1
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Li Y, Zhang P, Tang G, Zhong J, Wang Z, Zhu B. Lowering expression of Epsin-3 inhibits migration and invasion of lung adenocarcinoma cells by inhibiting the epithelial-mesenchymal transition. Sci Rep 2024; 14:17069. [PMID: 39048677 PMCID: PMC11269644 DOI: 10.1038/s41598-024-68193-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 07/22/2024] [Indexed: 07/27/2024] Open
Abstract
The epithelial-mesenchymal transition (EMT) is a genetic reprogramming that tumor cells utilize for metastasis. Epsin-3 (EPN3) is an endocytic adapter protein involved in clathrin-mediated endocytosis and had been previously linked to EMT in breast cancer and glioma metastasis. In this study, identified the role of epsin-3 in lung adenocarcinoma and metastasis and epsin-3 levels identified using an expression profile analysis of patient data indicated the protein was abnormally overexpressed in lung adenocarcinoma patients and this was directly linked to disease severity. Gene knockdowns of EPN3 in human adenocarcinoma cell line A549 and the non-small cell lung carcinoma cell line H1299 decreased the levels of mesenchymal markers, including vimentin (VIM), N-cadherin (NCAD) and embryonic transcription factors like zinc finger E-box binding homeobox 1(ZEB1), snail, and the key molecules of Wnt pathway such as β-catenin and resulted in increased expression of the epithelial marker E-cadherin (ECAD). Our data links EPN3 to the EMT process in lung cancer and inhibition of its expression reduced the metastatic and invasive ability of lung adenocarcinoma cells by inhibiting the EMT process.
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Affiliation(s)
- Yunhe Li
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Pei Zhang
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guoxu Tang
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jiahui Zhong
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Zhenghong Wang
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Bing Zhu
- Department of Thoracic and Cardiovascular Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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2
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Troost T, Seib E, Airich A, Vüllings N, Necakov A, De Renzis S, Klein T. The meaning of ubiquitylation of the DSL ligand Delta for the development of Drosophila. BMC Biol 2023; 21:260. [PMID: 37974242 PMCID: PMC10655352 DOI: 10.1186/s12915-023-01759-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Ubiquitylation (ubi) of the intracellular domain of the Notch ligand Delta (Dl) by the E3 ligases Neuralized (Neur) and Mindbomb1 (Mib1) on lysines (Ks) is thought to be essential for the its signalling activity. Nevertheless, we have previously shown that DlK2R-HA, a Dl variant where all Ks in its intracellular domain (ICD) are replaced by the structurally similar arginine (R), still possess weak activity if over-expressed. This suggests that ubi is not absolutely required for Dl signalling. However, it is not known whether the residual activity of DlK2R-HA is an effect of over-expression and, if not, whether DlK2R can provide sufficient activity for the whole development of Drosophila. RESULTS To clarify these issues, we generated and analysed DlattP-DlK2R-HA, a knock-in allele into the Dl locus. Our analysis of this allele reveals that the sole presence of one copy of DlattP-DlK2R-HA can provide sufficient activity for completion of development. It further indicates that while ubi is required for the full activity of Dl in Mib1-dependent processes, it is not essential for Neur-controlled neural development. We identify three modes of Dl signalling that are either dependent or independent of ubi. Importantly, all modes depend on the presence of the endocytic adapter Epsin. During activation of Dl, direct binding of Epsin appears not to be an essential requirement. In addition, our analysis further reveals that the Ks are required to tune down the cis-inhibitory interaction of Dl with Notch. CONCLUSIONS Our results indicate that Dl can activate the Notch pathway without ubi of its ICD. It signals via three modes. Ubi is specifically required for the Mib1-dependent processes and the adjustment of cis-inhibition. In contrast to Mib1, Neur can efficiently activate Dl without ubi. Neur probably acts as an endocytic co-adapter in addition to its role as E3 ligase. Endocytosis, regulated in a ubi-dependent or ubi-independent manner is required for signalling and also suppression of cis-inhibition. The findings clarify the role of ubi of the ligands during Notch signalling.
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Affiliation(s)
- Tobias Troost
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Alina Airich
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Nicole Vüllings
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany
| | - Aleksandar Necakov
- Department of Biological Science, Brock University, 1030, Ontario, L2S3A1, Canada
| | - Stefano De Renzis
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117, Heidelberg, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, 40225, Duesseldorf, Germany.
