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Dangelmaier C, Vari HR, Vajipayajula DN, Elzoheiry M, Wright M, Iyer A, Tsygankov AY, Kunapuli SP. Phosphorylation of (Ser 291) in the linker insert of Syk negatively regulates ITAM signaling in platelets. Platelets 2024; 35:2369766. [PMID: 38904212 DOI: 10.1080/09537104.2024.2369766] [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] [Indexed: 06/22/2024]
Abstract
Receptor-induced tyrosine phosphorylation of spleen tyrosine kinase (Syk) has been studied extensively in hematopoietic cells. Metabolic mapping and high-resolution mass spectrometry, however, indicate that one of the most frequently detected phosphorylation sites encompassed S297 (S291 in mice) located within the linker B region of Syk. It has been reported that Protein kinase C (PKC) phosphorylates Syk S297, thus influencing Syk activity. However, conflicting studies suggest that this phosphorylation enhances as well as reduces Syk activity. To clarify the function of this site, we generated Syk S291A knock-in mice. We used platelets as a model system as they possess Glycoprotein VI (GPVI), a receptor containing an immunoreceptor tyrosine-based activation motif (ITAM) which transduces signals through Syk. Our analysis of the homozygous mice indicated that the knock-in platelets express only one isoform of Syk, while the wild-type expresses two isoforms at 69 and 66 kDa. When the GPVI receptor was activated with collagen-related peptide (CRP), we observed an increase in functional responses and phosphorylations in Syk S291A platelets. This potentiation did not occur with AYPGKF or 2-MeSADP, although they also activate PKC isoforms. Although there was potentiation of platelet functional responses, there was no difference in tail bleeding times. However, the time to occlusion in the FeCl3 injury model was enhanced. These data indicate that the effects of Syk S291 phosphorylation represent a significant outcome on platelet activation and signaling in vitro but also reveals its multifaceted nature demonstrated by the differential effects on physiological responses in vivo.
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Affiliation(s)
- Carol Dangelmaier
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Hymavathi Reddy Vari
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Dhruv N Vajipayajula
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Manal Elzoheiry
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Monica Wright
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Ashvin Iyer
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Alexander Y Tsygankov
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Satya P Kunapuli
- Sol Sherry Thrombosis Research Center, Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
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Capener JL, Vasta JD, Katis VL, Michaud A, Beck MT, Daglish SCD, Cohen-Kedar S, Barda ES, Howell S, Dotan I, Robers MB, Axtman AD, Bashore FM. Development of SYK NanoBRET Cellular Target Engagement Assays for Gain-of-Function Variants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598544. [PMID: 38915605 PMCID: PMC11195201 DOI: 10.1101/2024.06.12.598544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Spleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase that is activated by phosphorylation events downstream of FcR, B-cell and T-cell receptors, integrins, and C-type lectin receptors. When the tandem Src homology 2 (SH2) domains of SYK bind to phosphorylated immunoreceptor tyrosine-based activation motifs (pITAMs) contained within these immunoreceptors, or when SYK is phosphorylated in interdomain regions A and B, SYK is activated. SYK gain-of-function (GoF) variants were previously identified in six patients that had higher levels of phosphorylated SYK and phosphorylated downstream proteins JNK and ERK. Furthermore, the increased SYK activation resulted in the clinical manifestation of immune dysregulation, organ inflammation, and a predisposition for lymphoma. The knowledge that the SYK GoF variants have enhanced activity was leveraged to develop a SYK NanoBRET cellular target engagement assay in intact live cells with constructs for the SYK GoF variants. Herein, we developed a potent SYK-targeted NanoBRET tracer using a SYK donated chemical probe, MRL-SYKi, that enabled a NanoBRET cellular target engagement assay for SYK GoF variants, SYK(S550Y), SYK(S550F), and SYK(P342T). We determined that ATP-competitive SYK inhibitors bind potently to these SYK variants in intact live cells. Additionally, we demonstrated that MRL-SYKi can effectively reduce the catalytic activity of SYK variants, and the phosphorylation levels of SYK(S550Y) in an epithelial cell line (SW480) stably expressing SYK(S550Y).
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Affiliation(s)
- Jacob L. Capener
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - James D. Vasta
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI 53711, USA
| | - Vittorio L. Katis
- ARUK Oxford Drug Discovery Institute, Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Ani Michaud
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI 53711, USA
| | - Michael T. Beck
- Promega Corporation, 2800 Woods Hollow Road, Madison, WI 53711, USA
| | - Sabrina C. D. Daglish
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sarit Cohen-Kedar
- Division of Gastroenterology, Rabin Medical Center, Petah-Tikva, Israel
- Felsenstein Medical Research Center, Faculty of Medical & Health Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Efrat Shaham Barda
- Division of Gastroenterology, Rabin Medical Center, Petah-Tikva, Israel
- Felsenstein Medical Research Center, Faculty of Medical & Health Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Stefanie Howell
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Iris Dotan
- Division of Gastroenterology, Rabin Medical Center, Petah-Tikva, Israel
- Felsenstein Medical Research Center, Faculty of Medical & Health Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Alison D. Axtman
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Frances M. Bashore
- Structural Genomics Consortium, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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3
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Singh PK, Dangelmaier CA, Vari HR, Tsygankov AY, Kunapuli SP. Biochemical characterization of spleen tyrosine kinase (SYK) isoforms in platelets. Platelets 2023; 34:2249549. [PMID: 37661351 PMCID: PMC10502920 DOI: 10.1080/09537104.2023.2249549] [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] [Received: 06/12/2023] [Revised: 07/12/2023] [Accepted: 08/14/2023] [Indexed: 09/05/2023]
Abstract
Alternate splicing is among the regulatory mechanisms imparting functional diversity in proteins. Studying protein isoforms generated through alternative splicing is therefore critical for understanding protein functions in many biological systems. Spleen tyrosine kinase (Syk) plays an essential role in ITAM/hemITAM signaling in many cell types, including platelets. However, the spectrum of Syk isoforms expressed in platelets has not been characterized. Syk has been shown to have a full-length long isoform SykL and a shorter SykS lacking 23 amino acid residues within its interdomain B. Furthermore, putative isoforms lacking another 23 amino acid-long sequence or a combination of the two deletions have been postulated to exist. In this report, we demonstrate that mouse platelets express full-length SykL and the previously described shorter isoform SykS, but lack other shorter isoforms, whereas human platelets express predominantly SykL. These results both indicate a possible role of alternative Syk splicing in the regulation of receptor signaling in mouse platelets and a difference between signaling regulation in mouse and human platelets.
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Affiliation(s)
- Pankaj Kumar Singh
- Sol Sherry Thrombosis Research Center and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Carol A. Dangelmaier
- Sol Sherry Thrombosis Research Center and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Hymavathi Reddy Vari
- Sol Sherry Thrombosis Research Center and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Alexander Y. Tsygankov
- Sol Sherry Thrombosis Research Center and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Satya P. Kunapuli
- Sol Sherry Thrombosis Research Center and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
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Zhang P, Solari FA, Heemskerk JWM, Kuijpers MJE, Sickmann A, Walter U, Jurk K. Differential Regulation of GPVI-Induced Btk and Syk Activation by PKC, PKA and PP2A in Human Platelets. Int J Mol Sci 2023; 24:ijms24097776. [PMID: 37175486 PMCID: PMC10178361 DOI: 10.3390/ijms24097776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023] Open
Abstract
Bruton's tyrosine kinase (Btk) and spleen tyrosine kinase (Syk) are major signaling proteins in human platelets that are implicated in atherothrombosis and thrombo-inflammation, but the mechanisms controlling their activities are not well understood. Previously, we showed that Syk becomes phosphorylated at S297 in glycoprotein VI (GPVI)-stimulated human platelets, which limits Syk activation. Here, we tested the hypothesis that protein kinases C (PKC) and A (PKA) and protein phosphatase 2A (PP2A) jointly regulate GPVI-induced Btk activation in platelets. The GPVI agonist convulxin caused rapid, transient Btk phosphorylation at S180 (pS180↑), Y223 and Y551, while direct PKC activation strongly increased Btk pS180 and pY551. This increase in Btk pY551 was also Src family kinase (SFK)-dependent, but surprisingly Syk-independent, pointing to an alternative mechanism of Btk phosphorylation and activation. PKC inhibition abolished convulxin-stimulated Btk pS180 and Syk pS297, but markedly increased the tyrosine phosphorylation of Syk, Btk and effector phospholipase Cγ2 (PLCγ2). PKA activation increased convulxin-induced Btk activation at Y551 but strongly suppressed Btk pS180 and Syk pS297. PP2A inhibition by okadaic acid only increased Syk pS297. Both platelet aggregation and PLCγ2 phosphorylation with convulxin stimulation were Btk-dependent, as shown by the selective Btk inhibitor acalabrutinib. Together, these results revealed in GPVI-stimulated platelets a transient Syk, Btk and PLCγ2 phosphorylation at multiple sites, which are differentially regulated by PKC, PKA or PP2A. Our work thereby demonstrated the GPVI-Syk-Btk signalosome as a tightly controlled protein kinase network, in agreement with its role in atherothrombosis.
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Affiliation(s)
- Pengyu Zhang
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., 44139 Dortmund, Germany
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
- Department of Biochemistry, CARIM, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Fiorella A Solari
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., 44139 Dortmund, Germany
| | - Johan W M Heemskerk
- Department of Biochemistry, CARIM, Maastricht University, 6229 ER Maastricht, The Netherlands
- Synapse Research Institute Maastricht, 6217 KD Maastricht, The Netherlands
| | - Marijke J E Kuijpers
- Department of Biochemistry, CARIM, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Albert Sickmann
- Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., 44139 Dortmund, Germany
- Medizinische Fakultät, Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44780 Bochum, Germany
- Department of Chemistry, College of Physical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
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Kunapuli SP, Tsygankov AY. TULA-Family Regulators of Platelet Activation. Int J Mol Sci 2022; 23:ijms232314910. [PMID: 36499237 PMCID: PMC9736690 DOI: 10.3390/ijms232314910] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/30/2022] Open
Abstract
The two members of the UBASH3/TULA/STS-protein family have been shown to critically regulate cellular processes in multiple biological systems. The regulatory function of TULA-2 (also known as UBASH3B or STS-1) in platelets is one of the best examples of the involvement of UBASH3/TULA/STS proteins in cellular regulation. TULA-2 negatively regulates platelet signaling mediated by ITAM- and hemITAM-containing membrane receptors that are dependent on the protein tyrosine kinase Syk, which currently represents the best-known dephosphorylation target of TULA-2. The biological responses of platelets to collagen and other physiological agonists are significantly downregulated as a result. The protein structure, enzymatic activity and regulatory functions of UBASH3/TULA/STS proteins in the context of platelet responses and their regulation are discussed in this review.
