Tyrosine Phosphorylation of the Fc Receptor γ-Chain in Collagen-stimulated Platelets

Gibbins, Jonathan M.; Asselin, J; Farndale, Richard W.; Barnes, Michael J.; Law, Che‐Leung; Watson, Steve P.

doi:10.1074/jbc.271.30.18095

Cited by 222 publications

(216 citation statements)

References 39 publications

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“…Syk is upstream in mediating high affinity IgE receptor (Fc⑀RI) (17), Fc receptor ␥-chain RII (19,47), IL-2R (48), and CD40 (49). Recently, Toll-like receptor (TLR)-2 or TLR-4 has been proven to mediate LPS-induced cellular signaling (50 -52).…”

Section: Discussionmentioning

confidence: 99%

Protein-Tyrosine Kinase Syk Expressed in Human Nasal Fibroblasts and Its Effect on RANTES Production

Yamada

Fujieda

Yanagi

et al. 2001

The Journal of Immunology

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Fibroblasts, a rich source of chemokines, interact with eosinophils and play a key role in the pathogenesis of airway disease. RANTES is produced by fibroblasts to attract and activate eosinophils. LPS is known to induce RANTES and cause protein tyrosine phosphorylation. Nonreceptor protein tyrosine kinase Syk is widely expressed and an important role in intracellular signal transduction in hemopoietic cells. In the present study, we examined whether Syk was expressed in a number of primary human nasal polyp tissue-derived fibroblast lines and whether it played some role in cellular function. Syk proteins were expressed in human nasal fibroblasts, but the expression level varied. There were positive correlations between the level of Syk expression and RANTES production induced by LPS. Overexpression of wild-type Syk by gene transfer enhanced RANTES production from nasal fibroblasts stimulated with LPS. The decrease of Syk expression by the administration of Syk antisense inhibited RANTES production. These results suggest that Syk expression affects RANTES production in fibroblasts of nasal polyps.

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Section: Discussionmentioning

confidence: 99%

Protein-Tyrosine Kinase Syk Expressed in Human Nasal Fibroblasts and Its Effect on RANTES Production

Yamada

Fujieda

Yanagi

et al. 2001

The Journal of Immunology

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“…The pellets were washed in lysis buffer followed by Trisbuffered saline (TBS-T; 20 mM Tris, 137 mM NaCl, 0.1% (v/v) Tween 20, pH 7.6) before the addition of Laemmli sample treatment buffer in preparation for SDS-PAGE. A GST fusion protein containing the tandem SH2 domains of Syk was prepared and used to precipitate the FcR ␥-chain as described previously (12).…”

Section: Methodsmentioning

confidence: 99%

“…The Src-like kinases Fyn and Lyn are believed to be involved in this phosphorylation (9 -11). Syk is able to bind to the tyrosine-phosphorylated ITAM of the FcR ␥-chain via its tandem SH2 domains (12) leading to autophosphorylation and activation. Syk plays a critical role in the regulation of PLC␥2 through phosphorylation of a number of key proteins including the adapters LAT and SLP-76 (13)(14)(15).…”

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confidence: 99%

Evidence for Two Distinct Epitopes within Collagen for Activation of Murine Platelets

Schulte¹,

Snell²,

Bergmeier³

et al. 2001

Journal of Biological Chemistry

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It has recently been shown that the monoclonal antibody JAQ1 to murine glycoprotein VI (GPVI) can cause aggregation of mouse platelets upon antibody crosslinking and that collagen-induced platelet aggregation can be inhibited by preincubation of platelets with JAQ1 in the absence of cross-linking (Nieswandt, B., Bergmeier, W., Schulte, V., Rackebrandt, K., Gessner, J. E., and Zirngibl, H. (2000) J. Biol. Chem. 275, 23998 -24002). In the present study, we have shown that crosslinking of GPVI by JAQ1 results in tyrosine phosphorylation of the same profile of proteins as that induced by collagen, including the Fc receptor (FcR) ␥-chain, Syk, LAT, SLP-76, and phospholipase C␥2. In contrast, platelet aggregation and tyrosine phosphorylation of these proteins were inhibited when mouse platelets were preincubated with JAQ1 in the absence of cross-linking and were subsequently stimulated with a collagen-related peptide (CRP) that is specific for GPVI and low concentrations of collagen. However, at higher concentrations of collagen, but not CRP, aggregation of platelets and tyrosine phosphorylation of the above proteins (except for the adapter LAT) is re-established despite the presence of JAQ1. These observations suggest that a second activatory binding site, which is distinct from the CRP binding site on GPVI on mouse platelets, is occupied in the presence of high concentrations of collagen. Although this could be a second site on GPVI that is activated by a novel motif within the collagen molecule, the absence of LAT phosphorylation in response to collagen in the presence of JAQ1 suggests that this is more likely to be caused by activation of a second receptor that is also coupled to the FcR ␥-chain. The possibility that this response is mediated by a receptor that is not coupled to FcR ␥-chain is excluded on the grounds that aggregation is absent in platelets from FcR ␥-chain-deficient mice.The platelet collagen receptor GPVI 1 plays a pivotal role in platelet activation following receptor cross-linking by collagen. This is highlighted by the impaired response to collagen in GPVI-deficient patients (2-4) and the bleeding disorders associated with this. GPVI is a 60 -65-kDa type I transmembrane glycoprotein belonging to the immunoglobulin superfamily (5), which forms a complex with the FcR ␥-chain at the cell surface in human and mouse platelets (1, 6, 7). Signaling through GPVI occurs via a similar pathway to that used by immunoreceptors (8) as revealed by the tyrosine phosphorylation of the FcR ␥-chain immunoreceptor tyrosine-based activation motif (ITAM) by a Src-like kinase (9, 10). The Src-like kinases Fyn and Lyn are believed to be involved in this phosphorylation (9 -11). Syk is able to bind to the tyrosine-phosphorylated ITAM of the FcR ␥-chain via its tandem SH2 domains (12) leading to autophosphorylation and activation. Syk plays a critical role in the regulation of PLC␥2 through phosphorylation of a number of key proteins including the adapters LAT and SLP-76 (13-15). These signaling events occur upon colla...