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3
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Liu JL, Zhang L, Huang Y, Li XH, Liu YF, Zhang SM, Zhao YE, Chen XJ, Liu Y, He LY, Dong Z, Liu FY, Sun L, Xiao L. Epsin1-mediated exosomal sorting of Dll4 modulates the tubular-macrophage crosstalk in diabetic nephropathy. Mol Ther 2023; 31:1451-1467. [PMID: 37016580 PMCID: PMC10188907 DOI: 10.1016/j.ymthe.2023.03.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 02/18/2023] [Accepted: 03/28/2023] [Indexed: 04/05/2023] Open
Abstract
Tubular epithelial cells (TECs) play critical roles in the development of diabetic nephropathy (DN), and can activate macrophages through the secretion of exosomes. However, the mechanism(s) of TEC-exosomes in macrophage activation under DN remains unknown. By mass spectrometry, 1,644 differentially expressed proteins, especially Dll4, were detected in the urine exosomes of DN patients compared with controls, which was confirmed by western blot assay. Elevated Epsin1 and Dll4/N1ICD expression was observed in kidney tissues in both DN patients and db/db mice and was positively associated with tubulointerstitial damage. Exosomes from high glucose (HG)-treated tubular cells (HK-2) with Epsin1 knockdown (KD) ameliorated macrophage activation, TNF-α, and IL-6 expression, and tubulointerstitial damage in C57BL/6 mice in vivo. In an in vitro study, enriched Dll4 was confirmed in HK-2 cells stimulated with HG, which was captured by THP-1 cells and promoted M1 macrophage activation. In addition, Epsin1 modulated the content of Dll4 in TEC-exosomes stimulated with HG. TEC-exosomes with Epsin1-KD significantly inhibited N1ICD activation and iNOS expression in THP-1 cells compared with incubation with HG alone. These findings suggested that Epsin1 could modulate tubular-macrophage crosstalk in DN by mediating exosomal sorting of Dll4 and Notch1 activation.
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Affiliation(s)
- Jia-Lu Liu
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lei Zhang
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ying Huang
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiao-Hui Li
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yi-Fei Liu
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Shu-Min Zhang
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yue-E Zhao
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiao-Jun Chen
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yu Liu
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li-Yu He
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zheng Dong
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China; Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Fu-You Liu
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lin Sun
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Li Xiao
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
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4
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A Bayesian network structure learning approach to identify genes associated with stress in spleens of chickens. Sci Rep 2022; 12:7482. [PMID: 35523843 PMCID: PMC9076669 DOI: 10.1038/s41598-022-11633-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/27/2022] [Indexed: 11/08/2022] Open
Abstract
Differences in the expression patterns of genes have been used to measure the effects of non-stress or stress conditions in poultry species. However, the list of genes identified can be extensive and they might be related to several biological systems. Therefore, the aim of this study was to identify a small set of genes closely associated with stress in a poultry animal model, the chicken (Gallus gallus), by reusing and combining data previously published together with bioinformatic analysis and Bayesian networks in a multi-step approach. Two datasets were collected from publicly available repositories and pre-processed. Bioinformatics analyses were performed to identify genes common to both datasets that showed differential expression patterns between non-stress and stress conditions. Bayesian networks were learnt using a Simulated Annealing algorithm implemented in the software Banjo. The structure of the Bayesian network consisted of 16 out of 19 genes together with the stress condition. Network structure showed CARD19 directly connected to the stress condition plus highlighted CYGB, BRAT1, and EPN3 as relevant, suggesting these genes could play a role in stress. The biological functionality of these genes is related to damage, apoptosis, and oxygen provision, and they could potentially be further explored as biomarkers of stress.
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5
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Seib E, Klein T. The role of ligand endocytosis in notch signalling. Biol Cell 2021; 113:401-418. [PMID: 34038572 DOI: 10.1111/boc.202100009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/05/2021] [Accepted: 05/17/2021] [Indexed: 12/12/2022]
Abstract
The Notch signalling receptor is a mechanoreceptor that is activated by force. This force elicits a conformational change in Notch that results in the release of its intracellular domain into the cytosol by two consecutive proteolytic cleavages. In most cases, the force is generated by pulling of the ligands on the receptor upon their endocytosis. In this review, we summarise recent work that shed a more detailed light on the role of endocytosis during ligand-dependent Notch activation and discuss the role of ubiquitylation of the ligands during this process.
