1
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Laletin V, Bernard PL, Montersino C, Yamanashi Y, Olive D, Castellano R, Guittard G, Nunès JA. DOK1 and DOK2 regulate CD8 T cell signaling and memory formation without affecting tumor cell killing. Sci Rep 2024; 14:15053. [PMID: 38956389 PMCID: PMC11220026 DOI: 10.1038/s41598-024-66075-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 06/26/2024] [Indexed: 07/04/2024] Open
Abstract
Targeting intracellular inhibiting proteins has been revealed to be a promising strategy to improve CD8+ T cell anti-tumor efficacy. Here, we are focusing on intracellular inhibiting proteins specific to TCR signaling: DOK1 and DOK2 expressed in T cells. We hypothesized that depletion of intracellular inhibition checkpoint DOK1 and DOK2 could improve CD8+ T-cell based cancer therapies. To evaluate the role of DOK1 and DOK2 depletion in physiology and effector function of CD8+ T lymphocytes and in cancer progression, we established a transgenic T cell receptor mouse model specific to melanoma antigen hgp100 (pmel-1 TCR Tg) in WT and Dok1/Dok2 DKO (double KO) mice. We showed that both DOK1 and DOK2 depletion in CD8+ T cells after an in vitro pre-stimulation induced a higher percentage of effector memory T cells as well as an up regulation of TCR signaling cascade- induced by CD3 mAbs, including the increased levels of pAKT and pERK, two major phosphoproteins involved in T cell functions. Interestingly, this improved TCR signaling was not observed in naïve CD8+ T cells. Despite this enhanced TCR signaling essentially shown upon stimulation via CD3 mAbs, pre-stimulated Dok1/Dok2 DKO CD8+ T cells did not show any increase in their activation or cytotoxic capacities against melanoma cell line expressing hgp100 in vitro. Altogether we demonstrate here a novel aspect of the negative regulation by DOK1 and DOK2 proteins in CD8+ T cells. Indeed, our results allow us to conclude that DOK1 and DOK2 have an inhibitory role following long term T cell stimulations.
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Affiliation(s)
- Vladimir Laletin
- Centre de Recherche en Cancérologie de Marseille, CRCM, Immunity and Cancer Team, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France
| | - Pierre-Louis Bernard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Immunity and Cancer Team, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France
| | - Camille Montersino
- Centre de Recherche en Cancérologie de Marseille, CRCM, TrGET Pre-Clinical Assay Platform, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France
| | - Yuji Yamanashi
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Daniel Olive
- Centre de Recherche en Cancérologie de Marseille, CRCM, Immunity and Cancer Team, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France
| | - Rémy Castellano
- Centre de Recherche en Cancérologie de Marseille, CRCM, TrGET Pre-Clinical Assay Platform, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France
| | - Geoffrey Guittard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Immunity and Cancer Team, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France
| | - Jacques A Nunès
- Centre de Recherche en Cancérologie de Marseille, CRCM, Immunity and Cancer Team, Institut Paoli-Calmettes, Inserm, CNRS, Aix Marseille University, Marseille, France.
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2
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Zhu P, Wu X, Zhang RY, Hsu CC, Zhang ZY, Tao WA. An Integrated Proteomic Strategy to Identify SHP2 Substrates. J Proteome Res 2022; 21:2515-2525. [PMID: 36103635 PMCID: PMC9597472 DOI: 10.1021/acs.jproteome.2c00481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein phosphatases play an essential role in normal cell physiology and the development of diseases such as cancer. The innate challenges associated with studying protein phosphatases have limited our understanding of their substrates, molecular mechanisms, and unique functions within highly coordinated networks. Here, we introduce a novel strategy using substrate-trapping mutants coupled with quantitative proteomics methods to identify physiological substrates of Src homology 2 containing protein tyrosine phosphatase 2 (SHP2) in a high-throughput manner. The technique integrates three parallel mass spectrometry-based proteomics experiments, including affinity isolation of substrate-trapping mutant complex using wild-type and SHP2 KO cells, in vivo global quantitative phosphoproteomics, and in vitro phosphatase reaction. We confidently identified 18 direct substrates of SHP2 in the epidermal growth factor receptor signaling pathways, including both known and novel SHP2 substrates. Docking protein 1 was further validated using biochemical assays as a novel SHP2 substrate, providing a mechanism for SHP2-mediated Ras activation. This advanced workflow improves the systemic identification of direct substrates of protein phosphatases, facilitating our understanding of the equally important roles of protein phosphatases in cellular signaling.
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Affiliation(s)
- Peipei Zhu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Xiaofeng Wu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ruo-Yu Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
| | - Chuan-Chih Hsu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Zhong-Yin Zhang
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, United States
| | - W Andy Tao
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, United States
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3
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Ochiai R, Hayashi K, Yamamoto H, Fujii R, Saichi N, Shinchi H, Ishida T, Honda T, Shimizu T, Matsutani N, Seki N, Kawamura M, Ueda K. Plasma exosomal
DOK3
reflects immunological states in lung tumor and predicts prognosis of gefitinib treatment. Cancer Sci 2022; 113:3960-3971. [DOI: 10.1111/cas.15512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 07/12/2022] [Accepted: 07/22/2022] [Indexed: 11/27/2022] Open
Affiliation(s)
- Ryosuke Ochiai
- Division of Medical Oncology, Department of Internal Medicine Teikyo University School of Medicine Tokyo Japan
| | - Kentaro Hayashi
- Division of Respiratory Medicine, Department of Internal Medicine Nihon University School of Medicine Tokyo Japan
| | - Hiroshi Yamamoto
- Department of Respiratory Medicine Tokyo Metropolitan Geriatric Hospital Tokyo Japan
| | - Risa Fujii
- Cancer Proteomics Group, Cancer Precision Medicine Center, Japanese Foundation for Cancer Research Tokyo Japan
| | - Naomi Saichi
- Cancer Proteomics Group, Cancer Precision Medicine Center, Japanese Foundation for Cancer Research Tokyo Japan
| | - Hiroki Shinchi
- Cancer Proteomics Group, Cancer Precision Medicine Center, Japanese Foundation for Cancer Research Tokyo Japan
| | - Tsuyoshi Ishida
- Department of Pathology Teikyo University School of Medicine Tokyo Japan
| | - Takeshi Honda
- Division of Medical Oncology, Department of Internal Medicine Teikyo University School of Medicine Tokyo Japan
| | - Tetsuo Shimizu
- Division of Respiratory Medicine, Department of Internal Medicine Nihon University School of Medicine Tokyo Japan
| | - Noriyuki Matsutani
- Department of Surgery Teikyo University Mizonokuchi Hospital Kanagawa Japan
| | - Nobuhiko Seki
- Division of Medical Oncology, Department of Internal Medicine Teikyo University School of Medicine Tokyo Japan
| | - Masafumi Kawamura
- Department of Surgery Teikyo University School of Medicine Tokyo Japan
| | - Koji Ueda
- Cancer Proteomics Group, Cancer Precision Medicine Center, Japanese Foundation for Cancer Research Tokyo Japan
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4
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Dok-1 regulates mast cell degranulation negatively through inhibiting calcium-dependent F-actin disassembly. Clin Immunol 2022; 238:109008. [PMID: 35421591 DOI: 10.1016/j.clim.2022.109008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/24/2022]
Abstract
In food allergies, antigen-induced aggregation of FcεRI on mast cells initiates highly ordered and sequential signaling events. Dok-1(downstream of tyrosine kinase 1), undergoes intense tyrosine phosphorylation upon FcεRI stimulation, which negatively regulates Ras/Erk signaling and the subsequent cytokine release, but it remains unclear whether Dok-1 regulates Fc-mediated degranulation. In this study, we investigated the role of Dok-1 in FcεRI-mediated degranulation. Dok-1 overexpressing RBL-2H3 cells were established. Degranulation, immunoprecipitation, co-immunoprecipitation, immunoblotting and flow cytometry assay were performed to explore the effects of Dok-1 and its underlying mechanisms. We found that, following FcεRI activation, Dok-1 was recruited to the plasma membrane, leading to tyrosine phosphorylation. Phosphorylated Dok-1 inhibits FcεRI-operated calcium influx, and negatively regulated degranulation by inhibiting calcium-dependent disassembly of actin filaments. Our data revealed that Dok-1 is a negative regulator of FcεRI-mediated mast cell degranulation. These findings contribute to the identification of therapeutic targets for food allergies.