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Wen Y, Ma J. Phase separation drives the formation of biomolecular condensates in the immune system. Front Immunol 2022; 13:986589. [PMID: 36439121 PMCID: PMC9685520 DOI: 10.3389/fimmu.2022.986589] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/19/2022] [Indexed: 08/12/2023] Open
Abstract
When the external conditions change, such as the temperature or the pressure, the multi-component system sometimes separates into several phases with different components and structures, which is called phase separation. Increasing studies have shown that cells condense related biomolecules into independent compartments in order to carry out orderly and efficient biological reactions with the help of phase separation. Biomolecular condensates formed by phase separation play a significant role in a variety of cellular processes, including the control of signal transduction, the regulation of gene expression, and the stress response. In recent years, many phase separation events have been discovered in the immune response process. In this review, we provided a comprehensive and detailed overview of the role and mechanism of phase separation in the innate and adaptive immune responses, which will help the readers to appreciate the advance and importance of this field.
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Affiliation(s)
- Yuqing Wen
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Cancer Research Institute and School of Basic Medical Science, Central South University, Changsha, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Hunan Key Laboratory of Cancer Metabolism, Changsha, China
| | - Jian Ma
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China
- Cancer Research Institute and School of Basic Medical Science, Central South University, Changsha, China
- Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Hunan Key Laboratory of Cancer Metabolism, Changsha, China
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7
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Proteomic profiling of cisplatin-resistant and cisplatin-sensitive germ cell tumour cell lines using quantitative mass spectrometry. World J Urol 2022; 40:373-383. [PMID: 35084545 PMCID: PMC8921118 DOI: 10.1007/s00345-022-03936-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 01/07/2022] [Indexed: 01/23/2023] Open
Abstract
Purpose Advanced testicular germ cell tumours (GCT) generally have a good prognosis owing to their unique sensitivity towards cisplatin-based chemotherapies. However, cisplatin-resistant GCT have a poor outcome. Further studies are mandatory to better understand resistance mechanisms and develop therapeutic strategies for refractory GCTs. Methods Protein levels in cisplatin-resistant GCT cell lines of NTERA-2, NCCIT and 2102EP were analyzed by quantitative proteomic mass spectrometry (MS) in combination with stable isotope labelling by amino acids in cell culture (SILAC). Differentially abundant protein markers of acquired cisplatin resistance were validated by Western blotting. Comprehensive bioinformatical annotation using gene set enrichment analyses (GSEA) and STRING interaction analysis were performed to identify commonly affected pathways in cisplatin resistance and the data were compared to the GCT cohort of the ‘The Cancer Genome Atlas’.
Results A total of 4375 proteins were quantified by MS, 144 of which were found to be differentially abundant between isogenic resistant and sensitive cell line pairs (24 proteins for NTERA-2, 60 proteins for NCCIT, 75 proteins for 2102EP). Western blotting confirmed regulation of key resistance-associated proteins (CBS, ANXA1, LDHA, CTH, FDXR). GSEA revealed a statistically significant enrichment of DNA repair-associated proteins in all three resistant cell lines and specific additional processes for individual cell lines. Conclusion High resolution MS combined with SILAC is a powerful tool and 144 significantly deregulated proteins were found in cisplatin-resistant GCT cell lines. Our study provides the largest proteomic in vitro library for cisplatin resistance in GCT, yet, enabling further studies to develop new treatment options for patients with refractory GCT. Supplementary Information The online version contains supplementary material available at 10.1007/s00345-022-03936-1.
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Richter A, Fichtner A, Joost J, Brockmeyer P, Kauffmann P, Schliephake H, Hammerstein-Equord A, Kueffer S, Urlaub H, Oellerich T, Ströbel P, Bohnenberger H, Bremmer F. Quantitative proteomics identifies biomarkers to distinguish pulmonary from head and neck squamous cell carcinomas by immunohistochemistry. JOURNAL OF PATHOLOGY CLINICAL RESEARCH 2021; 8:33-47. [PMID: 34647699 PMCID: PMC8682946 DOI: 10.1002/cjp2.244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/23/2021] [Accepted: 09/01/2021] [Indexed: 12/16/2022]
Abstract
The differentiation between a pulmonary metastasis and a newly developed squamous cell carcinoma of the lung in patients with prior head and neck squamous cell carcinoma (HNSCC) is difficult due to a lack of biomarkers but is crucially important for the prognosis and therapy of the affected patient. By using high‐resolution mass spectrometry in combination with stable isotope labelling by amino acids in cell culture, we identified 379 proteins that are differentially expressed in squamous cell carcinomas of the lung and the head and neck. Of those, CAV1, CAV2, LGALS1, LGALS7, CK19, and UGDH were tested by immunohistochemistry on 194 tissue samples (98 lung and 96 HNSCCs). The combination of CAV1 and LGALS7 was able to distinguish the origin of the squamous cell carcinoma with high accuracy (area under the curve 0.876). This biomarker panel was tested on a cohort of 12 clinically classified lung tumours of unknown origin after HNSCC. Nine of those tumours were immunohistochemically classifiable.
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Affiliation(s)
- Annika Richter
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | - Alexander Fichtner
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | - Jasmin Joost
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | - Philipp Brockmeyer
- Department of Oral and Maxillofacial Surgery, University Medical Centre Göttingen, Göttingen, Germany
| | - Philipp Kauffmann
- Department of Oral and Maxillofacial Surgery, University Medical Centre Göttingen, Göttingen, Germany
| | - Henning Schliephake
- Department of Oral and Maxillofacial Surgery, University Medical Centre Göttingen, Göttingen, Germany
| | | | - Stefan Kueffer
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Centre Göttingen, Göttingen, Germany
| | - Thomas Oellerich
- Department of Medicine II, Haematology/Oncology, Goethe University, Frankfurt, Germany.,German Cancer Research Centre and German Cancer Consortium, Heidelberg, Germany
| | - Philipp Ströbel
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
| | | | - Felix Bremmer
- Institute of Pathology, University Medical Centre Göttingen, Göttingen, Germany
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9
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Shiravand Y, Walter U, Jurk K. Fine-Tuning of Platelet Responses by Serine/Threonine Protein Kinases and Phosphatases-Just the Beginning. Hamostaseologie 2021; 41:206-216. [PMID: 34192779 DOI: 10.1055/a-1476-7873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Comprehensive proteomic analyses of human and murine platelets established an extraordinary intracellular repertoire of signaling components, which control crucial functions. The spectrum of platelet serine/threonine protein kinases (more than 100) includes the AGC family (protein kinase A, G, C [PKA, PKG, PKC]), the mitogen-activated protein kinases (MAPKs), and others. PKA and PKG have multiple significantly overlapping substrates in human platelets, which possibly affect functions with clear "signaling nodes" of regulation by multiple protein kinases/phosphatases. Signaling nodes are intracellular Ca2+ stores, the contractile system (myosin light chains), and other signaling components such as G-proteins, protein kinases, and protein phosphatases. An example for this fine-tuning is the tyrosine kinase Syk, a crucial component of platelet activation, which is controlled by several serine/threonine and tyrosine protein kinases as well as phosphatases. Other protein kinases including PKA/PKG modulate protein phosphatase 2A, which may be a master regulator of MAPK signaling in human platelets. Protein kinases and in particular MAPKs are targeted by an increasing number of clinically used inhibitors. However, the precise regulation and fine-tuning of these protein kinases and their effects on other signaling components in platelets are only superficially understood-just the beginning. However, promising future approaches are in sight.
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Affiliation(s)
- Yavar Shiravand
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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10
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Makhoul S, Kumm E, Zhang P, Walter U, Jurk K. The Serine/Threonine Protein Phosphatase 2A (PP2A) Regulates Syk Activity in Human Platelets. Int J Mol Sci 2020; 21:ijms21238939. [PMID: 33255747 PMCID: PMC7728356 DOI: 10.3390/ijms21238939] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/14/2020] [Accepted: 11/19/2020] [Indexed: 12/21/2022] Open
Abstract
Distinct membrane receptors activate platelets by Src-family-kinase (SFK)-, immunoreceptor-tyrosine-based-activation-motif (ITAM)-dependent stimulation of spleen tyrosine kinase (Syk). Recently, we reported that platelet activation via glycoprotein (GP) VI or GPIbα stimulated the well-established Syk tyrosine (Y)-phosphorylation, but also stoichiometric, transient protein kinase C (PKC)-mediated Syk serine(S)297 phosphorylation in the regulatory interdomain-B, suggesting possible feedback inhibition. The transient nature of Syk S297 phosphorylation indicated the presence of an unknown Syk pS297 protein phosphatase. In this study, we hypothesize that the S-protein phosphatase 2A (PP2A) is responsible for Syk pS297 dephosphorylation, thereby affecting Syk Y-phosphorylation and activity in human washed platelets. Using immunoblotting, we show that specific inhibition of PP2A by okadaic acid (OA) alone leads to stoichiometric Syk S297 phosphorylation, as analyzed by Zn2+-Phos-tag gels, without affecting Syk Y-phosphorylation. Pharmacological inhibition of Syk by PRT060318 or PKC by GF109203X only minimally reduced OA-induced Syk S297 phosphorylation. PP2A inhibition by OA preceding GPVI-mediated platelet activation induced by convulxin extended Syk S297 phosphorylation but inhibited Syk Y-phosphorylation. Our data demonstrate a novel biochemical and functional link between the S-protein phosphatase PP2A and the Y-protein kinase Syk in human platelets, and suggest that PP2A represents a potential enhancer of GPVI-mediated Syk activity caused by Syk pS297 dephosphorylation.
