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Deng W, Gu L, Li X, Zheng J, Zhang Y, Duan B, Cui J, Dong J, Du J. CD24 associates with EGFR and supports EGF/EGFR signaling via RhoA in gastric cancer cells. J Transl Med 2016; 14:32. [PMID: 26830684 PMCID: PMC5439121 DOI: 10.1186/s12967-016-0787-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 01/18/2016] [Indexed: 02/06/2023] Open
Abstract
Background CD24, a mucin-like membrane glycoprotein, plays a critical role in carcinogenesis, but its role in human gastric cancer and the underlying mechanism remains undefined. Methods The contents of CD24 and epidermal growth factor receptor (EGFR) in gastric cancer cells (SGC-7901 and BGC-823) and non-malignant gastric epithelial cells (GES-1) were evaluated by Western blotting assay. Cellular EGFR staining was examined by immunofluorescence assay. Cell migration rate was measured by wound healing assay. The effects of depletion/overexperssion of CD24 on EGFR expression and activation of EGF/EGFR singaling pathways were evaluated by immunofluorescence, qPCR, Western blotting and flow cytometry techniques. RhoA activity was assessed by pulldown assay. CD24 and EGFR expression patterns in human gastric tumor samples were also investigated by immunohistochemistry staining. Results CD24 was overexpressed in human gastric cancer cells. Ectopic expression of CD24 in gastric epithelial cells augmented the expression of EGFR, while knockdown of CD24 in gastric cancer cells decreased the level of EGFR and cell migration velocity. To further explore the mechanisms, we investigated the effect of CD24 expression on EGF/EGFR signaling. We noticed that this effect of CD24 on EGFR expression was dependent on promoting EGFR internalization and degradation. Lower ERK and Akt phosphorylations in response to EGF stimulation were observed in CD24-depleted cells. In addition, we noticed that the effect of CD24 on EGFR stability was mediated by RhoA activity in SGC-7901 gastric cancer cells. Analysis of gastric cancer specimens revealed a positive correlation between CD24 and EGFR levels and an association between CD24 expression and worse prognosis. Conclusion Thus, these findings suggest for the first time that CD24 regulates EGFR signaling by inhibiting EGFR internalization and degradation in a RhoA-dependent manner in gastric cancer cells. Electronic supplementary material The online version of this article (doi:10.1186/s12967-016-0787-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wenjie Deng
- Cancer Center, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, Jiangsu, China. .,Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Luo Gu
- Cancer Center, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, Jiangsu, China. .,Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China. .,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Xiaojie Li
- Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Jianchao Zheng
- Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Yujie Zhang
- Cancer Center, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, Jiangsu, China. .,Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China. .,Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Biao Duan
- Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Jie Cui
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Jing Dong
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China. .,Epidemiology and Biostatistics and Ministry of Education (MOE) Key Laboratory for Modern Toxicology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Jun Du
- Cancer Center, Nanjing Medical University, 140 Hanzhong Road, Nanjing, 210029, Jiangsu, China. .,Department of Physiology, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
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Matalkah F, Martin E, Zhao H, Agazie YM. SHP2 acts both upstream and downstream of multiple receptor tyrosine kinases to promote basal-like and triple-negative breast cancer. Breast Cancer Res 2016; 18:2. [PMID: 26728598 PMCID: PMC4700603 DOI: 10.1186/s13058-015-0659-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 11/25/2015] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Dysregulated receptor tyrosine kinase (RTK) signaling is a common occurrence in basal-like and triple-negative breast cancer (BTBC). As a result, RTK-targeting therapies have been initiated but proved difficult, mainly owing to the multiplicity of dysregulated RTKs. Hence, targeting master regulators of RTK signaling might alleviate this obstacle. Before that, however, defining the mechanism of such molecules is required. In this report, we show that the Src homology phosphotyrosyl phosphatase 2 (SHP2) is a master regulator of RTK expression and signaling in BTBC. METHODS Xenograft tumor growth studies were used to determine the effect of SHP2 inhibition on tumorigenesis and/or metastasis. Cell proliferation rate, anchorage-independent growth, mammosphere formation, and ALDEFLUOR assays were used to compare the relative functional importance of SHP2 and the epidermal growth factor receptor (EGFR) in BTBC cells. Immunohistochemistry and immunofluorescence analyses were used to determine the state of SHP2 and EGFR coexpression in BTBC. Analysis of mitogenic and cell survival signaling was performed to show SHP2's role in signaling by multiple RTKs. RESULTS Inhibition of SHP2 in BTBC cells suppresses their tumorigenic and metastatic properties. Because EGFR is the most commonly dysregulated RTK in BTBC, we first tested the effect of SHP2 inhibition on EGFR signaling and found that SHP2 is important not only for mediation of the Ras/extracellular signal-regulated kinase and the phosphatidyl inositol 3-kinase/Akt signaling pathways but also for the expression of the receptor itself. The existence of a tight association between SHP2 and EGFR expression in tumors and cell lines further suggested the importance of SHP2 in EGFR expression. Comparison of relative biological significance showed the superiority of SHP2 inhibition over that of EGFR, suggesting the existence of additional RTKs regulated by SHP2. Indeed, we found that the expression as well as the signaling efficiency of c-Met and fibroblast growth factor receptor 1, two other RTKs known to be dysregulated in BTBC, are SHP2-dependent. To our knowledge, this is the first demonstration of SHP2 acting both upstream and downstream of RTKs to promote signaling. CONCLUSIONS SHP2 upregulates the expression and signaling of multiple RTKs to promote BTBC. These findings provide a mechanistic explanation for the superiority of SHP2 inhibition in BTBC.
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Affiliation(s)
- Fatimah Matalkah
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Elisha Martin
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Hua Zhao
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Yehenew M Agazie
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA. .,The Marry Babb Randolph Cancer Center, School of Medicine, West Virginia University, Morgantown, WV 26506, USA.
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Demers A, Samami S, Lauzier B, Des Rosiers C, Ngo Sock ET, Ong H, Mayer G. PCSK9 Induces CD36 Degradation and Affects Long-Chain Fatty Acid Uptake and Triglyceride Metabolism in Adipocytes and in Mouse Liver. Arterioscler Thromb Vasc Biol 2015; 35:2517-25. [PMID: 26494228 DOI: 10.1161/atvbaha.115.306032] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/12/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes the degradation of the low-density lipoprotein receptor thereby elevating plasma low-density lipoprotein cholesterol levels and the risk of coronary heart disease. Thus, the use of PCSK9 inhibitors holds great promise to prevent heart disease. Previous work found that PCSK9 is involved in triglyceride metabolism, independently of its action on low-density lipoprotein receptor, and that other yet unidentified receptors could mediate this effect. Therefore, we assessed whether PCSK9 enhances the degradation of CD36, a major receptor involved in transport of long-chain fatty acids and triglyceride storage. APPROACH AND RESULTS Overexpressed or recombinant PCSK9 induced CD36 degradation in cell lines and primary adipocytes and reduced the uptake of the palmitate analog Bodipy FL C16 and oxidized low-density lipoprotein in 3T3-L1 adipocytes and hepatic HepG2 cells, respectively. Surface plasmon resonance, coimmunoprecipitation, confocal immunofluorescence microscopy, and protein degradation pathway inhibitors revealed that PCSK9 directly interacts with CD36 and targets the receptor to lysosomes through a mechanism involving the proteasome. Importantly, the level of CD36 protein was increased by >3-fold upon small interfering RNA knockdown of endogenous PCSK9 in hepatic cells and similarly increased in the liver and visceral adipose tissue of Pcsk9(-/-) mice. In Pcsk9(-/-) mice, increased hepatic CD36 was correlated with an amplified uptake of fatty acid and accumulation of triglycerides and lipid droplets. CONCLUSIONS Our results demonstrate an important role of PCSK9 in modulating the function of CD36 and triglyceride metabolism. PCSK9-mediated CD36 degradation may serve to limit fatty acid uptake and triglyceride accumulation in tissues, such as the liver.
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Affiliation(s)
- Annie Demers
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Samaneh Samami
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Benjamin Lauzier
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Christine Des Rosiers
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Emilienne Tudor Ngo Sock
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Huy Ong
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Gaetan Mayer
- From the Laboratory of Molecular Cell Biology (A.D., S.S., E.T.N.S., G.M.) and Laboratory of Metabolomic (C.D.R.), Montreal Heart Institute, Montréal, Québec, Canada; Université de Nantes, L'institut du thorax, Inserm UMR 1087 / CNRS UMR 6291, Nantes, France (B.L.); and Faculty of Pharmacy (H.O.), Université de Montréal, Department of Pharmacology, Faculty of Medicine (S.S., E.T.N.S., G.M.), Department of Nutrition, Faculty of Medicine (C.D.R.), and Department of Medicine (G.M.), Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada.
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Influence of cellular trafficking pathway on bluetongue virus infection in ovine cells. Viruses 2015; 7:2378-403. [PMID: 25984713 PMCID: PMC4452911 DOI: 10.3390/v7052378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/06/2015] [Indexed: 11/27/2022] Open
Abstract
Bluetongue virus (BTV), a non-enveloped arbovirus, causes hemorrhagic disease in ruminants. However, the influence of natural host cell proteins on BTV replication process is not defined. In addition to cell lysis, BTV also exits non-ovine cultured cells by non-lytic pathways mediated by nonstructural protein NS3 that interacts with virus capsid and cellular proteins belonging to calpactin and ESCRT family. The PPXY late domain motif known to recruit NEDD4 family of HECT ubiquitin E3 ligases is also highly conserved in NS3. In this study using a mixture of molecular, biochemical and microscopic techniques we have analyzed the importance of ovine cellular proteins and vesicles in BTV infection. Electron microscopic analysis of BTV infected ovine cells demonstrated close association of mature particles with intracellular vesicles. Inhibition of Multi Vesicular Body (MVB) resident lipid phosphatidylinositol-3-phosphate resulted in decreased total virus titre suggesting that the vesicles might be MVBs. Proteasome mediated inhibition of ubiquitin or modification of virus lacking the PPXY in NS3 reduced virus growth. Thus, our study demonstrated that cellular components comprising of MVB and exocytic pathways proteins are involved in BTV replication in ovine cells.
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Wang H, Sang N, Zhang C, Raghupathi R, Tanzi RE, Saunders A. Cathepsin L Mediates the Degradation of Novel APP C-Terminal Fragments. Biochemistry 2015; 54:2806-16. [PMID: 25910068 PMCID: PMC4521409 DOI: 10.1021/acs.biochem.5b00329] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease (AD) is characterized by the deposition of amyloid β (Aβ), a peptide generated from proteolytic processing of its precursor, amyloid precursor protein (APP). Canonical APP proteolysis occurs via α-, β-, and γ-secretases. APP is also actively degraded by protein degradation systems. By pharmacologically inhibiting protein degradation with ALLN, we observed an accumulation of several novel APP C-terminal fragments (CTFs). The two major novel CTFs migrated around 15 and 25 kDa and can be observed across multiple cell types. The process was independent of cytotoxicity or protein synthesis. We further determine that the accumulation of the novel CTFs is not mediated by proteasome or calpain inhibition, but by cathepsin L inhibition. Moreover, these novel CTFs are not generated by an increased amount of BACE. Here, we name the CTF of 25 kDa as η-CTF (eta-CTF). Our data suggest that under physiological conditions, a subset of APP undergoes alternative processing and the intermediate products, the 15 kDa CTFs, and the η-CTFs aret rapidly degraded and/or processed via the protein degradation machinery, specifically, cathepsin L.
