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Yuan F, Gollapudi S, Day K, Ashby G, Sangani A, Malady B, Wang L, Lafer EM, Huibregtse J, Stachowiak J. Ubiquitin-driven protein condensation initiates clathrin-mediated endocytosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.21.554139. [PMID: 37662320 PMCID: PMC10473642 DOI: 10.1101/2023.08.21.554139] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Clathrin-mediated endocytosis is an essential cellular pathway that enables signaling and recycling of transmembrane proteins and lipids. During endocytosis, dozens of cytosolic proteins come together at the plasma membrane, assembling into a highly interconnected network that drives endocytic vesicle biogenesis. Recently, multiple groups have reported that early endocytic proteins form flexible condensates, which provide a platform for efficient assembly of endocytic vesicles. Given the importance of this network in the dynamics of endocytosis, how might cells regulate its stability? Many receptors and endocytic proteins are ubiquitylated, while early endocytic proteins such as Eps15 contain ubiquitin-interacting motifs. Therefore, we examined the influence of ubiquitin on the stability of the early endocytic protein network. In vitro, we found that recruitment of small amounts of polyubiquitin dramatically increased the stability of Eps15 condensates, suggesting that ubiquitylation could nucleate endocytic assemblies. In live cell imaging experiments, a version of Eps15 that lacked the ubiquitin-interacting motif failed to rescue defects in endocytic initiation created by Eps15 knockout. Furthermore, fusion of Eps15 to a deubiquitylase enzyme destabilized nascent endocytic sites within minutes. In both in vitro and live cell settings, dynamic exchange of Eps15 proteins, a hallmark of liquidlike systems, was modulated by Eps15-Ub interactions. These results collectively suggest that ubiquitylation drives assembly of the flexible protein network responsible for catalyzing endocytic events. More broadly, this work illustrates a biophysical mechanism by which ubiquitylated transmembrane proteins at the plasma membrane could regulate the efficiency of endocytic recycling.
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2
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Cowan DB, Wu H, Chen H. Epsin Endocytic Adaptor Proteins in Angiogenic and Lymphangiogenic Signaling. Cold Spring Harb Perspect Med 2024; 14:a041165. [PMID: 37217282 PMCID: PMC10759987 DOI: 10.1101/cshperspect.a041165] [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] [Indexed: 05/24/2023]
Abstract
Circulating vascular endothelial growth factor (VEGF) ligands and receptors are central regulators of vasculogenesis, angiogenesis, and lymphangiogenesis. In response to VEGF ligand binding, VEGF receptor tyrosine kinases initiate the chain of events that transduce extracellular signals into endothelial cell responses such as survival, proliferation, and migration. These events are controlled by intricate cellular processes that include the regulation of gene expression at multiple levels, interactions of numerous proteins, and intracellular trafficking of receptor-ligand complexes. Endocytic uptake and transport of macromolecular complexes through the endosome-lysosome system helps fine-tune endothelial cell responses to VEGF signals. Clathrin-dependent endocytosis remains the best understood means of macromolecular entry into cells, although the importance of non-clathrin-dependent pathways is increasingly recognized. Many of these endocytic events rely on adaptor proteins that coordinate internalization of activated cell-surface receptors. In the endothelium of both blood and lymphatic vessels, epsins 1 and 2 are functionally redundant adaptors involved in receptor endocytosis and intracellular sorting. These proteins are capable of binding both lipids and proteins and are important for promoting curvature of the plasma membrane as well as binding ubiquitinated cargo. Here, we discuss the role of epsin proteins and other endocytic adaptors in governing VEGF signaling in angiogenesis and lymphangiogenesis and discuss their therapeutic potential as molecular targets.