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5
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Src Family Tyrosine Kinases in Intestinal Homeostasis, Regeneration and Tumorigenesis. Cancers (Basel) 2020; 12:cancers12082014. [PMID: 32717909 PMCID: PMC7464719 DOI: 10.3390/cancers12082014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 01/11/2023] Open
Abstract
Src, originally identified as an oncogene, is a membrane-anchored tyrosine kinase and the Src family kinase (SFK) prototype. SFKs regulate the signalling induced by a wide range of cell surface receptors leading to epithelial cell growth and adhesion. In the intestine, the SFK members Src, Fyn and Yes regulate epithelial cell proliferation and migration during tissue regeneration and transformation, thus implicating conserved and specific functions. In patients with colon cancer, SFK activity is a marker of poor clinical prognosis and a potent driver of metastasis formation. These tumorigenic activities are linked to SFK capacity to promote the dissemination and tumour-initiating capacities of epithelial tumour cells. However, it is unclear how SFKs promote colon tumour formation and metastatic progression because SFK-encoding genes are unfrequently mutated in human cancer. Here, we review recent findings on SFK signalling during intestinal homeostasis, regeneration and tumorigenesis. We also describe the key nongenetic mechanisms underlying SFK tumour activities in colorectal cancer, and discuss how these mechanisms could be exploited in therapeutic strategies to target SFK signalling in metastatic colon cancer.
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6
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CD5 signalosome coordinates antagonist TCR signals to control the generation of Treg cells induced by foreign antigens. Proc Natl Acad Sci U S A 2020; 117:12969-12979. [PMID: 32434911 DOI: 10.1073/pnas.1917182117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
CD5 is characterized as an inhibitory coreceptor with an important regulatory role during T cell development. The molecular mechanism by which CD5 operates has been puzzling and its function in mature T cells suggests promoting rather than repressing effects on immune responses. Here, we combined quantitative mass spectrometry and genetic studies to analyze the components and the activity of the CD5 signaling machinery in primary T cells. We found that T cell receptor (TCR) engagement induces the selective phosphorylation of CD5 tyrosine 429, which serves as a docking site for proteins with adaptor functions (c-Cbl, CIN85, CRKL), connecting CD5 to positive (PI3K) and negative (UBASH3A, SHIP1) regulators of TCR signaling. c-CBL acts as a coordinator in this complex enabling CD5 to synchronize positive and negative feedbacks on TCR signaling through the other components. Disruption of CD5 signalosome in mutant mice reveals that it modulates TCR signal outputs to selectively repress the transactivation of Foxp3 and limit the inopportune induction of peripherally induced regulatory T cells during immune responses against foreign antigen. Our findings bring insights into the paradigm of coreceptor signaling, suggesting that, in addition to providing dualistic enhancing or dampening inputs, coreceptors can engage concomitant stimulatory and inhibitory signaling events, which act together to promote specific functional outcomes.
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7
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Abstract
Breast cancer, which is the most common type of cancer among women, is a heterogenous disease. It results from progressive accumulation of genetic and epigenetic alterations in different genes. The Dok1 protein has been identified as the major substrate of protein tyrosine kinases in hematopoietic cells. It is considered as a tumor suppressor due to the reports which describe its inhibitory effect on major oncogenic signaling pathways such as Mek/Erk/PI3k/Akt and Wnt/β-catenin. In this study, we investigated the mutation frequency of the DOK1 gene in 118 breast tumors using Sanger sequencing and DOK1 mRNA expression level in 63 breast cancer samples using qRT-PCR methods. Although the mutation frequency was low DOK1 mRNA expression levels were significantly reduced (63.5%) in the tumors compared to adjacent non-cancerous tissue. We also correlated expression changes with clinicopathological characteristics. Low mRNA levels correlated with age (p = 0.01) and c-erbB-2 (p = 0.05). In most of the previous reports, down-regulation of DOK1 mRNA expression has been associated with promoter methylation. We identified four different coding sequence alterations in 5.1% (6/118) of the tumor samples. However, all of these alterations were located in the functional domains of the protein. Therefore, these mutations may affect the function and/or cellular localization of the protein and contribute to cancer progression by this way. In conclusion our data indicate that DOK1 acts as a tumor suppressor in breast cancer and association of Dok1 with the c-erbB-2 mediated mechanism of action in breast cancer needs to be investigated.
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8
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Lahmidi S, Strunk U, Smiley JR, Pearson A, Duplay P. Herpes simplex virus 1 infection of T cells causes VP11/12-dependent phosphorylation and degradation of the cellular protein Dok-2. Virology 2017; 511:66-73. [PMID: 28841444 DOI: 10.1016/j.virol.2017.08.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/04/2017] [Accepted: 08/14/2017] [Indexed: 12/15/2022]
Abstract
Previous studies have shown that HSV-1 infection of lymphocytes induces the tyrosine phosphorylation of several proteins that might correspond to viral or host proteins. VP11/12, a viral tegument protein, is the major HSV-induced tyrosine phosphorylated protein identified thus far. In this report, we demonstrated that the cellular adaptor proteins Dok-2 and Dok-1 are tyrosine phosphorylated upon HSV-1 infection. In addition, HSV-1 induced the selective degradation of Dok-2. Finally, we provide evidence that Dok-2 interacts with VP11/12, and that HSV-induced tyrosine phosphorylation and degradation of Dok-2 require VP11/12. Inactivation of either the Src Family Kinases binding motifs or the SHC binding motif of VP11/12 eliminated the interaction of Dok-2 with VP11/12. Elimination of the binding of Dok-2 to VP11/12 prevented Dok-2 phosphorylation and degradation. We propose that HSV-induced Dok phosphorylation and Dok-2 degradation is an immune evasion mechanism to inactivate T cells that might play an important role in HSV pathogenesis.