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Affiliation(s)
- Haizhi Wang
- Department of Biology, College of Art and Sciences, Drexel University, Philadelphia, Pennsylvania 19104, United States
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Nianli Sang
- Department of Biology, College of Art and Sciences, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Can Zhang
- Harvard University and Massachusetts General Hospital, Boston, Massachusetts 02114, United States
| | - Ramesh Raghupathi
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Rudolph E. Tanzi
- Harvard University and Massachusetts General Hospital, Boston, Massachusetts 02114, United States
| | - Aleister Saunders
- Department of Biology, College of Art and Sciences, Drexel University, Philadelphia, Pennsylvania 19104, United States
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19104, United States
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19104, United States
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Ping Y, Hahm ET, Waro G, Song Q, Vo-Ba DA, Licursi A, Bao H, Ganoe L, Finch K, Tsunoda S. Linking aβ42-induced hyperexcitability to neurodegeneration, learning and motor deficits, and a shorter lifespan in an Alzheimer's model. PLoS Genet 2015; 11:e1005025. [PMID: 25774758 PMCID: PMC4361604 DOI: 10.1371/journal.pgen.1005025] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 01/25/2015] [Indexed: 11/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly. β-amyloid (Aβ) accumulation in the brain is thought to be a primary event leading to eventual cognitive and motor dysfunction in AD. Aβ has been shown to promote neuronal hyperactivity, which is consistent with enhanced seizure activity in mouse models and AD patients. Little, however, is known about whether, and how, increased excitability contributes to downstream pathologies of AD. Here, we show that overexpression of human Aβ42 in a Drosophila model indeed induces increased neuronal activity. We found that the underlying mechanism involves the selective degradation of the A-type K+ channel, Kv4. An age-dependent loss of Kv4 leads to an increased probability of AP firing. Interestingly, we find that loss of Kv4 alone results in learning and locomotion defects, as well as a shortened lifespan. To test whether the Aβ42-induced increase in neuronal excitability contributes to, or exacerbates, downstream pathologies, we transgenically over-expressed Kv4 to near wild-type levels in Aβ42-expressing animals. We show that restoration of Kv4 attenuated age-dependent learning and locomotor deficits, slowed the onset of neurodegeneration, and partially rescued premature death seen in Aβ42-expressing animals. We conclude that Aβ42-induced hyperactivity plays a critical role in the age-dependent cognitive and motor decline of this Aβ42-Drosophila model, and possibly in AD.
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Affiliation(s)
- Yong Ping
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Eu-Teum Hahm
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Girma Waro
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Qian Song
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Dai-An Vo-Ba
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ashley Licursi
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Han Bao
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Logan Ganoe
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kelly Finch
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Susan Tsunoda
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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Kwak SY, Kim BY, Ahn HJ, Yoo JO, Kim J, Bae IH, Han YH. Ionizing radiation-inducible miR-30e promotes glioma cell invasion through EGFR stabilization by directly targeting CBL-B. FEBS J 2015; 282:1512-25. [PMID: 25691332 DOI: 10.1111/febs.13238] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/26/2015] [Accepted: 02/12/2015] [Indexed: 02/06/2023]
Abstract
MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression at the transcriptional and post-transcriptional levels. Here we show that miR-30e, which was previously identified as an ionizing radiation-inducible miRNA, enhances cellular invasion by promoting secretion of the matrix metalloproteinase MMP-2. The enhancement of cellular invasion by miR-30e involved up-regulation of the epidermal growth factor receptor (EGFR) and subsequent activation of its downstream signaling mediators, AKT and extracellular signal-regulated kinase. EGFR up-regulation by miR-30e occurred due to stabilization of the EGFR protein. The E3 ubiquitin ligase casitas B-lineage lymphoma B (CBL-B) was down-regulated by miR-30e, and this led to increased EGFR abundance. A 3' UTR reporter assay confirmed that CBL-B is a direct target of miR-30e. Knocking down CBL-B expression phenocopied the effects of miR-30e, whereas ectopic expression of CBL-B suppressed miR-30e-induced EGFR up-regulation and invasion. Collectively, our results suggest that targeting miR-30e may limit the invasiveness induced during glioma radiotherapy.
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Affiliation(s)
- Seo-Young Kwak
- Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; Laboratory of Biochemistry, School of Life Sciences and Biotechnology, Korea University, Seoul, Korea
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Gui Y, Yeganeh M, Donates YC, Tobelaim WS, Chababi W, Mayhue M, Yoshimura A, Ramanathan S, Saucier C, Ilangumaran S. Regulation of MET receptor tyrosine kinase signaling by suppressor of cytokine signaling 1 in hepatocellular carcinoma. Oncogene 2015; 34:5718-28. [PMID: 25728680 DOI: 10.1038/onc.2015.20] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 12/18/2014] [Accepted: 01/20/2015] [Indexed: 01/11/2023]
Abstract
Suppressor of cytokine signaling 1 (SOCS1) is considered as a tumor suppressor protein in hepatocellular carcinoma (HCC), but the underlying mechanisms remain unclear. Previously, we have shown that SOCS1-deficient hepatocytes displayed increased responsiveness to hepatocyte growth factor (HGF) due to enhanced signaling via the MET receptor tyrosine kinase. As aberrant MET activation occurs in many tumors including HCC, here we elucidated the mechanisms of SOCS1-mediated regulation. SOCS1 attenuated HGF-induced proliferation of human and mouse HCC cell lines and their growth as tumors in NOD.scid.gamma mice. Tumors formed by SOCS1 expressing HCC cells showed significantly reduced MET expression, indicating that SOCS1 not only attenuates MET signaling but also regulates MET expression. Mechanistically, SOCS1 interacted with MET via the Src homology 2 domain and this interaction was promoted by MET tyrosine kinase activity. The SOCS1-mediated reduction in MET expression does not require the juxtamembrane Y1003 residue implicated in Cbl-mediated downmodulation. Moreover, the proteasome inhibitor MG-132, but not the inhibitors of lysosomal degradation bafilomycin and chloroquine, reversed the SOCS1-mediated reduction in MET expression, indicating that this process is distinct from Cbl-mediated downmodulation. Accordingly, SOCS1 promoted polyubiquitination of MET via K48-dependent but not K63-mediated ubiquitin chain elongation. Furthermore, siRNA-mediated downmodulation of Cbl did not abolish SOCS1-mediated reduction in MET expression in HCC cells. SOCS1-dependent ubiquitination of endogenous MET receptor occurred rapidly following HGF stimulation in HCC cells, leading to proteasomal degradation of phosphorylated MET receptor. These findings indicate that SOCS1 mediates its tumor suppressor functions, at least partly, by binding to MET and interfering with downstream signaling pathways as well as by promoting the turnover of the activated MET receptor. We propose that loss of this control mechanism due to epigenetic repression of SOCS1 could contribute to oncogenic MET signaling in HCC and other cancers, and that MET inhibitors might be useful in treating these patients.
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Affiliation(s)
- Y Gui
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - M Yeganeh
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Y-C Donates
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - W-S Tobelaim
- Department of Anatomy and Cell biology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - W Chababi
- Department of Anatomy and Cell biology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - M Mayhue
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - A Yoshimura
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
| | - S Ramanathan
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - C Saucier
- Department of Anatomy and Cell biology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - S Ilangumaran
- Immunology Division, Department of Pediatrics, Faculty of Medicine and Health Sciences, University of Sherbrooke, Centre de Recherche Clinique Etienne-Le Bel, Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Quebec, Canada
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Estrogen receptor alpha mediates epithelial to mesenchymal transition, expression of specific matrix effectors and functional properties of breast cancer cells. Matrix Biol 2015; 43:42-60. [PMID: 25728938 DOI: 10.1016/j.matbio.2015.02.008] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 02/20/2015] [Accepted: 02/20/2015] [Indexed: 12/29/2022]
Abstract
The 17β-estradiol (E2)/estrogen receptor alpha (ERα) signaling pathway is one of the most important pathways in hormone-dependent breast cancer. E2 plays pivotal roles in cancer cell growth, survival, and architecture as well as in gene expression regulatory mechanisms. In this study, we established stably transfected MCF-7 cells by knocking down the ERα gene (designated as MCF-7/SP10+ cells), using specific shRNA lentiviral particles, and compared them with the control cells (MCF-7/c). Interestingly, ERα silencing in MCF-7 cells strongly induced cellular phenotypic changes accompanied by significant changes in gene and protein expression of several markers typical of epithelial to mesenchymal transition (EMT). Notably, these cells exhibited enhanced cell proliferation, migration and invasion. Moreover, ERα suppression strongly affected the gene and protein expression of EGFR and HER2 receptor tyrosine kinases, and various extracellular matrix (ECM) effectors, including matrix metalloproteinases and their endogenous inhibitors (MMPs/TIMPs) and components of the plasminogen activation system. The action caused by E2 in MCF-7/c cells in the expression of HER2, MT1-MMP, MMP1, MMP9, uPA, tPA, and PAI-1 was abolished in MCF-7/SP10+ cells lacking ERα. These data suggested a regulatory role for the E2/ERα pathway in respect to the composition and activity of the extracellular proteolytic molecular network. Notably, loss of ERα promoted breast cancer cell migration and invasion by inducing changes in the expression levels of certain matrix macromolecules (especially uPA, tPA, PAI-1) through the EGFR-ERK signaling pathway. In conclusion, loss of ERα in breast cancer cells results in a potent EMT characterized by striking changes in the expression profile of specific matrix macromolecules highlighting the potential nodal role of matrix effectors in breast cancer endocrine resistance.
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Hong Z, Cao X, Li N, Zhang Y, Lan L, Zhou Y, Pan X, Shen L, Yin Z, Luo L. Luteolin is effective in the non-small cell lung cancer model with L858R/T790M EGF receptor mutation and erlotinib resistance. Br J Pharmacol 2014; 171:2842-53. [PMID: 24471765 DOI: 10.1111/bph.12610] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 01/03/2014] [Accepted: 01/23/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Non-small cell lung cancer (NSCLC) is one of the most commonly diagnosed malignancies in the world. Small-molecule inhibitors of the EGF receptor's tyrosine kinase domain (TKIs), including gefitinib and erlotinib, have been widely used for treating NSCLC. Unfortunately, nearly all patients after initially experiencing a marked improvement while on these drugs, eventually progress to acquire resistance to TKIs. Because there is no effective therapeutic strategy to treat TKI-resistant NSCLC, we evaluated the effects of luteolin, a naturally occurring flavanoid, on T790M mutant NSCLC cells. EXPERIMENTAL APPROACH The effect of luteolin on the viability of NSCLC and normal cell lines was investigated using the Cell Counting Kit-8 (CCK-8) assay. Luteolin-induced apoptosis was assessed by bivariate FITC-annexin V/PI assay, and Western blots were used to measured apoptotic proteins. Co-immunoprecipitation was used to determine the effect of luteolin on the interaction between Hsp90 and mutant EGF receptors. The effect of luteolin on the Akt/mTOR pathway was studied using Western blotting analysis. Its anti-tumour efficacy in vivo was examined in a mouse xenograft model. KEY RESULTS Luteolin exerted significant anti-tumourigenic effects on the EGF receptor L858R/T790M mutation and erlotinib-resistant NSCLC both at the cellular and animal levels. Mechanistically, luteolin induced degradation of the EGF receptor by inhibiting the association of Hsp90 with the mutant EGF receptor, and, therefore, prevented PI3K/Akt/mTOR signalling, which resulted in NSCLC cell apoptosis. CONCLUSION AND IMPLICATIONS Luteolin may be a potential candidate for NSCLC therapy, especially for treatment of patients with acquired erlotinib-resistant NSCLC.
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Affiliation(s)
- Zhuan Hong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China; Jiangsu Cancer Hospital, Nanjing, Jiangsu, China
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Lin YC, Wu MH, Wei TT, Lin YC, Huang WC, Huang LY, Lin YT, Chen CC. Metformin sensitizes anticancer effect of dasatinib in head and neck squamous cell carcinoma cells through AMPK-dependent ER stress. Oncotarget 2014; 5:298-308. [PMID: 24457597 PMCID: PMC3960210 DOI: 10.18632/oncotarget.1628] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Head and neck squamous cell carcinoma (HNSCC) is an important endemic disease in Taiwan with aggressive course and dismal outcome. Dasatinib is a Bcr-bl and Src kinase inhibitor that has potential against HNSCC. We recently disclosed that EGFR degradation is critical for dasatinib-induced apoptosis. Here, we further demonstrate that AMPK-dependent ER stress is responsible for this event. Dasatinib induced ER stress which mediated EGFR degradation in a c-cbl-dependent manner. AMPK activation induced by dasatinib might be due to ATP decrease through the up-regulation of pyruvate dehydrogenase kinase 4 (PDK4). Furthermore, activation of AMPK by metformin sensitized dasatinib-induced in vitro and in vivo anti-cancer effect. The correlation of AMPK activation and EGFR expression was seen in HNSCC cells and human tumor specimens. Our results disclose that AMPK-dependent ER stress plays a crucial role in the anti-cancer effect of dasatinib in HNSCC and further activation of AMPK by metformin might enhance dasatinib efficacy.