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Affiliation(s)
- Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, Duesseldorf, 40225, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstr. 1, Duesseldorf, 40225, Germany
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6
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Dutta D, Sharma V, Mutsuddi M, Mukherjee A. Regulation of Notch signaling by E3 ubiquitin ligases. FEBS J 2021; 289:937-954. [PMID: 33644958 DOI: 10.1111/febs.15792] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 02/07/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022]
Abstract
Notch signaling is an evolutionarily conserved pathway that is widely used for multiple cellular events during development. Activation of the Notch pathway occurs when the ligand from a neighboring cell binds to the Notch receptor and induces cleavage of the intracellular domain of Notch, which further translocates into the nucleus to activate its downstream genes. The involvement of the Notch pathway in diverse biological events is possible due to the complexity in its regulation. In order to maintain tight spatiotemporal regulation, the Notch receptor, as well as its ligand, undergoes a series of physical and biochemical modifications that, in turn, helps in proper maintenance and fine-tuning of the signaling outcome. Ubiquitination is the post-translational addition of a ubiquitin molecule to a substrate protein, and the process is regulated by E3 ubiquitin ligases. The present review describes the involvement of different E3 ubiquitin ligases that play an important role in the regulation and maintenance of proper Notch signaling and how perturbation in ubiquitination results in abnormal Notch signaling leading to a number of human diseases.
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Affiliation(s)
- Debdeep Dutta
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Vartika Sharma
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, India
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7
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Cui K, Dong Y, Wang B, Cowan DB, Chan SL, Shyy J, Chen H. Endocytic Adaptors in Cardiovascular Disease. Front Cell Dev Biol 2020; 8:624159. [PMID: 33363178 PMCID: PMC7759532 DOI: 10.3389/fcell.2020.624159] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Endocytosis is the process of actively transporting materials into a cell by membrane engulfment. Traditionally, endocytosis was divided into three forms: phagocytosis (cell eating), pinocytosis (cell drinking), and the more selective receptor-mediated endocytosis (clathrin-mediated endocytosis); however, other important endocytic pathways (e.g., caveolin-dependent endocytosis) contribute to the uptake of extracellular substances. In each, the plasma membrane changes shape to allow the ingestion and internalization of materials, resulting in the formation of an intracellular vesicle. While receptor-mediated endocytosis remains the best understood pathway, mammalian cells utilize each form of endocytosis to respond to their environment. Receptor-mediated endocytosis permits the internalization of cell surface receptors and their ligands through a complex membrane invagination process that is facilitated by clathrin and adaptor proteins. Internalized vesicles containing these receptor-ligand cargoes fuse with early endosomes, which can then be recycled back to the plasma membrane, delivered to other cellular compartments, or destined for degradation by fusing with lysosomes. These intracellular fates are largely determined by the interaction of specific cargoes with adaptor proteins, such as the epsins, disabled-homolog 2 (Dab2), the stonin proteins, epidermal growth factor receptor substrate 15, and adaptor protein 2 (AP-2). In this review, we focus on the role of epsins and Dab2 in controlling these sorting processes in the context of cardiovascular disease. In particular, we will focus on the function of epsins and Dab2 in inflammation, cholesterol metabolism, and their fundamental contribution to atherogenicity.
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Affiliation(s)
- Kui Cui
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - Beibei Wang
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - Douglas B Cowan
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States.,Department of Cardiology, Boston Children's Hospital, Boston, MA, United States
| | - Siu-Lung Chan
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - John Shyy
- Division of Cardiology, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
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8
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Dho SE, Silva-Gagliardi N, Morgese F, Coyaud E, Lamoureux E, Berry DM, Raught B, McGlade CJ. Proximity interactions of the ubiquitin ligase Mind bomb 1 reveal a role in regulation of epithelial polarity complex proteins. Sci Rep 2019; 9:12471. [PMID: 31462741 PMCID: PMC6713736 DOI: 10.1038/s41598-019-48902-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/14/2019] [Indexed: 02/07/2023] Open
Abstract
MIB1 belongs to the RING domain containing family of E3 ubiquitin ligases. In vertebrates, MIB1 plays an essential role in activation of Notch signaling during development, through the ubiquitination and endocytosis of Notch ligands. More recently, Notch independent functions for MIB1 have been described in centriole homeostasis, dendritic spine outgrowth and directional cell migration. Here we use proximity-dependent biotin identification (BioID) to define the MIB1 interactome that included 163 high confidence interactions with polypeptides linked to centrosomes and cilia, endosomal trafficking, RNA and DNA processing, the ubiquitin system, and cell adhesion. Biochemical analysis identified several proteins within these groups including CCDC14 and EPS15 that were ubiquitinated but not degraded when co-expressed with MIB1. The MIB1 interactome included the epithelial cell polarity protein, EPB41L5. MIB1 binds to and ubiquitinates EPB41L5 resulting in its degradation. Furthermore, MIB1 ubiquitinates the EPB41L5-associated polarity protein CRB1, an important determinant of the apical membrane. In polarized cells, MIB1 localized to the lateral membrane with EPB41L5 and to the tight junction with CRB1, CRB3 and ZO1. Furthermore, over expression of MIB1 resulted in altered epithelial cell morphology and apical membrane expansion. These results support a role for MIB1 in regulation of polarized epithelial cell morphology.