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Affiliation(s)
- Stephanie Makhoul
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, D-55131 Mainz, Germany; (S.M.); (E.K.); (P.Z.)
| | - Elena Kumm
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, D-55131 Mainz, Germany; (S.M.); (E.K.); (P.Z.)
| | - Pengyu Zhang
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, D-55131 Mainz, Germany; (S.M.); (E.K.); (P.Z.)
- Leibniz-Institut für Analytische Wissenschaften, D-44227 Dortmund, Germany
| | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, D-55131 Mainz, Germany; (S.M.); (E.K.); (P.Z.)
- Correspondence: (U.W.); (K.J.)
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, D-55131 Mainz, Germany; (S.M.); (E.K.); (P.Z.)
- Correspondence: (U.W.); (K.J.)
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11
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Jiménez C, Chan GG, Xu L, Tsakmaklis N, Kofides A, Demos MG, Chen J, Liu X, Munshi M, Yang G, Castillo JJ, Wiestner A, García-Sanz R, Treon SP, Hunter ZR. Genomic evolution of ibrutinib-resistant clones in Waldenström macroglobulinaemia. Br J Haematol 2020; 189:1165-1170. [PMID: 32103491 DOI: 10.1111/bjh.16463] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/06/2019] [Indexed: 12/28/2022]
Abstract
Ibrutinib is highly active in Waldenström macroglobulinaemia (WM) patients, but disease progression can occur due to acquired mutations in BTK, the target of ibrutinib, or PLCG2, the protein downstream of BTK. However, not all resistant patients harbour these alterations. We have performed a whole-exome sequencing study to identify alternative molecular mechanisms that can drive ibrutinib resistance. Our findings include deletions on chromosomes 6q, including homozygous deletions, and 8p, which encompass key regulators of BTK, MYD88/NF-κB, and apoptotic signalling. Moreover, we have identified recurring mutations in ubiquitin ligases, innate immune signalling, and TLR/MYD88 pathway regulators in ibrutinib-resistant WM patients.
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Affiliation(s)
- Cristina Jiménez
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Gloria G Chan
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Lian Xu
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Nickolas Tsakmaklis
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Amanda Kofides
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Maria G Demos
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jiaji Chen
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Xia Liu
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Manit Munshi
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Guang Yang
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jorge J Castillo
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Adrian Wiestner
- Hematology Branch, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Ramón García-Sanz
- Servicio de Hematología, Hospital Universitario de Salamanca, Instituto de Investigación Biomédica de Salamanca, Centro de Investigación Biomédica en Red Cáncer, Salamanca, Spain
| | - Steven P Treon
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Zachary R Hunter
- Bing Center for Waldenstrom's Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
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12
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Tripartite phase separation of two signal effectors with vesicles priming B cell responsiveness. Nat Commun 2020; 11:848. [PMID: 32051419 PMCID: PMC7016142 DOI: 10.1038/s41467-020-14544-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Accepted: 01/13/2020] [Indexed: 01/12/2023] Open
Abstract
Antibody-mediated immune responses rely on antigen recognition by the B cell antigen receptor (BCR) and the proper engagement of its intracellular signal effector proteins. Src homology (SH) 2 domain-containing leukocyte protein of 65 kDa (SLP65) is the key scaffold protein mediating BCR signaling. In resting B cells, SLP65 colocalizes with Cbl-interacting protein of 85 kDa (CIN85) in cytoplasmic granules whose formation is not fully understood. Here we show that effective B cell activation requires tripartite phase separation of SLP65, CIN85, and lipid vesicles into droplets via vesicle binding of SLP65 and promiscuous interactions between nine SH3 domains of the trimeric CIN85 and the proline-rich motifs (PRMs) of SLP65. Vesicles are clustered and the dynamical structure of SLP65 persists in the droplet phase in vitro. Our results demonstrate that phase separation driven by concerted transient interactions between scaffold proteins and vesicles is a cellular mechanism to concentrate and organize signal transducers. Antibody-mediated immune responses rely on antigen recognition by the B cell antigen receptor (BCR) and SLP65 is a key scaffold protein mediating BCR signaling. Here authors show that effective B cell activation requires tripartite phase separation of SLP65, CIN85, and lipid vesicles.
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13
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Feedback Regulation of Syk by Protein Kinase C in Human Platelets. Int J Mol Sci 2019; 21:ijms21010176. [PMID: 31881809 PMCID: PMC6981976 DOI: 10.3390/ijms21010176] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 02/08/2023] Open
Abstract
The spleen tyrosine kinase (Syk) is essential for immunoreceptor tyrosine-based activation motif (ITAM)-dependent platelet activation, and it is stimulated by Src-family kinase (SFK)-/Syk-mediated phosphorylation of Y352 (interdomain-B) and Y525/526 (kinase domain). Additional sites for Syk phosphorylation and protein interactions are known but remain elusive. Since Syk S297 phosphorylation (interdomain-B) was detected in platelets, we hypothesized that this phosphorylation site regulates Syk activity via protein kinase C (PKC)-and cyclic adenosine monophosphate (cAMP)-dependent pathways. ADP, the GPVI-agonist convulxin, and the GPIbα-agonist echicetin beads (EB) were used to stimulate human platelets with/without effectors. Platelet aggregation and intracellular messengers were analyzed, along with phosphoproteins, by immunoblotting using phosphosite-specific antibodies or phos-tags. ADP, convulxin, and EB upregulated Syk S297 phosphorylation, which was inhibited by iloprost (cAMP pathway). Convulxin-stimulated Syk S297 phosphorylation was stoichiometric, transient, abolished by the PKC inhibitor GF109203X, and mimicked by the PKC activator PDBu. Convulxin/EB stimulated Syk S297, Y352, and Y525/526 phosphorylation, which was inhibited by SFK and Syk inhibitors. GFX and iloprost inhibited convulxin/EB-induced Syk S297 phosphorylation but enhanced Syk tyrosine (Y352/Y525/526) and substrate (linker adaptor for T cells (LAT), phospholipase γ2 (PLC γ2)) phosphorylation. GFX enhanced convulxin/EB-increases of inositol monophosphate/Ca2+. ITAM-activated Syk stimulates PKC-dependent Syk S297 phosphorylation, which is reduced by SFK/Syk/PKC inhibition and cAMP. Inhibition of Syk S297 phosphorylation coincides with enhanced Syk activation, suggesting that S297 phosphorylation represents a mechanism for feedback inhibition in human platelets.
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14
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Blazquez R, Rietkötter E, Wenske B, Wlochowitz D, Sparrer D, Vollmer E, Müller G, Seegerer J, Sun X, Dettmer K, Barrantes-Freer A, Stange L, Utpatel K, Bleckmann A, Treiber H, Bohnenberger H, Lenz C, Schulz M, Reimelt C, Hackl C, Grade M, Büyüktas D, Siam L, Balkenhol M, Stadelmann C, Kube D, Krahn MP, Proescholdt MA, Riemenschneider MJ, Evert M, Oefner PJ, Klein CA, Hanisch UK, Binder C, Pukrop T. LEF1 supports metastatic brain colonization by regulating glutathione metabolism and increasing ROS resistance in breast cancer. Int J Cancer 2019; 146:3170-3183. [PMID: 31626715 DOI: 10.1002/ijc.32742] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/13/2019] [Accepted: 09/30/2019] [Indexed: 02/06/2023]
Abstract
More than half of all brain metastases show infiltrating rather than displacing growth at the macro-metastasis/organ parenchyma interface (MMPI), a finding associated with shorter survival. The lymphoid enhancer-binding factor-1 (LEF1) is an epithelial-mesenchymal transition (EMT) transcription factor that is commonly overexpressed in brain-colonizing cancer cells. Here, we overexpressed LEF1 in an in vivo breast cancer brain colonization model. It shortened survival, albeit without engaging EMT at the MMPI. By differential proteome analysis, we identified a novel function of LEF1 as a regulator of the glutathione (GSH) system, the principal cellular redox buffer. LEF1 overexpression also conferred resistance against therapeutic GSH depletion during brain colonization and improved management of intracellular ROS. We conclude that besides EMT, LEF1 facilitates metastasis by improving the antioxidative capacity of epithelial breast cancer cells, in particular during colonization of the brain parenchyma.
