201
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Tanaka T, Zhou Y, Ozawa T, Okizono R, Banba A, Yamamura T, Oga E, Muraguchi A, Sakurai H. Ligand-activated epidermal growth factor receptor (EGFR) signaling governs endocytic trafficking of unliganded receptor monomers by non-canonical phosphorylation. J Biol Chem 2017; 293:2288-2301. [PMID: 29255092 DOI: 10.1074/jbc.m117.811299] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/15/2017] [Indexed: 01/16/2023] Open
Abstract
The canonical description of transmembrane receptor function is initial binding of ligand, followed by initiation of intracellular signaling and then internalization en route to degradation or recycling to the cell surface. It is known that low concentrations of extracellular ligand lead to a higher proportion of receptor that is recycled and that non-canonical mechanisms of receptor activation, including phosphorylation by the kinase p38, can induce internalization and recycling. However, no connections have been made between these pathways; i.e. it has yet to be established what happens to unbound receptors following stimulation with ligand. Here we demonstrate that a minimal level of activation of epidermal growth factor receptor (EGFR) tyrosine kinase by low levels of ligand is sufficient to fully activate downstream mitogen-activated protein kinase (MAPK) pathways, with most of the remaining unbound EGFR molecules being efficiently phosphorylated at intracellular serine/threonine residues by activated mitogen-activated protein kinase. This non-canonical, p38-mediated phosphorylation of the C-tail of EGFR, near Ser-1015, induces the clathrin-mediated endocytosis of the unliganded EGFR monomers, which occurs slightly later than the canonical endocytosis of ligand-bound EGFR dimers via tyrosine autophosphorylation. EGFR endocytosed via the non-canonical pathway is largely recycled back to the plasma membrane as functional receptors, whereas p38-independent populations are mainly sorted for lysosomal degradation. Moreover, ligand concentrations balance these endocytic trafficking pathways. These results demonstrate that ligand-activated EGFR signaling controls unliganded receptors through feedback phosphorylation, identifying a dual-mode regulation of the endocytic trafficking dynamics of EGFR.
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Affiliation(s)
| | - Yue Zhou
- From the Departments of Cancer Cell Biology and.,the MOE Key Laboratory for Standardization of Chinese Medicines and the Shanghai Key Laboratory of Compound Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Tatsuhiko Ozawa
- Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan and
| | | | - Ayako Banba
- From the Departments of Cancer Cell Biology and
| | | | - Eiji Oga
- From the Departments of Cancer Cell Biology and
| | - Atsushi Muraguchi
- Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan and
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202
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Coulter EM, Pepper A, Mele S, Folarin N, Townsend W, Cuthill K, Phillips EH, Patten PEM, Devereux S. In vitro and in vivo evidence for uncoupling of B-cell receptor internalization and signaling in chronic lymphocytic leukemia. Haematologica 2017; 103:497-505. [PMID: 29242301 PMCID: PMC5830387 DOI: 10.3324/haematol.2017.176164] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 12/12/2017] [Indexed: 12/24/2022] Open
Abstract
B-cell receptor activation, occurring within lymph nodes, plays a key role in the pathogenesis of chronic lymphocytic leukemia and is linked to prognosis. As well as activation of downstream signaling, receptor ligation triggers internalization, transit to acidified endosomes and degradation of ligand-receptor complexes. Herein, we investigated the relationship between these two processes in normal and leukemic B cells. We found that leukemic B cells, particularly anergic cases lacking the capacity to initiate downstream signaling, internalize and accumulate ligand in acidified endosomes more efficiently than normal B cells. Furthermore, ligation of either surface CD79B, a B-cell receptor component required for downstream signaling, or surface Immunoglobulin M (IgM) by cognate agonistic antibody, showed that the two molecules internalize independently of each other in leukemic but not normal B cells. Since association with surface CD79B is required for surface retention of IgM, this suggests that uncoupling of B-cell receptor internalization from signaling may be due to the dissociation of these two molecules in leukemic cells. A comparison of lymph node with peripheral blood cells from chronic lymphocytic leukemia patients showed that, despite recent B-cell receptor activation, lymph node B cells expressed higher levels of surface IgM. This surprising finding suggests that the B-cell receptors of lymph node- and peripheral blood-derived leukemic cells might be functionally distinct. Finally, long-term therapy with the Bruton’s tyrosine kinase inhibitors ibrutinib or acalabrutinib resulted in a switch to an anergic pattern of B-cell receptor function with reduced signaling capacity, surface IgM expression and more efficient internalization.
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Affiliation(s)
- Eve M Coulter
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London
| | - Andrea Pepper
- Brighton and Sussex Medical School, Medical research Building, University of Sussex, Brighton
| | - Silvia Mele
- St John's Institute of Dermatology, Department of Genetics and Molecular Medicine, King's College London
| | | | - William Townsend
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London
| | - Kirsty Cuthill
- Department of Haematological Medicine, Kings College Hospital, London, UK
| | - Elizabeth H Phillips
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London
| | - Piers E M Patten
- School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences and Medicine, King's College London.,Department of Haematological Medicine, Kings College Hospital, London, UK
| | - Stephen Devereux
- Department of Haematological Medicine, Kings College Hospital, London, UK
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203
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Dihydroartemisinin selectively inhibits PDGFRα-positive ovarian cancer growth and metastasis through inducing degradation of PDGFRα protein. Cell Discov 2017; 3:17042. [PMID: 29387451 PMCID: PMC5787695 DOI: 10.1038/celldisc.2017.42] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/22/2017] [Indexed: 02/06/2023] Open
Abstract
To develop traditional medicines as modern pharmacotherapies, understanding their molecular mechanisms of action can be very helpful. We have recently reported that Artemisinin and its derivatives, which are clinically used anti-malarial drugs, have significant effects against ovarian cancer, but the direct molecular targets and related combination therapy have been unclear. Herein, we report that dihydroartemisinin, one of the most active derivatives of Artemisinin, directly targets platelet-derived growth factor receptor-alpha (PDGFRα) to inhibit ovarian cancer cell growth and metastasis. Dihydroartemisinin directly binds to the intercellular domain of PDGFRα, reducing its protein stability by accelerating its ubiquitin-mediated degradation, which further inactivates downstream phosphoinositide 3-Kinase and mitogen-activated protein kinase pathways and subsequently represses epithelial–mesenchymal transition, inhibiting cell growth and metastasis of PDGFRα-positive ovarian cancer in vitro and in vivo. A combinational treatment reveals that dihydroartemisinin sensitizes ovarian cancer cells to PDGFR inhibitors. Our clinical study also finds that PDGFRα is overexpressed and positively correlated with high grade and metastasis in human ovarian cancer. Considering that Artemisinin compounds are currently clinically used drugs with favorable safety profiles, the results from this study will potentiate their use in combination with clinically used PDGFRα inhibitors, leading to maximal therapeutic efficacy with minimal adverse effects in PDGFRα-positive cancer patients. These findings also shed high light on future development of novel Artemisinin-based targeted therapy.
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204
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Aleksic T, Verrill C, Bryant RJ, Han C, Worrall AR, Brureau L, Larré S, Higgins GS, Fazal F, Sabbagh A, Haider S, Buffa FM, Cole D, Macaulay VM. IGF-1R associates with adverse outcomes after radical radiotherapy for prostate cancer. Br J Cancer 2017; 117:1600-1606. [PMID: 28972962 PMCID: PMC5729437 DOI: 10.1038/bjc.2017.337] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 07/20/2017] [Accepted: 08/30/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Activated type 1 insulin-like growth factor receptors (IGF-1Rs) undergo internalisation and nuclear translocation, promoting cell survival. We previously reported that IGF-1R inhibition delays DNA damage repair, sensitising prostate cancer cells to ionising radiation. Here we tested the clinical relevance of these findings. METHODS We assessed associations between IGF-1R and clinical outcomes by immunohistochemistry in diagnostic biopsies of 136 men treated with 55-70 Gy external beam radiotherapy for prostate cancer, comparing results with publicly available transcriptional data in surgically treated patients. RESULTS Following radiotherapy, overall recurrence-free survival was shorter in patients whose tumours contained high total, cytoplasmic and internalised (nuclear/cytoplasmic) IGF-1R. High total IGF-1R associated with high primary Gleason grade and risk of metastasis, and cytoplasmic and internalised IGF-1R with biochemical recurrence, which includes patients experiencing local recurrence within the radiation field indicating radioresistance. In multivariate analysis, cytoplasmic, internalised and total IGF-1R were independently associated with risk of overall recurrence, and cytoplasmic IGF-1R was an independent predictor of biochemical recurrence post radiotherapy. Insulin-like growth factor receptors expression did not associate with biochemical recurrence after radical prostatectomy. CONCLUSIONS These data reveal increased risk of post-radiotherapy recurrence in men whose prostate cancers contain high levels of total or cytoplasmic IGF-1R.
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Affiliation(s)
- Tamara Aleksic
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Clare Verrill
- Department of Cellular Pathology, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Oxford OX3 9DU UK
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Richard J Bryant
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Cheng Han
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
- Oxford Cancer and Haematology Centre, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Andrew Ross Worrall
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Laurent Brureau
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Stephane Larré
- Nuffield Department of Surgical Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Geoff S Higgins
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
- Oxford Cancer and Haematology Centre, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Fahad Fazal
- Oxford Cancer and Haematology Centre, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Ahmad Sabbagh
- Oxford Cancer and Haematology Centre, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Syed Haider
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Francesca M Buffa
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - David Cole
- Oxford Cancer and Haematology Centre, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital, Oxford OX3 7LJ, UK
| | - Valentine M Macaulay
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
- Oxford Cancer and Haematology Centre, Oxford University Hospitals NHS Foundation Trust, Churchill Hospital, Oxford OX3 7LJ, UK
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205
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Takahara M, Wakabayashi R, Minamihata K, Goto M, Kamiya N. Primary Amine-Clustered DNA Aptamer for DNA-Protein Conjugation Catalyzed by Microbial Transglutaminase. Bioconjug Chem 2017; 28:2954-2961. [PMID: 29131594 DOI: 10.1021/acs.bioconjchem.7b00594] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
DNA-protein conjugates are promising biomolecules for use in areas ranging from therapeutics to analysis because of the dual functionalities of DNA and protein. Conjugation requires site-specific and efficient covalent bond formation without impairing the activity of both biomolecules. Herein, we have focused on the use of a microbial transglutaminase (MTG) that catalyzes the cross-linking reaction between a glutamine residue and a primary amine. In a model bioconjugation, a highly MTG-reactive Gln (Q)-donor peptide (FYPLQMRG, FQ) was fused to enhanced green fluorescent protein (FQ-EGFP) and a primary amine-clustered DNA aptamer was enzymatically synthesized as a novel acyl-acceptor substrate of MTG, whose combination leads to efficient and convenient preparation of DNA-protein conjugates with high purity. Dual functionality of the obtained DNA-EGFP conjugate was evaluated by discrimination of cancer cells via c-Met receptor recognition ability of the DNA aptamer. The DNA aptamer-EGFP conjugate only showed fluorescence toward cells with c-Met overexpression, indicating the retention of the biochemical properties of the DNA and EGFP in the conjugated form.