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Ahmad G, Mohapatra BC, Schulte NA, Nadeau SA, Luan H, Zutshi N, Tom E, Ortega-Cava C, Tu C, Sanada M, Ogawa S, Toews ML, Band V, Band H. Cbl-family ubiquitin ligases and their recruitment of CIN85 are largely dispensable for epidermal growth factor receptor endocytosis. Int J Biochem Cell Biol 2014; 57:123-34. [PMID: 25449262 DOI: 10.1016/j.biocel.2014.10.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 10/03/2014] [Accepted: 10/16/2014] [Indexed: 11/15/2022]
Abstract
Members of the casitas B-lineage lymphoma (Cbl) family (Cbl, Cbl-b and Cbl-c) of ubiquitin ligases serve as negative regulators of receptor tyrosine kinases (RTKs). An essential role of Cbl-family protein-dependent ubiquitination for efficient ligand-induced lysosomal targeting and degradation is now well-accepted. However, a more proximal role of Cbl and Cbl-b as adapters for CIN85-endophilin recruitment to mediate ligand-induced initial internalization of RTKs is supported by some studies but refuted by others. Overexpression and/or incomplete depletion of Cbl proteins in these studies is likely to have contributed to this dichotomy. To address the role of endogenous Cbl and Cbl-b in the internalization step of RTK endocytic traffic, we established Cbl/Cbl-b double-knockout (DKO) mouse embryonic fibroblasts (MEFs) and demonstrated that these cells lack the expression of both Cbl-family members as well as endophilin A, while they express CIN85. We show that ligand-induced ubiquitination of EGFR, as a prototype RTK, was abolished in DKO MEFs, and EGFR degradation was delayed. These traits were reversed by ectopic human Cbl expression. EGFR endocytosis, assessed using the internalization of (125)I-labeled or fluorescent EGF, or of EGFR itself, was largely retained in Cbl/Cbl-b DKO compared to wild type MEFs. EGFR internalization was also largely intact in Cbl/Cbl-b depleted MCF-10A human mammary epithelial cell line. Inducible shRNA-mediated knockdown of CIN85 in wild type or Cbl/Cbl-b DKO MEFs had no impact on EGFR internalization. Our findings, establish that, at physiological expression levels, Cbl, Cbl-b and CIN85 are largely dispensable for EGFR internalization. Our results support the model that Cbl-CIN85-endophilin complex is not required for efficient internalization of EGFR, a prototype RTK.
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Affiliation(s)
- Gulzar Ahmad
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Bhopal C Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Nancy A Schulte
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Scott A Nadeau
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Haitao Luan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Neha Zutshi
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Pathology & Microbiology, College of Medicine, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Eric Tom
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Cesar Ortega-Cava
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Chun Tu
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Masashi Sanada
- Department of Pathology and Tumor Biology, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Seishi Ogawa
- Department of Pathology and Tumor Biology, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Myron L Toews
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Vimla Band
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA
| | - Hamid Band
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Department of Pathology & Microbiology, College of Medicine, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center, Omaha, NE 68198-5950, USA.
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Li B, Lu D, Shan L. Ubiquitination of pattern recognition receptors in plant innate immunity. MOLECULAR PLANT PATHOLOGY 2014; 15:737-746. [PMID: 25275148 PMCID: PMC4183980 DOI: 10.1111/mpp.12128] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Lacking an adaptive immune system, plants largely rely on plasma membrane-resident pattern recognition receptors (PRRs) to sense pathogen invasion. The activation of PRRs leads to the profound immune responses that coordinately contribute to the restriction of pathogen multiplication. Protein post-translational modifications dynamically shape the intensity and duration of the signalling pathways. In this review, we discuss the specific regulation of PRR activation and signalling by protein ubiquitination, endocytosis and degradation, with a particular focus on the bacterial flagellin receptor FLS2 (flagellin sensing 2) in Arabidopsis.
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Affiliation(s)
- Bo Li
- Department of Plant Pathology and Microbiology, and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA
- The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Dongping Lu
- Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China
| | - Libo Shan
- Department of Plant Pathology and Microbiology, and Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA
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Bertelsen V, Stang E. The Mysterious Ways of ErbB2/HER2 Trafficking. MEMBRANES 2014; 4:424-46. [PMID: 25102001 PMCID: PMC4194043 DOI: 10.3390/membranes4030424] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/01/2014] [Accepted: 07/22/2014] [Indexed: 12/14/2022]
Abstract
The EGFR- or ErbB-family of receptor tyrosine kinases consists of EGFR/ErbB1, ErbB2/HER2, ErbB3/HER3 and ErbB4/HER4. Receptor activation and downstream signaling are generally initiated upon ligand-induced receptor homo- or heterodimerization at the plasma membrane, and endocytosis and intracellular membrane transport are crucial for regulation of the signaling outcome. Among the receptors, ErbB2 is special in several ways. Unlike the others, ErbB2 has no known ligand, but is still the favored dimerization partner. Furthermore, while the other receptors are down-regulated either constitutively or upon ligand-binding, ErbB2 is resistant to down-regulation, and also inhibits down-regulation of its partner upon heterodimerization. The reason(s) why ErbB2 is resistant to down-regulation are the subject of debate. Contrary to other ErbB-proteins, mature ErbB2 needs Hsp90 as chaperone. Several data suggest that Hsp90 is an important regulator of factors like ErbB2 stability, dimerization and/or signaling. Hsp90 inhibitors induce degradation of ErbB2, but whether Hsp90 directly makes ErbB2 endocytosis resistant is unclear. Exposure to anti-ErbB2 antibodies can also induce down-regulation of ErbB2. Down-regulation induced by Hsp90 inhibitors or antibodies does at least partly involve internalization and endosomal sorting to lysosomes for degradation, but also retrograde trafficking to the nucleus has been reported. In this review, we will discuss different molecular mechanisms suggested to be important for making ErbB2 resistant to down-regulation, and review how membrane trafficking is involved when down-regulation and/or relocalization of ErbB2 is induced.
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Affiliation(s)
- Vibeke Bertelsen
- Department of Pathology, Oslo University Hospital, Rikshospitalet, Post Box 4950 Nydalen, 0424 Oslo, Norway.
| | - Espen Stang
- Department of Pathology, Oslo University Hospital, Rikshospitalet, Post Box 4950 Nydalen, 0424 Oslo, Norway.
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Hwang GW, Murai Y, Takahashi T, Naganuma A. The protein transportation pathway from Golgi to vacuoles via endosomes plays a role in enhancement of methylmercury toxicity. Sci Rep 2014; 4:5888. [PMID: 25074250 PMCID: PMC4118254 DOI: 10.1038/srep05888] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/14/2014] [Indexed: 11/09/2022] Open
Abstract
Methylmercury causes serious damage to the central nervous system, but the molecular mechanisms of methylmercury toxicity are only marginally understood. In this study, we used a gene-deletion mutant library of budding yeast to conduct genome-wide screening for gene knockouts affecting the sensitivity of methylmercury toxicity. We successfully identified 31 genes whose deletions confer resistance to methylmercury in yeast, and 18 genes whose deletions confer hypersensitivity to methylmercury. Yeast genes whose deletions conferred resistance to methylmercury included many gene encoding factors involved in protein transport to vacuoles. Detailed examination of the relationship between the factors involved in this transport system and methylmercury toxicity revealed that mutants with loss of the factors involved in the transportation pathway from the trans-Golgi network (TGN) to the endosome, protein uptake into the endosome, and endosome-vacuole fusion showed higher methylmercury resistance than did wild-type yeast. The results of our genetic engineering study suggest that this vesicle transport system (proteins moving from the TGN to vacuole via endosome) is responsible for enhancing methylmercury toxicity due to the interrelationship between the pathways. There is a possibility that there may be proteins in the cell that enhance methylmercury toxicity through the protein transport system.
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Affiliation(s)
- Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Yasutaka Murai
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Tsutomu Takahashi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
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Rush JS, Boeving MA, Berry WL, Ceresa BP. Antagonizing c-Cbl enhances EGFR-dependent corneal epithelial homeostasis. Invest Ophthalmol Vis Sci 2014; 55:4691-9. [PMID: 24985478 DOI: 10.1167/iovs.14-14133] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE In many cell types, the E3 ubiquitin ligase, c-Cbl, induces ligand-dependent ubiquitylation of the epidermal growth factor receptor (EGFR) and targets the receptor for lysosomal degradation. The goal of this study was to determine whether c-Cbl is a negative regulator of EGFR in the corneal epithelium and if it can be inhibited to promote corneal epithelial homeostasis. METHODS Expression and activity of c-Cbl were blocked in immortalized human corneal epithelial cells (hTCEpi) using RNAi and pharmacological agents ([4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo-d-3,4-pyrimidine] or PP1). Following c-Cbl inhibition, cells were assessed for ligand-dependent receptor ubiquitylation, receptor phosphorylation, and in vitro wound healing. Subsequent experiments used PP1 in hTCEpi cells and monitored in vivo murine corneal epithelial wound healing. RESULTS Knockdown and inhibition of c-Cbl decreased ligand-dependent ubiquitylation of the EGFR and prolonged receptor activity as measured by tyrosine phosphorylation. Further, these treatments also increased the extent of ligand-dependent corneal epithelial wound healing in vitro and in vivo. CONCLUSION Manipulating the duration of EGFR activity can enhance the rate of restoration of the corneal epithelial layer. Based on our findings, c-Cbl is a new therapeutic target to enhance EGFR-mediated corneal epithelial homeostasis that bypasses the limitations of previous approaches.
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Affiliation(s)
- Jamie S Rush
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, United States
| | - Michael A Boeving
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, United States
| | - William L Berry
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, United States
| | - Brian P Ceresa
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, United States Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, United States
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Ceresa BP, Peterson JL. Cell and molecular biology of epidermal growth factor receptor. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 313:145-78. [PMID: 25376492 DOI: 10.1016/b978-0-12-800177-6.00005-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The epidermal growth factor receptor (EGFR) has been one of the most intensely studied cell surface receptors due to its well-established roles in developmental biology, tissue homeostasis, and cancer biology. The EGFR has been critical for creating paradigms for numerous aspects of cell biology, such as ligand binding, signal transduction, and membrane trafficking. Despite this history of discovery, there is a continual stream of evidence that only the surface has been scratched. New ways of receptor regulation continue to be identified, each of which is a potential molecular target for manipulating EGFR signaling and the resultant changes in cell and tissue biology. This chapter is an update on EGFR-mediated signaling, and describes some recent developments in the regulation of receptor biology.
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Affiliation(s)
- Brian P Ceresa
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
| | - Joanne L Peterson
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
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Gomes AV. Genetics of proteasome diseases. SCIENTIFICA 2013; 2013:637629. [PMID: 24490108 PMCID: PMC3892944 DOI: 10.1155/2013/637629] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 11/18/2013] [Indexed: 05/28/2023]
Abstract
The proteasome is a large, multiple subunit complex that is capable of degrading most intracellular proteins. Polymorphisms in proteasome subunits are associated with cardiovascular diseases, diabetes, neurological diseases, and cancer. One polymorphism in the proteasome gene PSMA6 (-8C/G) is associated with three different diseases: type 2 diabetes, myocardial infarction, and coronary artery disease. One type of proteasome, the immunoproteasome, which contains inducible catalytic subunits, is adapted to generate peptides for antigen presentation. It has recently been shown that mutations and polymorphisms in the immunoproteasome catalytic subunit PSMB8 are associated with several inflammatory and autoinflammatory diseases including Nakajo-Nishimura syndrome, CANDLE syndrome, and intestinal M. tuberculosis infection. This comprehensive review describes the disease-related polymorphisms in proteasome genes associated with human diseases and the physiological modulation of proteasome function by these polymorphisms. Given the large number of subunits and the central importance of the proteasome in human physiology as well as the fast pace of detection of proteasome polymorphisms associated with human diseases, it is likely that other polymorphisms in proteasome genes associated with diseases will be detected in the near future. While disease-associated polymorphisms are now readily discovered, the challenge will be to use this genetic information for clinical benefit.