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Affiliation(s)
- Raquel Blazquez
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Eva Rietkötter
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Britta Wenske
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Darius Wlochowitz
- Institute of Medical Bioinformatics, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Daniela Sparrer
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
| | - Elena Vollmer
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
| | - Gunnar Müller
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
| | - Julia Seegerer
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
| | - Xueni Sun
- Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - Katja Dettmer
- Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
- Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany
| | - Lena Stange
- Department of Neuropathology, University Hospital Regensburg, Regensburg, Germany
| | - Kirsten Utpatel
- Institute of Pathology, University of Regensburg, Regensburg, Germany
| | - Annalen Bleckmann
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
- Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany
| | - Hannes Treiber
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
- Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | | | - Christof Lenz
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Matthias Schulz
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Christian Reimelt
- Experimental Medicine and Therapy Research, University of Regensburg, Regensburg, Germany
| | - Christina Hackl
- Department of Surgery, University Hospital Regensburg, Regensburg, Germany
| | - Marian Grade
- Department of General, Visceral and Pediatric Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Deram Büyüktas
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Laila Siam
- Department of Neurosurgery, University Medical Center Göttingen, Göttingen, Germany
| | - Marko Balkenhol
- Comprehensive Cancer Center, University Medical Center Göttingen, Göttingen, Germany
| | - Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Dieter Kube
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Michael P Krahn
- Internal Medicine D, University Hospital Münster, Münster, Germany
| | | | | | - Matthias Evert
- Institute of Pathology, University of Regensburg, Regensburg, Germany
| | - Peter J Oefner
- Institute of Functional Genomics, University of Regensburg, Regensburg, Germany
| | - Chistoph A Klein
- Experimental Medicine and Therapy Research, University of Regensburg, Regensburg, Germany
- Project Group "Personalized Tumour Therapy", Fraunhofer Institute for Toxicology and Experimental Medicine, Regensburg, Germany
| | - Uwe K Hanisch
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Claudia Binder
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Pukrop
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Regensburg, Germany
- Department of Hematology and Medical Oncology, University Medical Center Göttingen, Göttingen, Germany
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15
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Makhoul S, Trabold K, Gambaryan S, Tenzer S, Pillitteri D, Walter U, Jurk K. cAMP- and cGMP-elevating agents inhibit GPIbα-mediated aggregation but not GPIbα-stimulated Syk activation in human platelets. Cell Commun Signal 2019; 17:122. [PMID: 31519182 PMCID: PMC6743169 DOI: 10.1186/s12964-019-0428-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 08/29/2019] [Indexed: 12/29/2022] Open
Abstract
Background The glycoprotein (GP) Ib-IX-V complex is a unique platelet plasma membrane receptor, which is essential for platelet adhesion and thrombus formation. GPIbα, part of the GPIb-IX-V complex, has several physiological ligands such as von Willebrand factor (vWF), thrombospondin and distinct coagulation factors, which trigger platelet activation. Despite having an important role, intracellular GPIb-IX-V signaling and its regulation by other pathways are not well defined. Our aim was to establish the intracellular signaling response of selective GPIbα activation in human platelets, in particular the role of the tyrosine kinase Syk and its regulation by cAMP/PKA and cGMP/PKG pathways, respectively. We addressed this using echicetin beads (EB), which selectively bind to GPIbα and induce platelet aggregation. Methods Purified echicetin from snake Echis carinatus venom was validated by mass spectrometry. Washed human platelets were incubated with EB, in the presence or absence of echicetin monomers (EM), Src family kinase (SFK) inhibitors, Syk inhibitors and the cAMP- and cGMP-elevating agents iloprost and riociguat, respectively. Platelet aggregation was analyzed by light transmission aggregometry, protein phosphorylation by immunoblotting. Intracellular messengers inositolmonophosphate (InsP1) and Ca2+i were measured by ELISA and Fluo-3 AM/FACS, respectively. Results EB-induced platelet aggregation was dependent on integrin αIIbβ3 and secondary mediators ADP and TxA2, and was antagonized by EM. EB stimulated Syk tyrosine phosphorylation at Y352, which was SFK-dependent and Syk-independent, whereas Y525/526 phosphorylation was SFK-dependent and partially Syk-dependent. Furthermore, phosphorylation of both Syk Y352 and Y525/526 was completely integrin αIIbβ3-independent but, in the case of Y525/526, was partially ADP/TxA2-dependent. Syk activation, observed as Y352/ Y525/Y526 phosphorylation, led to the phosphorylation of direct substrates (LAT Y191, PLCγ2 Y759) and additional targets (Akt S473). PKA/PKG pathways inhibited EB-induced platelet aggregation and Akt phosphorylation but, surprisingly, enhanced Syk and LAT/PLCγ2 tyrosine phosphorylation. A similar PKA/PKG effect was confirmed with convulxin−/GPVI-stimulated platelets. EB-induced InsP1 accumulation/InsP3 production and Ca2+-release were Syk-dependent, but only partially inhibited by PKA/PKG pathways. Conclusion EB and EM are specific agonists and antagonists, respectively, of GPIbα-mediated Syk activation leading to platelet aggregation. The cAMP/PKA and cGMP/PKG pathways do not inhibit but enhance GPIbα−/GPVI-initiated, SFK-dependent Syk activation, but strongly inhibit further downstream responses including aggregation. These data establish an important intracellular regulatory network induced by GPIbα. Graphical abstract ![]()
Electronic supplementary material The online version of this article (10.1186/s12964-019-0428-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephanie Makhoul
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katharina Trabold
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stepan Gambaryan
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany.,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Stefan Tenzer
- Core Facility for Mass Spectrometry, Institute for Immunology, University Medical Center Mainz, Mainz, Germany
| | | | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany.
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Proteomic Comparison of Malignant Human Germ Cell Tumor Cell Lines. DISEASE MARKERS 2019; 2019:8298524. [PMID: 31565104 PMCID: PMC6745167 DOI: 10.1155/2019/8298524] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/10/2019] [Accepted: 06/25/2019] [Indexed: 11/17/2022]
Abstract
Malignant germ cell tumors (GCT) are the most common malignant tumors in young men between 18 and 40 years. The correct identification of histological subtypes, in difficult cases supported by immunohistochemistry, is essential for therapeutic management. Furthermore, biomarkers may help to understand pathophysiological processes in these tumor types. Two GCT cell lines, TCam-2 with seminoma-like characteristics, and NTERA-2, an embryonal carcinoma-like cell line, were compared by a quantitative proteomic approach using high-resolution mass spectrometry (MS) in combination with stable isotope labelling by amino acid in cell culture (SILAC). We were able to identify 4856 proteins and quantify the expression of 3936. 347 were significantly differentially expressed between the two cell lines. For further validation, CD81, CBX-3, PHF6, and ENSA were analyzed by western blot analysis. The results confirmed the MS results. Immunohistochemical analysis on 59 formalin-fixed and paraffin-embedded (FFPE) normal and GCT tissue samples (normal testis, GCNIS, seminomas, and embryonal carcinomas) of these proteins demonstrated the ability to distinguish different GCT subtypes, especially seminomas and embryonal carcinomas. In addition, siRNA-mediated knockdown of these proteins resulted in an antiproliferative effect in TCam-2, NTERA-2, and an additional embryonal carcinoma-like cell line, NCCIT. In summary, this study represents a proteomic resource for the discrimination of malignant germ cell tumor subtypes and the observed antiproliferative effect after knockdown of selected proteins paves the way for the identification of new potential drug targets.
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17
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Regulation of Microtubule Nucleation in Mouse Bone Marrow-Derived Mast Cells by Protein Tyrosine Phosphatase SHP-1. Cells 2019; 8:cells8040345. [PMID: 30979083 PMCID: PMC6523986 DOI: 10.3390/cells8040345] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/30/2019] [Accepted: 04/10/2019] [Indexed: 12/20/2022] Open
Abstract
The antigen-mediated activation of mast cells initiates signaling events leading to their degranulation, to the release of inflammatory mediators, and to the synthesis of cytokines and chemokines. Although rapid and transient microtubule reorganization during activation has been described, the molecular mechanisms that control their rearrangement are largely unknown. Microtubule nucleation is mediated by γ-tubulin complexes. In this study, we report on the regulation of microtubule nucleation in bone marrow-derived mast cells (BMMCs) by Src homology 2 (SH2) domain-containing protein tyrosine phosphatase 1 (SHP-1; Ptpn6). Reciprocal immunoprecipitation experiments and pull-down assays revealed that SHP-1 is present in complexes containing γ-tubulin complex proteins and protein tyrosine kinase Syk. Microtubule regrowth experiments in cells with deleted SHP-1 showed a stimulation of microtubule nucleation, and phenotypic rescue experiments confirmed that SHP-1 represents a negative regulator of microtubule nucleation in BMMCs. Moreover, the inhibition of the SHP-1 activity by inhibitors TPI-1 and NSC87877 also augmented microtubule nucleation. The regulation was due to changes in γ-tubulin accumulation. Further experiments with antigen-activated cells showed that the deletion of SHP-1 stimulated the generation of microtubule protrusions, the activity of Syk kinase, and degranulation. Our data suggest a novel mechanism for the suppression of microtubule formation in the later stages of mast cell activation.
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18
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Mansueto MS, Reens A, Rakhilina L, Chi A, Pan BS, Miller JR. A reevaluation of the spleen tyrosine kinase (SYK) activation mechanism. J Biol Chem 2019; 294:7658-7668. [PMID: 30923129 DOI: 10.1074/jbc.ra119.008045] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/25/2019] [Indexed: 11/06/2022] Open
Abstract
Spleen tyrosine kinase (SYK) is a signaling node in many immune pathways and comprises two tandem Src homology (SH) 2 domains, an SH2-kinase linker, and a C-terminal tyrosine kinase domain. Two prevalent models of SYK activation exist. The "OR-gate" model contends that SYK can be fully activated by phosphorylation or binding of its SH2 domains to a dual-phosphorylated immune-receptor tyrosine-based activation motif (ppITAM). An alternative model proposes that SYK activation requires ppITAM binding and phosphorylation of the SH2-kinase linker by a SRC family kinase such as LYN proto-oncogene, SRC family tyrosine kinase (LYN). To evaluate these two models, we generated directly comparable unphosphorylated (upSYK) and phosphorylated (pSYK) proteins with or without an N-terminal glutathione S-transferase (GST) tag, resulting in monomeric or obligatory dimeric SYK, respectively. We assessed the ability of a ppITAM peptide and LYN to activate these SYK proteins. The ppITAM peptide strongly activated GST-SYK but was less effective in activating upSYK untagged with GST. LYN alone activated untagged upSYK to a greater extent than did ppITAM, and inclusion of both proteins rapidly and fully activated upSYK. Using immunoblot and phosphoproteomic approaches, we correlated the kinetics and order of site-specific SYK phosphorylation. Our results are consistent with the alternative model, indicating that ppITAM binding primes SYK for rapid LYN-mediated phosphorylation of Tyr-352 and then Tyr-348 of the SH2-kinase linker, which facilitates activation loop phosphorylation and full SYK activation. This gradual activation mechanism may also explain how SYK maintains ligand-independent tonic signaling, important for B-cell development and survival.