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Affiliation(s)
- Mari Takahara
- Department of Applied Chemistry, Graduate School of Engineering and ‡Division of Biotechnology, Center for Future Chemistry, Kyushu University , 744 Motooka, Fukuoka 819-0395, Japan
| | - Rie Wakabayashi
- Department of Applied Chemistry, Graduate School of Engineering and ‡Division of Biotechnology, Center for Future Chemistry, Kyushu University , 744 Motooka, Fukuoka 819-0395, Japan
| | - Kosuke Minamihata
- Department of Applied Chemistry, Graduate School of Engineering and ‡Division of Biotechnology, Center for Future Chemistry, Kyushu University , 744 Motooka, Fukuoka 819-0395, Japan
| | - Masahiro Goto
- Department of Applied Chemistry, Graduate School of Engineering and ‡Division of Biotechnology, Center for Future Chemistry, Kyushu University , 744 Motooka, Fukuoka 819-0395, Japan
| | - Noriho Kamiya
- Department of Applied Chemistry, Graduate School of Engineering and ‡Division of Biotechnology, Center for Future Chemistry, Kyushu University , 744 Motooka, Fukuoka 819-0395, Japan
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206
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Neben CL, Lo M, Jura N, Klein OD. Feedback regulation of RTK signaling in development. Dev Biol 2017; 447:71-89. [PMID: 29079424 DOI: 10.1016/j.ydbio.2017.10.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/17/2017] [Accepted: 10/23/2017] [Indexed: 02/07/2023]
Abstract
Precise regulation of the amplitude and duration of receptor tyrosine kinase (RTK) signaling is critical for the execution of cellular programs and behaviors. Understanding these control mechanisms has important implications for the field of developmental biology, and in recent years, the question of how augmentation or attenuation of RTK signaling via feedback loops modulates development has become of increasing interest. RTK feedback regulation is also important for human disease research; for example, germline mutations in genes that encode RTK signaling pathway components cause numerous human congenital syndromes, and somatic alterations contribute to the pathogenesis of diseases such as cancers. In this review, we survey regulators of RTK signaling that tune receptor activity and intracellular transduction cascades, with a focus on the roles of these genes in the developing embryo. We detail the diverse inhibitory mechanisms utilized by negative feedback regulators that, when lost or perturbed, lead to aberrant increases in RTK signaling. We also discuss recent biochemical and genetic insights into positive regulators of RTK signaling and how these proteins function in tandem with negative regulators to guide embryonic development.
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Affiliation(s)
- Cynthia L Neben
- Department of Orofacial Sciences and Program in Craniofacial Biology, University of California, San Francisco, San Francisco 94143, USA
| | - Megan Lo
- Department of Orofacial Sciences and Program in Craniofacial Biology, University of California, San Francisco, San Francisco 94143, USA; Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Natalia Jura
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
| | - Ophir D Klein
- Department of Orofacial Sciences and Program in Craniofacial Biology, University of California, San Francisco, San Francisco 94143, USA; Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, San Francisco 94143, USA.
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207
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TIE2 Associates with Caveolae and Regulates Caveolin-1 To Promote Their Nuclear Translocation. Mol Cell Biol 2017; 37:MCB.00142-17. [PMID: 28760776 DOI: 10.1128/mcb.00142-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/21/2017] [Indexed: 01/20/2023] Open
Abstract
DNA repair pathways are aberrant in cancer, enabling tumor cells to survive standard therapies-chemotherapy and radiotherapy. Our group previously reported that, upon irradiation, the membrane-bound tyrosine kinase receptor TIE2 translocates into the nucleus and phosphorylates histone H4 at Tyr51, recruiting ABL1 to the DNA repair complexes that participate in the nonhomologous end-joining pathway. However, no specific molecular mechanisms of TIE2 endocytosis have been reported. Here, we show that irradiation or ligand-induced TIE2 trafficking is dependent on caveolin-1, the main component of caveolae. Subcellular fractionation and confocal microscopy demonstrated TIE2/caveolin-1 complexes in the nucleus, and using inhibitor or small interfering RNAs (siRNAs) against caveolin-1 or Tie2 inhibited their trafficking. TIE2 was found in caveolae and directly phosphorylated caveolin-1 at Tyr14 in vitro and in vivo This modification regulated the generation of TIE2/caveolin-1 complexes and was essential for TIE2/caveolin-1 nuclear translocation. Our data further demonstrate that the combination of TIE2 and caveolin-1 inhibitors resulted in significant radiosensitization of malignant glioma cells, which will guide the development of combinatorial treatment with radiotherapy for patients with glioblastoma.
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208
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Zhou XX, Fan LZ, Li P, Shen K, Lin MZ. Optical control of cell signaling by single-chain photoswitchable kinases. Science 2017; 355:836-842. [PMID: 28232577 DOI: 10.1126/science.aah3605] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 11/15/2016] [Accepted: 01/23/2017] [Indexed: 12/31/2022]
Abstract
Protein kinases transduce signals to regulate a wide array of cellular functions in eukaryotes. A generalizable method for optical control of kinases would enable fine spatiotemporal interrogation or manipulation of these various functions. We report the design and application of single-chain cofactor-free kinases with photoswitchable activity. We engineered a dimeric protein, pdDronpa, that dissociates in cyan light and reassociates in violet light. Attaching two pdDronpa domains at rationally selected locations in the kinase domain, we created the photoswitchable kinases psRaf1, psMEK1, psMEK2, and psCDK5. Using these photoswitchable kinases, we established an all-optical cell-based assay for screening inhibitors, uncovered a direct and rapid inhibitory feedback loop from ERK to MEK1, and mediated developmental changes and synaptic vesicle transport in vivo using light.
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Affiliation(s)
- Xin X Zhou
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Linlin Z Fan
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Pengpeng Li
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA, USA
| | - Kang Shen
- Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford, CA, USA
| | - Michael Z Lin
- Department of Bioengineering, Stanford University, Stanford, CA, USA. .,Department of Neurobiology, Stanford University, Stanford, CA, USA
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209
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Ranches G, Lukasser M, Schramek H, Ploner A, Stasyk T, Mayer G, Mayer G, Hüttenhofer A. In Vitro Selection of Cell-Internalizing DNA Aptamers in a Model System of Inflammatory Kidney Disease. MOLECULAR THERAPY. NUCLEIC ACIDS 2017; 8:198-210. [PMID: 28918021 PMCID: PMC5504087 DOI: 10.1016/j.omtn.2017.06.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/22/2017] [Accepted: 06/22/2017] [Indexed: 12/29/2022]
Abstract
Chronic kidney disease (CKD) is a progressive pathological condition marked by a gradual loss of kidney function. Treatment of CKD is most effective when diagnosed at an early stage and patients are still asymptomatic. However, current diagnostic biomarkers (e.g., serum creatinine and urine albumin) are insufficient for prediction of the pathogenesis of the disease. To address this need, we applied a cell-SELEX (systematic evolution of ligands by exponential enrichment) approach and identified a series of DNA aptamers, which exhibit high affinity and selectivity for cytokine-stimulated cells, resembling some aspects of a CKD phenotype. The cell-SELEX approach was driven toward the enrichment of aptamers that internalize via the endosomal pathway by isolating the endosomal fractions in each selection cycle. Indeed, we demonstrated co-localization of selected aptamers with lysosomal-associated membrane protein 1 (LAMP-1), a late endosomal and lysosomal marker protein, by fluorescence in situ hybridization. These findings are consistent with binding and subsequent internalization of the aptamers into cytokine-stimulated cells. Thus, our study sets the stage for applying selected DNA aptamers as theragnostic reagents for the development of targeted therapies to combat CKD.
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Affiliation(s)
- Glory Ranches
- Division of Genomics and RNomics, Biocenter, Medical University Innsbruck, Innsbruck 6020, Austria; Division of Medical Biochemistry, Biocenter, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Melanie Lukasser
- Division of Genomics and RNomics, Biocenter, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Herbert Schramek
- Division of Nephrology and Hypertension, Department of Internal Medicine IV, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Andreas Ploner
- Division of Genomics and RNomics, Biocenter, Medical University Innsbruck, Innsbruck 6020, Austria; Sandoz GmbH, Biochemiestrasse 10, Kundl 6250, Austria
| | - Taras Stasyk
- Division of Cell Biology, Biocenter, Medical University Innsbruck, Innsbruck 6020, Austria
| | - Gert Mayer
- Division of Nephrology and Hypertension, Department of Internal Medicine IV, Medical University Innsbruck, Innsbruck 6020, Austria.
| | - Günter Mayer
- Life and Medical Sciences Institute, Chemical Biology and Chemical Genetics, University of Bonn, Bonn 53115, Germany; Centre of Aptamer Research and Development, University of Bonn, Bonn 53115, Germany
| | - Alexander Hüttenhofer
- Division of Genomics and RNomics, Biocenter, Medical University Innsbruck, Innsbruck 6020, Austria.
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210
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Pilling C, Cooper JA. SOCS2 Binds to and Regulates EphA2 through Multiple Mechanisms. Sci Rep 2017; 7:10838. [PMID: 28883622 PMCID: PMC5589800 DOI: 10.1038/s41598-017-11040-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 08/15/2017] [Indexed: 02/08/2023] Open
Abstract
Suppressors of cytokine signaling (SOCS) proteins inhibit signaling by serving as substrate receptors for the Cullin5-RING E3 ubiquitin ligase (CRL5) and through a variety of CRL5-independent mechanisms. CRL5, SOCS2 and SOCS6 are implicated in suppressing transformation of epithelial cells. We identified cell proteins that interact with SOCS2 and SOCS6 using two parallel proteomics techniques: BioID and Flag affinity purification mass spectrometry. The receptor tyrosine kinase ephrin type-A receptor 2 (EphA2) was identified as a SOCS2-interacting protein. SOCS2-EphA2 binding requires the SOCS2 SH2 domain and EphA2 activation loop autophosphorylation, which is stimulated by Ephrin A1 (EfnA1) or by phosphotyrosine phosphatase inhibition. Surprisingly, EfnA1-stimulated EphA2-SOCS2 binding is delayed until EphA2 has been internalized into endosomes. This suggests that SOCS2 binds to EphA2 in the context of endosomal membranes. We also found that SOCS2 overexpression decreases steady state levels of EphA2, consistent with increased EphA2 degradation. This effect is indirect: SOCS2 induces EfnA1 expression, and EfnA1 induces EphA2 down-regulation. Other RTKs have been reported to bind, and be regulated by, over-expressed SOCS proteins. Our data suggest that SOCS protein over-expression may regulate receptor tyrosine kinases through indirect and direct mechanisms.
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Affiliation(s)
- Carissa Pilling
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, Washington, 98109, USA.,Molecular and Cellular Biology Program, 1959 NE Pacific Street, HSB T-466, University of Washington, Box 357275, Seattle, WA, 98195-7275, USA
| | - Jonathan A Cooper
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, Washington, 98109, USA.
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211
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Assay to visualize specific protein oxidation reveals spatio-temporal regulation of SHP2. Nat Commun 2017; 8:466. [PMID: 28878211 PMCID: PMC5587708 DOI: 10.1038/s41467-017-00503-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/29/2017] [Indexed: 12/21/2022] Open
Abstract
Reactive oxygen species are produced transiently in response to cell stimuli, and function as second messengers that oxidize target proteins. Protein-tyrosine phosphatases are important reactive oxygen species targets, whose oxidation results in rapid, reversible, catalytic inactivation. Despite increasing evidence for the importance of protein-tyrosine phosphatase oxidation in signal transduction, the cell biological details of reactive oxygen species-catalyzed protein-tyrosine phosphatase inactivation have remained largely unclear, due to our inability to visualize protein-tyrosine phosphatase oxidation in cells. By combining proximity ligation assay with chemical labeling of cysteine residues in the sulfenic acid state, we visualize oxidized Src homology 2 domain-containing protein-tyrosine phosphatase 2 (SHP2). We find that platelet-derived growth factor evokes transient oxidation on or close to RAB5+/ early endosome antigen 1− endosomes. SHP2 oxidation requires NADPH oxidases (NOXs), and oxidized SHP2 co-localizes with platelet-derived growth factor receptor and NOX1/4. Our data demonstrate spatially and temporally limited protein oxidation within cells, and suggest that platelet-derived growth factor-dependent “redoxosomes,” contribute to proper signal transduction. Protein-tyrosine phosphatases (PTPs) are thought to be major targets of receptor-activated reactive oxygen species (ROS). Here the authors describe a method that allows the localized visualization of oxidized intermediates of PTPs inside cells during signaling, and provide support for the “redoxosome” model.