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Affiliation(s)
- Soumia Lahmidi
- INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, Canada H7V 1B7
| | - Ulrike Strunk
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | - James R Smiley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | - Angela Pearson
- INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
| | - Pascale Duplay
- INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
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9
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Astsaturov I. The right and wrong of DOKing the nuclear receptor. EBioMedicine 2016; 8:7. [PMID: 27428403 PMCID: PMC4919501 DOI: 10.1016/j.ebiom.2016.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 05/27/2016] [Indexed: 11/16/2022] Open
Affiliation(s)
- Igor Astsaturov
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA, USA
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10
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Subcellular compartmentalization of docking protein-1 contributes to progression in colorectal cancer. EBioMedicine 2016; 8:159-172. [PMID: 27428427 PMCID: PMC4919572 DOI: 10.1016/j.ebiom.2016.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 04/19/2016] [Accepted: 05/04/2016] [Indexed: 12/20/2022] Open
Abstract
Full-length (FL) docking protein-1 (DOK1) is an adapter protein which inhibits growth factor and immune response pathways in normal tissues, but is frequently lost in human cancers. Small DOK1 variants remain in cells of solid tumors and leukemias, albeit, their functions are elusive. To assess the so far unknown role of DOK1 in colorectal cancer (CRC), we generated DOK1 mutants which mimic the domain structure and subcellular distribution of DOK1 protein variants in leukemia patients. We found that cytoplasmic DOK1 activated peroxisome-proliferator-activated-receptor-gamma (PPARγ) resulting in inhibition of the c-FOS promoter and cell proliferation, whereas nuclear DOK1 was inactive. PPARγ-agonist increased expression of endogenous DOK1 and interaction with PPARγ. Forward translation of this cell-based signaling model predicted compartmentalization of DOK1 in patients. In a large series of CRC patients, loss of DOK1 protein was associated with poor prognosis at early tumor stages (*p = 0.001; n = 1492). In tumors with cytoplasmic expression of DOK1, survival was improved, whereas nuclear localization of DOK1 correlated with poor outcome, indicating that compartmentalization of DOK1 is critical for CRC progression. Thus, DOK1 was identified as a prognostic factor for non-metastatic CRC, and, via its drugability by PPARγ-agonist, may constitute a potential target for future cancer treatments. Forward translation of a cell-based signaling model predicted clinical relevance for DOK1 in colorectal cancer (CRC). DOK1 is an independent prognostic factor in CRC patients, and its loss associated with poor survival. Cancer cell growth inhibition by DOK1 was increased (“drugable”) by PPARγ-agonist. Poor survival due to failure to respond to clinical therapies prevents effective treatment of cancer. Thus, there is a high medical need for novel drug targets and biomarkers. DOK1 blocks pro-cancer signaling in the healthy body, but is often lost in tumors. We show that colorectal cancer patients who are positive for DOK1 have a better survival outcome than patients who are negative. Anti-diabetic drugs up-regulated DOK1 and promoted its protective actions against tumor cells. Our study therefore suggests DOK1 as a marker for good prognosis and as a potential drug target for therapy of colorectal cancer.
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11
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Hennig A, Markwart R, Esparza-Franco MA, Ladds G, Rubio I. Ras activation revisited: role of GEF and GAP systems. Biol Chem 2016; 396:831-48. [PMID: 25781681 DOI: 10.1515/hsz-2014-0257] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 03/09/2015] [Indexed: 12/13/2022]
Abstract
Ras is a prototypical small G-protein and a central regulator of growth, proliferation and differentiation processes in virtually every nucleated cell. As such, Ras becomes engaged and activated by multiple growth factors, mitogens, cytokines or adhesion receptors. Ras activation comes about by changes in the steady-state equilibrium between the inactive guanosine diphosphate (GDP)-bound and active guanosine triphosphate (GTP)-bound states of Ras, resulting in the mostly transient accumulation of Ras-GTP. Three decades of intense Ras research have disclosed various families of guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) as the two principal regulatory elements of the Ras-GDP/GTP loading status. However, with the possible exception of the GEF Sos, we still have only a rudimentary knowledge of the precise role played by many GEF and GAP members in the signalling network upstream of Ras. As for GAPs, we even lack the fundamental understanding of whether they function as genuine signal transducers in the context of growth factor-elicited Ras activation or rather act as passive modulators of the Ras-GDP/GTP cycle. Here we sift through the large body of Ras literature and review the relevant data for understanding the participation and precise role played by GEFs and GAPs in the process of Ras activation.
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12
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Hughan SC, Spring CM, Schoenwaelder SM, Sturgeon S, Alwis I, Yuan Y, McFadyen JD, Westein E, Goddard D, Ono A, Yamanashi Y, Nesbitt WS, Jackson SP. Dok-2 adaptor protein regulates the shear-dependent adhesive function of platelet integrin αIIbβ3 in mice. J Biol Chem 2014; 289:5051-60. [PMID: 24385425 DOI: 10.1074/jbc.m113.520148] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Dok proteins are a family of adaptor molecules that have a well defined role in regulating cellular migration, immune responses, and tumor progression. Previous studies have demonstrated that Doks-1 to 3 are expressed in platelets and that Dok-2 is tyrosine-phosphorylated downstream of integrin αIIbβ3, raising the possibility that it participates in integrin αIIbβ3 outside-in signaling. We demonstrate that Dok-2 in platelets is primarily phosphorylated by Lyn kinase. Moreover, deficiency of Dok-2 leads to dysregulated integrin αIIbβ3-dependent cytosolic calcium flux and phosphatidylinositol(3,4)P2 accumulation. Although agonist-induced integrin αIIbβ3 affinity regulation was unaltered in Dok-2(-/-) platelets, Dok-2 deficiency was associated with a shear-dependent increase in integrin αIIbβ3 adhesive function, resulting in enhanced platelet-fibrinogen and platelet-platelet adhesive interactions under flow. This increase in adhesion was restricted to discoid platelets and involved the shear-dependent regulation of membrane tethers. Dok-2 deficiency was associated with an increased rate of platelet aggregate formation on thrombogenic surfaces, leading to accelerated thrombus growth in vivo. Overall, this study defines an important role for Dok-2 in regulating biomechanical adhesive function of discoid platelets. Moreover, they define a previously unrecognized prothrombotic mechanism that is not detected by conventional platelet function assays.
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Affiliation(s)
- Sascha C Hughan
- From the Australian Centre for Blood Diseases, Faculty of Medicine, Nursing, and Health Sciences, Monash University, Alfred Medical Research and Education Precinct, Commercial Road, Melbourne, Victoria 3004
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13
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Hrdinka M, Horejsi V. PAG - a multipurpose transmembrane adaptor protein. Oncogene 2013; 33:4881-92. [DOI: 10.1038/onc.2013.485] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/25/2013] [Accepted: 09/25/2013] [Indexed: 12/25/2022]
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14
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Berger AH, Chen M, Morotti A, Janas JA, Niki M, Bronson RT, Taylor BS, Ladanyi M, Van Aelst L, Politi K, Varmus HE, Pandolfi PP. DOK2 inhibits EGFR-mutated lung adenocarcinoma. PLoS One 2013; 8:e79526. [PMID: 24255704 PMCID: PMC3821857 DOI: 10.1371/journal.pone.0079526] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 09/27/2013] [Indexed: 11/25/2022] Open
Abstract
Somatic mutations in the EGFR proto-oncogene occur in ~15% of human lung adenocarcinomas and the importance of EGFR mutations for the initiation and maintenance of lung cancer is well established from mouse models and cancer therapy trials in human lung cancer patients. Recently, we identified DOK2 as a lung adenocarcinoma tumor suppressor gene. Here we show that genomic loss of DOK2 is associated with EGFR mutations in human lung adenocarcinoma, and we hypothesized that loss of DOK2 might therefore cooperate with EGFR mutations to promote lung tumorigenesis. We tested this hypothesis using genetically engineered mouse models and find that loss of Dok2 in the mouse accelerates lung tumorigenesis initiated by oncogenic EGFR, but not that initiated by mutated Kras. Moreover, we find that DOK2 participates in a negative feedback loop that opposes mutated EGFR; EGFR mutation leads to recruitment of DOK2 to EGFR and DOK2-mediated inhibition of downstream activation of RAS. These data identify DOK2 as a tumor suppressor in EGFR-mutant lung adenocarcinoma.