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Affiliation(s)
- Aldrin V. Gomes
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA 95616, USA
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA
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HER. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Sirisaengtaksin N, Gireud M, Yan Q, Kubota Y, Meza D, Waymire JC, Zage PE, Bean AJ. UBE4B protein couples ubiquitination and sorting machineries to enable epidermal growth factor receptor (EGFR) degradation. J Biol Chem 2013; 289:3026-39. [PMID: 24344129 DOI: 10.1074/jbc.m113.495671] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The signaling of plasma membrane proteins is tuned by internalization and sorting in the endocytic pathway prior to recycling or degradation in lysosomes. Ubiquitin modification allows recognition and association of cargo with endosomally associated protein complexes, enabling sorting of proteins to be degraded from those to be recycled. The mechanism that provides coordination between the cellular machineries that mediate ubiquitination and endosomal sorting is unknown. We report that the ubiquitin ligase UBE4B is recruited to endosomes in response to epidermal growth factor receptor (EGFR) activation by binding to Hrs, a key component of endosomal sorting complex required for transport (ESCRT) 0. We identify the EGFR as a substrate for UBE4B, establish UBE4B as a regulator of EGFR degradation, and describe a mechanism by which UBE4B regulates endosomal sorting, affecting cellular levels of the EGFR and its downstream signaling. We propose a model in which the coordinated action of UBE4B, ESCRT-0, and the deubiquitinating enzyme USP8 enable the endosomal sorting and lysosomal degradation of the EGFR.
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Affiliation(s)
- Natalie Sirisaengtaksin
- From the Department of Neurobiology and Anatomy and the Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas 77030
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Roskoski R. The ErbB/HER family of protein-tyrosine kinases and cancer. Pharmacol Res 2013; 79:34-74. [PMID: 24269963 DOI: 10.1016/j.phrs.2013.11.002] [Citation(s) in RCA: 890] [Impact Index Per Article: 80.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 11/08/2013] [Indexed: 10/26/2022]
Abstract
The human epidermal growth factor receptor (EGFR) family consists of four members that belong to the ErbB lineage of proteins (ErbB1-4). These receptors consist of a glycosylated extracellular domain, a single hydrophobic transmembrane segment, and an intracellular portion with a juxtamembrane segment, a protein kinase domain, and a carboxyterminal tail. Seven ligands bind to EGFR including epidermal growth factor and transforming growth factor α, none bind to ErbB2, two bind to ErbB3, and seven ligands bind to ErbB4. The ErbB proteins function as homo and heterodimers. The heterodimer consisting of ErbB2, which lacks a ligand, and ErbB3, which is kinase impaired, is surprisingly the most robust signaling complex of the ErbB family. Growth factor binding to EGFR induces a large conformational change in the extracellular domain, which leads to the exposure of a dimerization arm in domain II of the extracellular segment. Two ligand-EGFR complexes unite to form a back-to-back dimer in which the ligands are on opposite sides of the aggregate. Following ligand binding, EGFR intracellular kinase domains form an asymmetric homodimer that resembles the heterodimer formed by cyclin and cyclin-dependent kinase. The carboxyterminal lobe of the activator kinase of the dimer interacts with the amino-terminal lobe of the receiver kinase thereby leading to its allosteric stimulation. Downstream ErbB signaling modules include the phosphatidylinositol 3-kinase/Akt (PKB) pathway, the Ras/Raf/MEK/ERK1/2 pathway, and the phospholipase C (PLCγ) pathway. Several malignancies are associated with the mutation or increased expression of members of the ErbB family including lung, breast, stomach, colorectal, head and neck, and pancreatic carcinomas and glioblastoma (a brain tumor). Gefitinib, erlotinib, and afatinib are orally effective protein-kinase targeted quinazoline derivatives that are used in the treatment of ERBB1-mutant lung cancer. Lapatinib is an orally effective quinazoline derivative used in the treatment of ErbB2-overexpressing breast cancer. Trastuzumab, pertuzumab, and ado-trastuzumab emtansine, which are given intravenously, are monoclonal antibodies that target the extracellular domain and are used for the treatment of ErbB2-positive breast cancer; ado-trastuzumab emtansine is an antibody-drug conjugate that delivers a cytotoxic drug to cells overexpressing ErbB2. Cetuximab and panitumumab are monoclonal antibodies that target ErbB1 and are used in the treatment of colorectal cancer. Cancers treated with these targeted drugs eventually become resistant to them. The role of combinations of targeted drugs or targeted drugs with cytotoxic therapies is being explored in an effort to prevent or delay drug resistance in the treatment of these malignancies.
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Affiliation(s)
- Robert Roskoski
- Blue Ridge Institute for Medical Research, 3754 Brevard Road, Suite 116, Box 19, Horse Shoe, NC 28742, USA.
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Mehra A, Zahra A, Thompson V, Sirisaengtaksin N, Wells A, Porto M, Köster S, Penberthy K, Kubota Y, Dricot A, Rogan D, Vidal M, Hill DE, Bean AJ, Philips JA. Mycobacterium tuberculosis type VII secreted effector EsxH targets host ESCRT to impair trafficking. PLoS Pathog 2013; 9:e1003734. [PMID: 24204276 PMCID: PMC3814348 DOI: 10.1371/journal.ppat.1003734] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 09/12/2013] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) disrupts anti-microbial pathways of macrophages, cells that normally kill bacteria. Over 40 years ago, D'Arcy Hart showed that Mtb avoids delivery to lysosomes, but the molecular mechanisms that allow Mtb to elude lysosomal degradation are poorly understood. Specialized secretion systems are often used by bacterial pathogens to translocate effectors that target the host, and Mtb encodes type VII secretion systems (TSSSs) that enable mycobacteria to secrete proteins across their complex cell envelope; however, their cellular targets are unknown. Here, we describe a systematic strategy to identify bacterial virulence factors by looking for interactions between the Mtb secretome and host proteins using a high throughput, high stringency, yeast two-hybrid (Y2H) platform. Using this approach we identified an interaction between EsxH, which is secreted by the Esx-3 TSSS, and human hepatocyte growth factor-regulated tyrosine kinase substrate (Hgs/Hrs), a component of the endosomal sorting complex required for transport (ESCRT). ESCRT has a well-described role in directing proteins destined for lysosomal degradation into intraluminal vesicles (ILVs) of multivesicular bodies (MVBs), ensuring degradation of the sorted cargo upon MVB-lysosome fusion. Here, we show that ESCRT is required to deliver Mtb to the lysosome and to restrict intracellular bacterial growth. Further, EsxH, in complex with EsxG, disrupts ESCRT function and impairs phagosome maturation. Thus, we demonstrate a role for a TSSS and the host ESCRT machinery in one of the central features of tuberculosis pathogenesis. Mycobacterium tuberculosis (Mtb) causes the disease tuberculosis, one of the world's most deadly infections. The host immune system can't eradicate Mtb because it grows within macrophages, cells that normally kill bacteria. One of the intracellular survival strategies of Mtb is to avoid delivery to lysosomes, a phenomenon described over 40 years ago, but for which the mechanism and molecular details remain incomplete. Mtb possess specialized secretion systems (Type VII secretion systems; TSSS) that transfer particular proteins out of the bacteria, but how these proteins promote infection is not well understood. In this study, we used a high stringency yeast two-hybrid system to identify interactions between secreted effectors from Mtb and human host factors. We identified ninety-nine such interactions and focused our attention on the interaction between EsxH, secreted by Esx-3, a TSSS of Mtb, and Hrs, a component of the host ESCRT machinery. We provide evidence that Mtb EsxH directly targets host Hrs to disrupt delivery of bacteria to lysosomes. Thus, this study demonstrates the role of a TSSS effector and the ESCRT machinery in what is one of the central features of tuberculosis pathogenesis, thereby providing molecular insight into why humans can't clear Mtb infection.
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Affiliation(s)
- Alka Mehra
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Aleena Zahra
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Victor Thompson
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Natalie Sirisaengtaksin
- Department of Neurobiology and Anatomy, and Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Ashley Wells
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Maura Porto
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Stefan Köster
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Kristen Penberthy
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Yoshihisha Kubota
- Department of Neurobiology and Anatomy, and Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Amelie Dricot
- Center for Cancer Systems Biology (CCSB) and Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Daniel Rogan
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
| | - Marc Vidal
- Center for Cancer Systems Biology (CCSB) and Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David E. Hill
- Center for Cancer Systems Biology (CCSB) and Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Andrew J. Bean
- Department of Neurobiology and Anatomy, and Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Division of Pediatrics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Jennifer A. Philips
- Division of Infectious Diseases, Department of Medicine, Department of Pathology and Department of Microbiology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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Role of phosphatidylinositol 4,5-bisphosphate in regulating EHD2 plasma membrane localization. PLoS One 2013; 8:e74519. [PMID: 24040268 PMCID: PMC3769341 DOI: 10.1371/journal.pone.0074519] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/02/2013] [Indexed: 01/29/2023] Open
Abstract
The four mammalian C-terminal Eps15 homology domain-containing proteins (EHD1-EHD4) play pivotal roles in endocytic membrane trafficking. While EHD1, EHD3 and EHD4 associate with intracellular tubular/vesicular membranes, EHD2 localizes to the inner leaflet of the plasma membrane. Currently, little is known about the regulation of EHD2. Thus, we sought to define the factors responsible for EHD2’s association with the plasma membrane. The subcellular localization of endogenous EHD2 was examined in HeLa cells using confocal microscopy. Although EHD partner proteins typically mediate EHD membrane recruitment, EHD2 was targeted to the plasma membrane independent of two well-characterized binding proteins, syndapin2 and EHBP1. Additionally, the EH domain of EHD2, which facilitates canonical EHD protein interactions, was not required to direct overexpressed EHD2 to the cell surface. On the other hand, several lines of evidence indicate that the plasma membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) plays a crucial role in regulating EHD2 subcellular localization. Pharmacologic perturbation of PIP2 metabolism altered PIP2 plasma membrane distribution (as assessed by confocal microscopy), and caused EHD2 to redistribute away from the plasma membrane. Furthermore, overexpressed EHD2 localized to PIP2-enriched vacuoles generated by active Arf6. Finally, we show that although cytochalasin D caused actin microfilaments to collapse, EHD2 was nevertheless maintained at the plasma membrane. Intriguingly, cytochalasin D induced relocalization of both PIP2 and EHD2 to actin aggregates, supporting a role of PIP2 in controlling EHD2 subcellular localization. Altogether, these studies emphasize the significance of membrane lipid composition for EHD2 subcellular distribution and offer new insights into the regulation of this important endocytic protein.