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Affiliation(s)
- Sascha E Dho
- Program in Cell Biology and The Arthur and Sonia Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada
| | - Nancy Silva-Gagliardi
- Program in Cell Biology and The Arthur and Sonia Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada
| | - Fabio Morgese
- Program in Cell Biology and The Arthur and Sonia Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada
| | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Emily Lamoureux
- Program in Cell Biology and The Arthur and Sonia Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada
| | - Donna M Berry
- Program in Cell Biology and The Arthur and Sonia Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - C Jane McGlade
- Program in Cell Biology and The Arthur and Sonia Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada. .,Department of Medical Biophysics, University of Toronto, Toronto, Canada.
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9
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Hunter GL, He L, Perrimon N, Charras G, Giniger E, Baum B. A role for actomyosin contractility in Notch signaling. BMC Biol 2019; 17:12. [PMID: 30744634 PMCID: PMC6369551 DOI: 10.1186/s12915-019-0625-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/04/2019] [Indexed: 12/24/2022] Open
Abstract
Background Notch-Delta signaling functions across a wide array of animal systems to break symmetry in a sheet of undifferentiated cells and generate cells with different fates, a process known as lateral inhibition. Unlike many other signaling systems, however, since both the ligand and receptor are transmembrane proteins, the activation of Notch by Delta depends strictly on cell-cell contact. Furthermore, the binding of the ligand to the receptor may not be sufficient to induce signaling, since recent work in cell culture suggests that ligand-induced Notch signaling also requires a mechanical pulling force. This tension exposes a cleavage site in Notch that, when cut, activates signaling. Although it is not known if mechanical tension contributes to signaling in vivo, others have suggested that this is how endocytosis of the receptor-ligand complex contributes to the cleavage and activation of Notch. In a similar way, since Notch-mediated lateral inhibition at a distance in the dorsal thorax of the pupal fly is mediated via actin-rich protrusions, it is possible that cytoskeletal forces generated by networks of filamentous actin and non-muscle myosin during cycles of protrusion extension and retraction also contribute to Notch signaling. Results To test this hypothesis, we carried out a detailed analysis of the role of myosin II-dependent tension in Notch signaling in the developing fly and in cell culture. Using dynamic fluorescence-based reporters of Notch, we found that myosin II is important for signaling in signal sending and receiving cells in both systems—as expected if myosin II-dependent tension across the Notch-Delta complex contributes to Notch activation. While myosin II was found to contribute most to signaling at a distance, it was also required for maximal signaling between adjacent cells that share lateral contacts and for signaling between cells in culture. Conclusions Together these results reveal a previously unappreciated role for non-muscle myosin II contractility in Notch signaling, providing further support for the idea that force contributes to the cleavage and activation of Notch in the context of ligand-dependent signaling, and a new paradigm for actomyosin-based mechanosensation. Electronic supplementary material The online version of this article (10.1186/s12915-019-0625-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ginger L Hunter
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA. .,MRC-LMCB, University College London, London, WC1E6BT, UK. .,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK. .,Present Address: Department of Biology, Clarkson University, Potsdam, NY, 13699, USA.
| | - Li He
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London, WC1E6BT, UK.,Department of Cell and Developmental Biology, University College London, London, WC1E6BT, UK
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA.
