1
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Harmych SJ, Tydings CW, Meiler J, Singh B. Sequence and structural insights of monoleucine-based sorting motifs contained within the cytoplasmic domains of basolateral proteins. Front Cell Dev Biol 2024; 12:1379224. [PMID: 38495621 PMCID: PMC10940456 DOI: 10.3389/fcell.2024.1379224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 02/21/2024] [Indexed: 03/19/2024] Open
Abstract
Delivery to the correct membrane domain in polarized epithelial cells is a critical regulatory mechanism for transmembrane proteins. The trafficking of these proteins is directed by short amino acid sequences known as sorting motifs. In six basolaterally-localized proteins lacking the canonical tyrosine- and dileucine-based basolateral sorting motifs, a monoleucine-based sorting motif has been identified. This review will discuss these proteins with an identified monoleucine-based sorting motif, their conserved structural features, as well as the future directions of study for this non-canonical basolateral sorting motif.
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Affiliation(s)
- Sarah J. Harmych
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, United States
| | - Claiborne W. Tydings
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Jens Meiler
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
- Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Bhuminder Singh
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, United States
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2
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Carlin CR, Ngalula S. Loss of EGF receptor polarity enables homeostatic imbalance in epithelial-cell models. Mol Biol Cell 2023; 34:ar116. [PMID: 37647145 PMCID: PMC10846618 DOI: 10.1091/mbc.e23-04-0133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/26/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023] Open
Abstract
The polarized distribution of membrane proteins into apical and basolateral domains provides the basis for specialized functions of epithelial tissues. The EGF receptor (EGFR) plays important roles in embryonic development, adult-epithelial tissue homeostasis, and growth and survival of many carcinomas. Typically targeted to basolateral domains, there is also considerable evidence of EGFR sorting plasticity but very limited knowledge regarding domain-specific EGFR substrates. Here we have investigated effects of selective EGFR mistargeting because of inactive-basolateral sorting signals on epithelial-cell homeostatic responses to growth-induced stress in MDCK cell models. Aberrant EGFR localization was associated with multilayer formation, anchorage-independent growth, and upregulated expression of the intermediate filament-protein vimentin characteristically seen in cells undergoing epithelial-to-mesenchymal transition. EGFRs were selectively retained following their internalization from apical membranes, and a signaling pathway involving the signaling adaptor Gab1 protein and extracellular signal-regulated kinase ERK5 had an essential role integrating multiple responses to growth-induced stress. Our studies highlight the potential importance of cellular machinery specifying EGFR polarity in epithelial pathologies associated with homeostatic imbalance.
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Affiliation(s)
- Cathleen R. Carlin
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106-4970
- Case Western Reserve University Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970
| | - Syntyche Ngalula
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106-4970
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3
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Morrison AR. Magnesium Homeostasis: Lessons from Human Genetics. Clin J Am Soc Nephrol 2023; 18:01277230-990000000-00067. [PMID: 36723340 PMCID: PMC10356123 DOI: 10.2215/cjn.0000000000000103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 02/02/2023]
Abstract
Mg2+, the fourth most abundant cation in the body, serves as a co-factor for about 600 cellular enzymes. One third of ingested Mg2+ is absorbed from the gut through a saturable transcellular process and a concentration-dependent paracellular process. Absorbed Mg2+ is excreted by the kidney and maintains serum Mg2+ within a narrow range of 0.7 to 1.25 mmol/L. The reabsorption of Mg2+ by the nephron is characterized by paracellular transport in the proximal tubule and thick ascending limb. The nature of the transport pathways in the gut epithelia and thick ascending limb has emerged from an understanding of the molecular mechanisms responsible for rare monogenetic disorders presenting with clinical hypomagnesemia. These human disorders due to loss-of function mutations, in concert with mouse models have led to a deeper understanding of Mg2+ transport in the gut and renal tubule. This review focuses on the nature of the transporters and channels revealed by human and mouse genetics and how they are integrated into an understanding of human Mg2+ physiology.
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Affiliation(s)
- Aubrey R Morrison
- Division of Nephrology Department of Medicine and Developmental Biology Washington University School of Medicine, St Louis MO, 63110 USA
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4
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Cui HY, Wei W, Qian MR, Tian RF, Fu X, Li HW, Nan G, Yang T, Lin P, Chen X, Zhu YM, Wang B, Sun XX, Dou JH, Jiang JL, Li L, Wang SJ, Chen ZN. PDGFA-associated protein 1 is a novel target of c-Myc and contributes to colorectal cancer initiation and progression. Cancer Commun (Lond) 2022; 42:750-767. [PMID: 35716012 PMCID: PMC9395323 DOI: 10.1002/cac2.12322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/26/2022] [Accepted: 06/06/2022] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The mechanism underlying colorectal cancer (CRC) initiation and progression remains elusive, and overall survival is far from satisfactory. Previous studies have shown that PDGFA-associated protein 1 (PDAP1) is upregulated in several cancers including CRC. Here, we aimed to identify the cause and consequence of PDAP1 dysregulation in CRC and evaluate its role as a potential therapeutic target. METHODS Multi-omics data analysis was performed to identify potential key players in CRC initiation and progression. Immunohistochemistry (IHC) staining was applied to determine the expression pattern of PDAP1 in CRC tissues. Pdap1 conditional knockout mice were used to establish colitis and CRC mouse models. RNA sequencing, a phosphoprotein antibody array, western blotting, histological analysis, 5-bromo-2'-deoxyuridine (BrdU) incorporation assay, and interactome analysis were applied to identify the underlying mechanisms of PDAP1. A human patient-derived xenograft (PDX) model was used to assess the potential of PDAP1 as a therapeutic target. RESULTS PDAP1 was identified as a potential key player in CRC development using multi-omics data analysis. PDAP1 was overexpressed in CRC cells and correlated with reduced overall survival. Further investigation showed that PDAP1 was critical for the regulation of cell proliferation, migration, invasion, and metastasis. Significantly, depletion of Pdap1 in intestinal epithelial cells impaired mucosal restitution in dextran sulfate sodium salt-induced colitis and inhibited tumor initiation and growth in colitis-associated cancers. Mechanistic studies showed that c-Myc directly transactivated PDAP1, which contributed to the high PDAP1 expression in CRC cells. PDAP1 interacted with the juxtamembrane domain of epidermal growth factor receptor (EGFR) and facilitated EGFR-mitogen-activated protein kinase (MAPK) signaling activation, which resulted in FOS-related antigen 1 (FRA-1) expression, thereby facilitating CRC progression. Notably, silencing of PDAP1 could hinder the growth of patient-derived xenografts that sustain high PDAP1 levels. CONCLUSIONS PDAP1 facilitates mucosal restitution and carcinogenesis in colitis-associated cancer. c-Myc-driven upregulation of PDAP1 promotes proliferation, migration, invasion, and metastasis of CRC cells via the EGFR-MAPK-FRA-1 signaling axis. These findings indicated that PDAP1 inhibition is warranted for CRC patients with PDAP1 overexpression.
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Affiliation(s)
- Hong-Yong Cui
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Wei Wei
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Mei-Rui Qian
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Ruo-Fei Tian
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Xin Fu
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Hong-Wei Li
- State Key Laboratory of Cancer Biology and National Clinical Research Center for Digestive Diseases, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Gang Nan
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Ting Yang
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China.,Department of Clinical Medicine, Medical College of Yan'an University, Yan'an, Shaanxi, 716000, P. R. China
| | - Peng Lin
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Xi Chen
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, Shaanxi, 710127, P. R. China
| | - Yu-Meng Zhu
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Bin Wang
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Xiu-Xuan Sun
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Jian-Hua Dou
- State Key Laboratory of Cancer Biology and National Clinical Research Center for Digestive Diseases, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Jian-Li Jiang
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Ling Li
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Shi-Jie Wang
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
| | - Zhi-Nan Chen
- National Translational Science Center for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, Xi'an, Shaanxi, 710032, P. R. China
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5
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Structural Insight and Development of EGFR Tyrosine Kinase Inhibitors. Molecules 2022; 27:molecules27030819. [PMID: 35164092 PMCID: PMC8838133 DOI: 10.3390/molecules27030819] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
Lung cancer has a high prevalence, with a growing number of new cases and mortality every year. Furthermore, the survival rate of patients with non-small-cell lung carcinoma (NSCLC) is still quite low in the majority of cases. Despite the use of conventional therapy such as tyrosine kinase inhibitor for Epidermal Growth Factor Receptor (EGFR), which is highly expressed in most NSCLC cases, there was still no substantial improvement in patient survival. This is due to the drug’s ineffectiveness and high rate of resistance among individuals with mutant EGFR. Therefore, the development of new inhibitors is urgently needed. Understanding the EGFR structure, including its kinase domain and other parts of the protein, and its activation mechanism can accelerate the discovery of novel compounds targeting this protein. This study described the structure of the extracellular, transmembrane, and intracellular domains of EGFR. This was carried out along with identifying the binding pose of commercially available inhibitors in the ATP-binding and allosteric sites, thereby clarifying the research gaps that can be filled. The binding mechanism of inhibitors that have been used clinically was also explained, thereby aiding the structure-based development of new drugs.