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212
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Conformational transitions and interactions underlying the function of membrane embedded receptor protein kinases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1417-1429. [DOI: 10.1016/j.bbamem.2017.01.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/08/2023]
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213
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Cell surface dynamics and cellular distribution of endogenous FcRn. PLoS One 2017; 12:e0182695. [PMID: 28817705 PMCID: PMC5560688 DOI: 10.1371/journal.pone.0182695] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/21/2017] [Indexed: 12/30/2022] Open
Abstract
A major role for FcRn is the salvage of pinocytosed IgG and albumin from a degradative fate in lysosomes. FcRn achieves this by binding IgG in a pH-dependent manner in acidic endosomes and recycling it to the plasma membrane to be released at neutral pH. This is important in maintaining high serum IgG and albumin levels and has the potential to be exploited to modulate the pharmacokinetics of antibody-based therapeutics. Although FcRn is responsible for the recycling of IgG, the dynamic behaviour of endogenous FcRn is not well understood. Our data shows that the majority of endogenous receptor is distributed throughout the endosomal system and is present only at a low percentage on the plasma membrane at steady state. A significant fraction of FcRn at the cell surface appears to be endocytosis resistant while the remainder can undergo rapid endocytosis. To maintain surface levels of the receptor, endocytosed FcRn is replaced with FcRn from the internal pool. This unexpected complexity in FcRn cell surface dynamics has led us to propose a model for FcRn trafficking that should be taken into account when targeting FcRn at the cell surface for therapeutic purposes.
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214
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Delos Santos RC, Bautista S, Lucarelli S, Bone LN, Dayam RM, Abousawan J, Botelho RJ, Antonescu CN. Selective regulation of clathrin-mediated epidermal growth factor receptor signaling and endocytosis by phospholipase C and calcium. Mol Biol Cell 2017; 28:2802-2818. [PMID: 28814502 PMCID: PMC5638584 DOI: 10.1091/mbc.e16-12-0871] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 07/10/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022] Open
Abstract
Clathrin-mediated endocytosis is a major regulator of cell-surface protein internalization. Clathrin and other proteins assemble into small invaginating structures at the plasma membrane termed clathrin-coated pits (CCPs) that mediate vesicle formation. In addition, epidermal growth factor receptor (EGFR) signaling is regulated by its accumulation within CCPs. Given the diversity of proteins regulated by clathrin-mediated endocytosis, how this process may distinctly regulate specific receptors is a key question. We examined the selective regulation of clathrin-dependent EGFR signaling and endocytosis. We find that perturbations of phospholipase Cγ1 (PLCγ1), Ca2+, or protein kinase C (PKC) impair clathrin-mediated endocytosis of EGFR, the formation of CCPs harboring EGFR, and EGFR signaling. Each of these manipulations was without effect on the clathrin-mediated endocytosis of transferrin receptor (TfR). EGFR and TfR were recruited to largely distinct clathrin structures. In addition to control of initiation and assembly of CCPs, EGF stimulation also elicited a Ca2+- and PKC-dependent reduction in synaptojanin1 recruitment to clathrin structures, indicating broad control of CCP assembly by Ca2+ signals. Hence EGFR elicits PLCγ1-calcium signals to facilitate formation of a subset of CCPs, thus modulating its own signaling and endocytosis. This provides evidence for the versatility of CCPs to control diverse cellular processes.
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Affiliation(s)
- Ralph Christian Delos Santos
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Stephen Bautista
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Stefanie Lucarelli
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Leslie N Bone
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Roya M Dayam
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - John Abousawan
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada
| | - Costin N Antonescu
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, ON M5B 2K3, Canada .,Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, ON M5B 1W8, Canada
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215
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Opaliński Ł, Sokołowska-Wędzina A, Szczepara M, Zakrzewska M, Otlewski J. Antibody-induced dimerization of FGFR1 promotes receptor endocytosis independently of its kinase activity. Sci Rep 2017; 7:7121. [PMID: 28769084 PMCID: PMC5540934 DOI: 10.1038/s41598-017-07479-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 06/27/2017] [Indexed: 12/22/2022] Open
Abstract
Fibroblast growth factors (FGFs) and their plasma membrane-localized receptors (FGFRs) play a key role in the regulation of developmental processes and metabolism. Aberrant FGFR signaling is associated with the progression of serious metabolic diseases and human cancer. Binding of FGFs to FGFRs induces receptor dimerization and transphosphorylation of FGFR kinase domains that triggers activation of intracellular signaling pathways. Following activation, FGFRs undergo internalization and subsequent lysosomal degradation, which terminates transmission of signals. Although factors that regulate FGFR endocytosis are continuously discovered, little is known about the molecular mechanism that initiates the internalization of FGFRs. Here, we analyzed the internalization of antibody fragments in various formats that target FGFR1. We show that FGFR1-specific antibody fragments in the monovalent scFv format bind to FGFR1, but are not internalized into cells that overproduce FGFR1. In contrast, the same scFv proteins in the bivalent scFv-Fc format are efficiently internalized via FGFR1-mediated, clathrin and dynamin dependent endocytosis. Interestingly, the receptor tyrosine kinase activity is dispensable for endocytosis of scFv-Fc-FGFR1 complexes, suggesting that only dimerization of receptor is required to trigger endocytosis of FGFR1 complexes.
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Affiliation(s)
- Łukasz Opaliński
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland.
| | - Aleksandra Sokołowska-Wędzina
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Martyna Szczepara
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Małgorzata Zakrzewska
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Jacek Otlewski
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland.
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216
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Pridgeon MG, Grohar PJ, Steensma MR, Williams BO. Wnt Signaling in Ewing Sarcoma, Osteosarcoma, and Malignant Peripheral Nerve Sheath Tumors. Curr Osteoporos Rep 2017. [PMID: 28647886 DOI: 10.1007/s11914-017-0377-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW Wnt signaling plays a central role in development and homeostasis, and its dysregulation is a common event in many types of human cancer. Here we explore in detail the contributions of Wnt signaling to the initiation and maintenance of three types of saroma: Ewing sarcoma, osteosarcoma, and malignant peripheral nerve sheath tumors. This review provides an overview of the Wnt signaling pathway and explores in detail the current knowledge about its role in the initiation or maintenance of three tumor types: Ewing sarcoma, osteosarcoma, and malignant peripheral nerve sheath tumors. RECENT FINDINGS Recent work has assessed the role(s) of Wnt signaling within these cell types. This review provides an overview of the mechanistic insights that have been gained from a number of recent studies to set the foundation for potential therapeutic applications. Wnt signaling has emerged as a potentially critical pathway in maintaining the growth of these types of tumors. Given the fact that many new inhibitors of the pathway have recently or will soon enter Phase 1 clinical trials, it is likely that assessment of their activity in these tumor types will occur in human patients.
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Affiliation(s)
- Matthew G Pridgeon
- Grand Rapids Medical Education Partners, Grand Rapids, MI, USA
- Spectrum Health Cancer Center, Spectrum Health System, Grand Rapids, MI, USA
- Helen De Vos Children's Hospital, Grand Rapids, MI, USA
| | - Patrick J Grohar
- Spectrum Health Cancer Center, Spectrum Health System, Grand Rapids, MI, USA
- Helen De Vos Children's Hospital, Grand Rapids, MI, USA
- Department of Pediatrics, Michigan State University, Grand Rapids, MI, USA
- Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, MI, USA
| | - Matthew R Steensma
- Spectrum Health Cancer Center, Spectrum Health System, Grand Rapids, MI, USA
- Helen De Vos Children's Hospital, Grand Rapids, MI, USA
- Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, MI, USA
- Department of Surgery, Michigan State University College of Human Medicine, Grand Rapids, MI, USA
| | - Bart O Williams
- Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, MI, USA.
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217
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Transcriptional mechanisms that control expression of the macrophage colony-stimulating factor receptor locus. Clin Sci (Lond) 2017; 131:2161-2182. [DOI: 10.1042/cs20170238] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/22/2017] [Accepted: 06/11/2017] [Indexed: 12/17/2022]
Abstract
The proliferation, differentiation, and survival of cells of the macrophage lineage depends upon signals from the macrophage colony-stimulating factor (CSF) receptor (CSF1R). CSF1R is expressed by embryonic macrophages and induced early in adult hematopoiesis, upon commitment of multipotent progenitors to the myeloid lineage. Transcriptional activation of CSF1R requires interaction between members of the E26 transformation-specific family of transcription factors (Ets) (notably PU.1), C/EBP, RUNX, AP-1/ATF, interferon regulatory factor (IRF), STAT, KLF, REL, FUS/TLS (fused in sarcoma/ranslocated in liposarcoma) families, and conserved regulatory elements within the mouse and human CSF1R locus. One element, the Fms-intronic regulatory element (FIRE), within intron 2, is conserved functionally across all the amniotes. Lineage commitment in multipotent progenitors also requires down-regulation of specific transcription factors such as MYB, FLI1, basic leucine zipper transcriptional factor ATF-like (BATF3), GATA-1, and PAX5 that contribute to differentiation of alternative lineages and repress CSF1R transcription. Many of these transcription factors regulate each other, interact at the protein level, and are themselves downstream targets of CSF1R signaling. Control of CSF1R transcription involves feed–forward and feedback signaling in which CSF1R is both a target and a participant; and dysregulation of CSF1R expression and/or function is associated with numerous pathological conditions. In this review, we describe the regulatory network behind CSF1R expression during differentiation and development of cells of the mononuclear phagocyte system.
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218
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Wills MKB, Lau HR, Jones N. The ShcD phosphotyrosine adaptor subverts canonical EGF receptor trafficking. J Cell Sci 2017; 130:2808-2820. [PMID: 28724758 DOI: 10.1242/jcs.198903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 07/09/2017] [Indexed: 12/15/2022] Open
Abstract
Shc family signalling adaptors connect activated transmembrane receptors to proximal effectors, and most also contain a sequence involved in clathrin-mediated receptor endocytosis. Notably, this AP2 adaptin-binding motif (AD) is absent from the ShcD (also known as Shc4) homolog, which also uniquely promotes ligand-independent phosphorylation of the epidermal growth factor receptor (EGFR). We now report that cultured cells expressing ShcD exhibit reduced EGF uptake, commensurate with a decrease in EGFR surface presentation. Under basal conditions, ShcD colocalises with the EGFR and facilitates its phosphorylation, ubiquitylation and accumulation in juxtanuclear vesicles identified as Rab11-positive endocytic recycling compartments. Accordingly, ShcD also functions as a constitutive binding partner for the E3 ubiquitin ligase Cbl. EGFR phosphorylation and focal accumulation likewise occur upon ShcD co-expression in U87 glioma cells. Loss of ShcD phosphotyrosine-binding function or insertion of the ShcA AD sequence each restore ligand acquisition through distinct mechanisms. The AD region also contains a nuclear export signal, indicating its multifunctionality. Overall, ShcD appears to possess several molecular permutations that actively govern the EGFR, which may have implications in development and disease.
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Affiliation(s)
- Melanie K B Wills
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Hayley R Lau
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Nina Jones
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
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219
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Internalized CD44s splice isoform attenuates EGFR degradation by targeting Rab7A. Proc Natl Acad Sci U S A 2017; 114:8366-8371. [PMID: 28716909 DOI: 10.1073/pnas.1701289114] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
CD44 has been postulated as a cell surface coreceptor for augmenting receptor tyrosine kinase (RTK) signaling. However, how exactly CD44 triggers RTK-dependent signaling remained largely unclear. Here we report an unexpected mechanism by which the CD44s splice isoform is internalized into endosomes to attenuate EGFR degradation. We identify a CD44s-interacting small GTPase, Rab7A, and show that CD44s inhibits Rab7A-mediated EGFR trafficking to lysosomes and subsequent degradation. Importantly, CD44s levels correlate with EGFR signature and predict poor prognosis in glioblastomas. Because Rab7A facilitates trafficking of many RTKs to lysosomes, our findings identify CD44s as a Rab7A regulator to attenuate RTK degradation.
