scholarly journals Inverse correlation between tyrosine phosphorylation and collagenase production in chondrocytes

1990 ◽  
Vol 269 (3) ◽  
pp. 717-721 ◽  
Author(s):  
T F Cruz ◽  
G Mills ◽  
K P H Pritzker ◽  
R A Kandel
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Potent Inhibitor ◽  
Inverse Correlation ◽  
Cell Types ◽  
Proteoglycan Synthesis ◽  
Serum Concentrations ◽  
Tyrosine Phosphatases ◽  
Synergistic Increase

Collagenase production by chondrocytes appears to play a major role in the development of osteoarthritis. Although the mechanisms regulating collagenase production by chondrocytes are not known, incubation of bovine chondrocytes in serum markedly decreases collagenase production. Since serum has been demonstrated to increase levels of phosphotyrosine (P-Tyr) in several cell types, we determined the effect of altering intracellular levels of P-Tyr on collagenase production. Both orthovanadate, a potent inhibitor of tyrosine phosphatases, and serum caused a marked increase in tyrosine phosphorylation. The increase in P-Tyr was associated with a decrease in the production of collagenase, suggesting that two processes may be linked. Orthovanadate caused an increase in P-Tyr in the absence of serum, suggesting that P-Tyr levels in resting chondrocytes are regulated through activity of both tyrosine kinases and phosphatases. Orthovanadate and serum induced a synergistic increase in P-Tyr levels, suggesting that serum functions through increasing kinase activity rather than decreasing phosphatase activity. In the absence of serum, concentrations of orthovanadate which maximally inhibited collagenase production primarily increased phosphorylation of a 36 kDa protein, suggesting that the phosphorylation of this protein may play a major role in regulating collagenase production. Orthovanadate had limited effects on chondrocyte proteoglycan synthesis, morphology or viability in the presence or absence of serum, suggesting that the decrease in collagenase production was not due to non-specific inhibition of protein synthesis or cellular toxicity. Inhibition of tyrosine phosphatases by orthovanadate or activation of tyrosine kinases by addition of serum correlated with the inhibition of collagenase production.

scholarly journals Activation of Phosphotyrosine-Mediated Signaling Pathways in the Cortex and Spinal Cord of SOD1G93A, a Mouse Model of Familial Amyotrophic Lateral Sclerosis

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Cinzia Mallozzi ◽  
Alida Spalloni ◽  
Patrizia Longone ◽  
Maria Rosaria Domenici
Keyword(s):  
Spinal Cord ◽  
Amyotrophic Lateral Sclerosis ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Tyrosine Phosphatases ◽  
Direct Stimulation ◽  
Tyrosine Kinase 2 ◽  
Lateral Sclerosis

Degeneration of cortical and spinal motor neurons is the typical feature of amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disease for which a pathogenetic role for the Cu/Zn superoxide dismutase (SOD1) has been demonstrated. Mice overexpressing a mutated form of the SOD1 gene (SOD1G93A) develop a syndrome that closely resembles the human disease. The SOD1 mutations confer to this enzyme a “gain-of-function,” leading to increased production of reactive oxygen species. Several oxidants induce tyrosine phosphorylation through direct stimulation of kinases and/or phosphatases. In this study, we analyzed the activities of src and fyn tyrosine kinases and of protein tyrosine phosphatases in synaptosomal fractions prepared from the motor cortex and spinal cord of transgenic mice expressing SOD1G93A. We found that (i) protein phosphotyrosine level is increased, (ii) src and fyn activities are upregulated, and (iii) the activity of tyrosine phosphatases, including the striatal-enriched tyrosine phosphatase (STEP), is significantly decreased. Moreover, the NMDA receptor (NMDAR) subunit GluN2B tyrosine phosphorylation was upregulated in SOD1G93A. Tyrosine phosphorylation of GluN2B subunits regulates the NMDAR function and the recruitment of downstream signaling molecules. Indeed, we found that proline-rich tyrosine kinase 2 (Pyk2) and ERK1/2 kinase are upregulated in SOD1G93A mice. These results point out an involvement of tyrosine kinases and phosphatases in the pathogenesis of ALS.

scholarly journals Differential Activation of the Tyrosine Kinases ZAP-70 and Syk After FcγRI Stimulation