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“…PKC may also play a role in the stabilizing function of other platelet collagen receptors. [37][38][39][40] Although there have been no studies of PKC involvement in platelet adhesion under flow conditions, several reports indicate that PKC inhibitors block adhesion under static conditions. In particular, Vuori and Ruoslahti 9 reported that calphostin C inhibits fibroblast adhesion to fibronectin.…”

Section: Discussion Platelet Adhesion To Collagen: Activation Of Pkc mentioning

confidence: 99%

“…35 Platelet adhesion under these conditions is very efficient, occurring within seconds, and in a plasma-free, Mg 2ϩ -containing buffer it is mediated primarily by the ␣ 2 ␤ 1 -integrin, 36 although other receptors or associated proteins may participate. [37][38][39][40] In the present study, we investigated the involvement of PKC in platelet adhesion to collagen under flow conditions by using several PKC inhibitors. In cases of vessel-wall injury, not only must platelet adhesion to the exposed adhesive proteins of the ECM be rapid (seconds to minutes), but also, the stability of the attached platelets must be sufficient to prevent blood loss and contribute to the healing process.…”

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confidence: 99%

Activation of Protein Kinase C Is Required for the Stable Attachment of Adherent Platelets to Collagen but Is Not Needed for the Initial Rapid Adhesion Under Flow Conditions

Polanowska-Grabowska

Gear

1999

ATVB

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Abstract-We have investigated the role of protein kinase C (PKC) in the initial events of ␣ 2 ␤ 1 -integrin-mediated platelet adhesion to collagen under flow conditions. Although adhesion caused activation of PKC, as evidenced by pleckstrin phosphorylation, the PKC inhibitors GF 109203X and Gö 6976 had no effect on adhesion, even though they prevented pleckstrin phosphorylation. The initial kinetics and extent of platelet adhesion to collagen (Ͻ5 seconds) and tyrosine phosphorylation of p125 FAK and p72 syk were not influenced by the PKC inhibitors, whereas adhesion to polylysine was prevented. These results indicate that adhesion to collagen and polylysine involve different mechanisms and requirements for PKC activation. Pretreatment with GF 109203X destabilized collagen-adherent platelets, accelerating their detachment, which was associated with tyrosine dephosphorylation of p125 FAK . Thus, although PKC activation was not required for rapid platelet adhesion to collagen, it appears to play an important role in stabilizing the attachment of adherent platelets to collagen. We also examined the effect of PKC activation by the phorbol ester phorbol 12-myristate 13-acetate (PMA) on platelet adhesion to collagen. PMA at 100 nmol/L strongly potentiated adhesion and tyrosine phosphorylation of p125 FAK and p72 syk and activated ␤ 1 -integrins, as determined by increased exposure of the 15/7 epitope. The PMA-stimulated adhesion was partially blocked by an anti-␣ 2 ␤ 1 antibody, was completely inhibited by GF 109203X, and was not correlated with the extent of pleckstrin phosphorylation. Therefore, strong PKC activation may lead to inside-out signaling, enhancing the role of ␤ 1 -integrins in adhesion. Pleckstrin phosphorylation does not appear to be involved in the initial phase of basic or PMA-stimulated adhesion but may help stabilize the adherent platelets. Key Words: platelets Ⅲ adhesion Ⅲ collagen Ⅲ PKC Ⅲ p125 FAK Ⅲ p72 syk P rotein kinase C (PKC) was initially identified as a threonine/serine protein kinase dependent on calcium and phospholipids and known to be activated during the earliest events of signal transduction, tumor promotion, and cell regulation. 1-4 Activation of PKC has been linked to reorganization of the actin cytoskeleton, cell motility, adhesion, and the formation of focal contacts. [5][6][7] The involvement of PKC in cell adhesion to extracellular matrix (ECM) proteins has long been proposed from the observations that direct stimulation of PKC by phorbol esters can activate integrins, potentiating adhesion and spreading, and that inhibitors of PKC prevent adhesion. 8 -13 There is also evidence that direct integrin binding to ECM proteins leads to PKC activation. 9,14 Although stimulation of PKC by phorbol esters can mediate integrin activation and enhance adhesion, there is little evidence that PKC directly regulates these events.Platelets are a good model to study signal transduction events during attachment of cells to ECM proteins or for cell-cell interactions. 15 Several studies suggest th...

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Tyrosine Phosphorylation of the Fc Receptor γ-Chain in Collagen-stimulated Platelets

Cited by 222 publications

References 39 publications

Protein-Tyrosine Kinase Syk Expressed in Human Nasal Fibroblasts and Its Effect on RANTES Production

Protein-Tyrosine Kinase Syk Expressed in Human Nasal Fibroblasts and Its Effect on RANTES Production

Evidence for Two Distinct Epitopes within Collagen for Activation of Murine Platelets

Activation of Protein Kinase C Is Required for the Stable Attachment of Adherent Platelets to Collagen but Is Not Needed for the Initial Rapid Adhesion Under Flow Conditions

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