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74
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de Juan-Sanz J, Núñez E, Villarejo-López L, Pérez-Hernández D, Rodriguez-Fraticelli AE, López-Corcuera B, Vázquez J, Aragón C. Na+/K+-ATPase is a new interacting partner for the neuronal glycine transporter GlyT2 that downregulates its expression in vitro and in vivo. J Neurosci 2013; 33:14269-81. [PMID: 23986260 PMCID: PMC6618510 DOI: 10.1523/jneurosci.1532-13.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/09/2013] [Accepted: 07/18/2013] [Indexed: 01/16/2023] Open
Abstract
The neuronal glycine transporter GlyT2 plays a fundamental role in the glycinergic neurotransmission by recycling the neurotransmitter to the presynaptic terminal. GlyT2 is the main supplier of glycine for vesicle refilling, a process that is absolutely necessary to preserve quantal glycine content in synaptic vesicles. Alterations in GlyT2 activity modify glycinergic neurotransmission and may underlie several neuromuscular disorders, such as hyperekplexia, myoclonus, dystonia, and epilepsy. Indeed, mutations in the gene encoding GlyT2 are the main presynaptic cause of hyperekplexia in humans and produce congenital muscular dystonia type 2 (CMD2) in Belgian Blue cattle. GlyT2 function is strictly coupled to the sodium electrochemical gradient actively generated by the Na+/K+-ATPase (NKA). GlyT2 cotransports 3Na+/Cl-/glycine generating large rises of Na+ inside the presynaptic terminal that must be efficiently reduced by the NKA to preserve Na+ homeostasis. In this work, we have used high-throughput mass spectrometry to identify proteins interacting with GlyT2 in the CNS. NKA was detected as a putative candidate and through reciprocal coimmunoprecipitations and immunocytochemistry analyses the association between GlyT2 and NKA was confirmed. NKA mainly interacts with the raft-associated active pool of GlyT2, and low and high levels of the specific NKA ligand ouabain modulate the endocytosis and total expression of GlyT2 in neurons. The ouabain-mediated downregulation of GlyT2 also occurs in vivo in two different systems: zebrafish embryos and adult rats, indicating that this NKA-mediated regulatory mechanism is evolutionarily conserved and may play a relevant role in the physiological control of inhibitory glycinergic neurotransmission.
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Affiliation(s)
- Jaime de Juan-Sanz
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
| | - Enrique Núñez
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
| | - Lucía Villarejo-López
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | | | - Alejo E. Rodriguez-Fraticelli
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Beatriz López-Corcuera
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
| | - Jesús Vázquez
- Centro Nacional de Investigaciones Cardiovasculares, 28029 Madrid, Spain, and
| | - Carmen Aragón
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras, ISCIII, 46010 Valencia, Spain
- IdiPAZ-Hospital Universitario La Paz, 28046 Madrid, Spain
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75
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Directed evolution of a virus exclusively utilizing human epidermal growth factor receptor as the entry receptor. J Virol 2013; 87:11231-43. [PMID: 23926357 DOI: 10.1128/jvi.01054-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Rational design and directed evolution are powerful tools to generate and improve protein function; however, their uses are mostly limited to enzyme and antibody engineering. Here we describe a directed-evolution strategy, named the tandem selection and enrichment system (TSES), and its use in generating virus with exclusive specificity for a particular cellular receptor. In TSES, evolving viruses are sequentially and iteratively transferred between two different host cells, one for selection of receptor specificity and the other for enrichment of the fittest virus. By combining rational design and TSES, we generated human epidermal growth factor receptor (EGFR)-specific virus 1 (ESV1). ESV1 has the backbone of Sindbis virus (SINV) and displays an EGF domain engrafted onto structural protein E2 after residue Pro192, together with eight amino acid changes stabilizing the E2-EGF chimera. ESV1 uses EGFR to initiate infection and has lost the capacity to interact with all known SINV receptors. A 12.2-Å cryoelectron microscopic (cryoEM) reconstruction of ESV1 reveals that the E2-EGF fusion adopts a fixed conformation, with EGF sitting at the top of the E2 spike; The EGFR binding interface faces outward, and the EGF domain completely masks SINV receptor binding. The cryoEM structure of ESV1 explains the desirable properties of ESV1 and provides insights for its further modification. TSES expands the scope of directed evolution and can be easily extended to other targeting molecules and viral systems.
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76
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Turtoi A, Blomme A, Bellahcène A, Gilles C, Hennequière V, Peixoto P, Bianchi E, Noel A, De Pauw E, Lifrange E, Delvenne P, Castronovo V. Myoferlin Is a Key Regulator of EGFR Activity in Breast Cancer. Cancer Res 2013; 73:5438-48. [DOI: 10.1158/0008-5472.can-13-1142] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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77
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Odin (ANKS1A) modulates EGF receptor recycling and stability. PLoS One 2013; 8:e64817. [PMID: 23825523 PMCID: PMC3692516 DOI: 10.1371/journal.pone.0064817] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/18/2013] [Indexed: 12/22/2022] Open
Abstract
The ANKS1A gene product, also known as Odin, was first identified as a tyrosine-phosphorylated component of the epidermal growth factor receptor network. Here we show that Odin functions as an effector of EGFR recycling. In EGF-stimulated HEK293 cells tyrosine phosphorylation of Odin was induced prior to EGFR internalization and independent of EGFR-to-ERK signaling. Over-expression of Odin increased EGF-induced EGFR trafficking to recycling endosomes and recycling back to the cell surface, and decreased trafficking to lysosomes and degradation. Conversely, Odin knockdown in both HEK293 and the non-small cell lung carcinoma line RVH6849, which expresses roughly 10-fold more EGF receptors than HEK293, caused decreased EGFR recycling and accelerated trafficking to the lysosome and degradation. By governing the endocytic fate of internalized receptors, Odin may provide a layer of regulation that enables cells to contend with receptor cell densities and ligand concentration gradients that are physiologically and pathologically highly variable.
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78
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Hepatitis B Virus-Encoded X Protein Downregulates EGFR Expression via Inducing MicroRNA-7 in Hepatocellular Carcinoma Cells. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:682380. [PMID: 23840262 PMCID: PMC3693120 DOI: 10.1155/2013/682380] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 05/23/2013] [Indexed: 12/18/2022]
Abstract
Hepatitis B virus (HBV) infection accounts for over a half of cases of hepatocellular carcinoma (HCC), the most frequent malignant tumor of the liver. HBV-encoded X (HBx) plays critical roles in HBV-associated hepatocarcinogenesis. However, it is unclear whether and how HBx regulates the expression of epidermal growth factor receptor (EGFR), an important gene for cell growth. Therefore, the study aimed to investigate the association between HBx and EGFR expression. In this study, we found that HBx upregulates miR-7 expression to target 3′UTR of EGFR mRNA, which in turn results in the reduction of EGFR protein expression in HCC cells. HBx-mediated EGFR suppression renders HCC cells a slow-growth behavior. Deprivation of HBx or miR-7 expression or restoration of EGFR expression can increase the growth rate of HCC cells. Our data showed the miR-7-dependent EGFR suppression by HBx, supporting an inhibitory role of HBx in the cell growth of HCC. These findings not only identify miR-7 as a novel regulatory target of HBx, but also suggest HBx-miR-7-EGFR as a critical signaling in controlling the growth rate of HCC cells.
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79
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Chapel A, Kieffer-Jaquinod S, Sagné C, Verdon Q, Ivaldi C, Mellal M, Thirion J, Jadot M, Bruley C, Garin J, Gasnier B, Journet A. An extended proteome map of the lysosomal membrane reveals novel potential transporters. Mol Cell Proteomics 2013; 12:1572-88. [PMID: 23436907 PMCID: PMC3675815 DOI: 10.1074/mcp.m112.021980] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 02/01/2013] [Indexed: 12/22/2022] Open
Abstract
Lysosomes are membrane-bound endocytic organelles that play a major role in degrading cell macromolecules and recycling their building blocks. A comprehensive knowledge of the lysosome function requires an extensive description of its content, an issue partially addressed by previous proteomic analyses. However, the proteins underlying many lysosomal membrane functions, including numerous membrane transporters, remain unidentified. We performed a comparative, semi-quantitative proteomic analysis of rat liver lysosome-enriched and lysosome-nonenriched membranes and used spectral counts to evaluate the relative abundance of proteins. Among a total of 2,385 identified proteins, 734 proteins were significantly enriched in the lysosomal fraction, including 207 proteins already known or predicted as endo-lysosomal and 94 proteins without any known or predicted subcellular localization. The remaining 433 proteins had been previously assigned to other subcellular compartments but may in fact reside on lysosomes either predominantly or as a secondary location. Many membrane-associated complexes implicated in diverse processes such as degradation, membrane trafficking, lysosome biogenesis, lysosome acidification, signaling, and nutrient sensing were enriched in the lysosomal fraction. They were identified to an unprecedented extent as most, if not all, of their subunits were found and retained by our screen. Numerous transporters were also identified, including 46 novel potentially lysosomal proteins. We expressed 12 candidates in HeLa cells and observed that most of them colocalized with the lysosomal marker LAMP1, thus confirming their lysosomal residency. This list of candidate lysosomal proteins substantially increases our knowledge of the lysosomal membrane and provides a basis for further characterization of lysosomal functions.
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Affiliation(s)
- Agnès Chapel
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Sylvie Kieffer-Jaquinod
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Corinne Sagné
- the ‖Université Paris Descartes, Sorbonne Paris Cité, CNRS, UMR 8192, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75006 Paris, France
| | - Quentin Verdon
- the ‖Université Paris Descartes, Sorbonne Paris Cité, CNRS, UMR 8192, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75006 Paris, France
- §§Graduate School ED 419, Université Paris-Sud 11, Hôpital Bicêtre, F-94276 Le Kremlin Bicêtre France, and
| | - Corinne Ivaldi
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Mourad Mellal
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Jaqueline Thirion
- the **Unité de Recherche en Physiologie Moléculaire, Namur Research Institute for Life Sciences, University of Namur (FUNDP), 61, Rue de Bruxelles B,-5000, Namur, Belgium
| | - Michel Jadot
- the **Unité de Recherche en Physiologie Moléculaire, Namur Research Institute for Life Sciences, University of Namur (FUNDP), 61, Rue de Bruxelles B,-5000, Namur, Belgium
| | - Christophe Bruley
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Jérôme Garin
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
| | - Bruno Gasnier
- the ‖Université Paris Descartes, Sorbonne Paris Cité, CNRS, UMR 8192, Centre Universitaire des Saints-Pères, 45 Rue des Saints-Pères, F-75006 Paris, France
| | - Agnès Journet
- From the ‡Commissariat à l'Energie Atomique, Institut de Recherches en Technologies et Sciences du Vivant, Laboratoire Biologie à Grande Echelle, F-38054 Grenoble, France
- §INSERM, U1038, F-38054 Grenoble, France
- the ¶Université Joseph Fourier, Grenoble 1, F-38000, France
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80
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Sak MM, Szymanska M, Bertelsen V, Hasmann M, Madshus IH, Stang E. Pertuzumab counteracts the inhibitory effect of ErbB2 on degradation of ErbB3. Carcinogenesis 2013; 34:2031-8. [PMID: 23698633 DOI: 10.1093/carcin/bgt173] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Overexpression of ErbB2 and ErbB3 is found in several human cancers, and ErbB2-ErbB3 heterodimers are known as the most potent signaling units among ErbB dimers. While ErbB2 probably undergoes weak endocytosis, ErbB3 is readily internalized even in the absence of added ligand and without requirement for kinase activity. Overexpression of ErbB2 has been demonstrated to inhibit epidermal growth factor-induced internalization and degradation of epidermal growth factor receptor. This happens due to epidermal growth factor receptor-ErbB2 dimerization and can be counteracted by the anti-ErbB2 antibody pertuzumab, which binds the dimerization arm of ErbB2. Pertuzumab does also inhibit ErbB2-ErbB3 dimerization, but to what extent this has effect on constitutive and/or ligand-induced downregulation of ErbB3 is not known. In this study, we demonstrate that expression of ErbB2 as such did not block constitutive internalization of ErbB3, but that heregulin-induced degradation of ErbB3 was significantly slowed in cells expressing high levels of ErbB2. Incubation with pertuzumab did, however, counteract this effect. This indicates that the formation of ErbB2-ErbB3 heterodimers inhibits downregulation of ErbB3 and supports the notion that pertuzumab inhibits ErbB2 dimerization. The inhibitory effect of pertuzumab on ligand-induced ErbB2-ErbB3 heterodimerization was confirmed by the observation that pertuzumab inhibited heregulin-induced phosphorylation of ErbB3 in cells expressing ErbB2 and efficiently reduced heregulin-induced downstream signaling in cells expressing low levels of ErbB2. Altogether the results indicate that pertuzumab can be a valuable therapeutic agent not only in cancers overexpressing ErbB2 but also in cancers co-expressing ErbB2 and ErbB3.