| | - Buzz Baum
- MRC-LMCB, University College London, London, WC1E6BT, UK.,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK
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10
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Berndt N, Seib E, Kim S, Troost T, Lyga M, Langenbach J, Haensch S, Kalodimou K, Delidakis C, Klein T. Ubiquitylation-independent activation of Notch signalling by Delta. eLife 2017; 6:27346. [PMID: 28960177 PMCID: PMC5675594 DOI: 10.7554/elife.27346] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/28/2017] [Indexed: 12/29/2022] Open
Abstract
Ubiquitylation (ubi) by the E3-ligases Mindbomb1 (Mib1) and Neuralized (Neur) is required for activation of the DSL ligands Delta (Dl) and Serrate (Ser) to activate Notch signalling. These ligases transfer ubiquitin to lysines of the ligands' intracellular domains (ICDs), which sends them into an Epsin-dependent endocytic pathway. Here, we have tested the requirement of ubi of Dl for signalling. We found that Dl requires ubi for its full function, but can also signal in two ubi-independent modes, one dependent and one independent of Neur. We identified two neural lateral specification processes where Dl signals in an ubi-independent manner. Neur, which is needed for these processes, was shown to be able to activate Dl in an ubi-independent manner. Our analysis suggests that one important role of DSL protein ubi by Mib1 is their release from cis-inhibitory interactions with Notch, enabling them to trans-activate Notch on adjacent cells.
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Affiliation(s)
- Nicole Berndt
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Ekaterina Seib
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Soya Kim
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany.,Molekulare Zellbiologie, Institut I für Anatomie, Uniklinik Köln, Universität zu Köln, Köln, Germany
| | - Tobias Troost
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Marvin Lyga
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Jessica Langenbach
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Sebastian Haensch
- Center of Advanced Imaging, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
| | - Konstantina Kalodimou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Christos Delidakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universitaet Duesseldorf, Duesseldorf, Germany
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11
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Kidd S, Lieber T. Mechanism of Notch Pathway Activation and Its Role in the Regulation of Olfactory Plasticity in Drosophila melanogaster. PLoS One 2016; 11:e0151279. [PMID: 26986723 PMCID: PMC4795742 DOI: 10.1371/journal.pone.0151279] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 02/25/2016] [Indexed: 12/20/2022] Open
Abstract
The neural plasticity of sensory systems is being increasingly recognized as playing a role in learning and memory. We have previously shown that Notch, part of an evolutionarily conserved intercellular signaling pathway, is required in adult Drosophila melanogaster olfactory receptor neurons (ORNs) for the structural and functional plasticity of olfactory glomeruli that is induced by chronic odor exposure. In this paper we address how long-term exposure to odor activates Notch and how Notch in conjunction with chronic odor mediates olfactory plasticity. We show that upon chronic odor exposure a non-canonical Notch pathway mediates an increase in the volume of glomeruli by a mechanism that is autonomous to ORNs. In addition to activating a pathway that is autonomous to ORNs, chronic odor exposure also activates the Notch ligand Delta in second order projection neurons (PNs), but this does not appear to require acetylcholine receptor activation in PNs. Delta on PNs then feeds back to activate canonical Notch signaling in ORNs, which restricts the extent of the odor induced increase in glomerular volume. Surprisingly, even though the pathway that mediates the increase in glomerular volume is autonomous to ORNs, nonproductive transsynaptic Delta/Notch interactions that do not activate the canonical pathway can block the increase in volume. In conjunction with chronic odor, the canonical Notch pathway also enhances cholinergic activation of PNs. We present evidence suggesting that this is due to increased acetylcholine release from ORNs. In regulating physiological plasticity, Notch functions solely by the canonical pathway, suggesting that there is no direct connection between morphological and physiological plasticity.