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6
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A novel selection strategy for antibody producing hybridoma cells based on a new transgenic fusion cell line. Sci Rep 2020; 10:1664. [PMID: 32015441 PMCID: PMC6997400 DOI: 10.1038/s41598-020-58571-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/14/2020] [Indexed: 12/28/2022] Open
Abstract
The use of monoclonal antibodies is ubiquitous in science and biomedicine but the generation and validation process of antibodies is nevertheless complicated and time-consuming. To address these issues we developed a novel selective technology based on an artificial cell surface construct by which secreted antibodies were connected to the corresponding hybridoma cell when they possess the desired antigen-specificity. Further the system enables the selection of desired isotypes and the screening for potential cross-reactivities in the same context. For the design of the construct we combined the transmembrane domain of the EGF-receptor with a hemagglutinin epitope and a biotin acceptor peptide and performed a transposon-mediated transfection of myeloma cell lines. The stably transfected myeloma cell line was used for the generation of hybridoma cells and an antigen- and isotype-specific screening method was established. The system has been validated for globular protein antigens as well as for haptens and enables a fast and early stage selection and validation of monoclonal antibodies in one step.
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7
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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8
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Di Martino R, Sticco L, Luini A. Regulation of cargo export and sorting at the trans‐Golgi network. FEBS Lett 2019; 593:2306-2318. [DOI: 10.1002/1873-3468.13572] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 12/28/2022]
Affiliation(s)
- Rosaria Di Martino
- Institute of Biochemistry and Cell Biology (IBBC) Italian National Research Council (CNR) Naples Italy
| | - Lucia Sticco
- Institute of Biochemistry and Cell Biology (IBBC) Italian National Research Council (CNR) Naples Italy
| | - Alberto Luini
- Institute of Biochemistry and Cell Biology (IBBC) Italian National Research Council (CNR) Naples Italy
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9
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Abdi K, Neves G, Pyun J, Kiziltug E, Ahrens A, Kuo CT. EGFR Signaling Termination via Numb Trafficking in Ependymal Progenitors Controls Postnatal Neurogenic Niche Differentiation. Cell Rep 2019; 28:2012-2022.e4. [PMID: 31433979 PMCID: PMC6768562 DOI: 10.1016/j.celrep.2019.07.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/02/2019] [Accepted: 07/17/2019] [Indexed: 12/30/2022] Open
Abstract
Specialized microenvironments, called niches, control adult stem cell proliferation and differentiation. The brain lateral ventricular (LV) neurogenic niche is generated from distinct postnatal radial glial progenitors (pRGPs), giving rise to adult neural stem cells (NSCs) and niche ependymal cells (ECs). Cellular-intrinsic programs govern stem versus supporting cell maturation during adult niche assembly, but how they are differentially initiated within a similar microenvironment remains unknown. Using chemical approaches, we discovered that EGFR signaling powerfully inhibits EC differentiation by suppressing multiciliogenesis. We found that EC pRGPs actively terminated EGF activation through receptor redistribution away from CSF-contacting apical domains and that randomized EGFR membrane targeting blocked EC differentiation. Mechanistically, we uncovered spatiotemporal interactions between EGFR and endocytic adaptor protein Numb. Ca2+-dependent basolateral targeting of Numb is necessary and sufficient for proper EGFR redistribution. These results reveal a previously unknown cellular mechanism for neighboring progenitors to differentially engage environmental signals, initiating adult stem cell niche assembly.
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Affiliation(s)
- Khadar Abdi
- Department of Cell Biology, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Gabriel Neves
- Department of Cell Biology, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Joon Pyun
- Department of Cell Biology, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Emre Kiziltug
- Department of Cell Biology, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Angelica Ahrens
- Department of Cell Biology, Duke University, School of Medicine, Durham, NC 27710, USA
| | - Chay T Kuo
- Department of Cell Biology, Duke University, School of Medicine, Durham, NC 27710, USA; Department of Neurobiology, Duke University, School of Medicine, Durham, NC 27710, USA; Preston Robert Tisch Brain Tumor Center, Duke University, School of Medicine, Durham, NC 27710, USA; Institute for Brain Sciences, Duke University, School of Medicine, Durham, NC 27710, USA.
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10
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Mao Y, Tu R, Huang Y, Mao D, Yang Z, Lau PK, Wang J, Ni J, Guo Y, Xie T. The exocyst functions in niche cells to promote germline stem cell differentiation by directly controlling EGFR membrane trafficking. Development 2019; 146:dev.174615. [PMID: 31142545 DOI: 10.1242/dev.174615] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 05/14/2019] [Indexed: 12/31/2022]
Abstract
The niche controls stem cell self-renewal and differentiation in animal tissues. Although the exocyst is known to be important for protein membrane trafficking and secretion, its role in stem cells and niches has never been reported. Here, this study shows that the exocyst functions in the niche to promote germline stem cell (GSC) progeny differentiation in the Drosophila ovary by directly regulating EGFR membrane trafficking and signaling. Inactivation of exocyst components in inner germarial sheath cells, which form the differentiation niche, causes a severe GSC differentiation defect. The exocyst is required for maintaining niche cells and preventing BMP signaling in GSC progeny by promoting EGFR membrane targeting and signaling through direct association with EGFR. Finally, it is also required for EGFR membrane targeting, recycling and signaling in human cells. Therefore, this study reveals a novel function of the exocyst in niche cells to promote stem cell progeny differentiation by directly controlling EGFR membrane trafficking and signaling in vivo, and also provides important insight into how the niche controls stem cell progeny differentiation at the molecular level.
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Affiliation(s)
- Ying Mao
- PKU-THU Joint Center for Life Sciences, College of Life Sciences, School of Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Renjun Tu
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Yan Huang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Decai Mao
- PKU-THU Joint Center for Life Sciences, College of Life Sciences, School of Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zhihao Yang
- PKU-THU Joint Center for Life Sciences, College of Life Sciences, School of Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Pik Ki Lau
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jinhui Wang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jianquan Ni
- PKU-THU Joint Center for Life Sciences, College of Life Sciences, School of Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yusong Guo
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Ting Xie
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
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11
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CALHM1/CALHM3 channel is intrinsically sorted to the basolateral membrane of epithelial cells including taste cells. Sci Rep 2019; 9:2681. [PMID: 30804437 PMCID: PMC6390109 DOI: 10.1038/s41598-019-39593-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/12/2018] [Indexed: 12/20/2022] Open
Abstract
The CALHM1/CALHM3 channel in the basolateral membrane of polarized taste cells mediates neurotransmitter release. However, mechanisms regulating its localization remain unexplored. Here, we identified CALHM1/CALHM3 in the basolateral membrane of type II taste cells in discrete puncta localized close to afferent nerve fibers. As in taste cells, CALHM1/CALHM3 was present in the basolateral membrane of model epithelia, although it was distributed throughout the membrane and did not show accumulation in puncta. We identified canonical basolateral sorting signals in CALHM1 and CALHM3: tyrosine-based and dileucine motifs. However, basolateral sorting remained intact in mutated channels lacking those signals, suggesting that non-canonical signals reside elsewhere. Our study demonstrates intrinsic basolateral sorting of CALHM channels in polarized cells, and provides mechanistic insights.
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12
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Greenwood E, Maisel S, Ebertz D, Russ A, Pandey R, Schroeder J. Llgl1 prevents metaplastic survival driven by epidermal growth factor dependent migration. Oncotarget 2018; 7:60776-60792. [PMID: 27542214 PMCID: PMC5308616 DOI: 10.18632/oncotarget.11320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/02/2016] [Indexed: 12/18/2022] Open
Abstract
We have previously demonstrated that Llgl1 loss results in a gain of mesenchymal phenotypes and a loss of apicobasal and planar polarity. We now demonstrate that these changes represent a fundamental shift in cellular phenotype. Llgl1 regulates the expression of multiple cell identity markers, including CD44, CD49f, and CD24, and the nuclear translocation of TAZ and Slug. Cells lacking Llgl1 form mammospheres, where survival and transplantability is dependent upon the Epidermal Growth Factor Receptor (EGFR). Additionally, Llgl1 loss allows cells to grow in soft-agar and maintain prolonged survival as orthotopic transplants in NOD-SCIDmice. Lineage tracing and wound healing experiments demonstrate that mammosphere survival is due to enhanced EGF-dependent migration. The loss of Llgl1 drives EGFR mislocalization and an EGFR mislocalization point mutation (P667A) drives these same phenotypes, including activation of AKT and TAZ nuclear translocation. Together, these data indicate that the loss of Llgl1 results in EGFR mislocalization, promoting pre-neoplastic changes.
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Affiliation(s)
- Erin Greenwood
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona
| | - Sabrina Maisel
- Arizona Cancer Center, University of Arizona, Tucson, Arizona.,Cancer Biology Program, University of Arizona, Tucson, Arizona
| | - David Ebertz
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona
| | - Atlantis Russ
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona.,Genetics Program, University of Arizona, Tucson, Arizona
| | - Ritu Pandey
- Arizona Cancer Center, University of Arizona, Tucson, Arizona.,Department of Cell and Molecular Medicine, University of Arizona, Tucson, Arizona
| | - Joyce Schroeder
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona.,Arizona Cancer Center, University of Arizona, Tucson, Arizona.,BIO5 Institute, University of Arizona, Tucson, Arizona.,Genetics Program, University of Arizona, Tucson, Arizona.,Cancer Biology Program, University of Arizona, Tucson, Arizona
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13
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Little AC, Sulovari A, Danyal K, Heppner DE, Seward DJ, van der Vliet A. Paradoxical roles of dual oxidases in cancer biology. Free Radic Biol Med 2017; 110:117-132. [PMID: 28578013 PMCID: PMC5535817 DOI: 10.1016/j.freeradbiomed.2017.05.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023]
Abstract
Dysregulated oxidative metabolism is a well-recognized aspect of cancer biology, and many therapeutic strategies are based on targeting cancers by altering cellular redox pathways. The NADPH oxidases (NOXes) present an important enzymatic source of biological oxidants, and the expression and activation of several NOX isoforms are frequently dysregulated in many cancers. Cell-based studies have demonstrated a role for several NOX isozymes in controlling cell proliferation and/or cell migration, further supporting a potential contributing role for NOX in promoting cancer. While various NOX isoforms are often upregulated in cancers, paradoxical recent findings indicate that dual oxidases (DUOXes), normally prominently expressed in epithelial lineages, are frequently suppressed in epithelial-derived cancers by epigenetic mechanisms, although the functional relevance of such DUOX silencing has remained unclear. This review will briefly summarize our current understanding regarding the importance of reactive oxygen species (ROS) and NOXes in cancer biology, and focus on recent observations indicating the unique and seemingly opposing roles of DUOX enzymes in cancer biology. We will discuss current knowledge regarding the functional properties of DUOX, and recent studies highlighting mechanistic consequences of DUOX1 loss in lung cancer, and its consequences for tumor invasiveness and current anticancer therapy. Finally, we will also discuss potentially unique roles for the DUOX maturation factors. Overall, a better understanding of mechanisms that regulate DUOX and the functional consequences of DUOX silencing in cancer may offer valuable new diagnostic insights and novel therapeutic opportunities.