Blood ◽  
1997 ◽  
Vol 89 (2) ◽  
pp. 388-396 ◽  
Author(s):  
Naomi Taylor ◽  
Thomas Jahn ◽  
Susan Smith ◽  
Thomas Lamkin ◽  
Lisa Uribe ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Signal Transduction Pathway ◽  
Protein Tyrosine Kinases ◽  
Monocytic Cell ◽  
Monocytic Cells ◽  
Kinase Activation ◽  
Receptor Aggregation

Abstract Engagement of the high-affinity IgG Fc receptor (FcγRI) activates a signal transduction pathway involving tyrosine phosphorylation of associated kinases. We compared the activation of the related protein tyrosine kinases (PTKs), Syk and ZAP-70, in FcγRI-mediated signaling. Cross-linking of the FcγRI multimeric receptor in monocytic cells results in tyrosine phosphorylation of the FcεRIγ subunit and association of Syk with this complex. We stably introduced ZAP-70 via a retroviral vector into two monocytic cell lines, U937 and THP-1, which normally do not express ZAP-70. Neither Syk nor MAP kinase activation was affected by the presence of ZAP-70. Although transduced ZAP-70 had in vitro kinase activity and associated with FcεRIγ after receptor aggregation, it was not tyrosine phosphorylated. In contrast, both ZAP-70 and Syk were phosphorylated in a T-cell line in which their respective levels of expression were similar to those detected in U937/ZAP-70 cells. Therefore, these results suggest that requirements for Syk and ZAP-70 phosphorylation are distinct in a monocytic cell context.

scholarly journals Specific proto-oncogenic tyrosine kinases of src family are enriched in cell-to-cell adherens junctions where the level of tyrosine phosphorylation is elevated.

1991 ◽  
Vol 113 (4) ◽  
pp. 867-879 ◽  
Author(s):  
S Tsukita ◽  
K Oishi ◽  
T Akiyama ◽  
Y Yamanashi ◽  
T Yamamoto ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Immunofluorescence Microscopy ◽  
Adherens Junctions ◽  
Tyrosine Phosphatase ◽  
Adult Tissues ◽  
High Level ◽  
Signal Mediators

To approach the transmembrane signaling pathway in the cell-to-cell adherens junctions (AJ), AJ-specific tyrosine phosphorylation was analyzed. When various types of rat adult tissues were pretreated with sodium orthovanadate, a potent inhibitor of tyrosine phosphatase, immunofluorescence microscopy showed that anti-phosphotyrosine polyclonal antibody specifically stained the undercoat of the cell-to-cell AJ. This indicates that the tyrosine kinase activity is elevated at the undercoat of the cell-to-cell AJ of adult tissues. To identify tyrosine kinases responsible for the high level of tyrosine phosphorylation at AJ, we have performed in vitro phosphorylation experiments with cell-to-cell AJ isolated from rat liver (Tsukita, Sh. and Sa. Tsukita. 1989. J. Cell Biol. 108:31-41) and immunoblotting analyses with specific antibodies for tyrosine kinases. As a result, three proto-oncogenic tyrosine kinases of src family, c-yes, c-src, and lyn kinases, were identified as major tyrosine kinases in the cell-to-cell AJ of hepatocytes. Furthermore, it was immunofluorescently shown that at least two of these kinases, c-yes and c-src kinases, were enriched at the cell-to-cell AJ of various types of cells including hepatocytes. Based on these findings, it is concluded that, in various types of cells, specific proto-oncogenic tyrosine kinases of src-family (c-yes and c-src) are enriched to work as signal mediators in the cell-to-cell AJ where the level of tyrosine phosphorylation is elevated.

scholarly journals Platelet αIIb-β3 integrin engagement induces the tyrosine phosphorylation of Cbl and its association with phosphoinositide 3-kinase and Syk

2000 ◽  
Vol 351 (3) ◽  
pp. 669-676 ◽  
Author(s):  
Abdelhafid SACI ◽  
Francine RENDU ◽  
Christilla BACHELOT-LOZA
Keyword(s):  
Signal Transduction ◽  
Platelet Aggregation ◽  
Tyrosine Phosphorylation ◽  
Platelet Activation ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Src Family Kinases ◽  
Β3 Integrin ◽  
Phosphoinositide 3 Kinase ◽  
Src Family Tyrosine Kinases