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220
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Erwig J, Ghareeb H, Kopischke M, Hacke R, Matei A, Petutschnig E, Lipka V. Chitin-induced and CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) phosphorylation-dependent endocytosis of Arabidopsis thaliana LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5 (LYK5). THE NEW PHYTOLOGIST 2017; 215:382-396. [PMID: 28513921 DOI: 10.1111/nph.14592] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/23/2017] [Indexed: 05/21/2023]
Abstract
To detect potential pathogens, plants perceive the fungal polysaccharide chitin through receptor complexes containing lysin motif receptor-like kinases (LysM-RLKs). To investigate the ligand-induced spatial dynamics of chitin receptor components, we studied the subcellular behaviour of two Arabidopsis thaliana LysM-RLKs involved in chitin signalling, CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) and LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5. We performed standard and quantitative confocal laser scanning microscopy on stably transformed A. thaliana plants expressing fluorescently tagged CERK1 and LYK5 from their native promoters. Microscopy approaches were complemented by biochemical analyses in plants and in vitro. Both CERK1 and LYK5 localized to the plasma membrane and showed constitutive endomembrane trafficking. After chitin treatment, however, CERK1 remained at the plasma membrane while LYK5 relocalized into mobile intracellular vesicles. Detailed analyses revealed that chitin perception transiently induced the internalization of LYK5 into late endocytic compartments. Plants that lacked CERK1 or expressed an enzymatically inactive CERK1 variant did not exhibit chitin-induced endocytosis of LYK5. CERK1 could phosphorylate LYK5 in vitro and chitin treatment induced CERK1-dependent phosphorylation of LYK5 in planta. Our results suggest that chitin-induced phosphorylation by CERK1 triggers LYK5 internalization. Thus, our work identifies phosphorylation as a key regulatory step in endocytosis of plant RLKs and also provides evidence for receptor complex dissociation after ligand perception.
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Affiliation(s)
- Jan Erwig
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Hassan Ghareeb
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
- Department of Plant Biotechnology, National Research Centre, El Buhouth St, Dokki, Cairo, Egypt
| | - Michaela Kopischke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Ronja Hacke
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Alexandra Matei
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Elena Petutschnig
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
| | - Volker Lipka
- Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
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221
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Lobocki M, Zakrzewska M, Szlachcic A, Krzyscik MA, Sokolowska-Wedzina A, Otlewski J. High-Yield Site-Specific Conjugation of Fibroblast Growth Factor 1 with Monomethylauristatin E via Cysteine Flanked by Basic Residues. Bioconjug Chem 2017; 28:1850-1858. [DOI: 10.1021/acs.bioconjchem.7b00158] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Michal Lobocki
- Department of Protein
Engineering,
Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14A, 50-383 Wroclaw, Poland
| | - Malgorzata Zakrzewska
- Department of Protein
Engineering,
Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14A, 50-383 Wroclaw, Poland
| | - Anna Szlachcic
- Department of Protein
Engineering,
Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14A, 50-383 Wroclaw, Poland
| | - Mateusz A. Krzyscik
- Department of Protein
Engineering,
Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14A, 50-383 Wroclaw, Poland
| | - Aleksandra Sokolowska-Wedzina
- Department of Protein
Engineering,
Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14A, 50-383 Wroclaw, Poland
| | - Jacek Otlewski
- Department of Protein
Engineering,
Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14A, 50-383 Wroclaw, Poland
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222
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Li J, Barylko B, Eichorst JP, Mueller JD, Albanesi JP, Chen Y. Association of Endophilin B1 with Cytoplasmic Vesicles. Biophys J 2017; 111:565-576. [PMID: 27508440 DOI: 10.1016/j.bpj.2016.06.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 01/21/2023] Open
Abstract
Endophilins are SH3- and BAR domain-containing proteins implicated in membrane remodeling and vesicle formation. Endophilins A1 and A2 promote the budding of endocytic vesicles from the plasma membrane, whereas endophilin B1 has been implicated in vesicle budding from intracellular organelles, including the trans-Golgi network and late endosomes. We previously reported that endophilins A1 and A2 exist almost exclusively as soluble dimers in the cytosol. Here, we present results of fluorescence fluctuation spectroscopy analyses indicating that, in contrast, the majority of endophilin B1 is present in multiple copies on small, highly mobile cytoplasmic vesicles. Formation of these vesicles was enhanced by overexpression of wild-type dynamin 2, but suppressed by expression of a catalytically inactive dynamin 2 mutant. Using dual-color heterospecies partition analysis, we identified the epidermal growth factor receptor on endophilin B1 vesicles. Moreover, a proportion of endophilin B1 vesicles also contained caveolin, whereas clathrin was almost undetectable on those vesicles. These results raise the possibility that endophilin B1 participates in dynamin 2-dependent formation of a population of transport vesicles distinct from those generated by A-type endophilins.
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Affiliation(s)
- Jinhui Li
- Department of Physics, University of Minnesota, Minneapolis, Minnesota
| | | | - John P Eichorst
- Department of Physics, University of Minnesota, Minneapolis, Minnesota
| | - Joachim D Mueller
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota
| | | | - Yan Chen
- Department of Physics, University of Minnesota, Minneapolis, Minnesota.
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223
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Serfass JM, Takahashi Y, Zhou Z, Kawasawa YI, Liu Y, Tsotakos N, Young MM, Tang Z, Yang L, Atkinson JM, Chroneos ZC, Wang HG. Endophilin B2 facilitates endosome maturation in response to growth factor stimulation, autophagy induction, and influenza A virus infection. J Biol Chem 2017; 292:10097-10111. [PMID: 28455444 PMCID: PMC5473216 DOI: 10.1074/jbc.m117.792747] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 04/27/2017] [Indexed: 12/19/2022] Open
Abstract
Endocytosis, and the subsequent trafficking of endosomes, requires dynamic physical alterations in membrane shape that are mediated in part by endophilin proteins. The endophilin B family of proteins contains an N-terminal Bin/amphiphysin/Rvs (N-BAR) domain that induces membrane curvature to regulate intracellular membrane dynamics. Whereas endophilin B1 (SH3GLB1/Bif-1) is known to be involved in a number of cellular processes, including apoptosis, autophagy, and endocytosis, the cellular function of endophilin B2 (SH3GLB2) is not well understood. In this study, we used genetic approaches that revealed that endophilin B2 is not required for embryonic development in vivo but that endophilin B2 deficiency impairs endosomal trafficking in vitro, as evidenced by suppressed endosome acidification, EGFR degradation, autophagic flux, and influenza A viral RNA nuclear entry and replication. Mechanistically, although the loss of endophilin B2 did not affect endocytic internalization and lysosomal function, endophilin B2 appeared to regulate the trafficking of endocytic vesicles and autophagosomes to late endosomes or lysosomes. Moreover, we also found that despite having an intracellular localization and tissue distribution similar to endophilin B1, endophilin B2 is dispensable for mitochondrial apoptosis. Taken together, our findings suggest that endophilin B2 positively regulates the endocytic pathway in response to growth factor signaling, autophagy induction, and viral entry.
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Affiliation(s)
| | | | - Zhixiang Zhou
- the Department of Pediatrics
- the College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China
| | - Yuka Imamura Kawasawa
- From the Department of Pharmacology
- the Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, and
| | - Ying Liu
- From the Department of Pharmacology
| | | | | | | | | | | | - Zissis C Chroneos
- the Department of Pediatrics
- the Department of Microbiology & Immunology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and
| | - Hong-Gang Wang
- From the Department of Pharmacology,
- the Department of Pediatrics
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224
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Duclos C, Lavoie C, Denault JB. Caspases rule the intracellular trafficking cartel. FEBS J 2017; 284:1394-1420. [PMID: 28371378 DOI: 10.1111/febs.14071] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/17/2017] [Accepted: 03/27/2017] [Indexed: 12/15/2022]
Abstract
During apoptosis, caspases feast on several hundreds of cellular proteins to orchestrate rapid cellular demise. Indeed, caspases are known to get a taste of every cellular process in one way or another, activating some, but most often shutting them down. Thus, it is not surprising that caspases proteolyze proteins involved in intracellular trafficking with particularly devastating consequences for this important process. This review article focuses on how caspases target the machinery responsible for smuggling goods within and outside the cell.
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Affiliation(s)
- Catherine Duclos
- Institut de Pharmacologie de Sherbrooke, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada
| | - Christine Lavoie
- Institut de Pharmacologie de Sherbrooke, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada
| | - Jean-Bernard Denault
- Institut de Pharmacologie de Sherbrooke, Department of Pharmacology-Physiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada
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225
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Ubrihien RP, Ezaz T, Taylor AM, Stevens MM, Krikowa F, Foster S, Maher WA. The response of Isidorella newcombi to copper exposure: Using an integrated biological framework to interpret transcriptomic responses from RNA-seq analysis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 185:183-192. [PMID: 28236764 DOI: 10.1016/j.aquatox.2017.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/11/2017] [Accepted: 02/10/2017] [Indexed: 06/06/2023]
Abstract
This study describes the transcriptomic response of the Australian endemic freshwater gastropod Isidorella newcombi exposed to 80±1μg/L of copper for 3days. Analysis of copper tissue concentration, lysosomal membrane destabilisation and RNA-seq were conducted. Copper tissue concentrations confirmed that copper was bioaccumulated by the snails. Increased lysosomal membrane destabilisation in the copper-exposed snails indicated that the snails were stressed as a result of the exposure. Both copper tissue concentrations and lysosomal destabilisation were significantly greater in snails exposed to copper. In order to interpret the RNA-seq data from an ecotoxicological perspective an integrated biological response model was developed that grouped transcriptomic responses into those associated with copper transport and storage, survival mechanisms and cell death. A conceptual model of expected transcriptomic changes resulting from the copper exposure was developed as a basis to assess transcriptomic responses. Transcriptomic changes were evident at all the three levels of the integrated biological response model. Despite lacking statistical significance, increased expression of the gene encoding copper transporting ATPase provided an indication of increased internal transport of copper. Increased expression of genes associated with endocytosis are associated with increased transport of copper to the lysosome for storage in a detoxified form. Survival mechanisms included metabolic depression and processes associated with cellular repair and recycling. There was transcriptomic evidence of increased cell death by apoptosis in the copper-exposed organisms. Increased apoptosis is supported by the increase in lysosomal membrane destabilisation in the copper-exposed snails. Transcriptomic changes relating to apoptosis, phagocytosis, protein degradation and the lysosome were evident and these processes can be linked to the degradation of post-apoptotic debris. The study identified contaminant specific transcriptomic markers as well as markers of general stress. From an ecotoxicological perspective, the use of a framework to group transcriptomic responses into those associated with copper transport, survival and cell death assisted with the complex process of interpretation of RNA-seq data. The broad adoption of such a framework in ecotoxicology studies would assist in comparison between studies and the identification of reliable transcriptomic markers of contaminant exposure and response.
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Affiliation(s)
- Rodney P Ubrihien
- Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
| | - Tariq Ezaz
- Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
| | - Anne M Taylor
- Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
| | - Mark M Stevens
- NSW Department of Primary Industries, Yanco Agricultural Institute, Private Mail Bag, Yanco, NSW, 2703, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Australia.
| | - Frank Krikowa
- Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
| | - Simon Foster
- Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
| | - William A Maher
- Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia.