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Affiliation(s)
| | | | | | - An Chi
- Chemical Biology, Merck & Co., Inc., Boston, Massachusetts 02115
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19
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Slomiany BL, Slomiany A. Syk: a new target for attenuation of Helicobacter pylori-induced gastric mucosal inflammatory responses. Inflammopharmacology 2019; 27:203-211. [PMID: 30820719 DOI: 10.1007/s10787-019-00577-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/19/2019] [Indexed: 02/07/2023]
Abstract
The magnitude of gastric mucosal inflammatory response to H. pylori relies primarily on the extent of its key endotoxin, LPS, engagement of Toll-like receptor-4 (TLR4) and the initiation of signal transduction events converging on mitogen-activated protein kinase (MAPK) and IκB complex (IKK) cascades. These cascades, in turn, exert their control over the assembly of transcription factors, NFκB and AP1, implicated in the induction of the expression of iNOS and COX-2 proinflammatory genes. The LPS-induced TLR4 activation and the ensuing phosphorylation of its intracellular tyrosine domain by Src-family kinases not only leads to recruitment to the cytoplasmic domain of TLR4 of adaptor molecules directly involved in propagation of the signaling cascades converging on MAPK and IKK, but also provides a propitious docking site for a non-receptor tyrosine kinase, spleen tyrosine kinase (Syk), the activation of which apparently leads to upregulation in the expression of proinflammatory genes. Here, we review the pathways engaged by H. pylori in the recruitment and interaction of Syk with TLR4 in gastric mucosa, and discuss the cascades involved in Syk-mediated amplification in proinflammatory signaling. We focus, moreover, on the potential role of drugs targeting Syk and TLR4 in the treatment of H. pylori-related gastric disease.
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Affiliation(s)
- Bronislaw L Slomiany
- Research Center, C855, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, 110 Bergen Street, PO Box 1709, Newark, NJ, 07103-2400, USA.
| | - Amalia Slomiany
- Research Center, C855, Rutgers School of Dental Medicine, Rutgers, The State University of New Jersey, 110 Bergen Street, PO Box 1709, Newark, NJ, 07103-2400, USA
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20
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SYK Inhibition Potentiates the Effect of Chemotherapeutic Drugs on Neuroblastoma Cells in Vitro. Cancers (Basel) 2019; 11:cancers11020202. [PMID: 30744170 PMCID: PMC6406899 DOI: 10.3390/cancers11020202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/04/2019] [Accepted: 02/06/2019] [Indexed: 12/13/2022] Open
Abstract
Neuroblastoma is a malignancy arising from the developing sympathetic nervous system and the most common and deadly cancer of infancy. New therapies are needed to improve the prognosis for high-risk patients and to reduce toxicity and late effects. Spleen tyrosine kinase (SYK) has previously been identified as a promising drug target in various inflammatory diseases and cancers but has so far not been extensively studied as a potential therapeutic target in neuroblastoma. In this study, we observed elevated SYK gene expression in neuroblastoma compared to neural crest and benign neurofibroma. While SYK protein was detected in the majority of examined neuroblastoma tissues it was less frequently observed in neuroblastoma cell lines. Depletion of SYK by siRNA and the use of small molecule SYK inhibitors significantly reduced the cell viability of neuroblastoma cell lines expressing SYK protein. Moreover, SYK inhibition decreased ERK1/2 and Akt phosphorylation. The SYK inhibitor BAY 61-3606 enhanced the effect of different chemotherapeutic drugs. Transient expression of a constitutive active SYK variant increased the viability of neuroblastoma cells independent of endogenous SYK levels. Collectively, our findings suggest that targeting SYK in combination with conventional chemotherapy should be further evaluated as a treatment option in neuroblastoma.
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21
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Precision medicine review: rare driver mutations and their biophysical classification. Biophys Rev 2019; 11:5-19. [PMID: 30610579 PMCID: PMC6381362 DOI: 10.1007/s12551-018-0496-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 12/18/2018] [Indexed: 02/07/2023] Open
Abstract
How can biophysical principles help precision medicine identify rare driver mutations? A major tenet of pragmatic approaches to precision oncology and pharmacology is that driver mutations are very frequent. However, frequency is a statistical attribute, not a mechanistic one. Rare mutations can also act through the same mechanism, and as we discuss below, “latent driver” mutations may also follow the same route, with “helper” mutations. Here, we review how biophysics provides mechanistic guidelines that extend precision medicine. We outline principles and strategies, especially focusing on mutations that drive cancer. Biophysics has contributed profoundly to deciphering biological processes. However, driven by data science, precision medicine has skirted some of its major tenets. Data science embodies genomics, tissue- and cell-specific expression levels, making it capable of defining genome- and systems-wide molecular disease signatures. It classifies cancer driver genes/mutations and affected pathways, and its associated protein structural data guide drug discovery. Biophysics complements data science. It considers structures and their heterogeneous ensembles, explains how mutational variants can signal through distinct pathways, and how allo-network drugs can be harnessed. Biophysics clarifies how one mutation—frequent or rare—can affect multiple phenotypic traits by populating conformations that favor interactions with other network modules. It also suggests how to identify such mutations and their signaling consequences. Biophysics offers principles and strategies that can help precision medicine push the boundaries to transform our insight into biological processes and the practice of personalized medicine. By contrast, “phenotypic drug discovery,” which capitalizes on physiological cellular conditions and first-in-class drug discovery, may not capture the proper molecular variant. This is because variants of the same protein can express more than one phenotype, and a phenotype can be encoded by several variants.
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22
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Gannoun-Zaki L, Pätzold L, Huc-Brandt S, Baronian G, Elhawy MI, Gaupp R, Martin M, Blanc-Potard AB, Letourneur F, Bischoff M, Molle V. PtpA, a secreted tyrosine phosphatase from Staphylococcus aureus, contributes to virulence and interacts with coronin-1A during infection. J Biol Chem 2018; 293:15569-15580. [PMID: 30131335 DOI: 10.1074/jbc.ra118.003555] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/16/2018] [Indexed: 11/06/2022] Open
Abstract
Secretion of bacterial signaling proteins and adaptation to the host, especially during infection, are processes that are often linked in pathogenic bacteria. The human pathogen Staphylococcus aureus is equipped with a large arsenal of immune-modulating factors, allowing it to either subvert the host immune response or to create permissive niches for its survival. Recently, we showed that one of the low-molecular-weight protein tyrosine phosphatases produced by S. aureus, PtpA, is secreted during growth. Here, we report that deletion of ptpA in S. aureus affects intramacrophage survival and infectivity. We also observed that PtpA is secreted during macrophage infection. Immunoprecipitation assays identified several host proteins as putative intracellular binding partners for PtpA, including coronin-1A, a cytoskeleton-associated protein that is implicated in a variety of cellular processes. Of note, we demonstrated that coronin-1A is phosphorylated on tyrosine residues upon S. aureus infection and that its phosphorylation profile is linked to PtpA expression. Our results confirm that PtpA has a critical role during infection as a bacterial effector protein that counteracts host defenses.
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Affiliation(s)
- Laila Gannoun-Zaki
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Linda Pätzold
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Sylvaine Huc-Brandt
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Grégory Baronian
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Mohamed Ibrahem Elhawy
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Rosmarie Gaupp
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Marianne Martin
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Anne-Béatrice Blanc-Potard
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - François Letourneur
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
| | - Markus Bischoff
- the Institute of Medical Microbiology and Hygiene, University of Saarland, 66421 Homburg/Saar, Germany
| | - Virginie Molle
- From the Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Université de Montpellier, CNRS, UMR 5235, Montpellier 34000, France and
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23
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Helicobacter pylori LPS-induced gastric mucosal spleen tyrosine kinase (Syk) recruitment to TLR4 and activation occurs with the involvement of protein kinase Cδ. Inflammopharmacology 2018; 26:805-815. [PMID: 29353412 DOI: 10.1007/s10787-017-0430-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 11/28/2017] [Indexed: 12/15/2022]
Abstract
Spleen tyrosine kinase (Syk) has emerged recently as a major effector of proinflammatory genes expression induced by LPS-elicited TLR4 activation, and manifested by the up-amplification in the production of inflammatory mediators, including PGE2 and NO. Here, we investigated the nature of factors involved in the recruitment and interaction of Syk with TLR4 in gastric mucosa in response to H. pylori LPS. We show that stimulation of gastric mucosal cells with the LPS leads to localization of Syk with the membrane-associated TLR4 complex and its activation through phosphorylation on Tyr. Furthermore, we reveal that the membrane translocation of Syk upon the LPS stimulation occurs with the involvement of protein kinase Cδ (PKCδ)-mediated phosphorylation of Syk on Ser. Thus, our findings demonstrate that H. pylori LPS-induced up-regulation in Syk activity proceeds through the stage of PKCδ-mediated Syk phosphorylation on Ser, required for its recruitment to the membrane-anchored TLR4, followed by the kinase activation through phosphorylation on Tyr. Hence, the phase of PKCδ-mediated Syk phosphorylation on Ser affects the extent of amplification in gastric mucosal inflammatory response to H. pylori.
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24
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Unperturbed Immune Function despite Mutation of C-Terminal Tyrosines in Syk Previously Implicated in Signaling and Activity Regulation. Mol Cell Biol 2017; 37:MCB.00216-17. [PMID: 28760774 DOI: 10.1128/mcb.00216-17] [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: 04/28/2017] [Accepted: 07/26/2017] [Indexed: 11/20/2022] Open
Abstract
The nonreceptor tyrosine kinase Syk, a central regulator of immune cell differentiation and activation, is a promising drug target for treatment of leukemia and allergic and inflammatory diseases. The clinical failure of Syk inhibitors underscores the importance of understanding the regulation of Syk function and activity. A series of previous studies emphasized the importance of three C-terminal tyrosines in Syk for kinase activity regulation, as docking sites for downstream effector molecules, and for Ca2+ mobilization. Here, we investigated the roles of these C-terminal tyrosines in the mouse. Surprisingly, expression of a triple tyrosine-to-phenylalanine human Syk mutant, SYK(Y3F), was not associated with discernible signaling defects either in reconstituted DT40 cells or in B or mast cells from mice expressing SYK(Y3F) instead of wild-type Syk. Remarkably, lymphocyte differentiation, calcium mobilization, and 2,4,6-trinitrophenyl (TNP)-specific immune responses were unperturbed in SYK(Y3F) mice. These results emphasize the capacity of immune cells to compensate for specific molecular defects, likely using redundant intermolecular interactions, and highlight the importance of in vivo analyses for understanding cellular signaling mechanisms.