Agonist-induced platelet activation triggers ‘inside-out’signalling which activates αIIb-β3, the most abundant integrin in platelet membranes. The engagement of activated αIIb-β3 integrin by linking fibrinogen is necessary for platelet aggregation, and this induces subsequent outside-in signalling, which enhances platelet activation. Here we studied the involvement of Cbl during αIIb-β3-integrin-mediated signal transduction. During thrombin-induced platelet activation, Cbl was tyrosine phosphorylated, and phosphoinositide 3-kinase (PI 3-kinase) activity measured in Cbl immunoprecipitates was increased. Both Cbl phosphorylation and its association with PI 3-kinase were dependent on αIIb-β3 engagement by linking fibrinogen. The P256 and anti-LIBS6 (ligand-induced binding site 6) antibodies, which activate platelets directly through αIIb-β3, induced Cbl phosphorylation and increased the PI 3-kinase activity associated with Cbl. Both thrombin and antibodies to αIIb-β3 induced association of Cbl with the tyrosine kinase, Syk. Experiments performed with inhibitors of tyrosine kinases indicated that both Src-family kinases and Syk contribute to phosphorylation of Cbl and its consequent association with PI 3-kinase. The results show that, following integrin αIIb-β3 engagement, Cbl is tyrosine phosphorylated, recruits PI 3-kinase to this integrin signalling pathway and possibly enhances PI 3-kinase activity, downstream of Src-family tyrosine kinases and Syk activation.

scholarly journals The Role of Protein Tyrosine Phosphatases in Inflammasome Activation

2020 ◽  
Vol 21 (15) ◽  
pp. 5481
Author(s):  
Marianne R. Spalinger ◽  
Marlene Schwarzfischer ◽  
Michael Scharl
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Protein Complexes ◽  
Protein Tyrosine Phosphatases ◽  
Inflammasome Activation ◽  
Tyrosine Phosphatases ◽  
Tyrosine Residues ◽  
Inflammasome Activity ◽  
Activation Status

Inflammasomes are multi-protein complexes that mediate the activation and secretion of the inflammatory cytokines IL-1β and IL-18. More than half a decade ago, it has been shown that the inflammasome adaptor molecule, ASC requires tyrosine phosphorylation to allow effective inflammasome assembly and sustained IL-1β/IL-18 release. This finding provided evidence that the tyrosine phosphorylation status of inflammasome components affects inflammasome assembly and that inflammasomes are subjected to regulation via kinases and phosphatases. In the subsequent years, it was reported that activation of the inflammasome receptor molecule, NLRP3, is modulated via tyrosine phosphorylation as well, and that NLRP3 de-phosphorylation at specific tyrosine residues was required for inflammasome assembly and sustained IL-1β/IL-18 release. These findings demonstrated the importance of tyrosine phosphorylation as a key modulator of inflammasome activity. Following these initial reports, additional work elucidated that the activity of several inflammasome components is dictated via their phosphorylation status. Particularly, the action of specific tyrosine kinases and phosphatases are of critical importance for the regulation of inflammasome assembly and activity. By summarizing the currently available literature on the interaction of tyrosine phosphatases with inflammasome components we here provide an overview how tyrosine phosphatases affect the activation status of inflammasomes.

scholarly journals EnteropathogenicEscherichia coliUse Redundant Tyrosine Kinases to Form Actin Pedestals

2004 ◽  
Vol 15 (8) ◽  
pp. 3520-3529 ◽  
Author(s):  
Alyson Swimm ◽  
Bettina Bommarius ◽  
Yue Li ◽  
David Cheng ◽  
Patrick Reeves ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Intestinal Inflammation ◽  
Cell Types ◽  
Tyrosine Kinase Activity ◽  
Intestinal Epithelia ◽  
Resistant Strains ◽  
Conventional Antibiotics ◽  
Different Cell Types ◽  
Pedestal Formation

Enteropathogenic Escherichia coli (EPEC) are deadly contaminants in water and food and induce protrusion of actin-rich membrane pedestals beneath themselves upon attachment to intestinal epithelia. EPEC then causes intestinal inflammation, diarrhea, and, among children, death. Here, we show that EPEC uses multiple tyrosine kinases for formation of pedestals, each of which is sufficient but not necessary. In particular, we show that Abl and Arg, members of the Abl family of tyrosine kinases, localize and are activated in pedestals. We also show that pyrido[2,3-d]pyrimidine (PD) compounds, which inhibit Abl, Arg, and related kinases, block pedestal formation. Finally, we show that Abl and Arg are sufficient for pedestal formation in the absence of other tyrosine kinase activity, but they are not necessary. Our results suggest that additional kinases that are sensitive to inhibition by PD also can suffice. Together, these results suggest that EPEC has evolved a mechanism to use any of several functionally redundant tyrosine kinases during pathogenesis, perhaps facilitating its capacity to infect different cell types. Moreover, PD compounds are being developed to treat cancers caused by dysregulated Abl. Our results raise the possibility that PD may be useful in treating EPEC infections, and because PD affects host and not bacterium, selecting resistant strains may be far less likely than with conventional antibiotics.