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Affiliation(s)
- Malgorzata Magdalena Sak
- Department of Pathology, Oslo University Hospital, Rikshospitalet, PO Box 4950 Nydalen, 0424 Oslo, Norway
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81
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Poon WW, Carlos AJ, Aguilar BL, Berchtold NC, Kawano CK, Zograbyan V, Yaopruke T, Shelanski M, Cotman CW. β-Amyloid (Aβ) oligomers impair brain-derived neurotrophic factor retrograde trafficking by down-regulating ubiquitin C-terminal hydrolase, UCH-L1. J Biol Chem 2013; 288:16937-16948. [PMID: 23599427 DOI: 10.1074/jbc.m113.463711] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We previously found that BDNF-dependent retrograde trafficking is impaired in AD transgenic mouse neurons. Utilizing a novel microfluidic culture chamber, we demonstrate that Aβ oligomers compromise BDNF-mediated retrograde transport by impairing endosomal vesicle velocities, resulting in impaired downstream signaling driven by BDNF/TrkB, including ERK5 activation, and CREB-dependent gene regulation. Our data suggest that a key mechanism mediating the deficit involves ubiquitin C-terminal hydrolase L1 (UCH-L1), a deubiquitinating enzyme that functions to regulate cellular ubiquitin. Aβ-induced deficits in BDNF trafficking and signaling are mimicked by LDN (an inhibitor of UCH-L1) and can be reversed by increasing cellular UCH-L1 levels, demonstrated here using a transducible TAT-UCH-L1 strategy. Finally, our data reveal that UCH-L1 mRNA levels are decreased in the hippocampi of AD brains. Taken together, our data implicate that UCH-L1 is important for regulating neurotrophin receptor sorting to signaling endosomes and supporting retrograde transport. Further, our results support the idea that in AD, Aβ may down-regulate UCH-L1 in the AD brain, which in turn impairs BDNF/TrkB-mediated retrograde signaling, compromising synaptic plasticity and neuronal survival.
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Affiliation(s)
- Wayne W Poon
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697.
| | - Anthony J Carlos
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
| | - Brittany L Aguilar
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
| | - Nicole C Berchtold
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
| | - Crystal K Kawano
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
| | - Vahe Zograbyan
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
| | - Tim Yaopruke
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
| | - Michael Shelanski
- Department of Pathology and the Taub Institute, Columbia University, New York, New York 10032
| | - Carl W Cotman
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California 92697
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82
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Haglund K, Dikic I. The role of ubiquitylation in receptor endocytosis and endosomal sorting. J Cell Sci 2013; 125:265-75. [PMID: 22357968 DOI: 10.1242/jcs.091280] [Citation(s) in RCA: 224] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ligand-induced activation of transmembrane receptors activates intracellular signaling cascades that control vital cellular processes, such as cell proliferation, differentiation, migration and survival. Receptor signaling is modulated by several mechanisms to ensure that the correct biological outcome is achieved. One such mechanism, which negatively regulates receptor signaling, involves the modification of receptors with ubiquitin. This post-translational modification can promote receptor endocytosis and targets receptors for lysosomal degradation, thereby ensuring termination of receptor signaling. In this Commentary, we review the roles of ubiquitylation in receptor endocytosis and degradative endosomal sorting by drawing on the epidermal growth factor receptor (EGFR) as a well-studied example. Furthermore, we elaborate on the molecular basis of ubiquitin recognition along the endocytic pathway through compartment-specific ubiquitin-binding proteins and highlight how endocytic sorting machineries control these processes. In addition, we discuss the importance of ubiquitin-dependent receptor endocytosis for the maintenance of cellular homeostasis and in the prevention of diseases such as cancer.
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Affiliation(s)
- Kaisa Haglund
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0310 Oslo, Norway.
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83
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Rougier JS, Gavillet B, Abriel H. Proteasome inhibitor (MG132) rescues Nav1.5 protein content and the cardiac sodium current in dystrophin-deficient mdx (5cv) mice. Front Physiol 2013; 4:51. [PMID: 23532763 PMCID: PMC3607792 DOI: 10.3389/fphys.2013.00051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 03/04/2013] [Indexed: 12/16/2022] Open
Abstract
The cardiac voltage-gated sodium channel, Nav1.5, plays a central role in cardiac excitability and impulse propagation and associates with the dystrophin multiprotein complex at the lateral membrane of cardiomyocytes. It was previously shown that Nav1.5 protein content and the sodium current (lNa) were both decreased in cardiomyocytes of dystrophin-deficient mdx5cv mice. In this study, wild-type and mdx5cv mice were treated for 7 days with the proteasome inhibitor MG132 (10 μg/Kg/24 h) using implanted osmotic mini pumps. MG132 rescued both the total amount of Nav1.5 protein and lNa but, unlike in previous studies, de novo expression of dystrophin was not observed in skeletal or cardiac muscle. This study suggests that the reduced expression of Nav1.5 in dystrophin-deficient cells is dependent on proteasomal degradation.
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84
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Kong F, Zhang J, Li Y, Hao X, Ren X, Li H, Zhou P. Engineering a single ubiquitin ligase for the selective degradation of all activated ErbB receptor tyrosine kinases. Oncogene 2013; 33:986-95. [PMID: 23416973 PMCID: PMC3930622 DOI: 10.1038/onc.2013.33] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 12/19/2012] [Accepted: 12/21/2012] [Indexed: 12/21/2022]
Abstract
Interrogating specific cellular activities often entails the dissection of posttranslational modifications or functional redundancy conferred by protein families, which demands more sophisticated research tools than simply eliminating a specific gene product by gene targeting or RNA interference. We have developed a novel methodology that involves engineering a single SCF(βTrCP)-based ubiquitin ligase that is capable of not only simultaneously targeting the entire family of ErbB receptor tyrosine kinases for ubiquitination and degradation, but also selectively recruiting only activated ErbBs. The engineered SCF(βTrCP) ubiquitin ligase effectively blocked ErbB signaling and attenuated oncogenicity in breast cancer cells, yet had little effect on the survival and growth of non-cancerous breast epithelial cells. Therefore, engineering ubiquitin ligases offers a simple research tool to dissect the specific traits of tumorigenic protein families, and provides a rapid and feasible means to expand the dimensionality of drug discovery by assessing protein families or posttranslational modifications as potential drug targets.
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Affiliation(s)
- F Kong
- 1] Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA [2] Key Laboratory of Cancer Prevention and Therapy, Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - J Zhang
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Y Li
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA
| | - X Hao
- Key Laboratory of Cancer Prevention and Therapy, Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - X Ren
- Key Laboratory of Cancer Prevention and Therapy, Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - H Li
- Key Laboratory of Cancer Prevention and Therapy, Department of Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - P Zhou
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA
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85
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Smith CJ, Berry DM, McGlade CJ. The E3 ubiquitin ligases RNF126 and Rabring7 regulate endosomal sorting of the epidermal growth factor receptor. J Cell Sci 2013; 126:1366-80. [PMID: 23418353 DOI: 10.1242/jcs.116129] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Activation of the epidermal growth factor receptor (EGFR) results in internalization and ubiquitin-dependent endosomal sorting, leading to lysosomal degradation. Here we describe the role of the RING-finger-domain-containing protein RNF126 and the related protein, Rabring7 in EGFR endosomal sorting. We demonstrate that RNF126 specifies K48-linked chains with UbcH5b and also functions with Ubc13/Uev1a to form K63-linked chains in vitro. RNF126 and Rabring7 associate with the EGFR through a ubiquitin-binding zinc finger domain and both E3 ubiquitin ligases promote ubiquitylation of EGFR. In the absence of c-Cbl or in cells expressing Cbl-70Z, the binding of RNF126 and Rabring7 to the EGFR is reduced, suggesting that RNF126 and Rabring7 function downstream of c-Cbl. In HeLa cells depleted of either RNF126 or Rabring7 the EGFR is retained in a late endocytic compartment and is inefficiently degraded. In addition, depletion of RNF126 or Rabring7 destabilizes ESCRT-II and reduces the number of multivesicular bodies formed after EGF stimulation. We also show that the depletion of Rabring7 attenuates the degradation of MET and that both RNF126 and Rabring7 regulate the sorting of CXCR4 from an early endocytic compartment. Together these data suggest that RNF126 and Rabring7 play a role in the ubiquitin-dependent sorting and downregulation of membrane receptors.
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Affiliation(s)
- Christopher J Smith
- Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
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86
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van de Kooij B, Verbrugge I, de Vries E, Gijsen M, Montserrat V, Maas C, Neefjes J, Borst J. Ubiquitination by the membrane-associated RING-CH-8 (MARCH-8) ligase controls steady-state cell surface expression of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptor 1. J Biol Chem 2013; 288:6617-28. [PMID: 23300075 PMCID: PMC3585101 DOI: 10.1074/jbc.m112.448209] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The eleven members of the membrane-associated RING-CH (MARCH) ubiquitin ligase family are relatively unexplored. Upon exogenous (over)expression, a number of these ligases can affect the trafficking of membrane molecules. However, only for MARCH-1 endogenous functions have been demonstrated. For the other endogenous MARCH proteins, no functions or substrates are known. We report here that TRAIL-R1 is a physiological substrate of the endogenous MARCH-8 ligase. Human TRAIL-R1 and R2 play a role in immunosurveillance and are targets for cancer therapy, because they selectively induce apoptosis in tumor cells. We demonstrate that TRAIL-R1 is down-regulated from the cell surface, with great preference over TRAIL-R2, by exogenous expression of MARCH ligases that are implicated in endosomal trafficking, such as MARCH-1 and -8. MARCH-8 attenuated TRAIL-R1 cell surface expression and apoptosis signaling by virtue of its ligase activity. This suggested that ubiquitination of TRAIL-R1 was instrumental in its down-regulation by MARCH-8. Indeed, in cells with endogenous MARCH expression, TRAIL-R1 was ubiquitinated at steady-state, with the conserved membrane-proximal lysine 273 as one of the potential acceptor sites. This residue was also essential for the interaction of TRAIL-R1 with MARCH-1 and MARCH-8 and its down-regulation by these ligases. Gene silencing identified MARCH-8 as the endogenous ligase that ubiquitinates TRAIL-R1 and attenuates its cell surface expression. These findings reveal that endogenous MARCH-8 regulates the steady-state cell surface expression of TRAIL-R1.
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Affiliation(s)
- Bert van de Kooij
- Division of Immunology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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87
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Shimizu K, Taniyama Y, Sanada F, Iwabayashi M, Azuma J, Iekushi K, Katsuragi N, Otsu R, Shibata K, Ishikawa Y, Rakugi H, Morishita R. Novel mechanism of hepatocyte growth factor against prevention of inflammation and oxidative stress. Inflamm Regen 2013. [DOI: 10.2492/inflammregen.33.136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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88
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Ceresa BP. Spatial regulation of epidermal growth factor receptor signaling by endocytosis. Int J Mol Sci 2012; 14:72-87. [PMID: 23344022 DOI: 10.3390/ijms14010072] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 12/10/2012] [Accepted: 12/12/2012] [Indexed: 12/26/2022] Open
Abstract
Signaling by cell surface receptors appears to be relatively straight-forward: ligand binds to the extracellular domain of the receptor and biochemical changes are communicated into the cell. However, this process is more complex than it first seems due to the various mechanisms that regulate signaling. In order to effectively target these receptors for pharmacological purposes, a more complete understanding of how their signaling is regulated is needed. Here, how the endocytic pathway regulates receptor signaling is discussed, using the epidermal growth factor receptor (EGFR) as a model. In particular, the spatial regulation of signaling is examined. Areas of discussion include: how endocytic trafficking affects biology/pathology, varying approaches for studying the relationship between receptor endocytosis and signaling, and developments in how the endocytic pathway controls EGFR:effector communication and EGFR-mediated cell biology.
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Affiliation(s)
- Brian P Ceresa
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA.