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Affiliation(s)
- Simon Kidd
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, New York, United States of America
| | - Toby Lieber
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, 701 West 168th Street, New York, New York, United States of America
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12
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Okano M, Matsuo H, Nishimura Y, Hozumi K, Yoshioka S, Tonoki A, Itoh M. Mib1 modulates dynamin 2 recruitment via Snx18 to promote Dll1 endocytosis for efficient Notch signaling. Genes Cells 2016; 21:425-41. [DOI: 10.1111/gtc.12350] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 01/28/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Makoto Okano
- Graduate School of Science; Nagoya University; Nagoya Aichi 464-8602 Japan
| | - Hiromi Matsuo
- Graduate School of Science; Nagoya University; Nagoya Aichi 464-8602 Japan
| | - Yuya Nishimura
- Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Katsuto Hozumi
- Department of Immunology; Tokai University School of Medicine; Isehara Kanagawa 259-1193 Japan
| | - Saho Yoshioka
- Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Ayako Tonoki
- Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
| | - Motoyuki Itoh
- Graduate School of Science; Nagoya University; Nagoya Aichi 464-8602 Japan
- Graduate School of Pharmaceutical Sciences; Chiba University; Chiba 260-8675 Japan
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13
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Chang B, Tessneer KL, McManus J, Liu X, Hahn S, Pasula S, Wu H, Song H, Chen Y, Cai X, Dong Y, Brophy ML, Rahman R, Ma JX, Xia L, Chen H. Epsin is required for Dishevelled stability and Wnt signalling activation in colon cancer development. Nat Commun 2015; 6:6380. [PMID: 25871009 PMCID: PMC4397653 DOI: 10.1038/ncomms7380] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/26/2015] [Indexed: 02/08/2023] Open
Abstract
Uncontrolled canonical Wnt signalling supports colon epithelial tumour expansion and malignant transformation. Understanding the regulatory mechanisms involved is crucial for elucidating the pathogenesis of and will provide new therapeutic targets for colon cancer. Epsins are ubiquitin-binding adaptor proteins upregulated in several human cancers; however, the involvement of epsins in colon cancer is unknown. Here we show that loss of intestinal epithelial epsins protects against colon cancer by significantly reducing the stability of the crucial Wnt signalling effector, dishevelled (Dvl2), and impairing Wnt signalling. Consistently, epsins and Dvl2 are correspondingly upregulated in colon cancer. Mechanistically, epsin binds Dvl2 via its epsin N-terminal homology domain and ubiquitin-interacting motifs and prohibits Dvl2 polyubiquitination and degradation. Our findings reveal an unconventional role for epsins in stabilizing Dvl2 and potentiating Wnt signalling in colon cancer cells to ensure robust colon cancer progression. The pro-carcinogenic role of Epsins suggests that they are potential therapeutic targets to combat colon cancer.
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Affiliation(s)
- Baojun Chang
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Kandice L Tessneer
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - John McManus
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Xiaolei Liu
- 1] Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA [2] Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Scott Hahn
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Satish Pasula
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Hao Wu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Hoogeun Song
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Yiyuan Chen
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Xiaofeng Cai
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Yunzhou Dong
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Megan L Brophy
- 1] Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA [2] Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Ruby Rahman
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
| | - Jian-Xing Ma
- Department of Endocrinology and Diabetes, Harold Hamm Oklahoma Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Lijun Xia
- 1] Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA [2] Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
| | - Hong Chen
- 1] Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA [2] Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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14
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Messa M, Fernández-Busnadiego R, Sun EW, Chen H, Czapla H, Wrasman K, Wu Y, Ko G, Ross T, Wendland B, De Camilli P. Epsin deficiency impairs endocytosis by stalling the actin-dependent invagination of endocytic clathrin-coated pits. eLife 2014; 3:e03311. [PMID: 25122462 PMCID: PMC4161027 DOI: 10.7554/elife.03311] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Epsin is an evolutionarily conserved endocytic clathrin adaptor whose most critical function(s) in clathrin coat dynamics remain(s) elusive. To elucidate such function(s), we generated embryonic fibroblasts from conditional epsin triple KO mice. Triple KO cells displayed a dramatic cell division defect. Additionally, a robust impairment in clathrin-mediated endocytosis was observed, with an accumulation of early and U-shaped pits. This defect correlated with a perturbation of the coupling between the clathrin coat and the actin cytoskeleton, which we confirmed in a cell-free assay of endocytosis. Our results indicate that a key evolutionary conserved function of epsin, in addition to other roles that include, as we show here, a low affinity interaction with SNAREs, is to help generate the force that leads to invagination and then fission of clathrin-coated pits.
