additional FN-stimulated pathways to ERK2 that do not involve Grb2 binding to FAK.

scholarly journals Direct interaction of v-Src with the focal adhesion kinase mediated by the Src SH2 domain.

1994 ◽  
Vol 5 (4) ◽  
pp. 413-421 ◽  
Author(s):  
Z Xing ◽  
H C Chen ◽  
J K Nowlen ◽  
S J Taylor ◽  
D Shalloway ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Intracellular Signaling ◽  
Direct Interaction ◽  
Sh2 Domain ◽  
Sh2 Domains ◽  
Intracellular Signaling Molecules

The recently described focal adhesion kinase (FAK) has been implicated in signal transduction pathways initiated by cell adhesion receptor integrins and by neuropeptide growth factors. To examine the mechanisms by which FAK relays signals from the membrane to the cell interior, we carried out a series of experiments to detect potential FAK interactions with proteins containing Src homology 2 (SH2) domains that are important intracellular signaling molecules. Using v-Src-transformed NIH3T3 cells, we showed that FAK was present in the immune-complex precipitated by anti-Src antibody, suggesting potential interaction of FAK with v-Src in vivo. We also showed potentially direct interaction of FAK with v-Src in vivo using the yeast two-hybrid system. Using recombinant FAK expressed in insect cells and bacterial fusion proteins containing Src SH2 domains, we showed direct binding of FAK to the Src SH2 domain but not to the SH3 domain in vitro. A kinase-defective mutant of FAK, which is not autophosphorylated, did not interact with the Src SH2 domain under the same conditions, suggesting the involvement of the FAK autophosphorylation sites. Treatment of FAK with a protein-tyrosine phosphatase decreased its binding to the Src SH2 domain, whereas autophosphorylation in vitro increased its binding. These results confirm the importance of FAK autophosphorylation sites in its interaction with SH2 domain-containing proteins. Taken together, these results suggest that FAK may mediate signal transduction events initiated on the cell surface by kinase activation and autophosphorylation that result in its binding to other key intracellular signaling molecules.

scholarly journals Autophosphorylation of the focal adhesion kinase, pp125FAK, directs SH2-dependent binding of pp60src

1994 ◽  
Vol 14 (3) ◽  
pp. 1680-1688
Author(s):  
M D Schaller ◽  
J D Hildebrand ◽  
J D Shannon ◽  
J W Fox ◽  
R R Vines ◽  
...  
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Cellular Protein ◽  
Sh2 Domain ◽  
Major Site ◽  
Sh2 Domains ◽  
High Affinity Binding Site

The phosphorylation of protein tyrosine kinases (PTKs) on tyrosine residues is a critical regulatory event that modulates catalytic activity and triggers the physical association of PTKs with Src homology 2 (SH2)-containing proteins. The integrin-linked focal adhesion kinase, pp125FAK, exhibits extracellular matrix-dependent phosphorylation on tyrosine and physically associates with two nonreceptor PTKs, pp60src and pp59fyn, via their SH2 domains. Herein, we identify Tyr-397 as the major site of tyrosine phosphorylation on pp125FAK both in vivo and in vitro. Tyrosine 397 is located at the juncture of the N-terminal and catalytic domains, a novel site for PTK autophosphorylation. Mutation of Tyr-397 to a nonphosphorylatable residue dramatically impairs the phosphorylation of pp125FAK on tyrosine in vivo and in vitro. The mutation of Tyr-397 to Phe also inhibits the formation of stable complexes with pp60src in cells expressing Src and FAK397F, suggesting that autophosphorylation of pp125FAK may regulate the association of pp125FAK with Src family kinases in vivo. The identification of Tyr-397 as a major site for FAK autophosphorylation provides one of the first examples of a cellular protein containing a high-affinity binding site for a Src family kinase SH2 domain. This finding has implications for models describing the mechanisms of action of pp125FAK, the regulation of the Src family of PTKs, and signal transduction through the integrins.

scholarly journals Autophosphorylation of the focal adhesion kinase, pp125FAK, directs SH2-dependent binding of pp60src.