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Affiliation(s)
- Andrew C Little
- Department of Pathology and Laboratory Medicine, Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT 05405, United States; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, United States
| | - Arvis Sulovari
- Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, United States; Department of Microbiology and Molecular Genetics, Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT 05405, United States
| | - Karamatullah Danyal
- Department of Pathology and Laboratory Medicine, Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT 05405, United States
| | - David E Heppner
- Department of Pathology and Laboratory Medicine, Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT 05405, United States
| | - David J Seward
- Department of Pathology and Laboratory Medicine, Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT 05405, United States
| | - Albert van der Vliet
- Department of Pathology and Laboratory Medicine, Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT 05405, United States; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, United States.
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14
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Balanis N, Carlin CR. Stress-induced EGF receptor signaling through STAT3 and tumor progression in triple-negative breast cancer. Mol Cell Endocrinol 2017; 451:24-30. [PMID: 28088463 PMCID: PMC5469704 DOI: 10.1016/j.mce.2017.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 01/12/2023]
Abstract
Elevated STAT3 activity is a hallmark of many epithelial carcinomas particularly in breast cancers where it is known to contribute to tumor progression through a variety of context-dependent biological responses. However, its role downstream of stress-exposed EGF receptors (EGFR) that are transactivated in endosomes independent of exogenous ligand has not been studied. This review discusses how STAT3 signaling induced by therapeutic stress in EGFR-driven triple-negative breast cancers (TNBC) might override normal epithelial homeostatic mechanisms and provide a survival advantage for tumor cells before they leave the primary tumor and spread to distant sites. Despite continued improvements in breast cancer treatment strategies, TNBC is still associated with poor prognosis and high risk of distant recurrence and death. Understanding EGFR-STAT3 signaling mechanisms regulating the earliest steps of tumor progression is a key to discovery of new targeted therapies against TNBC.
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Affiliation(s)
- Nikolas Balanis
- Departments of Physiology and Biophysics, USA; Molecular Biology and Microbiology, USA
| | - Cathleen R Carlin
- Departments of Physiology and Biophysics, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA.
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15
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Cianciola NL, Chung S, Manor D, Carlin CR. Adenovirus Modulates Toll-Like Receptor 4 Signaling by Reprogramming ORP1L-VAP Protein Contacts for Cholesterol Transport from Endosomes to the Endoplasmic Reticulum. J Virol 2017; 91:e01904-16. [PMID: 28077646 PMCID: PMC5331795 DOI: 10.1128/jvi.01904-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 01/05/2017] [Indexed: 12/27/2022] Open
Abstract
Human adenoviruses (Ads) generally cause mild self-limiting infections but can lead to serious disease and even be fatal in high-risk individuals, underscoring the importance of understanding how the virus counteracts host defense mechanisms. This study had two goals. First, we wished to determine the molecular basis of cholesterol homeostatic responses induced by the early region 3 membrane protein RIDα via its direct interaction with the sterol-binding protein ORP1L, a member of the evolutionarily conserved family of oxysterol-binding protein (OSBP)-related proteins (ORPs). Second, we wished to determine how this interaction regulates innate immunity to adenovirus. ORP1L is known to form highly dynamic contacts with endoplasmic reticulum-resident VAP proteins that regulate late endosome function under regulation of Rab7-GTP. Our studies have demonstrated that ORP1L-VAP complexes also support transport of LDL-derived cholesterol from endosomes to the endoplasmic reticulum, where it was converted to cholesteryl esters stored in lipid droplets when ORP1L was bound to RIDα. The virally induced mechanism counteracted defects in the predominant cholesterol transport pathway regulated by the late endosomal membrane protein Niemann-Pick disease type C protein 1 (NPC1) arising during early stages of viral infection. However, unlike NPC1, RIDα did not reconstitute transport to endoplasmic reticulum pools that regulate SREBP transcription factors. RIDα-induced lipid trafficking also attenuated proinflammatory signaling by Toll-like receptor 4, which has a central role in Ad pathogenesis and is known to be tightly regulated by cholesterol-rich "lipid rafts." Collectively, these data show that RIDα utilizes ORP1L in a way that is distinct from its normal function in uninfected cells to fine-tune lipid raft cholesterol that regulates innate immunity to adenovirus in endosomes.IMPORTANCE Early region 3 proteins encoded by human adenoviruses that attenuate immune-mediated pathology have been a particularly rich source of information regarding intracellular protein trafficking. Our studies with the early region 3-encoded RIDα protein also provided fundamental new information regarding mechanisms of nonvesicular lipid transport and the flow of molecular information at membrane contacts between different organelles. We describe a new pathway that delivers cholesterol from endosomes to the endoplasmic reticulum, where it is esterified and stored in lipid droplets. Although lipid droplets are attracting renewed interest from the standpoint of normal physiology and human diseases, including those resulting from viral infections, experimental model systems for evaluating how and why they accumulate are still limited. Our studies also revealed an intriguing relationship between lipid droplets and innate immunity that may represent a new paradigm for viruses utilizing these organelles.
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Affiliation(s)
- Nicholas L Cianciola
- Departments of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Stacey Chung
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Danny Manor
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
- the Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Cathleen R Carlin
- Departments of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
- the Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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16
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Caceres PS, Benedicto I, Lehmann GL, Rodriguez-Boulan EJ. Directional Fluid Transport across Organ-Blood Barriers: Physiology and Cell Biology. Cold Spring Harb Perspect Biol 2017; 9:a027847. [PMID: 28003183 PMCID: PMC5334253 DOI: 10.1101/cshperspect.a027847] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Directional fluid flow is an essential process for embryo development as well as for organ and organism homeostasis. Here, we review the diverse structure of various organ-blood barriers, the driving forces, transporters, and polarity mechanisms that regulate fluid transport across them, focusing on kidney-, eye-, and brain-blood barriers. We end by discussing how cross talk between barrier epithelial and endothelial cells, perivascular cells, and basement membrane signaling contribute to generate and maintain organ-blood barriers.
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Affiliation(s)
- Paulo S Caceres
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Ignacio Benedicto
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Guillermo L Lehmann
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
| | - Enrique J Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Department of Ophthalmology, Weill Cornell Medical College, New York, New York 10065
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17
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Klinger SC, Højland A, Jain S, Kjolby M, Madsen P, Svendsen AD, Olivecrona G, Bonifacino JS, Nielsen MS. Polarized trafficking of the sorting receptor SorLA in neurons and MDCK cells. FEBS J 2016; 283:2476-93. [PMID: 27192064 DOI: 10.1111/febs.13758] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 05/03/2016] [Accepted: 05/13/2016] [Indexed: 01/19/2023]
Abstract
The sorting receptor SorLA is highly expressed in neurons and is also found in other polarized cells. The receptor has been reported to participate in the trafficking of several ligands, some of which are linked to human diseases, including the amyloid precursor protein, TrkB, and Lipoprotein Lipase (LpL). Despite this, only the trafficking in nonpolarized cells has been described so far. Due to the many differences between polarized and nonpolarized cells, we examined the localization and trafficking of SorLA in epithelial Madin-Darby canine kidney (MDCK) cells and rat hippocampal neurons. We show that SorLA is mainly found in sorting endosomes and on the basolateral surface of MDCK cells and in the somatodendritic domain of neurons. This polarized distribution of SorLA respectively depends on an acidic cluster and an extended version of this cluster and involves the cellular adaptor complex AP-1. Furthermore, we show that SorLA can mediate transcytosis across a tight cell layer.
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Affiliation(s)
- Stine C Klinger
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark.,Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anne Højland
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
| | - Shweta Jain
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Mads Kjolby
- Department of Biomedicine, The MIND Centre, Aarhus University, Denmark.,Department of Biomedicine, The Danish Diabetes Academy, Aarhus University, Denmark
| | - Peder Madsen
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
| | - Anna Dorst Svendsen
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
| | - Gunilla Olivecrona
- Department of Medical Biosciences, Physiological Chemistry, Umeå University, Sweden
| | - Juan S Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Morten S Nielsen
- Department of Biomedicine, The Lundbeck Foundation Initiative on Brain Barriers and Drug Delivery, Aarhus University, Denmark.,Department of Biomedicine, The MIND Centre, Aarhus University, Denmark
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18
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Hatzold J, Beleggia F, Herzig H, Altmüller J, Nürnberg P, Bloch W, Wollnik B, Hammerschmidt M. Tumor suppression in basal keratinocytes via dual non-cell-autonomous functions of a Na,K-ATPase beta subunit. eLife 2016; 5. [PMID: 27240166 PMCID: PMC4973367 DOI: 10.7554/elife.14277] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/28/2016] [Indexed: 01/11/2023] Open
Abstract
The molecular pathways underlying tumor suppression are incompletely understood. Here, we identify cooperative non-cell-autonomous functions of a single gene that together provide a novel mechanism of tumor suppression in basal keratinocytes of zebrafish embryos. A loss-of-function mutation in atp1b1a, encoding the beta subunit of a Na,K-ATPase pump, causes edema and epidermal malignancy. Strikingly, basal cell carcinogenesis only occurs when Atp1b1a function is compromised in both the overlying periderm (resulting in compromised epithelial polarity and adhesiveness) and in kidney and heart (resulting in hypotonic stress). Blockade of the ensuing PI3K-AKT-mTORC1-NFκB-MMP9 pathway activation in basal cells, as well as systemic isotonicity, prevents malignant transformation. Our results identify hypotonic stress as a (previously unrecognized) contributor to tumor development and establish a novel paradigm of tumor suppression.