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Affiliation(s)
- Mirko Messa
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Rubén Fernández-Busnadiego
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Elizabeth Wen Sun
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Hong Chen
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Heather Czapla
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Kristie Wrasman
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Yumei Wu
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Genevieve Ko
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
| | - Theodora Ross
- Department of Internal Medicine, UT Southwestern Medical Center, Dallas, United States
| | - Beverly Wendland
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Pietro De Camilli
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, United States
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15
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Ubiquitinations in the notch signaling pathway. Int J Mol Sci 2013; 14:6359-81. [PMID: 23519106 PMCID: PMC3634445 DOI: 10.3390/ijms14036359] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/11/2013] [Accepted: 03/14/2013] [Indexed: 12/22/2022] Open
Abstract
The very conserved Notch pathway is used iteratively during development and adulthood to regulate cell fates. Notch activation relies on interactions between neighboring cells, through the binding of Notch receptors to their ligands, both transmembrane molecules. This inter-cellular contact initiates a cascade of events eventually transforming the cell surface receptor into a nuclear factor acting on the transcription of specific target genes. This review highlights how the various processes undergone by Notch receptors and ligands that regulate the pathway are linked to ubiquitination events.
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16
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Kang YL, Yochem J, Bell L, Sorensen EB, Chen L, Conner SD. Caenorhabditis elegans reveals a FxNPxY-independent low-density lipoprotein receptor internalization mechanism mediated by epsin1. Mol Biol Cell 2012; 24:308-18. [PMID: 23242996 PMCID: PMC3564534 DOI: 10.1091/mbc.e12-02-0163] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A genome-wide RNA interference screen using Caenorhabditis elegans LRP-1/megalin as a model for LDLR transport was employed to identify factors critical to LDLR uptake. We provide evidence that epsin1 promotes LDLR internalization via a FxNPxY-independent pathway. We complement C. elegans in vivo approaches with loss-of-function and biochemical analyses, using mammalian cell culture systems to evaluate epsin1’s mode of action in LDLR endocytosis. Low-density lipoprotein receptor (LDLR) internalization clears cholesterol-laden LDL particles from circulation in humans. Defects in clathrin-dependent LDLR endocytosis promote elevated serum cholesterol levels and can lead to atherosclerosis. However, our understanding of the mechanisms that control LDLR uptake remains incomplete. To identify factors critical to LDLR uptake, we pursued a genome-wide RNA interference screen using Caenorhabditis elegans LRP-1/megalin as a model for LDLR transport. In doing so, we discovered an unanticipated requirement for the clathrin-binding endocytic adaptor epsin1 in LDLR endocytosis. Epsin1 depletion reduced LDLR internalization rates in mammalian cells, similar to the reduction observed following clathrin depletion. Genetic and biochemical analyses of epsin in C. elegans and mammalian cells uncovered a requirement for the ubiquitin-interaction motif (UIM) as critical for receptor transport. As the epsin UIM promotes the internalization of some ubiquitinated receptors, we predicted LDLR ubiquitination as necessary for endocytosis. However, engineered ubiquitination-impaired LDLR mutants showed modest internalization defects that were further enhanced with epsin1 depletion, demonstrating epsin1-mediated LDLR endocytosis is independent of receptor ubiquitination. Finally, we provide evidence that epsin1-mediated LDLR uptake occurs independently of either of the two documented internalization motifs (FxNPxY or HIC) encoded within the LDLR cytoplasmic tail, indicating an additional internalization mechanism for LDLR.
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Affiliation(s)
- Yuan-Lin Kang
- Department of Genetics, Cell Biology, and Development and the Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
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17
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Lee JH, Fischer JA. Drosophila Tel2 is expressed as a translational fusion with EpsinR and is a regulator of wingless signaling. PLoS One 2012; 7:e46357. [PMID: 23029494 PMCID: PMC3460857 DOI: 10.1371/journal.pone.0046357] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 08/29/2012] [Indexed: 11/19/2022] Open
Abstract
Tel2, a protein conserved from yeast to vertebrates, is an essential regulator of diverse cellular processes including telomere maintenance, DNA damage checkpoints, DNA repair, biological clocks, and cell signaling. The Drosophila Tel2 protein is produced as a translational fusion with EpsinR, a Clathrin adapter that facilitates vesicle trafficking between the Golgi and endosomes. EpsinR and Tel2 are encoded by a Drosophila gene called lqfR. lqfR is required for viability, and its specific roles include cell growth, proliferation, and planar cell polarity. We find that all of these functions of lqfR are attributed entirely to Tel2, not EpsinR. In addition, we find that Drosophila LqfR/Tel2 is a component of one or more protein complexes that contain E-cadherin and Armadillo. Moreover, Tel2 modulates E-cadherin and Armadillo cellular dynamics. We propose that at least one of the functions of Drosophila Tel2 is regulation of Wingless signaling.