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25
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Caruso JA, Carruthers N, Shin N, Gill R, Stemmer PM, Rosenspire A. Mercury alters endogenous phosphorylation profiles of SYK in murine B cells. BMC Immunol 2017; 18:37. [PMID: 28716125 PMCID: PMC5514489 DOI: 10.1186/s12865-017-0221-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/07/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Epidemiological evidence and animal models suggest that exposure to low and non-neurotoxic concentrations of mercury may contribute to idiosyncratic autoimmune disease. Since defects in function and signaling in B cells are often associated with autoimmunity, we investigated whether mercury exposure might alter B cell responsiveness to self-antigens by interfering with B cell receptor (BCR) signal transduction. In this study we determined the effects of mercury on the protein tyrosine kinase SYK, a critical protein involved in regulation of the BCR signaling pathway. METHODS Phosphorylation sites of murine SYK were mapped before and after treatment of WEHI cell cultures with mercury, or with anti-IgM antibody (positive control) or pervanadate (a potent phosphatase inhibitor). Phosphopeptides were enriched by either titanium dioxide chromatography or anti-phosphotyrosine immunoaffinity, and analyzed by liquid chromatography-mass spectrometry. Select SYK phosphosite cluster regions were profiled for responsiveness to treatments using multiple reaction monitoring (MRM) methodology. RESULTS A total of 23 phosphosites were identified with high probability in endogenous SYK, including 19 tyrosine and 4 serine residues. For 10 of these sites phosphorylation levels were increased following BCR activation. Using MRM to profile changes in phosphorylation status we found that 4 cluster regions, encompassing 8 phosphosites, were activated by mercury and differentially responsive to all 3 treatments. Phosphorylation of tyrosine-342 and -346 residues were most sensitive to mercury exposure. This cluster is known to propagate normal BCR signal transduction by recruiting adaptor proteins such as PLC-γ and Vav-1 to SYK during formation of the BCR signalosome. CONCLUSIONS Our data shows that mercury alters the phosphorylation status of SYK on tyrosine sites known to have a role in promoting BCR signals. Considering the importance of SYK in the BCR signaling pathway, these data suggest that mercury can alter BCR signaling in B cells, which might affect B cell responsiveness to self-antigen and have implications with respect to autoimmunity and autoimmune disease.
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Affiliation(s)
- Joseph A Caruso
- Institute of Environmental Health Sciences, Center for Urban Responses to Environmental Stressors (CURES), Wayne State University, Detroit, MI, 48201, USA.
| | - Nicholas Carruthers
- Institute of Environmental Health Sciences, Center for Urban Responses to Environmental Stressors (CURES), Wayne State University, Detroit, MI, 48201, USA
| | - Namhee Shin
- Institute of Environmental Health Sciences, Center for Urban Responses to Environmental Stressors (CURES), Wayne State University, Detroit, MI, 48201, USA
| | - Randal Gill
- Department of Immunology and Microbiology, Center for Urban Responses to Environmental Stressors (CURES), Wayne State University, Detroit, MI, 48201, USA
| | - Paul M Stemmer
- Institute of Environmental Health Sciences, Center for Urban Responses to Environmental Stressors (CURES), Wayne State University, Detroit, MI, 48201, USA
| | - Allen Rosenspire
- Department of Immunology and Microbiology, Center for Urban Responses to Environmental Stressors (CURES), Wayne State University, Detroit, MI, 48201, USA
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26
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Qin X, Lin L, Cao L, Zhang X, Song X, Hao J, Zhang Y, Wei R, Huang X, Lu J, Ge Q. Extracellular matrix protein Reelin promotes myeloma progression by facilitating tumor cell proliferation and glycolysis. Sci Rep 2017; 7:45305. [PMID: 28345605 PMCID: PMC5366887 DOI: 10.1038/srep45305] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 02/22/2017] [Indexed: 12/24/2022] Open
Abstract
Reelin is an extracellular matrix protein that is crucial for neuron migration, adhesion, and positioning. We examined the expression of Reelin in a large cohort of multiple myeloma patients recorded in Gene Expression Omnibus (GEO) database and used over-expression and siRNA knockdown of Reelin to investigate the role of Reelin in myeloma cell growth. We find that Reelin expression is negatively associated with myeloma prognosis. Reelin promotes myeloma cell proliferation in vitro as well as in vivo. The Warburg effect, evidenced by increased glucose uptake and lactate production, is also enhanced in Reelin-expressing cells. The activation of FAK/Syk/Akt/mTOR and STAT3 pathways contributes to Reelin-induced cancer cell growth and metabolic reprogramming. Our findings further reveal that activated Akt and STAT3 pathways induce the upregulation of HIF1α and its downstream targets (LDHA and PDK1), leading to increased glycolysis in myeloma cells. Together, our results demonstrate the critical contributions of Reelin to myeloma growth and metabolism. It presents an opportunity for myeloma therapeutic intervention by inhibiting Reelin and its signaling pathways.
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Affiliation(s)
- Xiaodan Qin
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Liang Lin
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Li Cao
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Xinwei Zhang
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Xiao Song
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Jie Hao
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Yan Zhang
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
| | - Risheng Wei
- Department of Biophysics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Xiaojun Huang
- Peking University Institute of Hematology, People's Hospital, Beijing, 100044, China
| | - Jin Lu
- Peking University Institute of Hematology, People's Hospital, Beijing, 100044, China
| | - Qing Ge
- Key Laboratory of Medical Immunology, Ministry of Health, Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xue Yuan Road, Beijing, 100191, China
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27
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Cottat M, Yasukuni R, Homma Y, Lidgi-Guigui N, Varin-Blank N, Lamy de la Chapelle M, Le Roy C. Phosphorylation impact on Spleen Tyrosine kinase conformation by Surface Enhanced Raman Spectroscopy. Sci Rep 2017; 7:39766. [PMID: 28054556 PMCID: PMC5214100 DOI: 10.1038/srep39766] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/28/2016] [Indexed: 12/12/2022] Open
Abstract
Spleen Tyrosine Kinase (Syk) plays a crucial role in immune cell signalling and its altered expression or activation are involved in several cancers. Syk activity relies on its phosphorylation status and its multiple phosphorylation sites predict several Syk conformations. In this report, we characterized Syk structural changes according to its phosphorylation/activation status by Surface Enhanced Raman Spectroscopy (SERS). Unphosphorylated/inactive and phosphorylated/active Syk forms were produced into two expression systems with different phosphorylation capability. Syk forms were then analysed by SERS that was carried out in liquid condition on a lithographically designed gold nanocylinders array. Our study demonstrated that SERS signatures of the two Syk forms were drastically distinct, indicating structural modifications related to their phosphorylation status. By comparison with the atomic structure of the unphosphorylated Syk, the SERS peak assignments of the phosphorylated Syk nearest gold nanostructures revealed a differential interaction with the gold surface. We finally described a model for Syk conformational variations according to its phosphorylation status. In conclusion, SERS is an efficient technical approach for studying in vitro protein conformational changes and might be a powerful tool to determine protein functions in tumour cells.
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Affiliation(s)
- Maximilien Cottat
- Université Paris 13, Sorbonne Paris Cité, Laboratoire CSPBAT, CNRS (UMR 7244), 74 rue Marcel Cachin, F-93017 Bobigny, France.,Université Paris 13, Sorbonne Paris Cité, Laboratoire ASIH, 74 rue Marcel Cachin, F-93017 Bobigny, France.,INSERM U978, Bobigny, France
| | - Ryohei Yasukuni
- Université Paris 13, Sorbonne Paris Cité, Laboratoire CSPBAT, CNRS (UMR 7244), 74 rue Marcel Cachin, F-93017 Bobigny, France
| | - Yo Homma
- Université Paris 13, Sorbonne Paris Cité, Laboratoire CSPBAT, CNRS (UMR 7244), 74 rue Marcel Cachin, F-93017 Bobigny, France.,Université Paris 13, Sorbonne Paris Cité, Laboratoire ASIH, 74 rue Marcel Cachin, F-93017 Bobigny, France.,INSERM U978, Bobigny, France
| | - Nathalie Lidgi-Guigui
- Université Paris 13, Sorbonne Paris Cité, Laboratoire CSPBAT, CNRS (UMR 7244), 74 rue Marcel Cachin, F-93017 Bobigny, France
| | - Nadine Varin-Blank
- Université Paris 13, Sorbonne Paris Cité, Laboratoire ASIH, 74 rue Marcel Cachin, F-93017 Bobigny, France.,INSERM U978, Bobigny, France
| | - Marc Lamy de la Chapelle
- Université Paris 13, Sorbonne Paris Cité, Laboratoire CSPBAT, CNRS (UMR 7244), 74 rue Marcel Cachin, F-93017 Bobigny, France
| | - Christine Le Roy
- Université Paris 13, Sorbonne Paris Cité, Laboratoire ASIH, 74 rue Marcel Cachin, F-93017 Bobigny, France.,INSERM U978, Bobigny, France
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28
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Manno B, Oellerich T, Schnyder T, Corso J, Lösing M, Neumann K, Urlaub H, Batista FD, Engelke M, Wienands J. The Dok-3/Grb2 adaptor module promotes inducible association of the lipid phosphatase SHIP with the BCR in a coreceptor-independent manner. Eur J Immunol 2016; 46:2520-2530. [PMID: 27550373 DOI: 10.1002/eji.201646431] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/28/2016] [Accepted: 08/16/2016] [Indexed: 01/19/2023]
Abstract
The SH2 domain-containing inositol 5'-phosphatase (SHIP) plays a key role in preventing autoimmune phenomena by limiting antigen-mediated B cell activation. SHIP function is thought to require the dual engagement of the BCR and negative regulatory coreceptors as only the latter appear capable of recruiting SHIP from the cytosol to the plasma membrane by the virtue of phosphorylated immunoreceptor tyrosine-based inhibitory motifs. Here, we demonstrate a coreceptor-independent membrane recruitment and function of SHIP in B cells. In the absence of coreceptor ligation, SHIP translocates to sites of BCR activation through a concerted action of the protein adaptor unit Dok-3/Grb2 and phosphorylated BCR signaling components. Our data reveal auto-inhibitory SHIP activation by the activated BCR and suggest an unexpected negative-regulatory capacity of immunoreceptor tyrosine-based activation motifs in Igα and Igβ.