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Affiliation(s)
- Alice H. Berger
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Departments of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ming Chen
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Departments of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alessandro Morotti
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Departments of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Justyna A. Janas
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Masaru Niki
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Roderick T. Bronson
- Rodent Histopathology Core, Dana-Farber/Harvard Cancer Center, Boston, Massachusetts, United States of America
| | - Barry S. Taylor
- Computational Biology Center, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Marc Ladanyi
- Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Linda Van Aelst
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Katerina Politi
- Cancer Biology and Genetics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Harold E. Varmus
- Cancer Biology and Genetics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Pier Paolo Pandolfi
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Departments of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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15
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Borger JG, Filby A, Zamoyska R. Differential polarization of C-terminal Src kinase between naive and antigen-experienced CD8+ T cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:3089-99. [PMID: 23427257 DOI: 10.4049/jimmunol.1202408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In CD8(+) T cells, engagement of the TCR with agonist peptide:MHC molecules causes dynamic redistribution of surface molecules including the CD8 coreceptor to the immunological synapse. CD8 associates with the Src-family kinase (SFK) Lck, which, in turn, initiates the rapid tyrosine phosphorylation events that drive cellular activation. Compared with naive T cells, Ag-experienced CD8(+) T cells make shorter contacts with APC, are less dependent on costimulation, and are triggered by lower concentrations of Ag, yet the molecular basis of this more efficient response of memory T cells is not fully understood. In this article, we show differences between naive and Ag-experienced CD8(+) T cells in colocalization of the SFKs and their negative regulator, C-terminal Src kinase (Csk). In naive CD8(+) T cells, there was pronounced colocalization of SFKs and Csk at the site of TCR triggering, whereas in Ag-experienced cells, Csk displayed a bipolar distribution with a proportion of the molecules sequestered within a cytosolic area in the distal pole of the cell. The data show that there is differential redistribution of a key negative regulator away from the site of TCR engagement in Ag-experienced CD8(+) T cells, which might be associated with the more efficient responses of these cells on re-exposure to Ag.
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Affiliation(s)
- Jessica G Borger
- Institute of Immunology and Infection Research, The University of Edinburgh, Edinburgh EH9 3JT, United Kingdom
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16
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Mashima R, Arimura S, Kajikawa S, Oda H, Nakae S, Yamanashi Y. Dok adaptors play anti-inflammatory roles in pulmonary homeostasis. Genes Cells 2012. [PMID: 23205702 DOI: 10.1111/gtc.12016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Asthma is a chronic inflammatory disease of the lung with airflow obstruction and bronchospasm, characterized by pulmonary eosinophilia, airway remodeling, increased airway hyperresponsiveness to environmental stimuli, and excessive Th2-type cytokine production. Recent studies indicate that crosstalk between the innate and adaptive immune systems is crucial for this disease. We and others have showed that the Dok (downstream of tyrosine kinases) family adaptors, Dok-1, Dok-2, and Dok-3, play essential roles in negative regulation of a wide variety of signaling pathways in both innate and adaptive immunities. Here, histopathology and bronchoalveolar lavage fluid (BALF) cellularity showed spontaneous pulmonary inflammation in Dok-1-/- Dok-2-/- Dok-3-/- (TKO) mice, but not in Dok-1-/- Dok-2-/- or Dok-3-/- mice, with hallmarks of asthma, including eosinophilia, goblet cell hyperplasia, and subepithelial fibrosis. Consistently, TKO mice, but not the other mutants, showed increased airway hyperresponsiveness to methacholine inhalation. In addition, Th2-type cytokine concentrations in BALF were increased in TKO mice. These findings provide strong evidence that Dok-1, Dok-2, and Dok-3 cooperatively play critical anti-inflammatory roles in lung homeostasis.
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Affiliation(s)
- Ryuichi Mashima
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
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17
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Sirvent A, Benistant C, Roche S. Oncogenic signaling by tyrosine kinases of the SRC family in advanced colorectal cancer. Am J Cancer Res 2012; 2:357-371. [PMID: 22860228 PMCID: PMC3410585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/31/2012] [Indexed: 06/01/2023] Open
Abstract
The non-receptor tyrosine kinases of the SRC family (SFK) play important roles in signal transduction induced by a large variety of extracellular stimuli, including growth factors and Integrins. When deregulated, SFKs show oncogenic activity, as originally reported for v-Src, the transforming product of the avian retrovirus RSV, and then, in many human cancers, particularly colorectal cancer (CRC). In CRC, SFK deregulation largely occurs in the absence of mutations of the corresponding genes, but the underlying molecular mechanisms involved are still unclear. In addition to a role in early tumor progression, SFK deregulation may also be important in advanced CRC, as suggested by the association between increased SFK activity and poor clinical outcome. However, SFK contribution to CRC metastasis formation is still poorly documented. Here, we will review recent findings that broaden our understanding of the mechanisms underlying SFK deregulation and signaling in advanced CRC. We will also discuss the implication of these observations for SFK-based therapy in metastatic CRC.
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Affiliation(s)
- Audrey Sirvent
- CNRS UMR5237, University of Montpellier 1 and 2, CRBM 34000 Montpellier, France
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18
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Schoenborn JR, Tan YX, Zhang C, Shokat KM, Weiss A. Feedback circuits monitor and adjust basal Lck-dependent events in T cell receptor signaling. Sci Signal 2012; 4:ra59. [PMID: 21917715 DOI: 10.1126/scisignal.2001893] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Src family kinase Lck is crucial for the initiation of TCR signaling. The activity of Lck is tightly controlled to prevent erroneous immune activation, yet it enables rapid cellular responses over a range of sensitivities to antigens. Here, in experiments with an analog-sensitive variant of the tyrosine kinase Csk, we report that Lck in T cells is dynamically controlled by an equilibrium between Csk and the tyrosine phosphatase CD45. By rapidly inhibiting Csk, we showed that changes in this equilibrium were sufficient to activate canonical TCR signaling pathways independently of ligand binding to the TCR. The activated signaling pathways showed sustained and enhanced phosphorylation compared to that in TCR-stimulated cells, revealing a feedback circuit that was sensitive to the basal signaling machinery. We identified the inhibitory adaptor molecule Dok-1 (downstream of kinase 1) as a candidate that may respond to alterations in basal signaling activity. Our results also suggest a role for Csk in the termination or dampening of TCR signals.
