Involvement of the Snake Toxin Receptor CLEC-2, in Podoplanin-mediated Platelet Activation, by Cancer Cells

Suzuki‐Inoue, Katsue; Kato, Yoshinori; Ito, Osamu; Kaneko, Mika K.; Mishima, Kazuhiko; Yatomi, Yutaka; Yamazaki, Yasuo; Narimatsu, Hisashi; Ozaki, Yukio

doi:10.1074/jbc.m702327200

Cited by 457 publications

(405 citation statements)

References 29 publications

Supporting

Mentioning

389

Contrasting

Unclassified

Order By: Relevance

“…10 mM Pervanadate was freshly prepared on the day for use by mixing sodium orthovanadate and hydrogen peroxide in phosphate-buffered saline to final concentrations 10 mM, then left for 5 min at room temperature and kept on ice. Other reagents were from previously described sources (6,8,24).…”

Section: Methodsmentioning

confidence: 99%

G6b-B Inhibits Constitutive and Agonist-induced Signaling by Glycoprotein VI and CLEC-2

Mori

Pearce

Spalton

et al. 2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

Platelets play an essential role in wound healing by forming thrombi that plug holes in the walls of damaged blood vessels. To achieve this, platelets express a diverse array of cell surface receptors and signaling proteins that induce rapid platelet activation. In this study we show that two platelet glycoprotein receptors that signal via an immunoreceptor tyrosine-based activation motif (ITAM) or an ITAM-like domain, namely the collagen receptor complex glycoprotein VI (GPVI)-FcR ␥-chain and the C-type lectin-like receptor 2 (CLEC-2), respectively, support constitutive (i.e. agonist-independent) signaling in a cell line model using a nuclear factor of activated T-cells (NFAT) transcriptional reporter assay that can detect low level activation of phospholipase C␥ (PLC␥). Constitutive and agonist signaling by both receptors is dependent on Src and Syk family kinases, and is inhibited by G6b-B, a platelet immunoglobulin receptor that has two immunoreceptor tyrosine-based inhibitory motifs in its cytosolic tail. Mutation of the conserved tyrosines in the two immunoreceptor tyrosine-based inhibitory motifs prevents the inhibitory action of G6b-B. Interestingly, the inhibitory activity of G6b-B is independent of the Src homology 2 (SH2)-domain containing tyrosine phosphatases, SHP1 and SHP2, and the inositol 5-phosphatase, SHIP. Constitutive signaling via Src and Syk tyrosine kinases is observed in platelets and is associated with tyrosine phosphorylation of GPVI-FcR ␥-chain and CLEC-2. We speculate that inhibition of constitutive signaling through Src and Syk tyrosine kinases by G6b-B may help to prevent unwanted platelet activation.The GPVI-FcR ␥-chain complex is the major signaling receptor for collagen on platelets and megakaryocytes (1, 2). Crosslinking of GPVI leads to Src-dependent phosphorylation of a tandem YXXL sequence on the FcR ␥-chain known as an immunoreceptor tyrosine-based activation motif (ITAM). 4 In turn, this leads to recruitment and activation of the tyrosine kinase Syk through its tandem SH2 domains. Syk initiates a signaling cascade that generates a linker for activation of T (LAT) cell-dependent signalosome, which mediates activation of phospholipase C␥2 (PLC␥-2) (3, 4). This pathway initiates a rise in intracellular Ca 2ϩ and activation of protein kinase C leading to platelet aggregation.CLEC-2 is a 32-kDa C-type lectin-like receptor that functions as a platelet receptor for the snake venom toxin rhodocytin and the lymphatic endothelial marker, podoplanin (5-7). Like glycoprotein (GP) VI, CLEC-2 signals via sequential activation of Src and Syk tyrosine kinases leading to activation of PLC␥2 (5). The regulation of PLC␥2 by CLEC-2 is distinct from that of GPVI in that it uses a single YXXL sequence and is only partially dependent on the adapter SLP-76 (5, 8).G6b is a recently identified member of the immunoglobulin superfamily that exists in several splice variants (9). G6b-B is the only one of these variants to contain both a transmembrane region and two immunoreceptor tyrosine-based inhibit...

show abstract

Section: Methodsmentioning

confidence: 99%

G6b-B Inhibits Constitutive and Agonist-induced Signaling by Glycoprotein VI and CLEC-2

Mori

Pearce

Spalton

et al. 2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Notably, podoplanin-deficient mice fail to develop a functional lymphatic system with a severe lymphedema in the extremities . A series of recent findings has shown that podoplanin activates a novel platelet receptor, C-type lectinlike receptor (CLEC)-2 of platelet, and has an essential role in blood -lymphatic separation during lymphatic development (see more information below) (Fu et al 2008;Kato et al 2008;Bertozzi et al 2010a,b;Suzuki-Inoue et al 2007Uhrin et al 2010;SuzukiInoue 2011). Moreover, some lymphatic vessels were found to express a high level of podoplanin (LEC podo-high ) and the others a low level of podoplanin (LEC podo-low ), and these two subpopulations differentially recruit CCR10-positive T lymphocytes during the inflammation response (Kriehuber et al 2001;Wick et al 2008).…”

Section: Initial Steps For Lymphatic Specification and Differentiationmentioning

confidence: 99%

The New Era of the Lymphatic System: No Longer Secondary to the Blood Vascular System