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Affiliation(s)
- Julia Hatzold
- Institute for Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Filippo Beleggia
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University Hospital Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Hannah Herzig
- Institute of Cardiology and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Janine Altmüller
- Institute of Human Genetics, University Hospital Cologne, Cologne, Germany.,Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Peter Nürnberg
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Institute of Cardiology and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Bernd Wollnik
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University Hospital Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
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19
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Evdokimov K, Biswas S, Schledzewski K, Winkler M, Gorzelanny C, Schneider SW, Goerdt S, Géraud C. Leda-1/Pianp is targeted to the basolateral plasma membrane by a distinct intracellular juxtamembrane region and modulates barrier properties and E-Cadherin processing. Biochem Biophys Res Commun 2016; 475:342-9. [PMID: 27216462 DOI: 10.1016/j.bbrc.2016.05.092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 05/19/2016] [Indexed: 12/19/2022]
Abstract
Leda-1/Pianp is a type-I transmembrane protein which is sorted to the basolateral membrane domain of polarized epithelial cells. Here, we investigated trafficking mechanisms and functions of Leda-1/Pianp in MDCK and MCF-7 cells. Basolateral sorting and posttranslational modifications depended on the intracellular juxtamembrane region. Functionally, Leda-1/Pianp increased the transepithelial electrical resistance generated by a polarized cell sheet. Furthermore, resistance to junctional destabilization by tumor cells was enhanced by Leda-1/Pianp indicating increased stability and tightness of intercellular junctions. While Claudin 1 and 4 expression and activities of small GTPases were not affected, γ-Secretase-mediated cleavage of E-Cadherin was attenuated by Leda-1/Pianp. Regulation of proteolytic processing is thus a molecular mechanism by which Leda-1/Pianp can affect junctional integrity and function.
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Affiliation(s)
- Konstantin Evdokimov
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Siladitta Biswas
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Kai Schledzewski
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Manuel Winkler
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Christian Gorzelanny
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Stefan W Schneider
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Sergij Goerdt
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany
| | - Cyrill Géraud
- Department of Dermatology, Venereology and Allergology, University Medical Center and Medical Faculty Mannheim, Heidelberg University and Center of Excellence in Dermatology, Mannheim, Germany.
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20
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Bañón-Rodríguez I, Gálvez-Santisteban M, Vergarajauregui S, Bosch M, Borreguero-Pascual A, Martín-Belmonte F. EGFR controls IQGAP basolateral membrane localization and mitotic spindle orientation during epithelial morphogenesis. EMBO J 2014; 33:129-45. [PMID: 24421325 DOI: 10.1002/embj.201385946] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Establishing the correct orientation of the mitotic spindle is an essential step in epithelial cell division in order to ensure that epithelial tubules form correctly during organ development and regeneration. While recent findings have identified some of the molecular mechanisms that underlie spindle orientation, many aspects of this process remain poorly understood. Here, we have used the 3D-MDCK model system to demonstrate a key role for a newly identified protein complex formed by IQGAP1 and the epithelial growth factor receptor (EGFR) in controlling the orientation of the mitotic spindle. IQGAP1 is a scaffolding protein that regulates many cellular pathways, from cell-cell adhesion to microtubule organization, and its localization in the basolateral membrane ensures correct spindle orientation. Through its IQ motifs, IQGAP1 binds to EGFR, which is responsible for maintaining IQGAP1 in the basolateral membrane domain. Silencing IQGAP1, or disrupting the basolateral localization of either IQGAP1 or EGFR, results in a non-polarized distribution of NuMA, mitotic spindle misorientation and defects in single lumen formation.
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Affiliation(s)
- Inmaculada Bañón-Rodríguez
- Centro de Biología Molecular Severo Ochoa Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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21
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Singh B, Coffey RJ. Trafficking of epidermal growth factor receptor ligands in polarized epithelial cells. Annu Rev Physiol 2013; 76:275-300. [PMID: 24215440 DOI: 10.1146/annurev-physiol-021113-170406] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A largely unilamellar epithelial layer lines body cavities and organ ducts such as the digestive tract and kidney tubules. This polarized epithelium is composed of biochemically and functionally separate apical and basolateral surfaces. The epidermal growth factor receptor (EGFR) signaling pathway is a critical regulator of epithelial homeostasis and is perturbed in a number of epithelial disorders. It is underappreciated that in vivo EGFR signaling is most often initiated by cell-surface delivery and processing of one of seven transmembrane ligands, resulting in release of the soluble form that binds EGFR. In polarized epithelial cells, EGFR is restricted largely to the basolateral surface, and apical or basolateral ligand delivery therefore has important biological consequences. In vitro approaches have been used to study the biosynthesis, cell-surface delivery, proteolytic processing, and release of soluble EGFR ligands in polarized epithelial cells. We review these results, discuss their relevance to normal physiology, and demonstrate the pathophysiological consequences of aberrant trafficking. These studies have uncovered a rich diversity of apico-basolateral trafficking mechanisms among the EGFR ligands, provided insights into the pathogenesis of an inherited magnesium-wasting disorder of the kidney (isolated renal hypomagnesemia), and identified a new mode of EGFR ligand signaling via exosomes.
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Affiliation(s)
- Bhuminder Singh
- Departments of Medicine and Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232; ,
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22
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Bryant KL, Antonyak MA, Cerione RA, Baird B, Holowka D. Mutations in the polybasic juxtamembrane sequence of both plasma membrane- and endoplasmic reticulum-localized epidermal growth factor receptors confer ligand-independent cell transformation. J Biol Chem 2013; 288:34930-42. [PMID: 24142702 DOI: 10.1074/jbc.m113.513333] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deregulation of ErbB receptor-tyrosine kinases is a hallmark of many human cancers. Conserved in the ErbB family is a cluster of basic amino acid residues in the cytoplasmic juxtamembrane region. We found that charge-silencing mutagenesis within this juxtamembrane region of the epidermal growth factor receptor (EGFR) results in the generation of a mutant receptor (EGFR Mut R1-6) that spontaneously transforms NIH 3T3 cells in a ligand-independent manner. A similar mutant with one additional basic residue, EGFR Mut R1-5, fails to exhibit ligand-independent transformation. The capacity of EGFR Mut R1-6 to mediate this transformation is maintained when this mutant is retained in the endoplasmic reticulum via a single point mutation, L393H, which we describe. We show that EGFR Mut R1-6 with or without L393H exhibits enhanced basal tyrosine phosphorylation when ectopically expressed, and the ligand-independent transforming activity of EGFR Mut R1-6 is sensitive to inhibition of EGFR kinase activity and is particularly dependent on PI3K and mTOR activity. Similar to EGFR Mut R1-6/L393H in NIH 3T3 cells, EGFR variant type III, a highly oncogenic mutant form of EGFR linked to human brain cancers, confers transforming activity while it is wholly endoplasmic reticulum-retained in U87 cells. Our findings highlight the importance of the polybasic juxtamembrane sequence in regulating the oncogenic potential of EGFR signaling.
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Affiliation(s)
- Kirsten L Bryant
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 and
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23
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24
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Masaki T. Polarization and myelination in myelinating glia. ISRN NEUROLOGY 2012; 2012:769412. [PMID: 23326681 PMCID: PMC3544266 DOI: 10.5402/2012/769412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/13/2012] [Indexed: 01/13/2023]
Abstract
Myelinating glia, oligodendrocytes in central nervous system and Schwann cells in peripheral nervous system, form myelin sheath, a multilayered membrane system around axons enabling salutatory nerve impulse conduction and maintaining axonal integrity. Myelin sheath is a polarized structure localized in the axonal side and therefore is supposed to be formed based on the preceding polarization of myelinating glia. Thus, myelination process is closely associated with polarization of myelinating glia. However, cell polarization has been less extensively studied in myelinating glia than other cell types such as epithelial cells. The ultimate goal of this paper is to provide insights for the field of myelination research by applying the information obtained in polarity study in other cell types, especially epithelial cells, to cell polarization of myelinating glia. Thus, in this paper, the main aspects of cell polarization study in general are summarized. Then, they will be compared with polarization in oligodendrocytes. Finally, the achievements obtained in polarization study for epithelial cells, oligodendrocytes, and other types of cells will be translated into polarization/myelination process by Schwann cells. Then, based on this model, the perspectives in the study of Schwann cell polarization/myelination will be discussed.