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Affiliation(s)
- Jamie R Schoenborn
- Rosalind Russell Medical Research Center for Arthritis, Division of Rheumatology, Department of Medicine, University of California, San Francisco, CA 94143, USA
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19
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Miyagaki H, Yamasaki M, Takahashi T, Kurokawa Y, Miyata H, Nakajima K, Takiguchi S, Fujiwara Y, Mori M, Doki Y. DOK2 as a marker of poor prognosis of patients with gastric adenocarcinoma after curative resection. Ann Surg Oncol 2011; 19:1560-7. [PMID: 22130622 DOI: 10.1245/s10434-011-2157-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Indexed: 01/23/2023]
Abstract
BACKGROUND DOK2 is known as the substrate of chmeric p210bcr/abl oncoprotein characterizing chronic myelogenous leukemia with Philadelphia chromosome. Reduced DOK2 expression was recently reported in lung adenocarcinoma, suggesting that this protein acts as a tumor suppressor in solid tumors. The purpose of this study was to determine the significance of DOK2 in gastric cancer. METHODS The study subjects were 118 patients who underwent curative surgery for gastric cancer, as well as 7 gastric cancer cell lines. The tissues and cell lines were analyzed for DOK2 gene and protein expressions by histopathology and immunohistochemistry, and also using a microsatellite marker for loss of heterozygosity. Correlation of survival with clinicopathological parameters was investigated by univariate and multivariate analyses. RESULTS DOK2 expression was confirmed in the normal gastric mucosa. Considerable differences in the gene expression were noted among the gastric cell lines. Positive DOK2 expression was noted in the noncancerous regions of all pathological specimens, whereas 59 (50.0%) specimens of 118 patients were negatively stained in the tumor. Loss of heterozygosity was observed in 54.5% of DOK2(-) cases. DOK2(-) patients were more likely to develop recurrence than DOK2(+) and showed poorer 5-year overall survival (59.1%) than DOK2(+) (76.4%, P = .0403). Multivariate analysis identified pT (hazard ratio [HR] = 2.748, 95% confidence interval [95% CI] = 1.061-8.927, P = .0361), pN (HR = 2.486, 95% CI = 1.264-4.932, P = .0086), and DOK2(-) (HR = 2.343, 95% CI = 1.211-4.727, P = .0112) as significant and independent determinants of poor survival. CONCLUSIONS Our data suggest the potential usefulness of DOK2 as a marker of poor prognosis in patients with gastric cancer after curative resection.
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Affiliation(s)
- Hiromichi Miyagaki
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
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20
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Abstract
Ever since their discovery as cellular counterparts of viral oncogenes more than 25 years ago, much progress has been made in understanding the complex networks of signal transduction pathways activated by oncogenic Ras mutations in human cancers. The activity of Ras is regulated by nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), and much emphasis has been put into the biochemical and structural analysis of the Ras/GAP complex. The mechanisms by which GAPs catalyze Ras-GTP hydrolysis have been clarified and revealed that oncogenic Ras mutations confer resistance to GAPs and remain constitutively active. However, it is yet unclear how cells coordinate the large and divergent GAP protein family to promote Ras inactivation and ensure a certain biological response. Different domain arrangements in GAPs to create differential protein-protein and protein-lipid interactions are probably key factors determining the inactivation of the 3 Ras isoforms H-, K-, and N-Ras and their effector pathways. In recent years, in vitro as well as cell- and animal-based studies examining GAP activity, localization, interaction partners, and expression profiles have provided further insights into Ras inactivation and revealed characteristics of several GAPs to exert specific and distinct functions. This review aims to summarize knowledge on the cell biology of RasGAP proteins that potentially contributes to differential regulation of spatiotemporal Ras signaling.
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Affiliation(s)
- Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
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21
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Saulnier A, Vaissière T, Yue J, Siouda M, Malfroy M, Accardi R, Creveaux M, Sebastian S, Shahzad N, Gheit T, Hussain I, Torrente M, Maffini FA, Calabrese L, Chiesa F, Cuenin C, Shukla R, Fathallah I, Matos E, Daudt A, Koifman S, Wünsch-Filho V, Menezes AMB, Curado MP, Zaridze D, Boffetta P, Brennan P, Tommasino M, Herceg Z, Sylla BS. Inactivation of the putative suppressor gene DOK1 by promoter hypermethylation in primary human cancers. Int J Cancer 2011; 130:2484-94. [PMID: 21796618 DOI: 10.1002/ijc.26299] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 06/22/2011] [Indexed: 12/31/2022]
Abstract
The DOK1 gene is a putative tumour suppressor gene located on the human chromosome 2p13 which is frequently rearranged in leukaemia and other human tumours. We previously reported that the DOK1 gene can be mutated and its expression down-regulated in human malignancies. However, the mechanism underlying DOK1 silencing remains largely unknown. We show here that unscheduled silencing of DOK1 expression through aberrant hypermethylation is a frequent event in a variety of human malignancies. DOK1 was found to be silenced in nine head and neck cancer (HNC) cell lines studied and DOK1 CpG hypermethylation correlated with loss of gene expression in these cells. DOK1 expression could be restored via demethylating treatment using 5-aza-2'deoxycytidine. In addition, transduction of cancer cell lines with DOK1 impaired their proliferation, consistent with the critical role of epigenetic silencing of DOK1 in the development and maintenance of malignant cells. We further observed that DOK1 hypermethylation occurs frequently in a variety of primary human neoplasm including solid tumours (93% in HNC, 81% in lung cancer) and haematopoietic malignancy (64% in Burkitt's lymphoma). Control blood samples and exfoliated mouth epithelial cells from healthy individuals showed a low level of DOK1 methylation, suggesting that DOK1 hypermethylation is a tumour specific event. Finally, an inverse correlation was observed between the level of DOK1 gene methylation and its expression in tumour and adjacent non tumour tissues. Thus, hypermethylation of DOK1 is a potentially critical event in human carcinogenesis, and may be a potential cancer biomarker and an attractive target for epigenetic-based therapy.
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22
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Mercier PL, Bachvarova M, Plante M, Gregoire J, Renaud MC, Ghani K, Têtu B, Bairati I, Bachvarov D. Characterization of DOK1, a candidate tumor suppressor gene, in epithelial ovarian cancer. Mol Oncol 2011; 5:438-53. [PMID: 21856257 DOI: 10.1016/j.molonc.2011.07.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 07/13/2011] [Indexed: 12/30/2022] Open
Abstract
In attempt to discover novel aberrantly hypermethylated genes with putative tumor suppressor function in epithelial ovarian cancer (EOC), we applied expression profiling following pharmacologic inhibition of DNA methylation in EOC cell lines. Among the genes identified, one of particular interest was DOK1, or downstream of tyrosine kinase 1, previously recognized as a candidate tumor suppressor gene (TSG) for leukemia and other human malignancies. Using bisulfite sequencing, we determined that a 5'-non-coding DNA region (located at nt -1158 to -850, upstream of the DOK1 translation start codon) was extensively hypermethylated in primary serous EOC tumors compared with normal ovarian specimens; however, this hypermethylation was not associated with DOK1 suppression. On the contrary, DOK1 was found to be strongly overexpressed in serous EOC tumors as compared to normal tissue and importantly, DOK1 overexpression significantly correlated with improved progression-free survival (PFS) values of serous EOC patients. Ectopic modulation of DOK1 expression in EOC cells and consecutive functional analyses pointed toward association of DOK1 expression with increased EOC cell migration and proliferation, and better sensitivity to cisplatin treatment. Gene expression profiling and consecutive network and pathway analyses were also confirmative for DOK1 association with EOC cell migration and proliferation. These analyses were also indicative for DOK1 protective role in EOC tumorigenesis, linked to DOK1-mediated induction of some tumor suppressor factors and its suppression of pro-metastasis genes. Taken together, our findings are suggestive for a possible tumor suppressor role of DOK1 in EOC; however its implication in enhanced EOC cell migration and proliferation restrain us to conclude that DOK1 represents a true TSG in EOC. Further studies are needed to more completely elucidate the functional implications of DOK1 and other members of the DOK gene family in ovarian tumorigenesis.