1994 ◽  
Vol 14 (3) ◽  
pp. 1680-1688 ◽  
Author(s):  
M D Schaller ◽  
J D Hildebrand ◽  
J D Shannon ◽  
J W Fox ◽  
R R Vines ◽  
...  
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Cellular Protein ◽  
Sh2 Domain ◽  
Major Site ◽  
Sh2 Domains ◽  
High Affinity Binding Site

The phosphorylation of protein tyrosine kinases (PTKs) on tyrosine residues is a critical regulatory event that modulates catalytic activity and triggers the physical association of PTKs with Src homology 2 (SH2)-containing proteins. The integrin-linked focal adhesion kinase, pp125FAK, exhibits extracellular matrix-dependent phosphorylation on tyrosine and physically associates with two nonreceptor PTKs, pp60src and pp59fyn, via their SH2 domains. Herein, we identify Tyr-397 as the major site of tyrosine phosphorylation on pp125FAK both in vivo and in vitro. Tyrosine 397 is located at the juncture of the N-terminal and catalytic domains, a novel site for PTK autophosphorylation. Mutation of Tyr-397 to a nonphosphorylatable residue dramatically impairs the phosphorylation of pp125FAK on tyrosine in vivo and in vitro. The mutation of Tyr-397 to Phe also inhibits the formation of stable complexes with pp60src in cells expressing Src and FAK397F, suggesting that autophosphorylation of pp125FAK may regulate the association of pp125FAK with Src family kinases in vivo. The identification of Tyr-397 as a major site for FAK autophosphorylation provides one of the first examples of a cellular protein containing a high-affinity binding site for a Src family kinase SH2 domain. This finding has implications for models describing the mechanisms of action of pp125FAK, the regulation of the Src family of PTKs, and signal transduction through the integrins.

scholarly journals Focal adhesion kinase and paxillin bind to peptides mimicking beta integrin cytoplasmic domains.

1995 ◽  
Vol 130 (5) ◽  
pp. 1181-1187 ◽  
Author(s):  
M D Schaller ◽  
C A Otey ◽  
J D Hildebrand ◽  
J T Parsons
Keyword(s):  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Cytoplasmic Domain ◽  
Embryo Cell ◽  
Vitro Assay ◽  
Protein Tyrosine ◽  
Signaling Complex

The integrins have recently been implicated in signal transduction. A likely mediator of integrin signaling is focal adhesion kinase (pp125FAK or FAK), a structurally distinct protein tyrosine kinase that becomes enzymatically activated upon engagement of integrins with their ligands. A second candidate signaling molecule is paxillin, a focal adhesion associated, cytoskeletal protein that coordinately becomes phosphorylated on tyrosine upon activation of pp125FAK. Paxillin physically complexes with two protein tyrosine kinases, pp60src and Csk (COOH-terminal src kinase), and the oncoprotein p47gag-crk, each of which could function as part of a paxillin signaling complex. Using an in vitro assay we have established that the cytoplasmic domain of the beta 1 integrin can bind to paxillin and pp125FAK from chicken embryo cell lysates. The NH2-terminal, noncatalytic domain of pp125FAK can bind directly to the cytoplasmic tail of beta 1 and recognizes integrin sequences distinct from those involved in binding to alpha-actinin. Paxillin binding is independent of pp125FAK binding despite the fact that both bind to the same region of beta 1. These results demonstrate that the cytoplasmic domain of the beta subunits of integrins contain binding sites for both signaling molecules and structural proteins suggesting that integrins can coordinate the generation of cytoplasmic signals in addition to their role in anchoring components of the cytoskeleton.

Cytoskeletal changes induced by GRAF, the GTPase regulator associated with focal adhesion kinase, are mediated by Rho

1999 ◽  
Vol 112 (2) ◽  
pp. 231-242 ◽  
Author(s):  
J.M. Taylor ◽  
M.M. Macklem ◽  
J.T. Parsons
Keyword(s):  
Focal Adhesion Kinase ◽  
Pc12 Cells ◽  
Focal Adhesion ◽  
Fiber Formation ◽  
Serum Starvation ◽  
3T3 Cells ◽  
Neurite Retraction ◽  
Swiss 3T3