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Affiliation(s)
- Toshihiro Masaki
- Department of Medical Science, Teikyo University of Science, 2-2-1 Senju-Sakuragi, Adachi-ku, Tokyo 120-0045, Japan
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25
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Cotton CU, Hobert ME, Ryan S, Carlin CR. Basolateral EGF receptor sorting regulated by functionally distinct mechanisms in renal epithelial cells. Traffic 2012. [PMID: 23205726 DOI: 10.1111/tra.12032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Proliferation of epithelial tissues is controlled by polarized distribution of signaling receptors including the EGF receptor (EGFR). In kidney, EGFRs are segregated from soluble ligands present in apical fluid of nephrons by selective targeting to basolateral membranes. We have shown previously that the epithelial-specific clathrin adaptor AP1B mediates basolateral EGFR sorting in established epithelia. Here we show that protein kinase C (PKC)-dependent phosphorylation of Thr654 regulates EGFR polarity as epithelial cells form new cell-cell junctional complexes. The AP1B-dependent pathway does not override a PKC-resistant T654A mutation, and conversely AP1B-defective EGFRs sort basolaterally by a PKC-dependent mechanism, in polarizing cells. Surprisingly, EGFR mutations that interfere with these different sorting pathways also produce very distinct phenotypes in three-dimensional organotypic cultures. Thus EGFRs execute different functions depending on the basolateral sorting route. Many renal disorders have defects in cell polarity and the notion that apically mislocalized EGFRs promote proliferation is still an attractive model to explain many aspects of polycystic kidney disease. Our data suggest EGFR also integrates various aspects of polarity by switching between different basolateral sorting programs in developing epithelial cells. Fundamental knowledge of basic mechanisms governing EGFR sorting therefore provides new insights into pathogenesis and advances drug discovery for these renal disorders.
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Affiliation(s)
- Calvin U Cotton
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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26
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Kufe DW. MUC1-C oncoprotein as a target in breast cancer: activation of signaling pathways and therapeutic approaches. Oncogene 2012; 32:1073-81. [PMID: 22580612 DOI: 10.1038/onc.2012.158] [Citation(s) in RCA: 309] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mucin 1 (MUC1) is a heterodimeric protein formed by two subunits that is aberrantly overexpressed in human breast cancer and other cancers. Historically, much of the early work on MUC1 focused on the shed mucin subunit. However, more recent studies have been directed at the transmembrane MUC1-C-terminal subunit (MUC1-C) that functions as an oncoprotein. MUC1-C interacts with EGFR (epidermal growth factor receptor), ErbB2 and other receptor tyrosine kinases at the cell membrane and contributes to activation of the PI3KAKT and mitogen-activated protein kinase kinase (MEK)extracellular signal-regulated kinase (ERK) pathways. MUC1-C also localizes to the nucleus where it activates the Wnt/β-catenin, signal transducer and activator of transcription (STAT) and NF (nuclear factor)-κB RelA pathways. These findings and the demonstration that MUC1-C is a druggable target have provided the experimental basis for designing agents that block MUC1-C function. Notably, inhibitors of the MUC1-C subunit have been developed that directly block its oncogenic function and induce death of breast cancer cells in vitro and in xenograft models. On the basis of these findings, a first-in-class MUC1-C inhibitor has entered phase I evaluation as a potential agent for the treatment of patients with breast cancers who express this oncoprotein.
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Affiliation(s)
- D W Kufe
- Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.
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27
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Abstract
The polarized distribution of proteins and lipids at the surface membrane of epithelial cells results in the formation of an apical and a basolateral domain, which are separated by tight junctions. The generation and maintenance of epithelial polarity require elaborate mechanisms that guarantee correct sorting and vectorial delivery of cargo molecules. This dynamic process involves the interaction of sorting signals with sorting machineries and the formation of transport carriers. Here we review the recent advances in the field of polarized sorting in epithelial cells. We especially highlight the role of lipid rafts in apical sorting.
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28
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Balanis N, Yoshigi M, Wendt MK, Schiemann WP, Carlin CR. β3 integrin-EGF receptor cross-talk activates p190RhoGAP in mouse mammary gland epithelial cells. Mol Biol Cell 2011; 22:4288-301. [PMID: 21937717 PMCID: PMC3216655 DOI: 10.1091/mbc.e10-08-0700] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Active RhoA localizes to plasma membrane, where it stimulates formation of focal adhesions and stress fibers. RhoA activity is inhibited by p190RhoGAP following integrin-mediated cell attachment to allow sampling of new adhesive environments. p190RhoGAP is itself activated by Src-dependent tyrosine phosphorylation, which facilitates complex formation with p120RasGAP. This complex then translocates to the cell surface, where p190RhoGAP down-regulates RhoA. Here we demonstrate that the epidermal growth factor receptor (EGFR) cooperates with β3 integrin to regulate p190RhoGAP activity in mouse mammary gland epithelial cells. Adhesion to fibronectin stimulates tyrosine phosphorylation of the EGFR in the absence of receptor ligands. Use of a dominant inhibitory EGFR mutant demonstrates that fibronectin-activated EGFR recruits p120RasGAP to the cell periphery. Expression of an inactive β3 integrin subunit abolishes p190RhoGAP tyrosine phosphorylation, demonstrating a mechanistic link between β3 integrin-activated Src and EGFR regulation of the RhoA inhibitor. The β3 integrin/EGFR pathway also has a positive role in formation of filopodia. Together our data suggest that EGFR constitutes an important intrinsic migratory cue since fibronectin is a key component of the microenvironment in normal mammary gland development and breast cancer. Our data also suggest that EGFR expressed at high levels has a role in eliciting cell shape changes associated with epithelial-to-mesenchymal transition.
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Affiliation(s)
- Nikolas Balanis
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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29
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Castorino JJ, Deborde S, Deora A, Schreiner R, Gallagher-Colombo SM, Rodriguez-Boulan E, Philp NJ. Basolateral sorting signals regulating tissue-specific polarity of heteromeric monocarboxylate transporters in epithelia. Traffic 2011; 12:483-98. [PMID: 21199217 DOI: 10.1111/j.1600-0854.2010.01155.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Many solute transporters are heterodimers composed of non-glycosylated catalytic and glycosylated accessory subunits. These transporters are specifically polarized to the apical or basolateral membranes of epithelia, but this polarity may vary to fulfill tissue-specific functions. To date, the mechanisms regulating the tissue-specific polarity of heteromeric transporters remain largely unknown. Here, we investigated the sorting signals that determine the polarity of three members of the proton-coupled monocarboxylate transporter (MCT) family, MCT1, MCT3 and MCT4, and their accessory subunit CD147. We show that MCT3 and MCT4 harbor strong redundant basolateral sorting signals (BLSS) in their C-terminal cytoplasmic tails that can direct fusion proteins with the apical marker p75 to the basolateral membrane. In contrast, MCT1 lacks a BLSS and its polarity is dictated by CD147, which contains a weak BLSS that can direct Tac, but not p75 to the basolateral membrane. Knockdown experiments in MDCK cells indicated that basolateral sorting of MCTs was clathrin-dependent but clathrin adaptor AP1B-independent. Our results explain the consistently basolateral localization of MCT3 and MCT4 and the variable localization of MCT1 in different epithelia. They introduce a new paradigm for the sorting of heterodimeric transporters in which a hierarchy of apical and BLSS in the catalytic and/or accessory subunits regulates their tissue-specific polarity.
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Affiliation(s)
- John J Castorino
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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30
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Liccardi G, Hartley JA, Hochhauser D. EGFR nuclear translocation modulates DNA repair following cisplatin and ionizing radiation treatment. Cancer Res 2011; 71:1103-14. [PMID: 21266349 DOI: 10.1158/0008-5472.can-10-2384] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Epidermal growth factor receptor (EGFR) overexpression is associated with resistance to chemotherapy and radiotherapy. It modulates DNA repair after radiation-induced damage through association with the catalytic subunit of DNA protein kinase (DNA-PKcs). We investigated the role of EGFR nuclear import and its association with DNA-PKcs on DNA repair after exposure to cisplatin or ionizing radiation (IR). The model system was based on EGFR-null murine NIH3T3 fibroblasts in which EGFR expression was restored with isoforms that were wild-type (wt), derived from human cancers (L858R, EGFRvIII), or mutated in the nuclear localization signal (NLS) sequence. In cells expressing wtEGFR or EGFRvIII, there was complete unhooking of cisplatin-induced interstrand cross-links and repair of IR-induced strand breaks. In contrast, cells expressing L858R or NLS mutations showed reduced unhooking of interstrand cross-links and repair of strand breaks. Immunoprecipitation showed wtEGFR and EGFRvIII binding to DNA-PKcs, increasing 2-fold 18 hours after cisplatin therapy. Confocal microscopy and proximity ligation assay showed that this interaction in the cytoplasm and nucleus was associated with increased DNA protein kinase complex (DNA-PK) activity. Cells expressing the EGFR L858R mutation, which has constitutive kinase activity, exhibited reduced DNA repair without nuclear localization. EGFR-NLS mutants showed impaired nuclear localization and DNA-PKcs association with reduced DNA repair and DNA-PK kinase activity. In summary, EGFR nuclear localization was required for modulation of cisplatin and IR-induced repair of DNA damage. EGFR-DNA-PKcs binding was induced by cisplatin or IR but not by EGFR nuclear translocation per se. Our findings show that EGFR subcellular distribution can modulate DNA repair kinetics, with implications for design of EGFR-targeted combinational therapies.