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Affiliation(s)
- Pierre-Luc Mercier
- Department of Molecular Medicine, Laval University, Quebec (Quebec), Canada
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23
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Oncogenic tyrosine kinases target Dok-1 for ubiquitin-mediated proteasomal degradation to promote cell transformation. Mol Cell Biol 2011; 31:2552-65. [PMID: 21536658 DOI: 10.1128/mcb.05045-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cellular transformation induced by oncogenic tyrosine kinases is a multistep process involving activation of growth-promoting signaling pathways and inactivation of suppressor molecules. Dok-1 is an adaptor protein that acts as a negative regulator of tyrosine kinase-initiated signaling and opposes oncogenic tyrosine kinase-mediated cell transformation. Findings that its loss facilitates transformation induced by oncogenic tyrosine kinases suggest that Dok-1 inactivation could constitute an intermediate step in oncogenesis driven by these oncoproteins. However, whether Dok-1 is subject to regulation by oncogenic tyrosine kinases remained unknown. In this study, we show that oncogenic tyrosine kinases, including p210(bcr-abl) and oncogenic forms of Src, downregulate Dok-1 by targeting it for degradation through the ubiquitin-proteasome pathway. This process is dependent on the tyrosine kinase activity of the oncoproteins and is mediated primarily by lysine-dependent polyubiquitination of Dok-1. Importantly, restoration of Dok-1 levels strongly suppresses transformation of cells expressing oncogenic tyrosine kinases, and this suppression is more pronounced in the context of a Dok-1 mutant that is largely refractory to oncogenic tyrosine kinase-induced degradation. Our findings suggest that proteasome-mediated downregulation of Dok-1 is a key mechanism by which oncogenic tyrosine kinases overcome the inhibitory effect of Dok-1 on cellular transformation and tumor progression.
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24
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Hedden L, Benes CH, Soltoff SP. P2X(7) receptor antagonists display agonist-like effects on cell signaling proteins. Biochim Biophys Acta Gen Subj 2011; 1810:532-42. [PMID: 21397667 DOI: 10.1016/j.bbagen.2011.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/14/2011] [Accepted: 03/07/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND The activation of various P2 receptors (P2R) by extracellular nucleotides promotes diverse cellular events, including the stimulation of cell signaling protein and increases in [Ca(2+)](i). We report that some agents that can block P2X(7)R receptors also promote diverse P2X(7)R-independent effects on cell signaling. METHODS We exposed native rat parotid acinar cells, salivary gland cell lines (Par-C10, HSY, HSG), and PC12 cells to suramin, DIDS (4,4'-diisothiocyano stilbene-2,2'-disulfonic acid), Cibacron Blue 3GA, Brilliant Blue G, and the P2X(7)R-selective antagonist A438079, and examined the activation/phosphorylation of ERK1/2, PKCδ, Src, CDCP1, and other signaling proteins. RESULTS With the exception of suramin, these agents blocked the phosphorylation of ERK1/2 by BzATP in rat parotid acinar cells; but higher concentrations of suramin blocked ATP-stimulated (45)Ca(2+) entry. Aside from A438079, these agents increased the phosphorylation of ERK1/2, Src, PKCδ, and other proteins (including Dok-1) within minutes in an agent- and cell type-specific manner in the absence of a P2X(7)R ligand. The stimulatory effect of these compounds on the tyrosine phosphorylation of CDCP1 and its Src-dependent association with PKCδ was blocked by knockdown of CDCP1, which also blocked Src and PKCδ phosphorylation. CONCLUSIONS Several agents used as P2X(7)R blockers promote the activation of various signaling proteins and thereby act more like receptor agonists than antagonists. GENERAL SIGNIFICANCE Some compounds used to block P2 receptors have complicated effects that may confound their use in blocking receptor activation and other biological processes for which they are employed, including their use as blockers of various ion transport proteins.
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Affiliation(s)
- Lee Hedden
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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25
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Mashima R, Hishida Y, Tezuka T, Yamanashi Y. The roles of Dok family adapters in immunoreceptor signaling. Immunol Rev 2010; 232:273-85. [PMID: 19909370 DOI: 10.1111/j.1600-065x.2009.00844.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mammalian Dok protein family has seven members (Dok-1-Dok-7). The Dok proteins share structural similarities characterized by the NH2-terminal pleckstrin homology and phosphotyrosine-binding domains followed by SH2 target motifs in the COOH-terminal moiety, indicating an adapter function. Indeed, Dok-1 was originally identified as a 62 kDa protein that binds with p120 rasGAP, a potent inhibitor of Ras, upon tyrosine phosphorylation by a variety of protein tyrosine kinases. Among the Dok family, only Dok-1, Dok-2, and Dok-3 are preferentially expressed in hematopoietic/immune cells. Dok-1 and its closest relative Dok-2 act as negative regulators of the Ras-Erk pathway downstream of many immunoreceptor-mediated signaling systems, and it is believed that recruitment of p120 rasGAP by Dok-1 and Dok-2 is critical to their negative regulation. By contrast, Dok-3 does not bind with p120 rasGAP. However, accumulating evidence has demonstrated that Dok-3 is a negative regulator of the activation of JNK and mobilization of Ca2+ in B-cell receptor-mediated signaling, where the interaction of Dok-3 with SHIP-1 and Grb2 appears to be important. Here, we review the physiological roles and underlying mechanisms of Dok family proteins.
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Affiliation(s)
- Ryuichi Mashima
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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26
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Berger AH, Niki M, Morotti A, Taylor BS, Socci ND, Viale A, Brennan C, Szoke J, Motoi N, Rothman PB, Teruya-Feldstein J, Gerald WL, Ladanyi M, Pandolfi PP. Identification of DOK genes as lung tumor suppressors. Nat Genet 2010; 42:216-23. [PMID: 20139980 DOI: 10.1038/ng.527] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 12/29/2009] [Indexed: 02/02/2023]
Abstract
Genome-wide analyses of human lung adenocarcinoma have identified regions of consistent copy-number gain or loss, but in many cases the oncogenes and tumor suppressors presumed to reside in these loci remain to be determined. Here we identify the downstream of tyrosine kinase (Dok) family members Dok1, Dok2 and Dok3 as lung tumor suppressors. Single, double or triple compound loss of these genes in mice results in lung cancer, with penetrance and latency dependent on the number of lost Dok alleles. Cancer development is preceded by an aberrant expansion and signaling profile of alveolar type II cells and bronchioalveolar stem cells. In human lung adenocarcinoma, we identify DOK2 as a target of copy-number loss and mRNA downregulation and find that DOK2 suppresses lung cancer cell proliferation in vitro and in vivo. Given the genomic localization of DOK2, we propose it as an 8p21.3 haploinsufficient human lung tumor suppressor.