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Affiliation(s)
- Birgit Manno
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany
| | - Thomas Oellerich
- Department of Hematology and Oncology, Johann Wolfgang Goethe University of Frankfurt, Frankfurt, Germany
| | - Tim Schnyder
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute London, UK
| | - Jasmin Corso
- Bioanalytical Mass Spectrometry, Max Planck Institute of Biophysical Chemistry, Göttingen
| | - Marion Lösing
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany.,Vivo Science GmbH, Gronau, Germany
| | - Konstantin Neumann
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany.,Institute of Clinical Chemistry, Hannover Medical School, Hannover, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute of Biophysical Chemistry, Göttingen.,Bioanalytics Department of Clincal Chemistry, University Medical Center Goettingen, Göttingen, Germany
| | - Facundo D Batista
- Lincoln's Inn Fields Laboratory, The Francis Crick Institute London, UK
| | - Michael Engelke
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany
| | - Jürgen Wienands
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Göttingen, Germany.
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29
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Justa-Schuch D, Silva-Garcia M, Pilla E, Engelke M, Kilisch M, Lenz C, Möller U, Nakamura F, Urlaub H, Geiss-Friedlander R. DPP9 is a novel component of the N-end rule pathway targeting the tyrosine kinase Syk. eLife 2016; 5. [PMID: 27614019 PMCID: PMC5039030 DOI: 10.7554/elife.16370] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/07/2016] [Indexed: 12/12/2022] Open
Abstract
The aminopeptidase DPP9 removes dipeptides from N-termini of substrates having a proline or alanine in second position. Although linked to several pathways including cell survival and metabolism, the molecular mechanisms underlying these outcomes are poorly understood. We identified a novel interaction of DPP9 with Filamin A, which recruits DPP9 to Syk, a central kinase in B-cell signalling. Syk signalling can be terminated by degradation, requiring the ubiquitin E3 ligase Cbl. We show that DPP9 cleaves Syk to produce a neo N-terminus with serine in position 1. Pulse-chases combined with mutagenesis studies reveal that Ser1 strongly influences Syk stability. Furthermore, DPP9 silencing reduces Cbl interaction with Syk, suggesting that DPP9 processing is a prerequisite for Syk ubiquitination. Consistently, DPP9 inhibition stabilizes Syk, thereby modulating Syk signalling. Taken together, we demonstrate DPP9 as a negative regulator of Syk and conclude that DPP9 is a novel integral aminopeptidase of the N-end rule pathway.
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Affiliation(s)
- Daniela Justa-Schuch
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Maria Silva-Garcia
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Esther Pilla
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Michael Engelke
- Institute of Cellular and Molecular Immunology, University Medical Center Goettingen, Goettingen, Germany
| | - Markus Kilisch
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Christof Lenz
- Department of Bioanalytics, Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ulrike Möller
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
| | - Fumihiko Nakamura
- Hematology Division, Department of Medicine, Harvard Medical School, Boston, United States.,Brigham and Women's Hospital, Boston, United States
| | - Henning Urlaub
- Department of Bioanalytics, Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany.,Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ruth Geiss-Friedlander
- Department of Molecular Biology, University Medical Center Goettingen, Goettingen, Germany
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30
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Reppschläger K, Gosselin J, Dangelmaier CA, Thomas DH, Carpino N, McKenzie SE, Kunapuli SP, Tsygankov AY. TULA-2 Protein Phosphatase Suppresses Activation of Syk through the GPVI Platelet Receptor for Collagen by Dephosphorylating Tyr(P)346, a Regulatory Site of Syk. J Biol Chem 2016; 291:22427-22441. [PMID: 27609517 DOI: 10.1074/jbc.m116.743732] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/30/2016] [Indexed: 12/14/2022] Open
Abstract
Protein-tyrosine phosphatase TULA-2 has been shown to regulate receptor signaling in several cell types, including platelets. Platelets are critical for maintaining vascular integrity; this function is mediated by platelet aggregation in response to recognition of the exposed basement membrane collagen by the GPVI receptor, which is non-covalently associated with the signal-transducing FcRγ polypeptide chain. Our previous studies suggested that TULA-2 plays an important role in negatively regulating signaling through GPVI-FcRγ and indicated that the tyrosine-protein kinase Syk is a key target of the regulatory action of TULA-2 in platelets. However, the molecular basis of the down-regulatory effect of TULA-2 on Syk activation via FcRγ remained unclear. In this study, we demonstrate that suppression of Syk activation by TULA-2 is mediated, to a substantial degree, by dephosphorylation of Tyr(P)346, a regulatory site of Syk, which becomes phosphorylated soon after receptor ligation and plays a critical role in initiating the process that yields fully activated Syk. TULA-2 is capable of dephosphorylating Tyr(P)346 with high efficiency, thus controlling the overall activation of Syk, but is less efficient in dephosphorylating other regulatory sites of this kinase. Therefore, dephosphorylation of Tyr(P)346 may be considered an important "checkpoint" in the regulation of Syk activation process. Putative biological functions of TULA-2-mediated dephosphorylation of Tyr(P)346 may include deactivation of receptor-activated Syk or suppression of Syk activation by suboptimal stimulation.
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Affiliation(s)
- Kevin Reppschläger
- From the Departments of Microbiology and Immunology and.,Ernst-Moritz-Arndt-University Greifswald, 17489 Greifswald, Germany
| | - Jeanne Gosselin
- From the Departments of Microbiology and Immunology and.,Polytech Clermont-Ferrand, Ingenieur Genie Biologique, Clermont-Ferrand, Auvergne 63178, France, and
| | - Carol A Dangelmaier
- the Sol Sherry Thrombosis Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania 19140
| | - Dafydd H Thomas
- the Sol Sherry Thrombosis Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania 19140.,PMV Pharmaceuticals, Cranbury Township, New Jersey 08512
| | - Nick Carpino
- the Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794
| | - Steven E McKenzie
- the Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Satya P Kunapuli
- the Sol Sherry Thrombosis Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania 19140.,Physiology and
| | - Alexander Y Tsygankov
- From the Departments of Microbiology and Immunology and .,the Sol Sherry Thrombosis Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania 19140
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31
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Chen CH, Piraner D, Gorenstein NM, Geahlen RL, Beth Post C. Differential recognition of syk-binding sites by each of the two phosphotyrosine-binding pockets of the Vav SH2 domain. Biopolymers 2016; 99:897-907. [PMID: 23955592 DOI: 10.1002/bip.22371] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 07/26/2013] [Accepted: 08/06/2013] [Indexed: 01/01/2023]
Abstract
The association of spleen tyrosine kinase (Syk), a central tyrosine kinase in B cell signaling, with Vav SH2 domain is controlled by phosphorylation of two closely spaced tyrosines in Syk linker B: Y342 and Y346. Previous studies established both singly phosphorylated and doubly phosphorylated forms play a role in signaling. The structure of the doubly phosphorylated form identified a new recognition of phosphotyrosine whereby two phosphotyrosines bind simultaneously to the Vav SH2 domain, one in the canonical pTyr pocket and one in the specificity pocket on the opposite side of the central β-sheet. It is unknown if the specificity pocket can bind phosphotyrosine independent of phosphotyrosine binding the pTyr pocket. To address this gap in knowledge, we determined the structure of the complex between Vav1 SH2 and a peptide (SykLB-YpY) modeling the singly phosphorylated-Y346 form of Syk with unphosphorylated Y342. The nuclear magnetic resonance (NMR) data conclusively establish that recognition of phosphotyrosine is swapped between the two pockets; phosphorylated pY346 binds the specificity pocket of Vav1 SH2, and unphosphorylated Y342 occupies what is normally the pTyr binding pocket. Nearly identical changes in chemical shifts occurred upon binding all three forms of singly and doubly phosphorylated peptides; however, somewhat smaller shift perturbations for SykLB-YpY from residues in regions of high internal mobility suggest that internal motions are coupled to binding affinity. The differential recognition that includes this swapped binding of phosphotyrosine to the specificity pocket of Vav SH2 increases the repertoire of possible phosphotyrosine binding by SH2 domains in regulating protein-protein interactions in cellular signaling.
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Affiliation(s)
- Chih-Hong Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, and Purdue Center for Cancer Research, Purdue University, West Lafayette, IN, 47907
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32
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Xu Q, Malecka KL, Fink L, Jordan EJ, Duffy E, Kolander S, Peterson JR, Dunbrack RL. Identifying three-dimensional structures of autophosphorylation complexes in crystals of protein kinases. Sci Signal 2015; 8:rs13. [PMID: 26628682 DOI: 10.1126/scisignal.aaa6711] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Protein kinase autophosphorylation is a common regulatory mechanism in cell signaling pathways. Crystal structures of several homomeric protein kinase complexes have a serine, threonine, or tyrosine autophosphorylation site of one kinase monomer located in the active site of another monomer, a structural complex that we call an "autophosphorylation complex." We developed and applied a structural bioinformatics method to identify all such autophosphorylation complexes in x-ray crystallographic structures in the Protein Data Bank (PDB). We identified 15 autophosphorylation complexes in the PDB, of which five complexes had not previously been described in the publications describing the crystal structures. These five complexes consist of tyrosine residues in the N-terminal juxtamembrane regions of colony-stimulating factor 1 receptor (CSF1R, Tyr(561)) and ephrin receptor A2 (EPHA2, Tyr(594)), tyrosine residues in the activation loops of the SRC kinase family member LCK (Tyr(394)) and insulin-like growth factor 1 receptor (IGF1R, Tyr(1166)), and a serine in a nuclear localization signal region of CDC-like kinase 2 (CLK2, Ser(142)). Mutations in the complex interface may alter autophosphorylation activity and contribute to disease; therefore, we mutated residues in the autophosphorylation complex interface of LCK and found that two mutations impaired autophosphorylation (T445V and N446A) and mutation of Pro(447) to Ala, Gly, or Leu increased autophosphorylation. The identified autophosphorylation sites are conserved in many kinases, suggesting that, by homology, these complexes may provide insight into autophosphorylation complex interfaces of kinases that are relevant drug targets.