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Affiliation(s)
- Gianmaria Liccardi
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, University College London, London, United Kingdom
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31
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Ryan S, Verghese S, Cianciola NL, Cotton CU, Carlin CR. Autosomal recessive polycystic kidney disease epithelial cell model reveals multiple basolateral epidermal growth factor receptor sorting pathways. Mol Biol Cell 2010; 21:2732-45. [PMID: 20519437 PMCID: PMC2912358 DOI: 10.1091/mbc.e09-12-1059] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have discovered that multiple basolateral pathways mediate EGF receptor sorting in renal epithelial cells. The polycystic kidney disease allele in the BPK mouse model, Bicc1, interferes with one specific EGF receptor pathway, causing nonpolar delivery of the receptor without affecting overall cell polarity. Sorting and maintenance of the EGF receptor on the basolateral surface of renal epithelial cells is perturbed in polycystic kidney disease and apical expression of receptors contributes to severity of disease. The goal of these studies was to understand the molecular basis for EGF receptor missorting using a well-established mouse model for the autosomal recessive form of the disease. We have discovered that multiple basolateral pathways mediate EGF receptor sorting in renal epithelial cells. The polycystic kidney disease allele in this model, Bicc1, interferes with one specific EGF receptor pathway without affecting overall cell polarity. Furthermore one of the pathways is regulated by a latent basolateral sorting signal that restores EGF receptor polarity in cystic renal epithelial cells via passage through a Rab11-positive subapical compartment. These studies give new insights to possible therapies to reconstitute EGF receptor polarity and function in order to curb disease progression. They also indicate for the first time that the Bicc1 gene that is defective in the mouse model used in these studies regulates cargo-specific protein sorting mediated by the epithelial cell specific clathrin adaptor AP-1B.
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Affiliation(s)
- Sean Ryan
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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32
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Block ER, Tolino MA, Lozano JS, Lathrop KL, Sullenberger RS, Mazie AR, Klarlund JK. Free edges in epithelial cell sheets stimulate epidermal growth factor receptor signaling. Mol Biol Cell 2010; 21:2172-81. [PMID: 20462956 PMCID: PMC2893982 DOI: 10.1091/mbc.e09-12-1026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Epithelia tend to migrate when edges are present, for instance, after wounding or during development. Using a new tissue culture model, we found that the existence of free edges is in itself a signal that causes activation of the epidermal growth factor and cell motility. The ability of epithelia to migrate and cover wounds is essential to maintaining their functions as physical barriers. Wounding induces many cues that may affect the transition to motility, including the immediate mechanical perturbation, release of material from broken cells, new interactions with adjacent extracellular matrix, and breakdown of physical separation of ligands from their receptors. Depending on the exact nature of wounds, some cues may be present only transiently or insignificantly. In many epithelia, activation of the epidermal growth factor receptor (EGFR) is a central event in induction of motility, and we find that its continuous activation is required for progression of healing of wounds in sheets of corneal epithelial cells. Here, we examine the hypothesis that edges, which are universally and continuously present in wounds, are a cue. Using a novel culture model we find that their presence is sufficient to cause activation of the EGFR and increased motility of cells in the absence of other cues. Edges that are bordered by agarose do not induce activation of the EGFR, indicating that activation is not due to loss of any specific type of cell–cell interaction but rather due to loss of physical constraints.
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Affiliation(s)
- Ethan R Block
- Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
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33
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Bitler BG, Goverdhan A, Schroeder JA. MUC1 regulates nuclear localization and function of the epidermal growth factor receptor. J Cell Sci 2010; 123:1716-23. [PMID: 20406885 DOI: 10.1242/jcs.062661] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alteration of protein trafficking and localization is associated with several diseases, including cystic fibrosis, breast cancer, colorectal cancer, leukemia and diabetes. Specifically, aberrant nuclear localization of the epidermal growth factor receptor (EGFR), a receptor tyrosine kinase, is a poor prognostic indicator in several epithelial carcinomas. It is now appreciated that in addition to signaling from the plasma membrane, EGFR also trafficks to the nucleus, and can directly bind the promoter regions of genes encoding cyclin D1 (CCND1) and B-Myb (MYBL2). We have previously established that loss of MUC1 in an EGFR-dependent transgenic mouse model of breast cancer correlates with the loss of cyclin D1 expression. Here, we provide evidence for a novel regulatory function of MUC1 in the trafficking and nuclear activity of EGFR. We found that MUC1 and EGFR interact in the nucleus of breast cancer cells, which promotes the accumulation of chromatin-bound EGFR. Additionally, the presence of MUC1 results in significant colocalization of EGFR and phosphorylated RNA polymerase II, indicating that MUC1 influences the association of EGFR with transcriptionally active promoter regions. Importantly, we found that the loss of MUC1 expression resulted in a decrease in the interaction between EGFR and the CCND1 promoter, which translated to a significant decrease in cyclin D1 protein expression. This data offers insights into a novel regulatory mechanism of EGFR nuclear function and could have important implications for evaluating nuclear localization in cancer.
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34
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Ye F, Gao Q, Cai MJ. Therapeutic targeting of EGFR in malignant gliomas. Expert Opin Ther Targets 2010; 14:303-16. [DOI: 10.1517/14728221003598948] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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35
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36
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Gonzalez A, Rodriguez-Boulan E. Clathrin and AP1B: key roles in basolateral trafficking through trans-endosomal routes. FEBS Lett 2009; 583:3784-95. [PMID: 19854182 DOI: 10.1016/j.febslet.2009.10.050] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 10/15/2009] [Accepted: 10/20/2009] [Indexed: 12/12/2022]
Abstract
Research following introduction of the MDCK model system to study epithelial polarity (1978) led to an initial paradigm that posited independent roles of the trans Golgi network (TGN) and recycling endosomes (RE) in the generation of, respectively, biosynthetic and recycling routes of plasma membrane (PM) proteins to apical and basolateral PM domains. This model dominated the field for 20 years. However, studies over the past decade and the discovery of the involvement of clathrin and clathrin adaptors in protein trafficking to the basolateral PM has led to a new paradigm. TGN and RE are now believed to cooperate closely in both biosynthetic and recycling trafficking routes. Here, we critically review these recent advances and the questions that remain unanswered.
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Affiliation(s)
- Alfonso Gonzalez
- Departamento de Inmunología Clínica y Reumatología, Facultad de Medicina, Centro de Regulación Celular y Patología and Centro de Envejecimiento y Regeneración, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6510260 Santiago, Chile.
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37
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Red Brewer M, Choi SH, Alvarado D, Moravcevic K, Pozzi A, Lemmon MA, Carpenter G. The juxtamembrane region of the EGF receptor functions as an activation domain. Mol Cell 2009; 34:641-51. [PMID: 19560417 DOI: 10.1016/j.molcel.2009.04.034] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 03/24/2009] [Accepted: 04/10/2009] [Indexed: 12/19/2022]
Abstract
In several growth factor receptors, the intracellular juxtamembrane (JM) region participates in autoinhibitory interactions that must be disrupted for tyrosine kinase activation. Using alanine scanning mutagenesis and crystallographic approaches, we define a domain within the JM region of the epidermal growth factor receptor (EGFR) that instead plays an activating--rather than autoinhibitory--role. Mutations in the C-terminal 19 residues of the EGFR JM region abolish EGFR activation. In a crystal structure of an asymmetric dimer of the tyrosine kinase domain, the JM region of an acceptor monomer makes extensive contacts with the C lobe of a donor monomer, thus stabilizing the dimer. We describe how an uncharacterized lung cancer mutation in this JM activation domain (V665M) constitutively activates EGFR by augmenting its capacity to act as an acceptor in the asymmetric dimer. This JM mutant promotes cellular transformation by EGFR in vitro and is tumorigenic in a xenograft assay.
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Affiliation(s)
- Monica Red Brewer
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37212, USA
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38
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Subramanian VS, Marchant JS, Boulware MJ, Ma TY, Said HM. Membrane targeting and intracellular trafficking of the human sodium-dependent multivitamin transporter in polarized epithelial cells. Am J Physiol Cell Physiol 2009; 296:C663-71. [PMID: 19211916 PMCID: PMC2670647 DOI: 10.1152/ajpcell.00396.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 02/06/2009] [Indexed: 11/22/2022]
Abstract
The human sodium-dependent multivitamin transporter (hSMVT) mediates sodium-dependent uptake of biotin in renal and intestinal epithelia. To date, however, there is nothing known about the structure-function relationship or targeting sequences in the hSMVT polypeptide that control its polarized expression within epithelia. Here, we focused on the role of the COOH-terminal tail of hSMVT in the targeting and functionality of this transporter. A full-length hSMVT-green fluorescent protein (GFP) fusion protein was functional and expressed at the apical membrane in renal and intestinal cell lines. Microtubule disrupting agents disrupted the mobility of trafficking vesicles and impaired cell surface delivery of hSMVT, which was also prevented in cells treated with dynamitin (p50), brefeldin, or monensin. Progressive truncation of the COOH-terminal tail impaired the functionality and targeting of the transporter. First, biotin transport decreased by approximately 20-30% on deletion of up to 15 COOH-terminal amino acids of hSMVT, a decrease mimicked solely by deletion of the terminal PDZ motif (TSL). Second, deletions into the COOH-terminal tail (between residues 584-612, containing a region of predicted high surface accessibility) resulted in a further drop in hSMVT transport (to approximately 40% of wild-type). Third, apical targeting was lost on deletion of a helical-prone region between amino acids 570-584. We conclude that the COOH tail of hSMVT contains several determinants important for polarized targeting and biotin transport.