Graf, the GTPase regulator associated with focal adhesion kinase was previously shown to have GAP activity for Ρ A and Cdc42 in vitro (Hildebrand et al 1996 Mol. Cell Biol. 16: 3169–3178). In this study we sought to determine whether Graf acted at the level of Cdc42, Rho, or both in vivo and whether Graf was a signal terminator or transducer for these proteins. Microinjection of Graf cDNA into subconfluent Swiss 3T3 cells (in the presence of serum) has marked effects on cell shape and actin localization. Graf expression causes clearing of stress fibers followed by formation of long actin based filopodial-like extensions. Similar phenotypes were observed following injection of the Rho-inhibitor, C3 into these cells. The Graf response was dependent on GAP activity, since injection of Graf cDNA containing point mutations in the GAP domain (R236Q or N351V) which block enzymatic activity, does not confer this phenotype. Injection of Graf into Swiss 3T3 cells in which Rho has been down-regulated by serum starvation has no effect on cell morphology. Using this system, we demonstrate that Graf blocks sphingosine-1-phosphate (SPP) stimulated (Rho-mediated) stress fiber formation. Conversely, Graf expression does not inhibit bradykinin stimulated (Cdc42-mediated) filopodial extensions. These data indicate that Graf is a GAP for Rho in vivo. To further substantiate these results we examined the effect of Graf over-expression on Rho-mediated neurite retraction in nerve growth factor (NGF)-differentiated PC12 cells. In PC12 cells, which express relatively high levels of endogenous Graf, overexpression of Graf (but not Graf containing the R236Q mutation) enhances SPP-induced neurite retraction. These data indicate the possibility that Graf may be an effector for Rho in certain cell types.

scholarly journals Focal adhesion kinase inhibitor TAE226 combined with Sorafenib slows down hepatocellular carcinoma by multiple epigenetics effects

2021 ◽  
Author(s):  
Ilaria Romito ◽  
Manuela Porru ◽  
Maria Rita Braghini ◽  
Luca Pompili ◽  
Nadia Panera ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Kinase Inhibitor ◽  
Malignant Tumours ◽  
Nurd Complex ◽  
Antitumor Effects ◽  
Combination Regimens

Abstract Background Hepatocellular carcinoma (HCC) is one of the most common and lethal malignant tumours worldwide. Sorafenib (SOR) is one of the most effective single-drug systemic therapy against advanced HCC, but the identification of novel combination regimens for a continued improvement in overall survival is a big challenge. Recent studies highlighted the crucial role of focal adhesion kinase (FAK) in HCC growth. The aim of this study was to investigate the antitumor effects of three different FAK inhibitors, alone or in combination with SOR, using in vitro and in vivo models of HCC. Methods The effect of PND1186, PF431396, TAE226 on cell viability was compared to SOR. Among them TAE226, emerging as the most effective FAKi, was then tested alone or in combination with SOR using 2D/3D human HCC cell line cultures and HCC xenograft murine models. The mechanisms of action were assessed by gene/protein expression and imaging approaches, combined with high-throughput methods. Results TAE226 emerged as the more effective FAKi to be combined with SOR against HCC. Combined TAE226 and SOR treatment reduced HCC growth both in vitro and in vivo by affecting tumour-promoting gene expression and inducing epigenetic changes via dysregulation of the nuclear interactome of FAK. We characterized a novel nuclear functional interaction between FAK and the NuRD complex. TAE226-mediated FAK depletion and SOR-promoted MAPK down-modulation causing an increase of histone H3 lysine 27 acetylation, counteracting its trimethylation by decreasing the nuclear amount of HDAC1/2. Conclusions Altogether, our findings provide the first evidence that TAE226 combined with SOR efficiently reduce HCC growth in vitro and in vivo. Our data also highlight that deep analysis of FAK nuclear interactome may lead to the identification of new promising therapeutic approaches for HCC.

scholarly journals Regulation of Focal Adhesion Kinase by a Novel Protein Inhibitor FIP200

2002 ◽  
Vol 13 (9) ◽  
pp. 3178-3191 ◽  
Author(s):  
Smita Abbi ◽  
Hiroki Ueda ◽  
Chuanhai Zheng ◽  
Lee Ann Cooper ◽  
Jihe Zhao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Cell Cycle Progression ◽  
Protein Inhibitor ◽  
Cellular Functions ◽  
Cycle Progression ◽  
Novel Protein