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Affiliation(s)
- Qifang Xu
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Kimberly L Malecka
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Lauren Fink
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - E Joseph Jordan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erin Duffy
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Samuel Kolander
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Jeffrey R Peterson
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Roland L Dunbrack
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
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Advances in Human Biology: Combining Genetics and Molecular Biophysics to Pave the Way for Personalized Diagnostics and Medicine. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/471836] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Advances in several biology-oriented initiatives such as genome sequencing and structural genomics, along with the progress made through traditional biological and biochemical research, have opened up a unique opportunity to better understand the molecular effects of human diseases. Human DNA can vary significantly from person to person and determines an individual’s physical characteristics and their susceptibility to diseases. Armed with an individual’s DNA sequence, researchers and physicians can check for defects known to be associated with certain diseases by utilizing various databases. However, for unclassified DNA mutations or in order to reveal molecular mechanism behind the effects, the mutations have to be mapped onto the corresponding networks and macromolecular structures and then analyzed to reveal their effect on the wild type properties of biological processes involved. Predicting the effect of DNA mutations on individual’s health is typically referred to as personalized or companion diagnostics. Furthermore, once the molecular mechanism of the mutations is revealed, the patient should be given drugs which are the most appropriate for the individual genome, referred to as pharmacogenomics. Altogether, the shift in focus in medicine towards more genomic-oriented practices is the foundation of personalized medicine. The progress made in these rapidly developing fields is outlined.
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Functional roles of Syk in macrophage-mediated inflammatory responses. Mediators Inflamm 2014; 2014:270302. [PMID: 25045209 PMCID: PMC4090447 DOI: 10.1155/2014/270302] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 05/27/2014] [Indexed: 01/09/2023] Open
Abstract
Inflammation is a series of complex biological responses to protect the host from pathogen invasion. Chronic inflammation is considered a major cause of diseases, such as various types of inflammatory/autoimmune diseases and cancers. Spleen tyrosine kinase (Syk) was initially found to be highly expressed in hematopoietic cells and has been known to play crucial roles in adaptive immune responses. However, recent studies have reported that Syk is also involved in other biological functions, especially in innate immune responses. Although Syk has been extensively studied in adaptive immune responses, numerous studies have recently presented evidence that Syk has critical functions in macrophage-mediated inflammatory responses and is closely related to innate immune response. This review describes the characteristics of Syk-mediated signaling pathways, summarizes the recent findings supporting the crucial roles of Syk in macrophage-mediated inflammatory responses and diseases, and discusses Syk-targeted drug development for the therapy of inflammatory diseases.
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Salonen J, Rönnholm G, Kalkkinen N, Vihinen M. Proteomic changes during B cell maturation: 2D-DIGE approach. PLoS One 2013; 8:e77894. [PMID: 24205016 PMCID: PMC3812168 DOI: 10.1371/journal.pone.0077894] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/06/2013] [Indexed: 11/18/2022] Open
Abstract
B cells play a pivotal role in adaptive immune system, since they maintain a delicate balance between recognition and clearance of foreign pathogens and tolerance to self. During maturation, B cells progress through a series of developmental stages defined by specific phenotypic surface markers and the rearrangement and expression of immunoglobulin (Ig) genes. To get insight into B cell proteome during the maturation pathway, we studied differential protein expression in eight human cell lines, which cover four distinctive developmental stages; early pre-B, pre-B, plasma cell and immature B cell upon anti-IgM stimulation. Our two-dimensional differential gel electrophoresis (2D-DIGE) and mass spectrometry based proteomic study indicates the involvement of large number of proteins with various functions. Notably, proteins related to cytoskeleton were relatively highly expressed in early pre-B and pre-B cells, whereas plasma cell proteome contained endoplasmic reticulum and Golgi system proteins. Our long time series analysis in anti-IgM stimulated Ramos B cells revealed the dynamic regulation of cytoskeleton organization, gene expression and metabolic pathways, among others. The findings are related to cellular processes in B cells and are discussed in relation to experimental information for the proteins and pathways they are involved in. Representative 2D-DIGE maps of different B cell maturation stages are available online at http://structure.bmc.lu.se/BcellProteome/.
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Affiliation(s)
- Johanna Salonen
- Institute of Biomedical Technology, University of Tampere, Tampere, Finland
- BioMediTech, Tampere, Finland
- Research Unit, Tampere University Hospital, Tampere, Finland
| | - Gunilla Rönnholm
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Nisse Kalkkinen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Mauno Vihinen
- Institute of Biomedical Technology, University of Tampere, Tampere, Finland
- BioMediTech, Tampere, Finland
- Research Unit, Tampere University Hospital, Tampere, Finland
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail:
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β2 integrin-derived signals induce cell survival and proliferation of AML blasts by activating a Syk/STAT signaling axis. Blood 2013; 121:3889-99, S1-66. [PMID: 23509157 DOI: 10.1182/blood-2012-09-457887] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Spleen tyrosine kinase (Syk) induces cell survival and proliferation in a high proportion of acute myeloid leukemia (AML) blasts, but the underlying molecular events of Syk signaling have not been investigated. Proteomic techniques have allowed us to identify the multiprotein complex that is nucleated by constitutively active Syk in AML cells. This complex differs from the B-lymphoid Syk interactome with respect to several proteins, especially the integrin receptor Mac-1, the Fc-γ receptor I (FcγRI), and the transcription factors STAT3 and STAT5. We show in several AML cell line models that tonic signals derived from the Fc-γ chain lead to Syk-dependent activation of STAT3 and STAT5, which in turn induces cell survival and proliferation. Moreover, stimulation of Mac-1 or FcγRI intensifies the constitutive Syk-mediated STAT3/5 activation in AML cells, a scenario likely to take place in the bone marrow niche. In accordance with these findings, we observed that β2 integrins, including Mac-1, trigger proliferation of AML cells in an AML cell/stroma coculture model. Taken together, we identified an oncogenic integrin/Syk/STAT3/5 signaling axis that might serve as a therapeutic target of AML in the future.
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Lösing M, Goldbeck I, Manno B, Oellerich T, Schnyder T, Bohnenberger H, Stork B, Urlaub H, Batista FD, Wienands J, Engelke M. The Dok-3/Grb2 protein signal module attenuates Lyn kinase-dependent activation of Syk kinase in B cell antigen receptor microclusters. J Biol Chem 2013; 288:2303-13. [PMID: 23223229 PMCID: PMC3554902 DOI: 10.1074/jbc.m112.406546] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/20/2012] [Indexed: 02/02/2023] Open
Abstract
Recruitment of the growth factor receptor-bound protein 2 (Grb2) by the plasma membrane-associated adapter protein downstream of kinase 3 (Dok-3) attenuates signals transduced by the B cell antigen receptor (BCR). Here we describe molecular details of Dok-3/Grb2 signal integration and function, showing that the Lyn-dependent activation of the BCR transducer kinase Syk is attenuated by Dok-3/Grb2 in a site-specific manner. This process is associated with the SH3 domain-dependent translocation of Dok-3/Grb2 complexes into BCR microsignalosomes and augmented phosphorylation of the inhibitory Lyn target SH2 domain-containing inositol 5' phosphatase. Hence, our findings imply that Dok-3/Grb2 modulates the balance between activatory and inhibitory Lyn functions with the aim to adjust BCR signaling efficiency.
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Affiliation(s)
- Marion Lösing
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Humboldtallee 34, 37073 Göttingen, Germany
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Grädler U, Schwarz D, Dresing V, Musil D, Bomke J, Frech M, Greiner H, Jäkel S, Rysiok T, Müller-Pompalla D, Wegener A. Structural and biophysical characterization of the Syk activation switch. J Mol Biol 2012; 425:309-33. [PMID: 23154170 DOI: 10.1016/j.jmb.2012.11.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/05/2012] [Accepted: 11/06/2012] [Indexed: 11/28/2022]
Abstract
Syk is an essential non-receptor tyrosine kinase in intracellular immunological signaling, and the control of Syk kinase function is considered as a valuable target for pharmacological intervention in autoimmune or inflammation diseases. Upon immune receptor stimulation, the kinase activity of Syk is regulated by binding of phosphorylated immune receptor tyrosine-based activating motifs (pITAMs) to the N-terminal tandem Src homology 2 (tSH2) domain and by autophosphorylation with consequences for the molecular structure of the Syk protein. Here, we present the first crystal structures of full-length Syk (fl-Syk) as wild type and as Y348F,Y352F mutant forms in complex with AMP-PNP revealing an autoinhibited conformation. The comparison with the crystal structure of the truncated Syk kinase domain in complex with AMP-PNP taken together with ligand binding studies by surface plasmon resonance (SPR) suggests conformational differences in the ATP sites of autoinhibited and activated Syk forms. This hypothesis was corroborated by studying the thermodynamic and kinetic interaction of three published Syk inhibitors with isothermal titration calorimetry and SPR, respectively. We further demonstrate the modulation of inhibitor binding affinities in the presence of pITAM and discuss the observed differences of thermodynamic and kinetic signatures. The functional relevance of pITAM binding to fl-Syk was confirmed by a strong stimulation of in vitro autophosphorylation. A structural feedback mechanism on the kinase domain upon pITAM binding to the tSH2 domain is discussed in analogy of the related family kinase ZAP-70 (Zeta-chain-associated protein kinase 70). Surprisingly, we observed distinct conformations of the tSH2 domain and the activation switch including Tyr348 and Tyr352 in the interdomain linker of Syk in comparison to ZAP-70.
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Affiliation(s)
- Ulrich Grädler
- Merck KGaA, Merck Serono Research, Small Molecule Platform/MIB, Frankfurter Str. 250, 64293 Darmstadt, Germany.
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