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226
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Messéant J, Ezan J, Delers P, Glebov K, Marchiol C, Lager F, Renault G, Tissir F, Montcouquiol M, Sans N, Legay C, Strochlic L. Wnt proteins contribute to neuromuscular junction formation through distinct signaling pathways. Development 2017; 144:1712-1724. [PMID: 28348167 DOI: 10.1242/dev.146167] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/20/2017] [Indexed: 01/05/2023]
Abstract
Understanding the developmental steps that shape formation of the neuromuscular junction (NMJ) connecting motoneurons to skeletal muscle fibers is crucial. Wnt morphogens are key players in the formation of this specialized peripheral synapse, but their individual and collaborative functions and downstream pathways remain poorly understood at the NMJ. Here, we demonstrate through Wnt4 and Wnt11 gain-of-function studies in cell culture or in mice that Wnts enhance acetylcholine receptor (AChR) clustering and motor axon outgrowth. By contrast, loss of Wnt11 or Wnt-dependent signaling in vivo decreases AChR clustering and motor nerve terminal branching. Both Wnt4 and Wnt11 stimulate AChR mRNA levels and AChR clustering downstream of activation of the β-catenin pathway. Strikingly, Wnt4 and Wnt11 co-immunoprecipitate with Vangl2, a core component of the planar cell polarity (PCP) pathway, which accumulates at embryonic NMJs. Moreover, mice bearing a Vangl2 loss-of-function mutation (loop-tail) exhibit fewer AChR clusters and overgrowth of motor axons bypassing AChR clusters. Together, our results provide genetic and biochemical evidence that Wnt4 and Wnt11 cooperatively contribute to mammalian NMJ formation through activation of both the canonical and Vangl2-dependent core PCP pathways.
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Affiliation(s)
- Julien Messéant
- CNRS UMR 8119, CNRS UMR 8194, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270 Cedex 06, France
| | - Jérôme Ezan
- INSERM, Neurocentre Magendie, U1215, Bordeaux 33077, France.,Université de Bordeaux, Neurocentre Magendie, U1215, Bordeaux 33077, France
| | - Perrine Delers
- CNRS UMR 8119, CNRS UMR 8194, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270 Cedex 06, France
| | - Konstantin Glebov
- INSERM, Neurocentre Magendie, U1215, Bordeaux 33077, France.,Université de Bordeaux, Neurocentre Magendie, U1215, Bordeaux 33077, France
| | - Carmen Marchiol
- INSERM U1016, Institut Cochin, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75014, France
| | - Franck Lager
- INSERM U1016, Institut Cochin, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75014, France
| | - Gilles Renault
- INSERM U1016, Institut Cochin, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75014, France
| | - Fadel Tissir
- Université Catholique de Louvain, Institute of Neuroscience, Brussels B1200, Belgium
| | - Mireille Montcouquiol
- INSERM, Neurocentre Magendie, U1215, Bordeaux 33077, France.,Université de Bordeaux, Neurocentre Magendie, U1215, Bordeaux 33077, France
| | - Nathalie Sans
- INSERM, Neurocentre Magendie, U1215, Bordeaux 33077, France.,Université de Bordeaux, Neurocentre Magendie, U1215, Bordeaux 33077, France
| | - Claire Legay
- CNRS UMR 8119, CNRS UMR 8194, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270 Cedex 06, France
| | - Laure Strochlic
- CNRS UMR 8119, CNRS UMR 8194, Université Paris Descartes, PRES Sorbonne Paris Cité, Paris 75270 Cedex 06, France
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227
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Roy N, Pacini G, Berlioz-Torrent C, Janvier K. Characterization of E3 ligases involved in lysosomal sorting of the HIV-1 restriction factor BST2. J Cell Sci 2017; 130:1596-1611. [PMID: 28320822 PMCID: PMC5450231 DOI: 10.1242/jcs.195412] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/17/2017] [Indexed: 12/17/2022] Open
Abstract
The cellular protein BST2 (also known as tetherin) acts as a major intrinsic antiviral protein that prevents the release of enveloped viruses by trapping nascent viral particles at the surface of infected cells. Viruses have evolved specific strategies to displace BST2 from viral budding sites in order to promote virus egress. In HIV-1, the accessory protein Vpu counters BST2 antiviral activity and promotes sorting of BST2 for lysosomal degradation. Vpu increases polyubiquitylation of BST2, a post-translation modification required for Vpu-induced BST2 downregulation, through recruitment of the E3 ligase complex SCF adaptors β-TrCP1 and β-TrCP2 (two isoforms encoded by BTRC and FBXW11, respectively). Herein, we further investigate the role of the ubiquitylation machinery in the lysosomal sorting of BST2. Using a small siRNA screen, we highlighted two additional regulators of BST2 constitutive ubiquitylation and sorting to the lysosomes: the E3 ubiquitin ligases NEDD4 and MARCH8. Interestingly, Vpu does not hijack the cellular machinery that is constitutively involved in BST2 ubiquitylation to sort BST2 for degradation in the lysosomes but instead promotes the recognition of BST2 by β-TrCP proteins. Altogether, our results provide further understanding of the mechanisms underlying BST2 turnover in cells. Highlighted Article: We identify two E3 ubiquitin ligases, NEDD4 and MARCH8, as regulators of BST2 (tetherin) – a protein that restricts viral release; we thus provide further understanding of the mechanisms underlying BST2 turnover in cells.
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Affiliation(s)
- Nicolas Roy
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Grégory Pacini
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Clarisse Berlioz-Torrent
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Katy Janvier
- Inserm, U1016, Institut Cochin, Paris, France .,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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228
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RCAN1.4 regulates VEGFR-2 internalisation, cell polarity and migration in human microvascular endothelial cells. Angiogenesis 2017; 20:341-358. [PMID: 28271280 PMCID: PMC5511620 DOI: 10.1007/s10456-017-9542-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/22/2017] [Indexed: 01/13/2023]
Abstract
Regulator of calcineurin 1 (RCAN1) is an endogenous inhibitor of the calcineurin pathway in cells. It is expressed as two isoforms in vertebrates: RCAN1.1 is constitutively expressed in most tissues, whereas transcription of RCAN1.4 is induced by several stimuli that activate the calcineurin-NFAT pathway. RCAN1.4 is highly upregulated in response to VEGF in human endothelial cells in contrast to RCAN1.1 and is essential for efficient endothelial cell migration and tubular morphogenesis. Here, we show that RCAN1.4 has a role in the regulation of agonist-stimulated VEGFR-2 internalisation and establishment of endothelial cell polarity. siRNA-mediated gene silencing revealed that RCAN1 plays a vital role in regulating VEGF-mediated cytoskeletal reorganisation and directed cell migration and sprouting angiogenesis. Adenoviral-mediated overexpression of RCAN1.4 resulted in increased endothelial cell migration. Antisense-mediated morpholino silencing of the zebrafish RCAN1.4 orthologue revealed a disrupted vascular development further confirming a role for the RCAN1.4 isoform in regulating vascular endothelial cell physiology. Our data suggest that RCAN1.4 plays a novel role in regulating endothelial cell migration by establishing endothelial cell polarity in response to VEGF.
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229
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Xu Y, Xia J, Liu S, Stein S, Ramon C, Xi H, Wang L, Xiong X, Zhang L, He D, Yang W, Zhao X, Cheng X, Yang X, Wang H. Endocytosis and membrane receptor internalization: implication of F-BAR protein Carom. Front Biosci (Landmark Ed) 2017; 22:1439-1457. [PMID: 28199211 DOI: 10.2741/4552] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Endocytosis is a cellular process mostly responsible for membrane receptor internalization. Cell membrane receptors bind to their ligands and form a complex which can be internalized. We previously proposed that F-BAR protein initiates membrane curvature and mediates endocytosis via its binding partners. However, F-BAR protein partners involved in membrane receptor endocytosis and the regulatory mechanism remain unknown. In this study, we established database mining strategies to explore mechanisms underlying receptor-related endocytosis. We identified 34 endocytic membrane receptors and 10 regulating proteins in clathrin-dependent endocytosis (CDE), a major process of membrane receptor internalization. We found that F-BAR protein FCHSD2 (Carom) may facilitate endocytosis via 9 endocytic partners. Carom is highly expressed, along with highly expressed endocytic membrane receptors and partners, in endothelial cells and macrophages. We established 3 models of Carom-receptor complexes and their intracellular trafficking based on protein interaction and subcellular localization. We conclude that Carom may mediate receptor endocytosis and transport endocytic receptors to the cytoplasm for receptor signaling and lysosome/proteasome degradation, or to the nucleus for RNA processing, gene transcription and DNA repair.
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Affiliation(s)
- Yanjie Xu
- Center Department of Cardiology, Second Affiliated Hospital of Nanchang University, Nan Chang, Jiang Xi, 330006, China, and Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Jixiang Xia
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Suxuan Liu
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140,and Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Sam Stein
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Cueto Ramon
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Hang Xi
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Luqiao Wang
- Center Department of Cardiology, Second Affiliated Hospital of Nanchang University, Nan Chang, Jiang Xi, 330006, China, and Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Xinyu Xiong
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Lixiao Zhang
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Dingwen He
- Department of Orthopedics, Second Affiliated Hospital of Nanchang University, Nan Chang, Jiang Xi, 330006, China
| | - William Yang
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140
| | - Xianxian Zhao
- Department of Cardiology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Xiaoshu Cheng
- Center Department of Cardiology, Second Affiliated Hospital of Nanchang University, Nan Chang, Jiang Xi, 330006, China
| | - Xiaofeng Yang
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140, and Cardiovascular Research, Temple University School of Medicine, Philadelphia, PA, 19140, and Thrombosis Research, Temple University School of Medicine
| | - Hong Wang
- Center for Metabolic Disease Research, Temple University School of Medicine, Philadelphia, PA, 19140, and Cardiovascular Research, Temple University School of Medicine, Philadelphia, PA, 19140, and Thrombosis Research, Temple University School of Medicine,
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230
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Neirinckx V, Hedman H, Niclou SP. Harnessing LRIG1-mediated inhibition of receptor tyrosine kinases for cancer therapy. Biochim Biophys Acta Rev Cancer 2017; 1868:109-116. [PMID: 28259645 DOI: 10.1016/j.bbcan.2017.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 02/07/2023]
Abstract
Leucine-rich repeats and immunoglobulin-like domains containing protein 1 (LRIG1) is an endogenous feedback regulator of receptor tyrosine kinases (RTKs) and was recently shown to inhibit growth of different types of malignancies. Additionally, this multifaceted RTK inhibitor was reported to be a tumor suppressor, a stem cell regulator, and a modulator of different cellular phenotypes. This mini-review provides a concise and up-to-date summary about the known functions of LRIG1 and its related family members, with a special emphasis on underlying molecular mechanisms and the opportunities for harnessing its therapeutic potential against cancer.
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Affiliation(s)
- Virginie Neirinckx
- NorLux Neuro-Oncology Laboratory, Department of Oncology, Luxembourg Institute of Health, 1526, Luxembourg
| | - Hakan Hedman
- Oncology Research Laboratory, Department of Radiation Sciences, Umeå University, 90187 Umeå, Sweden
| | - Simone P Niclou
- NorLux Neuro-Oncology Laboratory, Department of Oncology, Luxembourg Institute of Health, 1526, Luxembourg; K.G. Jebsen Brain Tumour Research Centre, Department of Biomedicine, University of Bergen, 5020 Bergen, Norway.