Focal adhesion kinase (FAK) is a major mediator of integrin signaling pathways. The mechanisms of regulation of FAK activity and its associated cellular functions are not very well understood. Here, we present data suggesting that a novel protein FIP200 functions as an inhibitor for FAK. We show the association of endogenous FIP200 with FAK, which is decreased upon integrin-mediated cell adhesion concomitant with FAK activation. In vitro- and in vivo-binding studies indicate that FIP200 interacts with FAK through multiple domains directly. FIP200 bound to the kinase domain of FAK inhibited its kinase activity in vitro and its autophosphorylation in vivo. Overexpression of FIP200 or its segments inhibited cell spreading, cell migration, and cell cycle progression, which correlated with their inhibition of FAK activity in vivo. The inhibition of these cellular functions by FIP200 could be rescued by coexpression of FAK. Last, we show that disruption of the functional interaction between endogenous FIP200 with FAK leads to increased FAK phosphorylation and partial restoration of cell cycle progression in cells plated on poly-l-lysine, providing further support for FIP200 as a negative regulator of FAK. Together, these results identify FIP200 as a novel protein inhibitor for FAK.

scholarly journals The Human c-Fes Tyrosine Kinase Binds Tubulin and Microtubules through Separate Domains and Promotes Microtubule Assembly

2004 ◽  
Vol 24 (21) ◽  
pp. 9351-9358 ◽  
Author(s):  
Charles E. Laurent ◽  
Frank J. Delfino ◽  
Haiyun Y. Cheng ◽  
Thomas E. Smithgall
Keyword(s):  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Morphological Changes ◽  
Neuronal Cells ◽  
Coiled Coil ◽  
Cell Types ◽  
Sh2 Domain ◽  
Microtubule Assembly

ABSTRACT The c-Fes protein-tyrosine kinase (Fes) has been implicated in the differentiation of vascular endothelial, myeloid hematopoietic, and neuronal cells, promoting substantial morphological changes in these cell types. The mechanism by which Fes promotes morphological aspects of cellular differentiation is unknown. Using COS-7 cells as a model system, we observed that Fes strongly colocalizes with microtubules in vivo when activated via coiled-coil mutation or by coexpression with an active Src family kinase. In contrast, wild-type Fes showed a diffuse cytoplasmic localization in this system, which correlated with undetectable kinase activity. Coimmunoprecipitation and immunofluorescence microscopy showed that the N-terminal Fes/CIP4 homology (FCH) domain is involved in Fes interaction with soluble unpolymerized tubulin. However, the FCH domain was not required for colocalization with polymerized microtubules in vivo. In contrast, a functional SH2 domain was essential for microtubule localization of Fes, consistent with the strong tyrosine phosphorylation of purified tubulin by Fes in vitro. Using a microtubule nucleation assay, we observed that purified c-Fes also catalyzed extensive tubulin polymerization in vitro. Taken together, these results identify c-Fes as a regulator of the tubulin cytoskeleton that may contribute to Fes-induced morphological changes in myeloid hematopoietic and neuronal cells.

MHC Class II and T Cell Receptor Signals Are Dispensable for IL-2-Induced Regulatory T Cell Proliferation In Vivo

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2181-2181
Author(s):  
Tao Zou ◽  
Atsushi Satake ◽  
Jonathan Maltzman ◽  
Taku Kambayashi
Keyword(s):  
T Cell ◽  
Conflicts Of Interest ◽  
Interleukin 2 ◽  
Adaptor Protein ◽  
Class Ii ◽  
Sh2 Domain ◽  
Tcr Signaling ◽  
Mhc Ii