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89
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Lin YC, Wu MH, Wei TT, Chuang SH, Chen KF, Cheng AL, Chen CC. Degradation of epidermal growth factor receptor mediates dasatinib-induced apoptosis in head and neck squamous cell carcinoma cells. Neoplasia 2012; 14:463-75. [PMID: 22787428 DOI: 10.1596/neo.12300] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 01/24/2023]
Abstract
Epidermal growth factor receptor (EGFR) is an important oncoprotein that promotes cell growth and proliferation. Dasatinib, a bcr-abl inhibitor, has been approved clinically for the treatment of chronic myeloid leukemia and demonstrated to be effective against solid tumors in vitro through Src inhibition. Here, we disclose that EGFR degradation mediated dasatinib-induced apoptosis in head and neck squamous cell carcinoma (HNSCC) cells. HNSCC cells, including Ca9-22, FaDu, HSC3, SAS, SCC-25, and UMSCC1, were treated with dasatinib, and cell viability, apoptosis, and underlying signal transduction were evaluated. Dasatinib exhibited differential sensitivities against HNSCC cells. Growth inhibition and apoptosis were correlated with its inhibition on Akt, Erk, and Bcl-2, irrespective of Src inhibition. Accordingly, we found that down-regulation of EGFR was a determinant of dasatinib sensitivity. Lysosome inhibitor reversed dasatinib-induced EGFR down-regulation, and c-cbl activity was increased by dasatinib, indicating that dasatinib-induced EGFR down-regulation might be through c-cbl-mediated lysosome degradation. Increased EGFR activation by ligand administration rescued cells from dasatinib-induced apoptosis, whereas inhibition of EGFR enhanced its apoptotic effect. Estrogen receptor α (ERα) was demonstrated to play a role in Bcl-2 expression, and dasatinib inhibited ERα at the pretranslational level. ERα was associated with EGFR in dasatinib-treated HNSCC cells. Furthermore, the xenograft model showed that dasatinib inhibited HSC3 tumor growth through in vivo down-regulation of EGFR and ERα. In conclusion, degradation of EGFR is a novel mechanism responsible for dasatinib-induced apoptosis in HNSCC cells.
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Affiliation(s)
- Yu-Chin Lin
- Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, Taiwan
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90
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Glogowska A, Stetefeld J, Weber E, Ghavami S, Hoang-Vu C, Klonisch T. Epidermal growth factor cytoplasmic domain affects ErbB protein degradation by the lysosomal and ubiquitin-proteasome pathway in human cancer cells. Neoplasia 2012; 14:396-409. [PMID: 22745586 DOI: 10.1596/neo.111514] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 04/15/2012] [Accepted: 04/16/2012] [Indexed: 12/19/2022]
Abstract
The cytoplasmic domains of EGF-like ligands, including EGF cytoplasmic domain (EGFcyt), have important biological functions. Using specific constructs and peptides of human EGF cytoplasmic domain, we demonstrate that EGFcyt facilitates lysosomal and proteasomal protein degradation, and this coincided with growth inhibition of human thyroid and glioma carcinoma cells. EGFcyt and exon 22-23-encoded peptide (EGF22.23) enhanced procathepsin B (procathB) expression and procathB-mediated lysosomal degradation of EGFR/ErbB1 as determined by inhibitors for procathB and the lysosomal ATPase inhibitor BafA1. Presence of mbEGFctF, EGFcyt, EGF22.23, and exon 23-encoded peptides suppressed the expression of the deubiqitinating enzyme ubiquitin C-terminal hydrolase-L1 (UCH-L1). This coincided with hyperubiquitination of total cellular proteins and ErbB1/2 and reduced proteasome activity. Upon small interfering RNA-mediated silencing of endogenously expressed UCH-L1, a similar hyperubiquitinylation phenotype, reduced ErbB1/2 content, and attenuated growth was observed. The exon 23-encoded peptide region of EGFcyt was important for these biologic actions. Structural homology modeling of human EGFcyt showed that this molecular region formed an exposed surface loop. Peptides derived from this EGFcyt loop structure may aid in the design of novel peptide therapeutics aimed at inhibiting growth of cancer cells.
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Affiliation(s)
- Aleksandra Glogowska
- Department of Human Anatomy and Cell Science, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
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91
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Shimizu K, Taniyama Y, Sanada F, Azuma J, Iwabayashi M, Iekushi K, Rakugi H, Morishita R. Hepatocyte Growth Factor Inhibits Lipopolysaccharide-Induced Oxidative Stress via Epithelial Growth Factor Receptor Degradation. Arterioscler Thromb Vasc Biol 2012; 32:2687-93. [DOI: 10.1161/atvbaha.112.300041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Lipopolysaccharide (LPS) triggers sepsis and systemic inflammatory response syndrome, which results in multiple organ failure. Our recent reports demonstrated that hepatocyte growth factor (HGF) attenuated angiotensin II–induced oxidative stress via epithelial growth factor receptor (EGFR) degradation in vascular smooth muscle cells. Here, we examined whether HGF can protect against systemic inflammatory response syndrome induced by LPS and investigated the mechanism.
Methods and Results—
HGF inhibited the increase in the expression of vascular cell adhesion molecule-1 and EGFR by LPS in vitro. HGF inhibited colocalization of EGFR and Src homology domain 2–containing inositol 5′-phosphatase 2. Furthermore, HGF inhibited reactive oxygen species production. We also injected LPS into HGF transgenic mice with increased HGF serum concentration and their littermates. HGF transgenic mice reduced LPS-induced vascular cell adhesion molecule-1 and reactive oxygen species compared with control, accompanied by significant EGFR degradation. Furthermore, HGF transgenic mice significantly improved survival in the LPS injection model.
Conclusion—
The present study revealed inhibition of LPS-induced vascular cell adhesion molecule-1 expression by HGF via the degradation of EGFR. We demonstrated that HGF regulated Src homology domain 2–containing inositol 5′-phosphatase 2 recruitment to EGFR and inhibited LPS-induced inflammation via EGFR degradation. This effect of HGF may be useful for the treatment of inflammatory disease.
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Affiliation(s)
- Kazutaka Shimizu
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Yoshiaki Taniyama
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Fumihiro Sanada
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Junya Azuma
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Masaaki Iwabayashi
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Kazuma Iekushi
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Hiromi Rakugi
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
| | - Ryuichi Morishita
- From the Departments of Clinical Gene Therapy (K.S., Y.T., F.S., J.A., M.I., K.I., R.M.) and Geriatric Medicine and Nephrology (Y.T., J.A., K.I., H.R.), Osaka University Graduate School of Medicine, Yamadaoka, Suita, Japan
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92
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Kang EL, Biscaro B, Piazza F, Tesco G. BACE1 protein endocytosis and trafficking are differentially regulated by ubiquitination at lysine 501 and the Di-leucine motif in the carboxyl terminus. J Biol Chem 2012; 287:42867-80. [PMID: 23109336 DOI: 10.1074/jbc.m112.407072] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
β-Site amyloid precursor protein-cleaving enzyme (BACE1) is a membrane-tethered member of the aspartyl proteases that has been identified as β-secretase. BACE1 is targeted through the secretory pathway to the plasma membrane and then is internalized to endosomes. Sorting of membrane proteins to the endosomes and lysosomes is regulated by the interaction of signals present in their carboxyl-terminal fragment with specific trafficking molecules. The BACE1 carboxyl-terminal fragment contains a di-leucine sorting signal ((495)DDISLL(500)) and a ubiquitination site at Lys-501. Here, we report that lack of ubiquitination at Lys-501 (BACE1K501R) does not affect the rate of endocytosis but produces BACE1 stabilization and accumulation of BACE1 in early and late endosomes/lysosomes as well as at the cell membrane. In contrast, the disruption of the di-leucine motif (BACE1LLAA) greatly impairs BACE1 endocytosis and produces a delayed retrograde transport of BACE1 to the trans-Golgi network (TGN) and a delayed delivery of BACE1 to the lysosomes, thus decreasing its degradation. Moreover, the combination of the lack of ubiquitination at Lys-501 and the disruption of the di-leucine motif (BACE1LLAA/KR) produces additive effects on BACE1 stabilization and defective internalization. Finally, BACE1LLAA/KR accumulates in the TGN, while its levels are decreased in EEA1-positive compartments indicating that both ubiquitination at Lys-501 and the di-leucine motif are necessary for the trafficking of BACE1 from the TGN to early endosomes. Our studies have elucidated a differential role for the di-leucine motif and ubiquitination at Lys-501 in BACE1 endocytosis, trafficking, and degradation and suggest the involvement of multiple adaptor molecules.
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Affiliation(s)
- Eugene L Kang
- Alzheimer's Disease Research Laboratory, Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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93
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Mohapatra B, Ahmad G, Nadeau S, Zutshi N, An W, Scheffe S, Dong L, Feng D, Goetz B, Arya P, Bailey TA, Palermo N, Borgstahl GEO, Natarajan A, Raja SM, Naramura M, Band V, Band H. Protein tyrosine kinase regulation by ubiquitination: critical roles of Cbl-family ubiquitin ligases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:122-39. [PMID: 23085373 DOI: 10.1016/j.bbamcr.2012.10.010] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/05/2012] [Accepted: 10/08/2012] [Indexed: 12/20/2022]
Abstract
Protein tyrosine kinases (PTKs) coordinate a broad spectrum of cellular responses to extracellular stimuli and cell-cell interactions during development, tissue homeostasis, and responses to environmental challenges. Thus, an understanding of the regulatory mechanisms that ensure physiological PTK function and potential aberrations of these regulatory processes during diseases such as cancer are of broad interest in biology and medicine. Aside from the expected role of phospho-tyrosine phosphatases, recent studies have revealed a critical role of covalent modification of activated PTKs with ubiquitin as a critical mechanism of their negative regulation. Members of the Cbl protein family (Cbl, Cbl-b and Cbl-c in mammals) have emerged as dominant "activated PTK-selective" ubiquitin ligases. Structural, biochemical and cell biological studies have established that Cbl protein-dependent ubiquitination targets activated PTKs for degradation either by facilitating their endocytic sorting into lysosomes or by promoting their proteasomal degradation. This mechanism also targets PTK signaling intermediates that become associated with Cbl proteins in a PTK activation-dependent manner. Cellular and animal studies have established that the relatively broadly expressed mammalian Cbl family members Cbl and Cbl-b play key physiological roles, including their critical functions to prevent the transition of normal immune responses into autoimmune disease and as tumor suppressors; the latter function has received validation from human studies linking mutations in Cbl to human leukemia. These newer insights together with embryonic lethality seen in mice with a combined deletion of Cbl and Cbl-b genes suggest an unappreciated role of the Cbl family proteins, and by implication the ubiquitin-dependent control of activated PTKs, in stem/progenitor cell maintenance. Future studies of existing and emerging animal models and their various cell lineages should help test the broader implications of the evolutionarily-conserved Cbl family protein-mediated, ubiquitin-dependent, negative regulation of activated PTKs in physiology and disease.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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94
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Mohapatra B, Ahmad G, Nadeau S, Zutshi N, An W, Scheffe S, Dong L, Feng D, Goetz B, Arya P, Bailey TA, Palermo N, Borgstahl GEO, Natarajan A, Raja SM, Naramura M, Band V, Band H. Protein tyrosine kinase regulation by ubiquitination: critical roles of Cbl-family ubiquitin ligases. BIOCHIMICA ET BIOPHYSICA ACTA 2012. [PMID: 23085373 DOI: 10.1016/j.bbamcr] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Protein tyrosine kinases (PTKs) coordinate a broad spectrum of cellular responses to extracellular stimuli and cell-cell interactions during development, tissue homeostasis, and responses to environmental challenges. Thus, an understanding of the regulatory mechanisms that ensure physiological PTK function and potential aberrations of these regulatory processes during diseases such as cancer are of broad interest in biology and medicine. Aside from the expected role of phospho-tyrosine phosphatases, recent studies have revealed a critical role of covalent modification of activated PTKs with ubiquitin as a critical mechanism of their negative regulation. Members of the Cbl protein family (Cbl, Cbl-b and Cbl-c in mammals) have emerged as dominant "activated PTK-selective" ubiquitin ligases. Structural, biochemical and cell biological studies have established that Cbl protein-dependent ubiquitination targets activated PTKs for degradation either by facilitating their endocytic sorting into lysosomes or by promoting their proteasomal degradation. This mechanism also targets PTK signaling intermediates that become associated with Cbl proteins in a PTK activation-dependent manner. Cellular and animal studies have established that the relatively broadly expressed mammalian Cbl family members Cbl and Cbl-b play key physiological roles, including their critical functions to prevent the transition of normal immune responses into autoimmune disease and as tumor suppressors; the latter function has received validation from human studies linking mutations in Cbl to human leukemia. These newer insights together with embryonic lethality seen in mice with a combined deletion of Cbl and Cbl-b genes suggest an unappreciated role of the Cbl family proteins, and by implication the ubiquitin-dependent control of activated PTKs, in stem/progenitor cell maintenance. Future studies of existing and emerging animal models and their various cell lineages should help test the broader implications of the evolutionarily-conserved Cbl family protein-mediated, ubiquitin-dependent, negative regulation of activated PTKs in physiology and disease.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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95
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HER2 stabilizes EGFR and itself by altering autophosphorylation patterns in a manner that overcomes regulatory mechanisms and promotes proliferative and transformation signaling. Oncogene 2012; 32:4169-80. [PMID: 23027125 PMCID: PMC3538112 DOI: 10.1038/onc.2012.418] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/19/2012] [Accepted: 07/25/2012] [Indexed: 12/24/2022]
Abstract
One of the causes of breast cancer is overexpression of the human epidermal growth factor receptor 2 (HER2). Enhanced receptor autophosphorylation and resistance to activation-induced down regulation have been suggested as mechanisms for HER2-induced sustained signaling and cell transformation. However, the molecular mechanisms underlying these possibilities remain incompletely understood. In the current report, we present evidence that show that HER2 overexpression does not lead to receptor hyper-autophosphorylation, but alters patterns in a manner that favors receptor stability and sustained signaling. Specifically, HER2 overexpression blocks EGFR tyrosine phosphorylation on Y1045 and Y1068, the known docking sites of c-Cbl and Grb2, respectively, while promoting phosphorylation on Y1173, the known docking site of the Gab adaptor proteins and phospholipase C gamma (PLCγ). Under these conditions, HER2 itself is phosphorylated on Y1221/1222, with no known role, and on Y1248 that corresponds to Y1173 of EGFR. Interestingly, suppressed EGFR autophosphorylation on the Grb2 and c-Cbl binding sites correlated with receptor stability and sustained signaling, suggesting that HER2 accomplishes these tasks by altering autophosphorylation patterns. In conformity with these findings, mutation of the Grb2 binding site on EGFR (Y1068F-EGFR) conferred resistance to ligand-induced degradation which in turn induced sustained signaling, and increased cell proliferation and transformation. These findings suggest that the Grb2 binding site on EGFR is redundant for signaling, but critical for receptor regulation. On the other hand, mutation of the putative Grb2 binding site in HER2 (Y1139) did not affect stability, signaling or transformation, suggesting that Y1139 in HER2 may not serve as a Grb2 binding site. In agreement with the role of EGFR in HER2 signaling, inhibition of EGFR expression reduced HER2-induced anchorage-independent growth and tumorigenesis. These results imply that complementing HER2-targeted therapies with anti-EGFR drugs may be beneficial in HER2-positive breast cancer.