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39
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Capdevila J, Elez E, Macarulla T, Ramos FJ, Ruiz-Echarri M, Tabernero J. Anti-epidermal growth factor receptor monoclonal antibodies in cancer treatment. Cancer Treat Rev 2009; 35:354-63. [PMID: 19269105 DOI: 10.1016/j.ctrv.2009.02.001] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 01/31/2009] [Accepted: 02/04/2009] [Indexed: 12/30/2022]
Abstract
Although the prognosis of cancer remains poor recent advances in the diagnostic methods, new approaches in surgical procedures and the development of new therapeutic agents have had a significant impact in the outcome of cancer patients. A better understanding of the molecular pathways that characterize cell growth, apoptosis, angiogenesis and invasion has provided novel targets in cancer therapy. The epidermal growth factor receptor (EGFR) mediated signal transduction has been one of the most studied pathways in carcinogenesis. The phosphorylation of EGFR activates multiple biological processes including apoptosis, differentiation, cellular proliferation, motility, invasion, adhesion, DNA repair and survival. Several therapies have been developed to inactivate the EGFR pathway including monoclonal antibodies against the extracellular domain of EGFR. In this review, the authors examine the development of monoclonal antibodies against EGFR and the effects of this blockage in cell cycle, as well as the most important trials with these monoclonal antibodies in several tumor types.
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Affiliation(s)
- Jaume Capdevila
- Medical Oncology Department, Vall d'Hebron University Hospital, Barcelona, Spain.
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40
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The epithelial polarity program: machineries involved and their hijacking by cancer. Oncogene 2008; 27:6939-57. [DOI: 10.1038/onc.2008.345] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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41
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Buvinic S, Bravo-Zehnder M, Boyer JL, Huidobro-Toro JP, González A. Nucleotide P2Y1 receptor regulates EGF receptor mitogenic signaling and expression in epithelial cells. J Cell Sci 2008; 120:4289-301. [PMID: 18057028 DOI: 10.1242/jcs.03490] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Epidermal growth factor receptor (EGFR) function is transregulated by a variety of stimuli, including agonists of certain G-protein-coupled receptors (GPCRs). One of the most ubiquitous GPCRs is the P2Y(1) receptor (P2RY1, hereafter referred to as P2Y(1)R) for extracellular nucleotides, mainly ADP. Here, we show in tumoral HeLa cells and normal FRT epithelial cells that P2Y(1)R broadcasts mitogenic signals by transactivating the EGFR. The pathway involves PKC, Src and cell surface metalloproteases. Stimulation of P2Y(1)R for as little as 15-60 minutes triggers mitogenesis, mirroring the half-life of extracellular ADP. Apyrase degradation of extracellular nucleotides and drug inhibition of P2Y(1)R, both reduced basal cell proliferation of HeLa and FRT cells, but not MDCK cells, which do not express P2Y(1)R. Thus, cell-released nucleotides constitute strong mitogenic stimuli, which act via P2Y(1)R. Strikingly, MDCK cells ectopically expressing P2Y(1)R display a highly proliferative phenotype that depends on EGFR activity associated with an increased level of EGFR, thus disclosing a novel aspect of GPCR-mediated regulation of EGFR function. These results highlight a role of P2Y(1)R in EGFR-dependent epithelial cell proliferation. P2Y(1)R could potentially mediate both trophic stimuli of basally released nucleotides and first-line mitogenic stimulation upon tissue damage. It could also contribute to carcinogenesis and serve as target for antitumor therapies.
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Affiliation(s)
- Sonja Buvinic
- Centro de Regulación Celular y Patología JV Luco, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 8330033, Santiago, Chile
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42
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Hake MJ, Choowongkomon K, Kostenko O, Carlin CR, Sönnichsen FD. Specificity determinants of a novel Nck interaction with the juxtamembrane domain of the epidermal growth factor receptor. Biochemistry 2008; 47:3096-108. [PMID: 18269246 DOI: 10.1021/bi701549a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nck is a ubiquitously expressed adaptor protein containing Src homology 2 (SH2) and Src homology 3 (SH3) domains. It integrates downstream effector proteins with cell membrane receptors, such as the epidermal growth factor receptor (EGFR). EGFR plays a critical role in cellular proliferation and differentiation. The 45-residue juxtamembrane domain of EGFR (JM), located between the transmembrane and kinase domains, regulates receptor activation and trafficking to the basolateral membrane of polarized epithelia through a proline-rich motif that resembles a consensus SH3 domain binding site. We demonstrate here that the JM region can bind to Nck, showing a notable binding preference for the second SH3 domain. To elucidate the structural determinants for this interaction, we have determined the NMR solution structures of both the first and second Nck SH3 domains (Nck1-1 and Nck1-2). These domains adopt a canonical SH3 beta-barrel-like fold, containing five antiparallel strands separated by three loop regions and one 3 10-helical turn. Chemical shift perturbation studies have identified the residues that form the binding cleft of Nck1-2, which are primarily located in the RT and n-Src loops. JM binds to Nck1-2 with an affinity of approximately 80 microM through a positively charged sequence near the N-terminus, as opposed to the polyproline sequence. The two Nck SH3 domains exhibit both steric and electrostatic differences in their RT-Src and n-Src loops, and a model of the Nck1-2 domain complexed with the JM highlights the factors that define the putative binding mode for this ligand.
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Affiliation(s)
- Michael J Hake
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA
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43
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Epidermal growth factor receptor juxtamembrane region regulates allosteric tyrosine kinase activation. Proc Natl Acad Sci U S A 2007; 104:19238-43. [PMID: 18042729 DOI: 10.1073/pnas.0703854104] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Structural studies of the extracellular and tyrosine kinase domains of the epidermal growth factor receptor (ErbB-1) provide considerable insight into facets of the receptor activation mechanism, but the contributions of other regions of ErbB-1 have not been ascertained. This study demonstrates that the intracellular juxtamembrane (JM) region plays a vital role in the kinase activation mechanism. In the experiments described herein, the entire ErbB-1 intracellular domain (ICD) has been expressed in mammalian cells to explore the significance of the JM region in kinase activity. Deletion of the JM region (DeltaJM) results in a severe loss of ICD tyrosine phosphorylation, indicating that this region is required for maximal activity of the tyrosine kinase domain. Coexpression of DeltaJM and dimerization-deficient kinase domain ICD mutants revealed that the JM region is indispensable for allosteric kinase activation and productive monomer interactions within a dimer. Studies with the intact receptor confirmed the role of the JM region in kinase activation. Within the JM region, Thr-654 is a known protein kinase C (PKC) phosphorylation site that modulates kinase activity in the context of the intact ErbB-1 receptor; yet, the mechanism is not known. Whereas a T654A mutation promotes increased ICD tyrosine phosphorylation, the phosphomimetic T654D mutant generates a 50% reduction in ICD tyrosine phosphorylation. Similar to the DeltaJM mutants, the T654D mutant ICD failed to interact with a wild-type monomer. This study reveals an integral role for the intracellular JM region of ErbB-1 in allosteric kinase activation.
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Groenestege WMT, Thébault S, van der Wijst J, van den Berg D, Janssen R, Tejpar S, van den Heuvel LP, van Cutsem E, Hoenderop JG, Knoers NV, Bindels RJ. Impaired basolateral sorting of pro-EGF causes isolated recessive renal hypomagnesemia. J Clin Invest 2007; 117:2260-7. [PMID: 17671655 PMCID: PMC1934557 DOI: 10.1172/jci31680] [Citation(s) in RCA: 234] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 05/08/2007] [Indexed: 12/11/2022] Open
Abstract
Primary hypomagnesemia constitutes a rare heterogeneous group of disorders characterized by renal or intestinal magnesium (Mg(2+)) wasting resulting in generally shared symptoms of Mg(2+) depletion, such as tetany and generalized convulsions, and often including associated disturbances in calcium excretion. However, most of the genes involved in the physiology of Mg(2+) handling are unknown. Through the discovery of a mutation in the EGF gene in isolated autosomal recessive renal hypomagnesemia, we have, for what we believe is the first time, identified a magnesiotropic hormone crucial for total body Mg(2+) balance. The mutation leads to impaired basolateral sorting of pro-EGF. As a consequence, the renal EGFR is inadequately stimulated, resulting in insufficient activation of the epithelial Mg(2+) channel TRPM6 (transient receptor potential cation channel, subfamily M, member 6) and thereby Mg(2+) loss. Furthermore, we show that colorectal cancer patients treated with cetuximab, an antagonist of the EGFR, develop hypomagnesemia, emphasizing the significance of EGF in maintaining Mg(2+) balance.
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Affiliation(s)
- Wouter M. Tiel Groenestege
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Stéphanie Thébault
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Dennis van den Berg
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rob Janssen
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Sabine Tejpar
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lambertus P. van den Heuvel
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Eric van Cutsem
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joost G. Hoenderop
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Nine V. Knoers
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - René J. Bindels
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Digestive Oncology Unit, Department of Internal Medicine, University Hospital Gasthuisberg and Catholic University Leuven, Leuven, Belgium.
Department of Pediatrics and
Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Ray RM, Bhattacharya S, Johnson LR. EGFR plays a pivotal role in the regulation of polyamine-dependent apoptosis in intestinal epithelial cells. Cell Signal 2007; 19:2519-27. [PMID: 17825525 PMCID: PMC2699668 DOI: 10.1016/j.cellsig.2007.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 08/06/2007] [Indexed: 11/16/2022]
Abstract
Intracellular polyamine synthesis is regulated by the enzyme ornithine decarboxylase (ODC), and its inhibition by alpha-difluromethylornithine (DFMO), confers resistance to apoptosis. We have previously shown that DFMO leads to the inhibition of de novo polyamine synthesis, which in turn rapidly activates Src, STAT3 and NF-kappaB via integrin beta3 in intestinal epithelial cells. One mechanism to explain these effects involves the activation of upstream growth factor receptors, such as the epidermal growth factor receptor (EGFR). We therefore hypothesized that EGFR phosphorylation regulates the early response to polyamine depletion. DFMO increased EGFR phosphorylation on tyrosine residues 1173 (pY1173) and 845 (pY845) within 5 min. Phosphorylation declined after 10 min and was prevented by the addition of exogenous putrescine to DFMO containing medium. Phosphorylation of EGFR was concomitant with the activation of ERK1/2. Pretreatment with either DFMO or EGF for 1 h protected cells from TNF-alpha/CHX-induced apoptosis. Exogenous addition of polyamines prevented the protective effect of DFMO. In addition, inhibition of integrin beta3 activity (with RGDS), Src activity (with PP2), or EGFR kinase activity (with AG1478), increased basal apoptosis and prevented protection conferred by either DFMO or EGF. Polyamine depletion failed to protect B82L fibroblasts lacking the EGFR (PRN) and PRN cells expressing either a kinase dead EGFR (K721A) or an EGFR (Y845F) mutant lacking the Src phosphorylation site. Conversely, expression of WT-EGFR (WT) restored the protective effect of polyamine depletion. Fibronectin activated the EGFR, Src, ERKs and protected cells from apoptosis. Taken together, our data indicate an essential role of EGFR kinase activity in MEK/ERK-mediated protection, which synergizes with integrin beta3 leading to Src-mediated protective responses in polyamine depleted cells.