Abstract Abstract 2181 Regulatory T cells (Tregs) protect the host from autoimmunity and inappropriate immune activation. Thus, to ensure immune tolerance in the steady state, an adequate number of peripheral Tregs must be constantly maintained. Prior work has suggested that major histocompatibility class II (MHC II) and interleukin-2 (IL-2) are both necessary to maintain peripheral Treg homeostasis and proliferation in vivo. However, we have recently reported that Treg proliferation may not strictly depend on MHC II, as the provision of IL-2 was sufficient to drive proliferation of Tregs in an MHC II-independent manner in vitro, as long as the Tregs interacted with dendritic cells (DC)s. Here, extending our previous in vitro observations, we tested the dependence of Treg proliferation on IL-2, DCs, and TCR signaling in vivo. Proliferation of adoptively transferred Tregs was detected in wildtype (WT) mice. This proliferation was markedly enhanced when the mice were injected with IL-2 immune complexes (IC)s but not when the IL-2 IC-injected mice lacked DCs, suggesting that IL-2-induced Treg proliferation was dependent on DCs in vivo. As previously reported, adoptively transferred Tregs did not proliferate in MHC II-deficient hosts. However, the injection of IL-2 ICs into these mice induced Treg proliferation comparable to those transferred into IL-2 IC-injected WT mice, suggesting that IL-2 signaling by Tregs obviated the need of MHC II for their proliferation. Furthermore, while the ablation of TCR signaling by conditional deletion of the adaptor protein SH2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) rendered Tregs unable to proliferate by themselves, IL-2 IC treatment partially rescued this deficiency. We next examined the signaling pathways involved in Treg proliferation downstream of the IL-2 receptor. Despite the importance of the Stat5 pathway in IL-2 receptor signaling during Treg development in the thymus, activation of Stat5b alone was insufficient to rescue proliferation of SLP-76-deficient Tregs, indicating that alternative pathways must also be activated for Treg proliferation. Additional studies investigating the role of other signaling molecules downstream of the IL-2 receptor are currently underway. In summary, we have demonstrated for the first time that Tregs do not require TCR signaling through interaction with MHC II for their proliferation in vivo. We propose that this MHC II-independent mode of Treg proliferation allows Tregs with multiple antigen specificities to proliferate, which ensures that a diverse TCR repertoire is continuously maintained in the Treg pool. Furthermore, we believe that exploitation of these pathways may be therapeutically beneficial in autoimmunity and in transplantation. Disclosures: No relevant conflicts of interest to declare.

The Shc adaptor protein forms interdependent phosphotyrosine-mediated protein complexes in mast cells stimulated with interleukin 3

Blood ◽  
2000 ◽  
Vol 96 (1) ◽  
pp. 132-138 ◽  
Author(s):  
Laura Velazquez ◽  
Gerald D. Gish ◽  
Peter van der Geer ◽  
Lorne Taylor ◽  
Johanna Shulman ◽  
...  
Keyword(s):  
Mast Cells ◽  
Protein Complexes ◽  
Adaptor Protein ◽  
Phospholipid Metabolism ◽  
Sh2 Domain ◽  
Interleukin 3 ◽  
Inositol Phosphatase ◽  
Ptb Domain

The Shc adaptor protein possesses 2 distinct phosphotyrosine (pTyr) recognition modules—the pTyr binding (PTB) domain and the Src homology 2 (SH2) domain—and multiple potential sites for tyrosine (Tyr) phosphorylation (Tyr residues 239, 240, and 317). On stimulation of hematopoietic cells with interleukin 3 (IL-3), Shc becomes phosphorylated and may therefore contribute to IL-3 signaling. We investigated the interactions mediated by the Shc modular domains and pTyr sites in IL-3–dependent IC2 premast cells. The Shc PTB domain, rather than the SH2 domain, associated both in vitro and in vivo with the Tyr-phosphorylated β subunit of the IL-3 receptor and with the SH2-containing 5′ inositol phosphatase (SHIP), and it recognized specific NXXpY phosphopeptides from these binding partners. In IL-3–stimulated mast cells, Shc phosphorylation occurred primarily on Tyr239 and 317 and was dependent on a functional PTB domain. Phosphorylated Tyr317, and to a lesser extent, Tyr239, bound the Grb2 adaptor and SHIP. Furthermore, a pTyr317 Shc phosphopeptide selectively recognized Grb2, Sos1, SHIP, and the p85 subunit of phosphatidylinositol 3′ kinase from mast cells, as characterized by mass spectrometry. These results indicate that Shc undergoes an interdependent series of pTyr-mediated interactions in IL-3–stimulated mast cells, resulting in the recruitment of proteins that regulate the Ras pathway and phospholipid metabolism.

Sign in / Sign up

Export Citation Format

Share Document