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Balaji K, Mooser C, Janson CM, Bliss JM, Hojjat H, Colicelli J. RIN1 orchestrates the activation of RAB5 GTPases and ABL tyrosine kinases to determine the fate of EGFR. J Cell Sci 2012; 125:5887-96. [PMID: 22976291 DOI: 10.1242/jcs.113688] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Stimulation of epidermal growth factor receptor (EGFR) initiates RAS signaling simultaneously with EGFR internalization. Endocytosed EGFR is then either recycled or degraded. EGFR fate is determined in part by the RAS effector RIN1, a guanine nucleotide exchange factor (GEF) for RAB5 GTPases. EGFR degradation was slowed by RIN1 silencing, enhanced by RIN1 overexpression and accelerated by RIN1 localization to the plasma membrane. RIN1 also directly activates ABL tyrosine kinases, which regulate actin remodeling, a function not previously connected to endocytosis. We report that RIN1-RAB5 signaling favors EGFR downregulation over EGFR recycling, whereas RIN1-ABL signaling stabilizes EGFR and inhibits macropinocytosis. RIN1(QM), a mutant that blocks ABL activation, caused EGF-stimulated membrane ruffling, actin remodeling, dextran uptake and EGFR degradation. An ABL kinase inhibitor phenocopied these effects in cells overexpressing RIN1. EGFR activation also promotes RIN1 interaction with BIN1, a membrane bending protein. These findings suggest that RIN1 orchestrates RAB5 activation, ABL kinase activation and BIN1 recruitment to determine EGFR fate.
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Affiliation(s)
- Kavitha Balaji
- Molecular Biology Institute, Jonsson Comprehensive Cancer Center and Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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97
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Ly P, Kim SB, Kaisani AA, Marian G, Wright WE, Shay JW. Aneuploid human colonic epithelial cells are sensitive to AICAR-induced growth inhibition through EGFR degradation. Oncogene 2012; 32:3139-46. [PMID: 22890317 DOI: 10.1038/onc.2012.339] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Trisomy for chromosome 7 is frequently observed as an initiating event in sporadic colorectal cancer. Although unstable chromosome numbers and recurrent aneuploidies drive a large fraction of human cancers, targeted therapies selective to pre-neoplastic trisomic cells are non-existent. We have previously characterized a trisomy 7 cell line (1CT+7) spontaneously derived from normal diploid human colonic epithelial cells that aberrantly expresses the epidermal growth factor receptor (EGFR, chromosome 7p11). Recent studies identified AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) as a pharmacological inhibitor of aneuploid murine fibroblast proliferation. Here, we report that AICAR induces profound cytostatic and metabolic effects on 1CT+7 cells, but not on their isogenic diploid counterpart. Dose-response experiments indicate that 1CT+7 cells are fourfold preferentially sensitive to AICAR compared to diploid cells. Unexpectedly, treatment of 1CT+7 cells with AICAR led to a reversible 3.5-fold reduction (P=0.0025) in EGFR overexpression. AICAR-induced depletion of EGFR protein can be abrogated through inhibition of the proteasome with MG132. AICAR also heavily promoted EGFR ubiquitination in cell-based immunoprecipitation assays, suggesting enhanced degradation of EGFR protein mediated by the proteasome. Moreover, treatment with AICAR reduced EGFR protein levels in a panel of human colorectal cancer cells in vitro and in xenograft tumors in vivo. Our data collectively support the pharmacological compound AICAR as a novel inhibitor of EGFR protein abundance and as a potential anticancer agent for aneuploidy-driven colorectal cancer.
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Affiliation(s)
- P Ly
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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98
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Glisic D, Lehmann C, Figiel M, Ödemis V, Lindner R, Engele J. A novel cross-talk between endothelin and ErbB receptors controlling glutamate transporter expression in astrocytes. J Neurochem 2012; 122:844-55. [PMID: 22671705 DOI: 10.1111/j.1471-4159.2012.07819.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The endothelin and epidermal growth factor (EGF) systems are central to the control of reactive brain processes and are thought to partly exert these tasks by endothelin-induced transactivation of the epidermal growth factor receptor (EGFR) Here we show that beyond EGFR transactivation, endothelins prevent the ligand-induced internalization of the EGFR. We unravel that endothelins abrogate internalization of the EGFR by either promoting the formation of "internalization-deficient" EGFR/ErB2-heterodimers or by activating c-Abl kinase, a negative regulator of EGFR internalization. We further provide evidence that this cross-talk is operational in the control of astrocytic glutamate transport. Specifically, we establish that the inhibitory effects exerted by endothelins on basal as well as EGF-induced expression of the major astroglial glutamate transporter subtype, glutamate transporter 1, are a direct consequence of the endothelin-dependent retention of the EGFR at the cell surface. Together our findings unravel a previously unknown cross-talk between endothelin and epidermal growth factor receptors, which may have implications for a variety of pathological conditions.
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Affiliation(s)
- Darko Glisic
- Institute of Anatomy, University of Leipzig, Medical Faculty, Leipzig, Germany
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99
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Gui A, Kobayashi A, Motoyama H, Kitazawa M, Takeoka M, Miyagawa S. Impaired degradation followed by enhanced recycling of epidermal growth factor receptor caused by hypo-phosphorylation of tyrosine 1045 in RBE cells. BMC Cancer 2012; 12:179. [PMID: 22591401 PMCID: PMC3476963 DOI: 10.1186/1471-2407-12-179] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 04/25/2012] [Indexed: 02/01/2023] Open
Abstract
Background Since cholangiocarcinoma has a poor prognosis, several epidermal growth factor receptor (EGFR)-targeted therapies with antibody or small molecule inhibitor treatment have been proposed. However, their effect remains limited. The present study sought to understand the molecular genetic characteristics of cholangiocarcinoma related to EGFR, with emphasis on its degradation and recycling. Methods We evaluated EGFR expression and colocalization by immunoblotting and immunofluorescence, cell surface EGFR expression by fluorescence-activated cell sorting (FACS), and EGFR ubiquitination and protein binding by immunoprecipitation in the human cholangiocarcinoma RBE and immortalized cholangiocyte MMNK-1 cell lines. Monensin treatment and Rab11a depletion by siRNA were adopted for inhibition of EGFR recycling. Results Upon stimulation with EGF, ligand-induced EGFR degradation was impaired and the expression of phospho-tyrosine 1068 and phospho-p44/42 MAPK was sustained in RBE cells as compared with MMNK-1 cells. In RBE cells, the process of EGFR sorting for lysosomal degradation was blocked at the early endosome stage, and non-degradated EGFR was recycled to the cell surface. A disrupted association between EGFR and the E3 ubiquitin ligase c-Cbl, as well as hypo-phosphorylation of EGFR at tyrosine 1045 (Tyr1045), were also observed in RBE cells. Conclusion In RBE cells, up-regulation of EGFR Tyr1045 phosphorylation is a potentially useful molecular alteration in EGFR-targeted therapy. The combination of molecular-targeted therapy determined by the characteristics of individual EGFR phosphorylation events and EGFR recycling inhibition show promise in future treatments of cholangiocarcinoma.
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Affiliation(s)
- Anping Gui
- First Department of Surgery, Shinshu University School of Medicine, Asahi, Matsumoto, Nagano, Japan
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100
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Sigismund S, Confalonieri S, Ciliberto A, Polo S, Scita G, Di Fiore PP. Endocytosis and signaling: cell logistics shape the eukaryotic cell plan. Physiol Rev 2012; 92:273-366. [PMID: 22298658 DOI: 10.1152/physrev.00005.2011] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Our understanding of endocytosis has evolved remarkably in little more than a decade. This is the result not only of advances in our knowledge of its molecular and biological workings, but also of a true paradigm shift in our understanding of what really constitutes endocytosis and of its role in homeostasis. Although endocytosis was initially discovered and studied as a relatively simple process to transport molecules across the plasma membrane, it was subsequently found to be inextricably linked with almost all aspects of cellular signaling. This led to the notion that endocytosis is actually the master organizer of cellular signaling, providing the cell with understandable messages that have been resolved in space and time. In essence, endocytosis provides the communications and supply routes (the logistics) of the cell. Although this may seem revolutionary, it is still likely to be only a small part of the entire story. A wealth of new evidence is uncovering the surprisingly pervasive nature of endocytosis in essentially all aspects of cellular regulation. In addition, many newly discovered functions of endocytic proteins are not immediately interpretable within the classical view of endocytosis. A possible framework, to rationalize all this new knowledge, requires us to "upgrade" our vision of endocytosis. By combining the analysis of biochemical, biological, and evolutionary evidence, we propose herein that endocytosis constitutes one of the major enabling conditions that in the history of life permitted the development of a higher level of organization, leading to the actuation of the eukaryotic cell plan.
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Affiliation(s)
- Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
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