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Affiliation(s)
- Ramesh M Ray
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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46
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Sebastian S, Settleman J, Reshkin SJ, Azzariti A, Bellizzi A, Paradiso A. The complexity of targeting EGFR signalling in cancer: from expression to turnover. Biochim Biophys Acta Rev Cancer 2006; 1766:120-39. [PMID: 16889899 DOI: 10.1016/j.bbcan.2006.06.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 06/08/2006] [Accepted: 06/15/2006] [Indexed: 12/22/2022]
Abstract
The epidermal growth factor receptor (ErbB1 or EGFR) has been found to be altered in a variety of human cancers. A number of agents targeting these receptors, including specific antibodies directed against the ligand-binding domain of the receptor and small molecules that inhibit kinase activity are either in clinical trials or are already approved for clinical treatment. However, identifying patients that are likely to respond to such treatments has been challenging. As a consequence, it still remains important to identify additional alterations of the tumor cell that contribute to the response to EGFR-targeted agents. While EGFR-mediated signalling pathways have been well established, there is still a rather limited understanding of how intracellular protein-protein interactions, ubiquitination, endocytosis and subsequent degradation of EGFR contribute to the determination of sensitivity to EGFR targeting agents and are emerging areas of investigation. This review primarily focuses on the basic signal transduction pathways mediated through activated membrane bound and/or endosomal EGFR and emphasizes the need to co-target additional proteins that function either upstream or downstream of EGFR to improve cancer therapy.
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Affiliation(s)
- Sinto Sebastian
- Clinical Experimental Oncology Laboratory, National Cancer Institute, Via Amendola, 209, 70126, Bari, Italy
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47
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Wild-Bode C, Fellerer K, Kugler J, Haass C, Capell A. A basolateral sorting signal directs ADAM10 to adherens junctions and is required for its function in cell migration. J Biol Chem 2006; 281:23824-9. [PMID: 16777847 DOI: 10.1074/jbc.m601542200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ADAM10 (a disintegrin and metalloprotease) initiates regulated intramembrane proteolysis by shedding the ectodomain of a number of different substrates. Shedding is followed by subsequent intramembrane proteolysis leading to the liberation of intracellular domains capable of nuclear signaling. ADAM10 substrates have been found at cell-cell contacts and are apparently involved in cell-cell interaction and cell migration. Here we have investigated the cellular mechanism that guides ADAM10 to substrates at cell-cell contacts. We demonstrate that intracellular trafficking of ADAM10 critically requires a novel sorting signal within its cytoplasmic domain. Sequential deletion of the cytoplasmic domain and site-directed mutagenesis suggest that a potential Src homology 3-binding domain is essential for ADAM10 sorting. In a polarized epithelial cell line this motif not only targets ADAM10 to adherens junctions but is also strictly required for ADAM10 function in E-cadherin processing and cell migration.
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Affiliation(s)
- Christine Wild-Bode
- Adolf Butenandt Institute, Department of Biochemistry, Laboratory for Alzheimer's and Parkinson's Disease Research, Ludwig Maximilians University, Schillerstrasse 44, 80336 Munich, Germany
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48
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Stetak A, Hoier EF, Croce A, Cassata G, Di Fiore PP, Hajnal A. Cell fate-specific regulation of EGF receptor trafficking during Caenorhabditis elegans vulval development. EMBO J 2006; 25:2347-57. [PMID: 16688213 PMCID: PMC1478196 DOI: 10.1038/sj.emboj.7601137] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 04/18/2006] [Indexed: 11/08/2022] Open
Abstract
By controlling the subcellular localization of growth factor receptors, cells can modulate the activity of intracellular signal transduction pathways. During Caenorhabditis elegans vulval development, a ternary complex consisting of the LIN-7, LIN-2 and LIN-10 PDZ domain proteins localizes the epidermal growth factor receptor (EGFR) to the basolateral compartment of the vulval precursor cells (VPCs) to allow efficient receptor activation by the inductive EGF signal from the anchor cell. We have identified EGFR substrate protein-8 (EPS-8) as a novel component of the EGFR localization complex that links receptor trafficking to cell fate specification. EPS-8 expression is upregulated in the primary VPCs, where it creates a positive feedback loop in the EGFR/RAS/MAPK pathway. The membrane-associated guanylate kinase LIN-2 recruits EPS-8 into the receptor localization complex to retain the EGFR on the basolateral plasma membrane, and thus allow maximal receptor activation in the primary cell lineage. Low levels of EPS-8 in the neighboring secondary VPCs result in the rapid degradation of the EGFR, allowing these cells to adopt the secondary cell fate. Extracellular signals thus regulate EGFR trafficking in a cell type-specific manner to control pattern formation during organogenesis.
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Affiliation(s)
- Attila Stetak
- Institute of Zoology, University of Zürich, Zürich, Switzerland
| | | | - Assunta Croce
- IFOM-FIRC Institute of Molecular Oncology, Milano, Italy
| | | | | | - Alex Hajnal
- Institute of Zoology, University of Zürich, Zürich, Switzerland
- Institute of Zoology, University of Zürich, Winterthurerstr. 190, 8057 Zürich, Switzerland. Tel.: +41 1 635 4854/4866; Fax: +41 1 635 6878; E-mail:
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49
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Choowongkomon K, Carlin CR, Sönnichsen FD. A structural model for the membrane-bound form of the juxtamembrane domain of the epidermal growth factor receptor. J Biol Chem 2005; 280:24043-52. [PMID: 15840573 DOI: 10.1074/jbc.m502698200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine kinase family involved in the regulation of cellular proliferation and differentiation. Its juxtamembrane domain (JX), the region located between the transmembrane and kinase domains, plays important roles in receptor trafficking. Two sorting signals, a PXXP motif and a 658LL659 motif, are responsible for basolateral sorting in polarized epithelial cells, and a 679LL680 motif targets the ligand-activated receptor for lysosomal degradation. To understand the regulation of these signals, we characterized the structural properties of recombinant JX domain in aqueous solution and in dodecylphosphocholine (DPC) detergent. JX is inherently unstructured in aqueous solution, albeit a nascent helix encompasses the lysosomal sorting signal. In DPC micelles, structures derived from NMR data showed three amphipathic, helical segments. A large, internally inconsistent group of long range nuclear Overhauser effects suggest a close proximity of the helices, and the presence of significant conformational averaging. Models were determined for the average JX conformation using restraints representing the translational restriction due to micelle-surface adsorption, and the helix orientations were determined from residual dipolar couplings. Two equivalent average structural models were obtained that differ only in the relative orientation between first and second helices. In these models, the 658LL659 and 679LL680 motifs are located in the first and second helices and face the micelle surface, whereas the PXXP motif is located in a flexible helix-connecting region. The data suggest that the activity of these signals may be regulated by their membrane association and restricted accessibility in the intact receptor.
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Affiliation(s)
- Kiattawee Choowongkomon
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4970, USA
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50
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Kawahara M, Ishii S, Tsumoto K, Kumagai I, Ueda H, Nagamune T. Reversal of antigen-dependent signaling by two mutations in antibody/receptor chimera: implication of inverse agonism in cytokine receptor superfamily. Biochem Pharmacol 2004; 68:539-48. [PMID: 15242820 DOI: 10.1016/j.bcp.2004.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Accepted: 04/21/2004] [Indexed: 01/01/2023]
Abstract
Understanding the receptor activation mechanism is essential for the rational design of pharmacologically active ligand molecules. However, the activation mechanism of most cytokine receptors remains still unclear, and while agonism and antagonism have been described for ligand-mimetic peptides, there has been no report of inverse agonism that has been characterized for G protein-coupled receptors (GPCRs). To explore the activation mechanism of cytokine receptors, here we tried to investigate how agonism and antagonism could be altered by randomizing antibody variable region of an antibody/cytokine receptor chimera recognizing hen egg lysozyme (HEL) as an agonist. Based on our previous finding that the co-expression of V(H)-gp130 and V(L)-erythropoietin receptor (EpoR) chimeras transduced strict and efficient HEL-dependent cell growth signal, a V(H)-gp130 library encoding four randomized CDR2 residues was retrovirally infected to IL-3-dependent Ba/F3 cells already transfected with V(L)-EpoR. The selection without IL-3 resulted in a clonal expansion of the transduced cells, and interestingly some of which showed HEL dose-dependent growth suppression. Our results clearly indicate that agonism and antagonism of the antibody/cytokine receptor chimera can be readily switched by a subtle modification of the ligand binding domain as well as that of GPCRs, also implying the existence of inverse agonism in cytokine receptor superfamily.
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Affiliation(s)
- Masahiro Kawahara
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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