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Affiliation(s)
- Alice H Berger
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Departments of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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27
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Src family tyrosine kinases-driven colon cancer cell invasion is induced by Csk membrane delocalization. Oncogene 2009; 29:1303-15. [PMID: 20010872 DOI: 10.1038/onc.2009.450] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The nonreceptor tyrosine kinases of the Src family (SFK) are frequently deregulated in human colorectal cancer (CRC), and they have been implicated in tumour growth and metastasis. How SFK are activated in this cancer has not been clearly established. Here, we show that the SFK-dependent invasion is induced by inactivation of the negative regulator C-terminal Src kinase, Csk. While the level of Csk was inconsistent with SFK activity in colon cancer cells, its membrane translocation, needed for efficient regulation of membrane-localized SFK activity, was impaired. Accordingly, Csk downregulation did not affect SFK oncogenic activity in these cells, whereas expression of a membrane-localized form of this kinase affected their invasive activity. Downregulation of the transmembrane and rafts-localized Csk-binding protein/phosphoprotein associated with glycosphingolipid-enriched microdomain (PAG), was instrumental for the cytoplasmic accumulation of Csk. Re-expression of PAG in cells from late-stage CRC inhibited SFK invasive activity in a Csk-dependent manner. Conversely, inactivation of its residual expression in early-stage CRC cells promoted SFK invasive activity. Finally, this mechanism was specific to CRC as Csk coupling to SFK was readily detected in breast cancer cells. Therefore, Csk mis-localization defines a novel mechanism for SFK oncogenic activation in CRC cells.
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28
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Identification of c-Src tyrosine kinase substrates in platelet-derived growth factor receptor signaling. Mol Oncol 2009; 3:439-50. [PMID: 19632164 DOI: 10.1016/j.molonc.2009.07.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 06/17/2009] [Accepted: 07/04/2009] [Indexed: 11/20/2022] Open
Abstract
c-Src non-receptor tyrosine kinase is an important component of the platelet-derived growth factor (PDGF) receptor signaling pathway. c-Src has been shown to mediate the mitogenic response to PDGF in fibroblasts. However, the exact components of PDGF receptor signaling pathway mediated by c-Src remain unclear. Here, we used stable isotope labeling with amino acids in cell culture (SILAC) coupled with mass spectrometry to identify Src-family kinase substrates involved in PDGF signaling. Using SILAC, we were able to detect changes in tyrosine phosphorylation patterns of 43 potential c-Src kinase substrates in PDGF receptor signaling. This included 23 known c-Src kinase substrates, of which 16 proteins have known roles in PDGF signaling while the remaining 7 proteins have not previously been implicated in PDGF receptor signaling. Importantly, our analysis also led to identification of 20 novel Src-family kinase substrates, of which 5 proteins were previously reported as PDGF receptor signaling pathway intermediates while the remaining 15 proteins represent novel signaling intermediates in PDGF receptor signaling. In validation experiments, we demonstrated that PDGF indeed induced the phosphorylation of a subset of candidate Src-family kinase substrates - Calpain 2, Eps15 and Trim28 - in a c-Src-dependent fashion.
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29
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Kobayashi R, Patenia R, Ashizawa S, Vykoukal J. Targeted mass spectrometric analysis of N-terminally truncated isoforms generated via alternative translation initiation. FEBS Lett 2009; 583:2441-5. [PMID: 19481542 DOI: 10.1016/j.febslet.2009.05.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 05/21/2009] [Accepted: 05/23/2009] [Indexed: 01/19/2023]
Abstract
Alternative translation initiation is a mechanism whereby functionally altered proteins are produced from a single mRNA. Internal initiation of translation generates N-terminally truncated protein isoforms, but such isoforms observed in immunoblot analysis are often overlooked or dismissed as degradation products. We identified an N-terminally truncated isoform of human Dok-1 with N-terminal acetylation as seen in the wild-type. This Dok-1 isoform exhibited distinct perinuclear localization whereas the wild-type protein was distributed throughout the cytoplasm. Targeted analysis of blocked N-terminal peptides provides rapid identification of protein isoforms and could be widely applied for the general evaluation of perplexing immunoblot bands.
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Affiliation(s)
- Ryuji Kobayashi
- FTN Institute, 1147 Mariner Cove, Sugar Land, TX 77498, USA.
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30
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Wu L, Bijian K, Shen SH, Shen SS. CD45 recruits adapter protein DOK-1 and negatively regulates JAK-STAT signaling in hematopoietic cells. Mol Immunol 2009; 46:2167-77. [PMID: 19481264 DOI: 10.1016/j.molimm.2009.04.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 04/29/2009] [Accepted: 04/29/2009] [Indexed: 12/26/2022]
Abstract
It has been extensively documented that CD45 positively regulates T cell receptor-mediated signaling through the activation of Src-family kinases. The mechanism whereby CD45 negatively regulates the JAK/STAT pathway, however, has not been fully elucidated. Here we describe the mechanism by which CD45 negatively regulates the JAK/STAT pathway through the recruitment of the inhibitory molecule Downstream of Kinase 1 (DOK-1) in hematopoietic cells. We present evidences that CD45 recruits DOK-1 to associate with tyrosine-phosphorylated DOK-1, and that the DOK-1-Y296F mutant completely abrogates its interaction with CD45. Moreover, CD45 expression is required for DOK-1 targeting to the plasma membrane in response to anti-CD3 stimulation. Functional studies further showed that stable expression of DOK-1 in K562 cells markedly decreased both JAK-2 and STAT-3/5 phosphorylation following IL-3 and IFN-alpha stimulation. Likewise, stable expression of DOK-1 in Jurkat cells significantly decreased JAK-2 phosphorylation. Similarly, both IL-3 and IFN-alpha-induced JAK-2 phosphorylations were significantly increased in CD45 deficient Jurkat cells. Consistently, silencing of the DOK-1 gene resulted in rescue of MAP kinases and JAKs activities in CD45 positive Jurkat cells. Accordingly, CD45 recruits adaptor DOK-1 to the proximal plasma membrane to serve as a downstream effector, resulting in negative regulation of the JAK/STAT signaling pathway.
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Affiliation(s)
- Liangtang Wu
- Department of Medicine, McGill University, Montreal, Quebec, Canada
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31
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Acuto O, Di Bartolo V, Michel F. Tailoring T-cell receptor signals by proximal negative feedback mechanisms. Nat Rev Immunol 2009; 8:699-712. [PMID: 18728635 DOI: 10.1038/nri2397] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The T-cell receptor (TCR) signalling machinery is central in determining the response of a T cell (establishing immunity or tolerance) following exposure to antigen. This process is made difficult by the narrow margin of self and non-self discrimination, and by the complexity of the genetic programmes that are induced for each outcome. Recent studies have identified novel negative feedback mechanisms that are rapidly induced by TCR engagement and that have key roles in the regulation of signal triggering and propagation. In vitro and in vivo data suggest that they are important in determining ligand discrimination by the TCR and in regulating signal output in response to antigen.
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Affiliation(s)
- Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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32
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Veracini L, Simon V, Richard V, Schraven B, Horejsi V, Roche S, Benistant C. The Csk-binding protein PAG regulates PDGF-induced Src mitogenic signaling via GM1. ACTA ACUST UNITED AC 2008; 182:603-14. [PMID: 18695048 PMCID: PMC2500143 DOI: 10.1083/jcb.200705102] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Spatial regulation is an important feature of signal specificity elicited by cytoplasmic tyrosine kinases of the Src family (SRC family protein tyrosine kinases [SFK]). Cholesterol-enriched membrane domains, such as caveolae, regulate association of SFK with the platelet-derived growth factor receptor (PDGFR), which is needed for kinase activation and mitogenic signaling. PAG, a ubiquitously expressed member of the transmembrane adaptor protein family, is known to negatively regulate SFK signaling though binding to Csk. We report that PAG modulates PDGFR levels in caveolae and SFK mitogenic signaling through a Csk-independent mechanism. Regulation of SFK mitogenic activity by PAG requires the first N-terminal 97 aa (PAG-N), which include the extracellular and transmembrane domains, palmitoylation sites, and a short cytoplasmic sequence. We also show that PAG-N increases ganglioside GM1 levels at the cell surface and, thus, displaces PDGFR from caveolae, a process that requires the ganglioside-specific sialidase Neu-3. In conclusion, PAG regulates PDGFR membrane partitioning and SFK mitogenic signaling by modulating GM1 levels within caveolae independently from Csk.