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231
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DeVay RM, Delaria K, Zhu G, Holz C, Foletti D, Sutton J, Bolton G, Dushin R, Bee C, Pons J, Rajpal A, Liang H, Shelton D, Liu SH, Strop P. Improved Lysosomal Trafficking Can Modulate the Potency of Antibody Drug Conjugates. Bioconjug Chem 2017; 28:1102-1114. [DOI: 10.1021/acs.bioconjchem.7b00013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Rachel M. DeVay
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Kathy Delaria
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Guoyun Zhu
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Charles Holz
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Davide Foletti
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Janette Sutton
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Gary Bolton
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Russell Dushin
- Worldwide
Medicinal Chemistry, Pfizer Inc., 445 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Christine Bee
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Jaume Pons
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Arvind Rajpal
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Hong Liang
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - David Shelton
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Shu-Hui Liu
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
| | - Pavel Strop
- Rinat
Laboratories, Pfizer Inc., 230 East Grand Avenue, South
San Francisco, California 94080, United States
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232
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Kapishon V, Allison S, Whitney RA, Cunningham MF, Szewczuk MR, Neufeld RJ. Oseltamivir-conjugated polymeric micelles prepared by RAFT living radical polymerization as a new active tumor targeting drug delivery platform. Biomater Sci 2017; 4:511-21. [PMID: 26788555 DOI: 10.1039/c5bm00519a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Targeted drug delivery using polymeric nanostructures has been at the forefront of cancer research, engineered for safer, more efficient and effective use of chemotherapy. Here, we designed a new polymeric micelle delivery system for active tumor targeting followed by micelle-drug internalization via receptor-induced endocytosis. We recently reported that oseltamivir phosphate targets and inhibits Neu1 sialidase activity associated with receptor tyrosine kinases such as epidermal growth factor receptors (EGFRs) which are overexpressed in cancer cells. By decorating micelles with oseltamivir, we investigated whether they actively targeted human pancreatic PANC1 cancer cells. Amphiphilic block copolymers with oseltamivir conjugated at the hydrophilic end, oseltamivir-pPEGMEMA-b-pMMA (oseltamivir-poly(polyethylene glycol methyl ether methacrylate)-block-poly(methyl methacrylate), were synthesized using reversible addition-fragmentation chain transfer (RAFT) living radical polymerization. Oseltamivir-conjugated micelles have self-assembling properties to give worm-like micellar structures with molecular weight of 80 000 g mol(-1). Oseltamivir-conjugated water soluble pPEGMEMA, dose dependently, both inhibited sialidase activity associated with Neu1, and reduced viability of PANC1 cells. In addition, oseltamivir-conjugated micelles, labelled with a hydrophobic fluorescent dye within the micelle core, were subsequently internalized by PANC1 cells. Blocking cell surface Neu1 with anti-Neu1 antibody, reduced internalization of oseltamivir-conjugated micelles, demonstrating that Neu1 binding linked to sialidase inhibition were prerequisite steps for subsequent internalization of the micelles. The mechanism of internalization is likely that of receptor-induced endocytosis demonstrating potential as a new nanocarrier system for not only targeting a tumor cell, but also for directly reducing viability through Neu1 inhibition, followed by intracellular delivery of hydrophobic cytotoxic chemotherapeutics.
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Affiliation(s)
- Vitaliy Kapishon
- Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6.
| | - Stephanie Allison
- Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6.
| | - Ralph A Whitney
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.
| | - Michael F Cunningham
- Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6. and Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.
| | - Myron R Szewczuk
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada K7L 3N6.
| | - Ronald J Neufeld
- Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6.
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233
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Hirai M, Arita Y, McGlade CJ, Lee KF, Chen J, Evans SM. Adaptor proteins NUMB and NUMBL promote cell cycle withdrawal by targeting ERBB2 for degradation. J Clin Invest 2017; 127:569-582. [PMID: 28067668 PMCID: PMC5272190 DOI: 10.1172/jci91081] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/10/2016] [Indexed: 12/20/2022] Open
Abstract
Failure of trabecular myocytes to undergo appropriate cell cycle withdrawal leads to ventricular noncompaction and heart failure. Signaling of growth factor receptor ERBB2 is critical for myocyte proliferation and trabeculation. However, the mechanisms underlying appropriate downregulation of trabecular ERBB2 signaling are little understood. Here, we have found that the endocytic adaptor proteins NUMB and NUMBL were required for downregulation of ERBB2 signaling in maturing trabeculae. Loss of NUMB and NUMBL resulted in a partial block of late endosome formation, resulting in sustained ERBB2 signaling and STAT5 activation. Unexpectedly, activated STAT5 overrode Hippo-mediated inhibition and drove YAP1 to the nucleus. Consequent aberrant cardiomyocyte proliferation resulted in ventricular noncompaction that was markedly rescued by heterozygous loss of function of either ERBB2 or YAP1. Further investigations revealed that NUMB and NUMBL interacted with small GTPase Rab7 to transition ERBB2 from early to late endosome for degradation. Our studies provide insight into mechanisms by which NUMB and NUMBL promote cardiomyocyte cell cycle withdrawal and highlight previously unsuspected connections between pathways that are important for cardiomyocyte cell cycle reentry, with relevance to ventricular noncompaction cardiomyopathy and regenerative medicine.
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Affiliation(s)
- Maretoshi Hirai
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UCSD, La Jolla, California, USA
| | - Yoh Arita
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UCSD, La Jolla, California, USA
| | - C. Jane McGlade
- Program in Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kuo-Fen Lee
- Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, California, USA
| | | | - Sylvia M. Evans
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UCSD, La Jolla, California, USA
- Department of Medicine and
- Department of Pharmacology, UCSD, La Jolla, California, USA
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234
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Canu N, Pagano I, La Rosa LR, Pellegrino M, Ciotti MT, Mercanti D, Moretti F, Sposato V, Triaca V, Petrella C, Maruyama IN, Levi A, Calissano P. Association of TrkA and APP Is Promoted by NGF and Reduced by Cell Death-Promoting Agents. Front Mol Neurosci 2017; 10:15. [PMID: 28197073 PMCID: PMC5281621 DOI: 10.3389/fnmol.2017.00015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/11/2017] [Indexed: 12/31/2022] Open
Abstract
The amyloid precursor protein (APP) interacts with the tropomyosin receptor kinase A (TrkA) in normal rat, mouse, and human brain tissue but not in Alzheimer's disease (AD) brain tissue. However, it has not been reported whether the two proteins interact directly, and if so, which domains are involved. Clarifying these points will increase our understanding of the role and regulation of the TrkA/APP interaction in normal brain functioning as well as in AD. Here we addressed these questions using bimolecular fluorescence complementation (BiFC) and the proximity ligation assay (PLA). We demonstrated that exogenously expressed APP and TrkA associate through their juxtamembrane/transmembrane domains, to form a complex that localizes mainly to the plasma membrane, endoplasmic reticulum (ER) and Golgi. Formation of the complex was inhibited by p75NTR, ShcC and Mint-2. Importantly, we demonstrated that the association between endogenous APP and TrkA in primary septal neurons were modified by NGF, or by drugs that either inhibit ER-to-Golgi transport or perturb microtubules and microfilaments. Interestingly, several agents that induce cell death [amyloid β (Aβ)-peptide, staurosporine and rapamycin], albeit via different mechanisms, all caused dissociation of APP/TrkA complexes and increased production of C-terminal fragment (β-CTF) APP fragment. These findings open new perspectives for investigating the interplay between these proteins during neurodegeneration and AD.
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Affiliation(s)
- Nadia Canu
- Department of System Medicine, University of Rome "Tor Vergata"Rome, Italy; Institute of Cellular Biology and Neurobiology, National Council of Research of RomeRome, Italy
| | - Ilaria Pagano
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Luca Rosario La Rosa
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Marsha Pellegrino
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Maria Teresa Ciotti
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Delio Mercanti
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Fabiola Moretti
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Valentina Sposato
- Institute of Cellular Biology and Neurobiology, National Council of Research of RomeRome, Italy; European Brain Research InstituteRome, Italy
| | - Viviana Triaca
- Institute of Cellular Biology and Neurobiology, National Council of Research of RomeRome, Italy; European Brain Research InstituteRome, Italy
| | - Carla Petrella
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Ichiro N Maruyama
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University Okinawa, Japan
| | - Andrea Levi
- Institute of Cellular Biology and Neurobiology, National Council of Research of Rome Rome, Italy
| | - Pietro Calissano
- European Brain Research InstituteRome, Italy; Institute of Cellular Biology and Neurobiology, National Council of Research of RomeRome, Italy
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235
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Abstract
Clathrin-mediated endocytosis is an essential cellular process that involves the concerted assembly and disassembly of many different proteins at the plasma membrane. In yeast, live-cell imaging has shown that the spatiotemporal dynamics of these proteins is highly stereotypical. Recent work has focused on determining how the timing and functions of endocytic proteins are regulated. In this Cell Science at a Glance article and accompanying poster, we review our current knowledge of the timeline of endocytic site maturation and discuss recent works focusing on how phosphorylation, ubiquitylation and lipids regulate various aspects of the process.
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Affiliation(s)
- Rebecca Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Yidi Sun
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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236
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Abstract
Ubiquitination of the epidermal growth factor receptor (EGFR) is an important intracellular signal that occurs upon EGF stimulation and controls EGFR trafficking at multiple steps, finally destining the receptor to lysosomal degradation. In this chapter, we give an overview of the biochemical methods to investigate EGFR ubiquitination.Firstly, we describe the in vitro ubiquitination assay, a method where, in the presence of the minimal ubiquitination machinery, the biological milieu for EGFR ubiquitination is reproduced in a test tube. In the second protocol, we explain how to immunoprecipitate the EGFR from total lysate and reveal its ubiquitinated form by western blot analysis. Then, with an ELISA-derived assay, we illustrate a robust and reliable method to assess EGFR ubiquitination from low amount of sample; lastly, we illustrate an immunofluorescence protocol to visualize ubiquitinated species (including the EGFR itself) within the EGFR-positive endocytic compartments upon EGF stimulation.
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Affiliation(s)
- Alexia Conte
- IFOM, The FIRC Institute for Molecular Oncology Foundation, Via Adamello 16, 20139, Milan, Italy
| | - Sara Sigismund
- IFOM, The FIRC Institute for Molecular Oncology Foundation, Via Adamello 16, 20139, Milan, Italy.
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237
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Mincione G, Di Marcantonio MC, Tarantelli C, Savino L, Ponti D, Marchisio M, Lanuti P, Sancilio S, Calogero A, Di Pietro R, Muraro R. Identification of the zinc finger 216 (ZNF216) in human carcinoma cells: a potential regulator of EGFR activity. Oncotarget 2016; 7:74947-74965. [PMID: 27732953 PMCID: PMC5342714 DOI: 10.18632/oncotarget.12509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/25/2016] [Indexed: 02/05/2023] Open
Abstract
Epidermal Growth Factor Receptor (EGFR), a member of the ErbB family of receptor tyrosine kinase (RTK) proteins, is aberrantly expressed or deregulated in tumors and plays pivotal roles in cancer onset and metastatic progression. ZNF216 gene has been identified as one of Immediate Early Genes (IEGs) induced by RTKs. Overexpression of ZNF216 protein sensitizes 293 cell line to TNF-α induced apoptosis. However, ZNF216 overexpression has been reported in medulloblastomas and metastatic nasopharyngeal carcinomas. Thus, the role of this protein is still not clearly understood. In this study, the inverse correlation between EGFR and ZNF216 expression was confirmed in various human cancer cell lines differently expressing EGFR. EGF treatment of NIH3T3 cells overexpressing both EGFR and ZNF216 (NIH3T3-EGFR/ZNF216), induced a long lasting activation of EGFR in the cytosolic fraction and an accumulation of phosphorylated EGFR (pEGFR) more in the nuclear than in the cytosolic fraction compared to NIH3T3-EGFR cells. Moreover, EGF was able to stimulate an increased expression of ZNF216 in the cytosolic compartment and its nuclear translocation in a time-dependent manner in NIH3T3-EGFR/ZNF216. A similar trend was observed in A431 cells endogenously expressing the EGFR and transfected with Znf216. The increased levels of pEGFR and ZNF216 in the nuclear fraction of NIH3T3-EGFR/ZNF216 cells were paralleled by increased levels of phospho-MAPK and phospho-Akt. Surprisingly, EGF treatment of NIH3T3-EGFR/ZNF216 cells induced a significant increase of apoptosis thus indicating that ZNF216 could sensitize cells to EGF-induced apoptosis and suggesting that it may be involved in the regulation and effects of EGFR signaling.