scholarly journals Deregulated Syk inhibits differentiation and induces growth factor–independent proliferation of pre–B cells

2006 ◽  
Vol 203 (13) ◽  
pp. 2829-2840 ◽  
Author(s):  
Thomas Wossning ◽  
Sebastian Herzog ◽  
Fabian Köhler ◽  
Sonja Meixlsperger ◽  
Yogesh Kulathu ◽  
...  
Keyword(s):  
B Cells ◽  
Growth Factor ◽  
Tyrosine Phosphorylation ◽  
B Lymphocytes ◽  
Kinase Activity ◽  
Specific Inhibitor ◽  
Cell Types ◽  
Syk Kinase ◽  
Immature B Cells ◽  
Developmental Block

The nonreceptor protein spleen tyrosine kinase (Syk) is a key mediator of signal transduction in a variety of cell types, including B lymphocytes. We show that deregulated Syk activity allows growth factor–independent proliferation and transforms bone marrow–derived pre–B cells that are then able to induce leukemia in mice. Syk-transformed pre–B cells show a characteristic pattern of tyrosine phosphorylation, increased c-Myc expression, and defective differentiation. Treatment of Syk-transformed pre–B cells with a novel Syk-specific inhibitor (R406) reduces tyrosine phosphorylation and c-Myc expression. In addition, R406 treatment removes the developmental block and allows the differentiation of the Syk-transformed pre–B cells into immature B cells. Because R406 treatment also prevents the proliferation of c-Myc–transformed pre–B cells, our data indicate that endogenous Syk kinase activity may be required for the survival of pre–B cells transformed by other oncogenes. Collectively, our data suggest that Syk is a protooncogene involved in the transformation of lymphocytes, thus making Syk a potential target for the treatment of leukemia.

scholarly journals Thrombin and thrombin receptor agonist peptide induce tyrosine phosphorylation and tyrosine kinases in the platelet cytoskeleton. Translocation of pp60c-src and integrin αIIbβ3 (glycoprotein IIb/IIIa) is not required for aggregation, but is dependent on formation of large aggregate structures

1993 ◽  
Vol 294 (1) ◽  
pp. 253-260 ◽  
Author(s):  
K M Pumiglia ◽  
M B Feinstein
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Receptor Agonist ◽  
Kinase Activity ◽  
Shear Stresses ◽  
Tyrosine Kinase Activity ◽  
Src Tyrosine Kinase ◽  
Agonist Peptide

The maximal aggregation of platelets induced by alpha-thrombin or by the receptor agonist peptide thrombin-(42-47)-peptide (TRP42/47) rapidly increased the pp60c-src associated with the cytoskeleton fraction. There was good correlation between the tyrosine kinase activity and the mass of pp60c-src. Tyrosine kinase activity associated with the cytoskeleton phosphorylated several endogenous cytoskeleton-associated proteins, as revealed by immunoblotting with anti-phosphotyrosine antibody following incubation with ATP in vitro. However, with the exception of pp60c-src, few phosphotyrosine-containing proteins were retained in the cytoskeleton in intact platelets when compared with total platelet lysates. Translocation of pp60c-src to the cytoskeleton induced by alpha-thrombin and TRP42/47 is dependent on glycoprotein IIb/IIIa (GPIIb/IIIa)-fibrinogen-mediated aggregation, but does not occur when ristocetin/von Willebrand factor produces GPIb-mediated platelet aggregation. The translocation of GPIIb/IIIa and pp60c-src to the cytoskeleton is not necessary for aggregation, as it is not seen when clearly visible small to moderate-sized aggregates are initially formed after exposure to thrombin. The linkage of these proteins to the cytoskeleton occurs only after later extensive formation of large aggregates. Translocation of GPIIa/IIIa to the cytoskeleton is not sufficient for the cytoskeletal association of pp60c-src, as the former occurs independently in platelets stimulated with concanavalin A in the absence of aggregation. Linkage of the integrin GPIIb/IIIa and pp60c-src to the internal cytoskeleton structure, and the corresponding tyrosine phosphorylation of certain proteins upon formation of large aggregates, may be an example of mechanochemical transduction by integrin receptors and may represent a structure with the requisite tensile strength to stabilize large platelet aggregates against high shear stresses.