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Affiliation(s)
- Laurence Veracini
- Centre de Recherche en Biochimie Macromoléculare, Centre National de la Recherche Scientifique UMR5237, Universities of Montpellier I and II, 34293 Montpellier, France
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Chatterjee B, Richards K, Bucan M, Lo C. Nt mutation causing laterality defects associated with deletion of rotatin. Mamm Genome 2007; 18:310-5. [PMID: 17551791 DOI: 10.1007/s00335-007-9023-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 04/10/2007] [Accepted: 04/13/2007] [Indexed: 10/23/2022]
Abstract
No turning (nt), a recessive lethal mutation causing left-right and axial patterning defects, was recovered in outbred CD-1 mice. Homozygous mutant embryos die at E11.5, exhibiting randomized heart tube looping and a failure to undergo embryonic turning. Previous studies showed notochordal defects associated with abnormal expression of HNF3beta, lefty, and nodal. To identify the genetic alteration underlying nt mutants, we intercrossed this mutation into a Mus musculus castaneus strain background and conducted a full-genome scan using polymorphic microsatellite DNA markers. We mapped the mutation to an 18-Mb interval in mouse chromosome 18, spanning marker D18mit189 and the distal end of the chromosome. RT-PCR analysis of known genes in the mapped interval showed no transcripts for four genes, including Rttn, CD226, Dok6, and Txndc10. Chromosome walking by serial PCR amplification of genomic DNA from homozygous mutants revealed a 1.6-Mb deletion spanning these four genes. A gene-trap mouse line with disruption of Rttn was previously also shown to have randomized heart tube looping, defects in embryonic turning, and abnormal expression of HNF3beta, lefty, and nodal. Together these findings suggest that nt is likely elicited by Rttn deficiency.
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Affiliation(s)
- Bishwanath Chatterjee
- Laboratory of Developmental Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Julien SG, Dubé N, Read M, Penney J, Paquet M, Han Y, Kennedy BP, Muller WJ, Tremblay ML. Protein tyrosine phosphatase 1B deficiency or inhibition delays ErbB2-induced mammary tumorigenesis and protects from lung metastasis. Nat Genet 2007; 39:338-46. [PMID: 17259984 DOI: 10.1038/ng1963] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Accepted: 12/18/2006] [Indexed: 11/08/2022]
Abstract
We investigated the role of protein tyrosine phosphatase 1B (PTP1B) in mammary tumorigenesis using both genetic and pharmacological approaches. It has been previously shown that transgenic mice with a deletion mutation in the region of Erbb2 encoding its extracellular domain (referred to as NDL2 mice, for 'Neu deletion in extracellular domain 2') develop mammary tumors that progress to lung metastasis. However, deletion of PTP1B activity in the NDL2 transgenic mice either by breeding with Ptpn1-deficient mice or by treatment with a specific PTP1B inhibitor results in significant mammary tumor latency and resistance to lung metastasis. In contrast, specific overexpression of PTP1B in the mammary gland leads to spontaneous breast cancer development. The regulation of ErbB2-induced mammary tumorigenesis by PTB1B occurs through the attenuation of both the MAP kinase (MAPK) and Akt pathways. This report provides a rationale for the development of PTP1B as a new therapeutic target in breast cancer.
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MESH Headings
- Animals
- Apoptosis
- Cell Line, Tumor
- Down-Regulation
- Female
- Lung/metabolism
- Lung Neoplasms/metabolism
- Lung Neoplasms/prevention & control
- Lung Neoplasms/secondary
- MAP Kinase Signaling System/physiology
- Mammary Glands, Animal/drug effects
- Mammary Neoplasms, Experimental/enzymology
- Mammary Neoplasms, Experimental/etiology
- Mammary Neoplasms, Experimental/pathology
- Mice
- Mice, Knockout
- Mice, Transgenic
- Molecular Sequence Data
- Phenotype
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatases/antagonists & inhibitors
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/physiology
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, ErbB-2/metabolism
- Receptor, ErbB-3/metabolism
- Signal Transduction
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Affiliation(s)
- Sofi G Julien
- McGill Cancer Centre, McGill University, 3655 Sir William Osler Promenade, Montreal, Quebec H3G 1Y6, Canada
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Dong S, Corre B, Foulon E, Dufour E, Veillette A, Acuto O, Michel F. T cell receptor for antigen induces linker for activation of T cell-dependent activation of a negative signaling complex involving Dok-2, SHIP-1, and Grb-2. ACTA ACUST UNITED AC 2006; 203:2509-18. [PMID: 17043143 PMCID: PMC2118126 DOI: 10.1084/jem.20060650] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Adaptor proteins positively or negatively regulate the T cell receptor for antigen (TCR) signaling cascade. We report that after TCR stimulation, the inhibitory adaptor downstream of kinase (Dok)-2 and its homologue Dok-1 are involved in a multimolecular complex including the lipid phosphatase Src homology 2 domain–containing inositol polyphosphate 5′-phosphatase (SHIP)-1 and Grb-2 which interacts with the membrane signaling scaffold linker for activation of T cells (LAT). Knockdown of LAT and SHIP-1 expression indicated that SHIP-1 favored recruitment of Dok-2 to LAT. Knockdown of Dok-2 and Dok-1 revealed their negative control on Akt and, unexpectedly, on Zap-70 activation. Our findings support the view that Dok-1 and -2 are critical elements of a LAT-dependent negative feedback loop that attenuates early TCR signal. Dok-1 and -2 may therefore exert a critical role in shaping the immune response and as gatekeepers for T cell tolerance.
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MESH Headings
- Adaptor Proteins, Signal Transducing/biosynthesis
- Adaptor Proteins, Signal Transducing/metabolism
- Adaptor Proteins, Signal Transducing/physiology
- Cell Line, Tumor
- DNA-Binding Proteins/physiology
- Down-Regulation/immunology
- Feedback, Physiological/immunology
- GRB2 Adaptor Protein/physiology
- Humans
- Inositol Polyphosphate 5-Phosphatases
- Jurkat Cells
- Ligands
- Lymphocyte Activation
- Membrane Proteins/biosynthesis
- Membrane Proteins/metabolism
- Membrane Proteins/physiology
- Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
- Phosphoproteins/physiology
- Phosphoric Monoester Hydrolases/physiology
- Phosphorylation
- RNA-Binding Proteins/physiology
- Receptor-CD3 Complex, Antigen, T-Cell/metabolism
- Receptor-CD3 Complex, Antigen, T-Cell/physiology
- Signal Transduction/immunology
- Tyrosine/metabolism
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Affiliation(s)
- Shen Dong
- Molecular Immunology Unit, Department of Immunology, Institut Pasteur, 75724 Paris Cedex 15, France
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