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Affiliation(s)
- Gabriella Mincione
- 1 Department of Medical, Oral and Biotechnological Sciences, University “G. d'Annunzio” Chieti-Pescara, Italy
- 2 Center for Aging Science and Translational Medicine (CeSI-MeT), Chieti, Italy
| | | | - Chiara Tarantelli
- 1 Department of Medical, Oral and Biotechnological Sciences, University “G. d'Annunzio” Chieti-Pescara, Italy
- 6 Current Address: Lymphoma and Genomics Research Program, IOR Institute of Oncology Research, Bellinzona, Switzerland
| | - Luca Savino
- 1 Department of Medical, Oral and Biotechnological Sciences, University “G. d'Annunzio” Chieti-Pescara, Italy
| | - Donatella Ponti
- 3 Department of Medico-Surgical Sciences and Biotechnologies, University of Rome Sapienza, Latina, Italy
| | - Marco Marchisio
- 2 Center for Aging Science and Translational Medicine (CeSI-MeT), Chieti, Italy
- 4 Department of Medicine and Ageing Sciences, University “G. d'Annunzio”, Chieti-Pescara, Italy
| | - Paola Lanuti
- 2 Center for Aging Science and Translational Medicine (CeSI-MeT), Chieti, Italy
- 4 Department of Medicine and Ageing Sciences, University “G. d'Annunzio”, Chieti-Pescara, Italy
| | - Silvia Sancilio
- 5 Department of Pharmacy, University “G. d'Annunzio”, Chieti-Pescara, Italy
| | - Antonella Calogero
- 3 Department of Medico-Surgical Sciences and Biotechnologies, University of Rome Sapienza, Latina, Italy
| | - Roberta Di Pietro
- 4 Department of Medicine and Ageing Sciences, University “G. d'Annunzio”, Chieti-Pescara, Italy
| | - Raffaella Muraro
- 1 Department of Medical, Oral and Biotechnological Sciences, University “G. d'Annunzio” Chieti-Pescara, Italy
- 2 Center for Aging Science and Translational Medicine (CeSI-MeT), Chieti, Italy
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238
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Abstract
ROR-family receptor tyrosine kinases form a small subfamily of receptor tyrosine kinases (RTKs), characterized by a conserved, unique domain architecture. ROR RTKs are evolutionary conserved throughout the animal kingdom and act as alternative receptors and coreceptors of WNT ligands. The intracellular signaling cascades activated downstream of ROR receptors are diverse, including but not limited to ROR-Frizzled-mediated activation of planar cell polarity signaling, RTK-like signaling, and antagonistic regulation of WNT/β-Catenin signaling. In line with their diverse repertoire of signaling functions, ROR receptors are involved in the regulation of multiple processes in embryonic development such as development of the axial and paraxial mesoderm, the nervous system and the neural crest, the axial and appendicular skeleton, and the kidney. In humans, mutations in the ROR2 gene cause two distinct developmental syndromes, recessive Robinow syndrome (RRS; MIM 268310) and dominant brachydactyly type B1 (BDB1; MIM 113000). In Robinow syndrome patients and animal models, the development of multiple organs is affected, whereas BDB1 results only in shortening of the distal phalanges of fingers and toes, reflecting the diversity of functions and signaling activities of ROR-family RTKs. In this chapter, we give an overview on ROR receptor structure and function. We discuss their signaling functions and role in vertebrate embryonic development with a focus on those developmental processes that are affected by mutations in the ROR2 gene in human patients.
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239
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Verma N, Müller AK, Kothari C, Panayotopoulou E, Kedan A, Selitrennik M, Mills GB, Nguyen LK, Shin S, Karn T, Holtrich U, Lev S. Targeting of PYK2 Synergizes with EGFR Antagonists in Basal-like TNBC and Circumvents HER3-Associated Resistance via the NEDD4–NDRG1 Axis. Cancer Res 2016; 77:86-99. [DOI: 10.1158/0008-5472.can-16-1797] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/22/2016] [Accepted: 10/04/2016] [Indexed: 12/12/2022]
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240
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Abstract
Lysosomes (or lytic bodies) were so named because they contain high levels of hydrolytic enzymes. Lysosome function and dysfunction have been found to play important roles in human disease, including cancer; however, the ways in which lysosomes contribute to tumorigenesis and cancer progression are still being uncovered. Beyond serving as a cellular recycling center, recent evidence suggests that the lysosome is involved in energy homeostasis, generating building blocks for cell growth, mitogenic signaling, priming tissues for angiogenesis and metastasis formation, and activating transcriptional programs. This review examines emerging knowledge of how lysosomal processes contribute to the hallmarks of cancer and highlights vulnerabilities that might be exploited for cancer therapy.
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Affiliation(s)
- Shawn M Davidson
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; , .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Matthew G Vander Heiden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; , .,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.,Dana-Farber Cancer Institute, Boston, Massachusetts 02215
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241
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Schwenk BM, Hartmann H, Serdaroglu A, Schludi MH, Hornburg D, Meissner F, Orozco D, Colombo A, Tahirovic S, Michaelsen M, Schreiber F, Haupt S, Peitz M, Brüstle O, Küpper C, Klopstock T, Otto M, Ludolph AC, Arzberger T, Kuhn PH, Edbauer D. TDP-43 loss of function inhibits endosomal trafficking and alters trophic signaling in neurons. EMBO J 2016; 35:2350-2370. [PMID: 27621269 PMCID: PMC5090220 DOI: 10.15252/embj.201694221] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/12/2016] [Indexed: 12/12/2022] Open
Abstract
Nuclear clearance of TDP-43 into cytoplasmic aggregates is a key driver of neurodegeneration in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), but the mechanisms are unclear. Here, we show that TDP-43 knockdown specifically reduces the number and motility of RAB11-positive recycling endosomes in dendrites, while TDP-43 overexpression has the opposite effect. This is associated with delayed transferrin recycling in TDP-43-knockdown neurons and decreased β2-transferrin levels in patient CSF Whole proteome quantification identified the upregulation of the ESCRT component VPS4B upon TDP-43 knockdown in neurons. Luciferase reporter assays and chromatin immunoprecipitation suggest that TDP-43 represses VPS4B transcription. Preventing VPS4B upregulation or expression of its functional antagonist ALIX restores trafficking of recycling endosomes. Proteomic analysis revealed the broad reduction in surface expression of key receptors upon TDP-43 knockdown, including ErbB4, the neuregulin 1 receptor. TDP-43 knockdown delays the surface delivery of ErbB4. ErbB4 overexpression, but not neuregulin 1 stimulation, prevents dendrite loss upon TDP-43 knockdown. Thus, impaired recycling of ErbB4 and other receptors to the cell surface may contribute to TDP-43-induced neurodegeneration by blocking trophic signaling.
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Affiliation(s)
- Benjamin M Schwenk
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | | | - Alperen Serdaroglu
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Institute for Advanced Study Technische Universität München, München, Germany
| | - Martin H Schludi
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | | | - Felix Meissner
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Denise Orozco
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Alessio Colombo
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Meike Michaelsen
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | | | | | - Michael Peitz
- Institute of Reconstructive Neurobiology University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology University of Bonn, Bonn, Germany
| | - Clemens Küpper
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.,Department of Neurology, Friedrich-Baur-Institute LMU Munich, Munich, Germany
| | - Thomas Klopstock
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.,Department of Neurology, Friedrich-Baur-Institute LMU Munich, Munich, Germany
| | - Markus Otto
- Department of Neurology, University of Ulm, Ulm, Germany
| | | | - Thomas Arzberger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Center for Neuropathology and Prion Research, LMU Munich, Munich, Germany.,Department of Psychiatry and Psychotherapy, LMU Munich, Munich, Germany
| | - Peer-Hendrik Kuhn
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Institute for Advanced Study Technische Universität München, München, Germany.,Institut für Allgemeine Pathologie Klinikum rechts der Isar der Technischen Universität München, München, Germany
| | - Dieter Edbauer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany .,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.,Institute for Metabolic Biochemistry LMU Munich, Munich, Germany
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242
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Che TF, Lin CW, Wu YY, Chen YJ, Han CL, Chang YL, Wu CT, Hsiao TH, Hong TM, Yang PC. Mitochondrial translocation of EGFR regulates mitochondria dynamics and promotes metastasis in NSCLC. Oncotarget 2016; 6:37349-66. [PMID: 26497368 PMCID: PMC4741934 DOI: 10.18632/oncotarget.5736] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 10/06/2015] [Indexed: 01/01/2023] Open
Abstract
Dysfunction of the mitochondria is well-known for being associated with cancer progression. In the present study, we analyzed the mitochondria proteomics of lung cancer cell lines with different invasion abilities and found that EGFR is highly expressed in the mitochondria of highly invasive non-small-cell lung cancer (NSCLC) cells. EGF induces the mitochondrial translocation of EGFR; further, it leads to mitochondrial fission and redistribution in the lamellipodia, upregulates cellular ATP production, and enhances motility in vitro and in vivo. Moreover, EGFR can regulate mitochondrial dynamics by interacting with Mfn1 and disturbing Mfn1 polymerization. Overexpression of Mfn1 reverses the phenotypes resulting from EGFR mitochondrial translocation. We show that the mitochondrial EGFR expressions are higher in paired samples of the metastatic lymph node as compared with primary lung tumor and are inversely correlated with the overall survival in NSCLC patients. Therefore, our results demonstrate that besides the canonical role of EGFR as a receptor tyrosine, the mitochondrial translocation of EGFR may enhance cancer invasion and metastasis through regulating mitochondria dynamics.
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Affiliation(s)
- Ting-Fang Che
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Ching-Wen Lin
- Institute of Biomedical Science, Academia Sinica, Taipei 115, Taiwan
| | - Yi-Ying Wu
- Institute of Clinical Medicine, College of Medicine, National Cheng-Kung University, Tainan 701, Taiwan
| | - Yu-Ju Chen
- Institute of Chemistry, Academia Sinica 115, Taipei, Taiwan
| | - Chia-Li Han
- Master Program for Clinical Pharmacogenomics and Pharmacoproteomics, School of Pharmacy, Taipei Medical University 110, Taipei, Taiwan
| | - Yih-leong Chang
- Department of Pathology and Graduate Institute of Pathology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chen-Tu Wu
- Department of Pathology and Graduate Institute of Pathology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Tzu-Hung Hsiao
- Department of Medical Research, Taichung Veterans General Hospital, Taichung 407, Taiwan
| | - Tse-Ming Hong
- Institute of Clinical Medicine, College of Medicine, National Cheng-Kung University, Tainan 701, Taiwan
| | - Pan-Chyr Yang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan.,Institute of Biomedical Science, Academia Sinica, Taipei 115, Taiwan.,NTU Center for Genomic Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan.,Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
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243
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MARCH1 regulates insulin sensitivity by controlling cell surface insulin receptor levels. Nat Commun 2016; 7:12639. [PMID: 27577745 PMCID: PMC5013666 DOI: 10.1038/ncomms12639] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 07/20/2016] [Indexed: 12/16/2022] Open
Abstract
Insulin resistance is a key driver of type 2 diabetes (T2D) and is characterized by defective insulin receptor (INSR) signalling. Although surface INSR downregulation is a well-established contributor to insulin resistance, the underlying molecular mechanisms remain obscure. Here we show that the E3 ubiquitin ligase MARCH1 impairs cellular insulin action by degrading cell surface INSR. Using a large-scale RNA interference screen, we identify MARCH1 as a negative regulator of INSR signalling. March1 loss-of-function enhances, and March1 overexpression impairs, hepatic insulin sensitivity in mice. MARCH1 ubiquitinates INSR to decrease cell surface INSR levels, but unlike other INSR ubiquitin ligases, MARCH1 acts in the basal state rather than after insulin stimulation. Thus, MARCH1 may help set the basal gain of insulin signalling. MARCH1 expression is increased in white adipose tissue of obese humans, suggesting that MARCH1 contributes to the pathophysiology of T2D and could be a new therapeutic target.