scholarly journals Interferon-β Interrupts Interleukin-6–Dependent Signaling Events in Myeloma Cells

Blood ◽  
1997 ◽  
Vol 89 (1) ◽  
pp. 261-271 ◽  
Author(s):  
Lloyd C. Berger ◽  
Robert G. Hawley
Keyword(s):  
Tyrosine Phosphorylation ◽  
Interleukin 6 ◽  
Tyrosine Kinases ◽  
Adaptor Protein ◽  
Cell Types ◽  
Myeloma Cell ◽  
Mitogen Activated Protein Kinase ◽  
Type I Interferons ◽  
Type I ◽  
Myeloma Cells

Type I interferons (IFNs-α and IFN-β) bind to a common receptor to exert strong antiproliferative activity on a broad range of cell types, including interleukin-6 (IL-6)–dependent myeloma cells. In this study, we investigated the effect of IFN-β pretreatment on IL-6–stimulated mitogenic signaling in the human myeloma cell line U266. IL-6 induced transient tyrosine phosphorylation of the IL-6 receptor signal-transducing subunit gp130, the gp130-associated protein tyrosine kinases Jak1, Jak2, and Tyk2, the phosphotyrosine phosphatase PTP1D/Syp, the adaptor protein Shc and the mitogen-activated protein kinase Erk2, and accumulation of GTP-bound p21ras. Prior treatment of U266 cells with IFN-β downregulated IL-6–induced tyrosine phosphorylation of gp130, Jak2, PTP1D/Syp, Shc, and Erk2, and GTP-loading of p21ras. Further analysis indicated that treatment with IFN-β disrupted IL-6–induced binding of PTP1D/Syp to gp130 and the adaptor protein Grb2; IFN-β pretreatment also interfered with IL-6–induced interaction of Shc with Grb2 and a 145-kD tyrosine-phosphorylated protein. These results suggest a novel mechanism whereby type I IFNs interrupt IL-6–promoted mitogenesis of myeloma cells in part by preventing the formation of essential signaling complexes leading to p21ras activation.

scholarly journals Csk enhances insulin-stimulated dephosphorylation of focal adhesion proteins.

1996 ◽  
Vol 16 (9) ◽  
pp. 4765-4772 ◽  
Author(s):  
K Tobe ◽  
H Sabe ◽  
T Yamamoto ◽  
T Yamauchi ◽  
S Asai ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Cell Physiology ◽  
Insulin Receptor Tyrosine Kinase ◽  
Adhesion Proteins ◽  
Focal Adhesion Proteins ◽  
Focal Adhesion Protein

Insulin has pleiotropic effects on the regulation of cell physiology through binding to its receptor. The wide variety of tyrosine phosphorylation motifs of insulin receptor substrate 1 (IRS-1), a substrate for the activated insulin receptor tyrosine kinase, may account for the multiple functions of insulin. Recent studies have shown that activation of the insulin receptor leads to the regulation of focal adhesion proteins, such as a dephosphorylation of focal adhesion kinase (pp125FAK). We show here that C-terminal Src kinase (Csk), which phosphorylates C-terminal tyrosine residues of Src family protein tyrosine kinases and suppresses their kinase activities, is involved in this insulin-stimulated dephosphorylation of focal adhesion proteins. We demonstrated that the overexpression of Csk enhanced and prolonged the insulin-induced dephosphorylation of pp125FAK. Another focal adhesion protein, paxillin, was also dephosphorylated upon insulin stimulation, and a kinase-negative mutant of Csk was able to inhibit the insulin-induced dephosphorylation of pp125FAK and paxillin. Although we have shown that the Csk Src homology 2 domain can bind to several tyrosine-phosphorylated proteins, including pp125FAK and paxillin, a majority of protein which bound to Csk was IRS-1 when cells were stimulated by insulin. Our data also indicated that tyrosine phosphorylation levels of IRS-1 appear to be paralleled by the dephosphorylation of the focal adhesion proteins. We therefore propose that the kinase activity of Csk, through the insulin-induced complex formation of Csk with IRS-1, is involved in insulin's regulation of the phosphorylation levels of the focal adhesion proteins, possibly through inactivation of the kinase activity of c-Src family kinases.

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