Choi

Lee²,

Hong

2012

Cold Spring Harbor Perspectives in Medicine

118

107

View full text Add to dashboard Cite

The blood and lymphatic systems are the two major circulatory systems in our body. Although the blood system has been studied extensively, the lymphatic system has received much less scientific and medical attention because of its elusive morphology and mysterious pathophysiology. However, a series of landmark discoveries made in the past decade has begun to change the previous misconception of the lymphatic system to be secondary to the more essential blood vascular system. In this article, we review the current understanding of the development and pathology of the lymphatic system. We hope to convince readers that the lymphatic system is no less essential than the blood circulatory system for human health and well-being.

show abstract

“…More recently, platelets were found to also express CLEC-2 and this receptor was shown to be a target of rhodocytin, a snake venom toxin that induces platelet aggregation [18][19][20]. In addition to rhodocytin, the mucin-like glycoprotein podoplanin (also known as GP38) has been identified as an endogenous ligand for CLEC-2 [21]. Podoplanin is a cell surface protein highly expressed by lymphatic endothelium [22], lymph node stroma [23], spleen stroma [24] and some cancer cells [22].…”

Section: Introductionmentioning

confidence: 99%

“…However, it is not known whether data obtained with overexpression of the chimeric receptor necessarily reflect the signaling properties of intact CLEC-2. The latter has been principally studied in platelets, where interaction of CLEC-2 with ligand was first shown to induce Syk recruitment and downstream signaling via LAT, SLP-76, Vav, Rac and other players and result in marked calcium elevation, which promotes platelet activation [19,21]. Thus, CLEC-2 signaling in platelets resembles Dectin-1 signaling in myeloid cells but its impact on gene expression cannot be evaluated as platelets lack a transcriptional apparatus.…”

mentioning

confidence: 99%

CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses

et al. 2011

View full text Add to dashboard Cite

Myeloid cells express a plethora of C-type lectin receptors (CLRs) that can regulate immune responses. CLEC-2 belongs to the Dectin-1 sub-family of CLRs that possess an extracellular C-type lectin-like domain and a single intracellular hemITAM motif. CLEC-2 is highly expressed on mouse and human platelets where it signals via Syk to promote aggregation. We generated a monoclonal antibody (mAb) against mouse CLEC-2 and found that CLEC-2 is additionally widely expressed on leukocytes and that its expression is upregulated during inflammation. MAb-mediated crosslinking of CLEC-2 leads to hemI-TAM-dependent signaling via Syk, Ca 21 and NFAT and, in myeloid cells, modulates the effect of toll-like receptor (TLR) agonists to selectively potentiate production of IL-10. A macrophage/dendritic cell-dependent increase in IL-10 is also observed in mice given anti-CLEC-2 mAb together with LPS. Collectively, these data indicate that CLEC-2 is expressed in myeloid cells and acts as a Syk-coupled CLR able to modulate TLR signaling and inflammatory responses.Key words: CLEC-2 . C-type lectin . HemITAM . IL-10 . Syk Supporting Information available online IntroductionSignaling by some members of the C-type lectin receptor (CLR) superfamily plays a key role in innate immunity and in regulation of myeloid cell function [1,2]. A classical example is Dectin-1, which is expressed by macrophages (MØs), neutrophils and dendritic cells (DCs) and acts as a pattern recognition receptor for b-glucans present on fungal and some bacterial cell walls. Dectin-1 signals via a phospho-tyrosine-based hemITAM motif in its intracellular domain that recruits spleen tyrosine kinase (Syk) [3,4]. Dectin-1 signaling through Syk in myeloid cells can variably lead to phagocytosis, production of reactive oxygen species (ROS) and/or induction of innate response genes, including those encoding pro-inflammatory cytokines [5,6]. 3040Pro-inflammatory Dectin-1 signaling requires CARD9-dependent activation of NF-kB [7] although Dectin-1 can also signal to NF-kB via a Syk-independent pathway [8]. Although many DC types are potently activated by Dectin-1 agonists, in other myeloid cells Dectin-1 signaling only weakly activates the proinflammatory gene program [9]. In those cells, Dectin-1 acts primarily in synergy with other innate immune receptors such as toll-like receptors (TLRs) [10,11]. Notably, both Dectin-1 and CARD9 are important for resistance to fungal infection in both mice [7,12,13] and humans [14,15], indicating the importance of the CLR/Syk signaling pathway in immunity.The features of Dectin-1, including type II membrane topology, single Dectin-1-like C-type lectin-like domain and intracellular hemITAM are shared by two other CLRs, DNGR-1 (CLEC9A) and CLEC-2 (CLEC1B). DNGR-1 is selectively expressed by DCs and acts as a receptor for dead cells, facilitating cross-priming to cell-associated antigens [16]. CLEC-2 was first identified in a screen for natural killer (NK) cell receptors and its mRNA was found in myeloid cells and in some NK-cell clones [...

show abstract

Involvement of the Snake Toxin Receptor CLEC-2, in Podoplanin-mediated Platelet Activation, by Cancer Cells

Cited by 457 publications

References 29 publications

G6b-B Inhibits Constitutive and Agonist-induced Signaling by Glycoprotein VI and CLEC-2

G6b-B Inhibits Constitutive and Agonist-induced Signaling by Glycoprotein VI and CLEC-2

The New Era of the Lymphatic System: No Longer Secondary to the Blood Vascular System

CLEC‐2 signaling via Syk in myeloid cells can regulate inflammatory responses

Contact Info

Product

Resources

About