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Affiliation(s)
| | - Janice A. Fischer
- Section of Molecular Cell and Developmental Biology, Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
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18
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Stachowiak JC, Schmid EM, Ryan CJ, Ann HS, Sasaki DY, Sherman MB, Geissler PL, Fletcher DA, Hayden CC. Membrane bending by protein-protein crowding. Nat Cell Biol 2012; 14:944-9. [PMID: 22902598 DOI: 10.1038/ncb2561] [Citation(s) in RCA: 388] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 07/12/2012] [Indexed: 02/07/2023]
Abstract
Curved membranes are an essential feature of dynamic cellular structures, including endocytic pits, filopodia protrusions and most organelles. It has been proposed that specialized proteins induce curvature by binding to membranes through two primary mechanisms: membrane scaffolding by curved proteins or complexes; and insertion of wedge-like amphipathic helices into the membrane. Recent computational studies have raised questions about the efficiency of the helix-insertion mechanism, predicting that proteins must cover nearly 100% of the membrane surface to generate high curvature, an improbable physiological situation. Thus, at present, we lack a sufficient physical explanation of how protein attachment bends membranes efficiently. On the basis of studies of epsin1 and AP180, proteins involved in clathrin-mediated endocytosis, we propose a third general mechanism for bending fluid cellular membranes: protein-protein crowding. By correlating membrane tubulation with measurements of protein densities on membrane surfaces, we demonstrate that lateral pressure generated by collisions between bound proteins drives bending. Whether proteins attach by inserting a helix or by binding lipid heads with an engineered tag, protein coverage above ~20% is sufficient to bend membranes. Consistent with this crowding mechanism, we find that even proteins unrelated to membrane curvature, such as green fluorescent protein (GFP), can bend membranes when sufficiently concentrated. These findings demonstrate a highly efficient mechanism by which the crowded protein environment on the surface of cellular membranes can contribute to membrane shape change.
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Affiliation(s)
- Jeanne C Stachowiak
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, Texas 78712, USA.
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19
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Kandachar V, Roegiers F. Endocytosis and control of Notch signaling. Curr Opin Cell Biol 2012; 24:534-40. [PMID: 22818956 DOI: 10.1016/j.ceb.2012.06.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 02/06/2023]
Abstract
The Notch signaling pathway controls patterning and cell fate decisions during development in metazoans, and is associated with human diseases such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and certain cancers. Studies over the last several years have revealed sophisticated regulation of both the membrane-bound Notch receptor and its ligands by vesicle trafficking. This is perhaps most evident in neural progenitor cells in Drosophila, which divide asymmetrically to segregate Numb, an endocytic adaptor protein that acts as a Notch pathway inhibitor, to one daughter cell. Here, we discuss recent findings addressing how receptor and ligand trafficking to specific membrane compartments control activation of the Notch pathway in asymmetrically dividing cells and other tissues.
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Affiliation(s)
- Vasundhara Kandachar
- Program in Cancer Biology, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
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20
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Meloty-Kapella L, Shergill B, Kuon J, Botvinick E, Weinmaster G. Notch ligand endocytosis generates mechanical pulling force dependent on dynamin, epsins, and actin. Dev Cell 2012; 22:1299-312. [PMID: 22658936 DOI: 10.1016/j.devcel.2012.04.005] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 02/15/2012] [Accepted: 04/04/2012] [Indexed: 12/17/2022]
Abstract
Notch signaling induced by cell surface ligands is critical to development and maintenance of many eukaryotic organisms. Notch and its ligands are integral membrane proteins that facilitate direct cell-cell interactions to activate Notch proteolysis and release the intracellular domain that directs Notch-specific cellular responses. Genetic studies suggest that Notch ligands require endocytosis, ubiquitylation, and epsin endocytic adaptors to activate signaling, but the exact role of ligand endocytosis remains unresolved. Here we characterize a molecularly distinct mode of clathrin-mediated endocytosis requiring ligand ubiquitylation, epsins, and actin for ligand cells to activate signaling in Notch cells. Using a cell-bead optical tweezers system, we obtained evidence for cell-mediated mechanical force dependent on this distinct mode of ligand endocytosis. We propose that the mechanical pulling force produced by endocytosis of Notch-bound ligand drives conformational changes in Notch that permit activating proteolysis.
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Affiliation(s)
- Laurence Meloty-Kapella
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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