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244
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KSR1 and EPHB4 Regulate Myc and PGC1β To Promote Survival of Human Colon Tumors. Mol Cell Biol 2016; 36:2246-61. [PMID: 27273865 DOI: 10.1128/mcb.00087-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/26/2016] [Indexed: 01/05/2023] Open
Abstract
Identification and characterization of survival pathways active in tumor cells but absent in normal tissues provide opportunities to develop effective anticancer therapies with reduced toxicity to the patient. We show here that, like kinase suppressor of Ras 1 (KSR1), EPH (erythropoietin-producing hepatocellular carcinoma) receptor B4 (EPHB4) is aberrantly overexpressed in human colon tumor cell lines and selectively required for their survival. KSR1 and EPHB4 support tumor cell survival by promoting the expression of downstream targets, Myc and the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator 1β (PGC1β). While KSR1 promotes the aberrant expression of Myc and the PGC1β protein via a posttranscriptional mechanism, EPHB4 has a greater effect on Myc and PGC1β expression via its ability to elevate mRNA levels. Subsequent analysis of the posttranscriptional regulation demonstrated that KSR1 promotes the translation of Myc protein. These findings reveal novel KSR1- and EPHB4-dependent signaling pathways supporting the survival of colorectal cancer cells through regulation of Myc and PGC1β, suggesting that inhibition of KSR1 or EPHB4 effectors may lead to selective toxicity in colorectal tumors.
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245
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Lemmon MA, Freed DM, Schlessinger J, Kiyatkin A. The Dark Side of Cell Signaling: Positive Roles for Negative Regulators. Cell 2016; 164:1172-1184. [PMID: 26967284 DOI: 10.1016/j.cell.2016.02.047] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Indexed: 12/12/2022]
Abstract
Cell signaling is dominated by analyzing positive responses to stimuli. Signal activation is balanced by negative regulators that are generally considered to terminate signaling. Rather than exerting only negative effects, however, many such regulators play important roles in enhancing cell-signaling control. Considering responses downstream of selected cell-surface receptors, we discuss how receptor internalization affects signaling specificity and how rapid kinase/phosphatase and GTP/GDP cycles increase responsiveness and allow kinetic proofreading in receptor signaling. We highlight the blurring of distinctions between positive and negative signals, recasting signal termination as the response to a switch-like transition into a new cellular state.
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Affiliation(s)
- Mark A Lemmon
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA.
| | - Daniel M Freed
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA
| | - Joseph Schlessinger
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA
| | - Anatoly Kiyatkin
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA; Yale Cancer Biology Institute, West Haven, CT 06516, USA
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246
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Numerous proteins with unique characteristics are degraded by the 26S proteasome following monoubiquitination. Proc Natl Acad Sci U S A 2016; 113:E4639-47. [PMID: 27385826 DOI: 10.1073/pnas.1608644113] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The "canonical" proteasomal degradation signal is a substrate-anchored polyubiquitin chain. However, a handful of proteins were shown to be targeted following monoubiquitination. In this study, we established-in both human and yeast cells-a systematic approach for the identification of monoubiquitination-dependent proteasomal substrates. The cellular wild-type polymerizable ubiquitin was replaced with ubiquitin that cannot form chains. Using proteomic analysis, we screened for substrates that are nevertheless degraded under these conditions compared with those that are stabilized, and therefore require polyubiquitination for their degradation. For randomly sampled representative substrates, we confirmed that their cellular stability is in agreement with our screening prediction. Importantly, the two groups display unique features: monoubiquitinated substrates are smaller than the polyubiquitinated ones, are enriched in specific pathways, and, in humans, are structurally less disordered. We suggest that monoubiquitination-dependent degradation is more widespread than assumed previously, and plays key roles in various cellular processes.
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247
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Choi E, Zhang X, Xing C, Yu H. Mitotic Checkpoint Regulators Control Insulin Signaling and Metabolic Homeostasis. Cell 2016; 166:567-581. [PMID: 27374329 DOI: 10.1016/j.cell.2016.05.074] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 12/09/2015] [Accepted: 05/24/2016] [Indexed: 01/08/2023]
Abstract
Insulin signaling regulates many facets of animal physiology. Its dysregulation causes diabetes and other metabolic disorders. The spindle checkpoint proteins MAD2 and BUBR1 prevent precocious chromosome segregation and suppress aneuploidy. The MAD2 inhibitory protein p31(comet) promotes checkpoint inactivation and timely chromosome segregation. Here, we show that whole-body p31(comet) knockout mice die soon after birth and have reduced hepatic glycogen. Liver-specific ablation of p31(comet) causes insulin resistance, hyperinsulinemia, glucose intolerance, and hyperglycemia and diminishes the plasma membrane localization of the insulin receptor (IR) in hepatocytes. MAD2 directly binds to IR and facilitates BUBR1-dependent recruitment of the clathrin adaptor AP2 to IR. p31(comet) blocks the MAD2-BUBR1 interaction and prevents spontaneous clathrin-mediated IR endocytosis. BUBR1 deficiency enhances insulin sensitivity in mice. BUBR1 depletion in hepatocytes or the expression of MAD2-binding-deficient IR suppresses the metabolic phenotypes of p31(comet) ablation. Our findings establish a major IR regulatory mechanism and link guardians of chromosome stability to nutrient metabolism.
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Affiliation(s)
- Eunhee Choi
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Xiangli Zhang
- Bioinformatics Core, Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Chao Xing
- Bioinformatics Core, Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Hongtao Yu
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA.
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248
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Hodgkinson CP, Bareja A, Gomez JA, Dzau VJ. Emerging Concepts in Paracrine Mechanisms in Regenerative Cardiovascular Medicine and Biology. Circ Res 2016; 118:95-107. [PMID: 26837742 DOI: 10.1161/circresaha.115.305373] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the past decade, substantial evidence supports the paradigm that stem cells exert their reparative and regenerative effects, in large part, through the release of biologically active molecules acting in a paracrine fashion on resident cells. The data suggest the existence of a tissue microenvironment where stem cell factors influence cell survival, inflammation, angiogenesis, repair, and regeneration in a temporal and spatial manner.
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Affiliation(s)
- Conrad P Hodgkinson
- From the Department of Medicine, Mandel Center for Hypertension Research and Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC
| | - Akshay Bareja
- From the Department of Medicine, Mandel Center for Hypertension Research and Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC
| | - José A Gomez
- From the Department of Medicine, Mandel Center for Hypertension Research and Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC
| | - Victor J Dzau
- From the Department of Medicine, Mandel Center for Hypertension Research and Duke Cardiovascular Research Center, Duke University Medical Center, Durham, NC.
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249
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Proenca CC, Song M, Lee FS. Differential effects of BDNF and neurotrophin 4 (NT4) on endocytic sorting of TrkB receptors. J Neurochem 2016; 138:397-406. [PMID: 27216821 DOI: 10.1111/jnc.13676] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 05/03/2016] [Accepted: 05/19/2016] [Indexed: 01/31/2023]
Abstract
Neurotrophins are a family of growth factors playing key roles in the survival, development, and function of neurons. The neurotrophins brain-derived neurotrophic factor (BDNF) and NT4 both bind to and activate TrkB receptors, however, they mediate distinct neuronal functions. The molecular mechanism of how TrkB activation by BDNF and NT4 leads to diverse outcomes is unknown. Here, we report that BDNF and NT4 lead to differential endocytic sorting of TrkB receptors resulting in diverse biological functions in cultured cortical neurons. Fluorescent microscopy and surface biotinylation experiments showed that both neurotrophins stimulate internalization of TrkB with similar kinetics. Exposure to BDNF for 2-3 h reduced the surface pool of TrkB receptors to half, whereas a longer treatment (4-5 h) with NT4 was necessary to achieve a similar level of down-regulation. Although BDNF and NT4 induced TrkB phosphorylation with similar intensities, BDNF induced more rapid ubiquitination and degradation of TrkB than NT4. Interestingly, TrkB receptor ubiquitination by these ligands have substantially different pH sensitivities, resulting in varying degrees of receptor ubiquitination at lower pH levels. Consequently, NT4 was capable of maintaining longer sustained downstream signaling activation that correlated with reduced TrkB ubiquitination at endosomal pH. Thus, by leading to altered endocytic trafficking itineraries for TrkB receptors, BDNF and NT4 elicit differential TrkB signaling in terms of duration, intensity, and specificity, which may contribute to their functional differences in vivo. The neurotrophins, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4), both bind to and activate TrkB receptors, however, they mediate distinct neuronal functions. Here, we propose that BDNF and NT4 lead to differential endocytic sorting of TrkB receptors resulting in diverse biological functions. BDNF induces more rapid ubiquitination and degradation of TrkB than NT4. Consequently, NT4 is capable of maintaining more sustained signaling downstream of TrkB receptors.
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Affiliation(s)
- Catia C Proenca
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Minseok Song
- Synaptic Circuit Plasticity Laboratory, Department of Structure & Function of Neural Network, Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, Korea
| | - Francis S Lee
- Department of Psychiatry, Weill Medical College of Cornell University, New York City, New York, USA.,Department of Pharmacology, Weill Medical College of Cornell University, New York City, New York, USA
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250
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Basagiannis D, Christoforidis S. Constitutive Endocytosis of VEGFR2 Protects the Receptor against Shedding. J Biol Chem 2016; 291:16892-903. [PMID: 27298320 DOI: 10.1074/jbc.m116.730309] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Indexed: 12/19/2022] Open
Abstract
VEGFR2 plays a fundamental role in blood vessel formation and in life threatening diseases, such as cancer angiogenesis and cardiovascular disorders. Although inactive growth factor receptors are mainly localized at the plasma membrane, VEGFR2 undergoes constitutive endocytosis (in the absence of ligand) and recycling. Intriguingly, the significance of these futile transport cycles of VEGFR2 remains unclear. Here we found that, unexpectedly, the function of constitutive endocytosis of VEGFR2 is to protect the receptor against plasma membrane cleavage (shedding), thereby preserving the functional state of the receptor until the time of activation by VEGF. Inhibition of constitutive endocytosis of VEGFR2, by interference with the function of clathrin, dynamin, or Rab5, increases dramatically the cleavage/shedding of VEGFR2. Shedding of VEGFR2 produces an N-terminal soluble fragment (100 kDa, s100), which is released in the extracellular space, and a residual C-terminal part (130 kDa, p130) that remains integrated at the plasma membrane. The released soluble fragment (s100) co-immunoprecipitates with VEGF, in line with the topology of the VEGF-binding domain at the N terminus of VEGFR2. Increased shedding of VEGFR2 (via inhibition of constitutive endocytosis) results in reduced response to VEGF, consistently with the loss of the VEGF-binding domain from the membrane remnant of VEGFR2. These data suggest that constitutive internalization of VEGFR2 protects the receptor against shedding and provides evidence for an unprecedented mechanism via which endocytosis can regulate the fate and activity of growth factor receptors.
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Affiliation(s)
- Dimitris Basagiannis
- From the Institute of Molecular Biology and Biotechnology-Biomedical Research, Foundation for Research and Technology, 45110 Ioannina and the Department of Medicine, Laboratory of Biological Chemistry, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece
| | - Savvas Christoforidis
- From the Institute of Molecular Biology and Biotechnology-Biomedical Research, Foundation for Research and Technology, 45110 Ioannina and the Department of Medicine, Laboratory of Biological Chemistry, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece
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