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Affiliation(s)
- Douglas B Cowan
- Vascular Biology Program, Boston Children's Hospital, and Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children's Hospital, and Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, and Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA
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3
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Johnson CP, Hart A, Jarvis KF, Latario SG, Shrestha S, Leclerc N, Khalil A, Kelley JB. The G-alpha Gpa1 directs septin localization in the mating projection of Saccharomyces cerevisiae through its Ubiquitination Domain and Endocytic Machinery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.16.545321. [PMID: 37398119 PMCID: PMC10312744 DOI: 10.1101/2023.06.16.545321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The yeast mating response uses a G-protein coupled receptor (GPCR), Ste2, to detect mating pheromone and initiate mating projection morphogenesis. The septin cytoskeleton plays a key role in the formation of the mating projection, forming structures at the base of the projection. Desensitization of the Gα, Gpa1, by the Regulator of G-protein Signaling (RGS), Sst2, is required for proper septin organization and morphogenesis. In cells where the Gα is hyperactive, septins are mislocalized to the site of polarity, and the cells are unable to track a pheromone gradient. We set out to identify the proteins that mediate Gα control of septins during the Saccharomyces cerevisiae mating response by making mutations to rescue septin localization in cells expressing the hyperactive Gα mutant gpa1G302S. We found that single deletions of the septin chaperone Gic1, the Cdc42 GAP Bem3, and the epsins Ent1 and Ent2 rescued the polar cap accumulation of septins in the hyperactive Gα. We created an agent-based model of vesicle trafficking that predicts how changes in endocytic cargo licensing alters localization of endocytosis that mirrors the septin localization we see experimentally. We hypothesized that hyperactive Gα may increase the rate of endocytosis of a pheromone responsive cargo, thereby altering where septins are localized. Both the GPCR and the Gα are known to be internalized by clathrin-mediated endocytosis during the pheromone response. Deletion of the GPCR C-terminus to block internalization partially rescued septin organization. However, deletion of the Gpa1 ubiquitination domain required for its endocytosis completely abrogated septin accumulation at the polarity site. Our data support a model where the location of endocytosis serves as a spatial mark for septin structure assembly and that desensitization of the Gα delays its endocytosis sufficiently that septins are placed peripheral to the site of Cdc42 polarity.
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Affiliation(s)
- Cory P. Johnson
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME
| | - Andrew Hart
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME
| | - Katherine F. Jarvis
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME
- CompuMAINE Laboratory University of Maine, Orono, ME
| | - Sarah G. Latario
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME
| | - Sudati Shrestha
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME
| | - Nicholas Leclerc
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME
| | - André Khalil
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME
- Department of Chemical and Biomedical Engineering, University of Maine, Orono, ME
- CompuMAINE Laboratory University of Maine, Orono, ME
| | - Joshua B. Kelley
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME
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4
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Zhao XW, Zhu HL, Qi YX, Wu T, Huang DW, Cheng GL, Yang YX, Bu DP, Hu H, Meng LF. Regulatory role of phosphoproteins in the development of bovine small intestine during early life. J Dairy Sci 2022; 105:9240-9252. [PMID: 36175223 DOI: 10.3168/jds.2022-21983] [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: 02/17/2022] [Accepted: 06/20/2022] [Indexed: 11/19/2022]
Abstract
The small intestine is the primary site of nutrient digestion and absorption, which plays a key role in the survival of neonatal calves. A comprehensive assessment of the phosphoproteomic changes in the small intestine of neonatal calves is unavailable; therefore, we used phosphopeptide enrichment coupled with liquid chromatography-tandem mass spectrometry to investigate the changes in the phosphoproteome profile in the bovine small intestine during the first 36 h of life. Twelve neonatal male calves were assigned to one of the following groups: (1) calves not fed colostrum and slaughtered approximately 2 h postpartum (n = 3), (2) calves fed colostrum at 1 to 2 h and slaughtered 8 h postpartum (n = 3), (3) calves fed 2 colostrum meals (at 1-2 and 10-12 h) and slaughtered 24 h postpartum (n = 3), (4) calves fed 3 colostrum meals (at 1-2, 10-12, and 22-24 h) and slaughtered 36 h postpartum (n = 3). Mid-duodenal, jejunal, and ileal samples of the calves were collected after slaughter. We identified 1,678 phosphoproteins with approximately 3,080 phosphosites, which were mainly Ser (89.9%), Thr (9.8%), and Tyr (0.3%) residues; they belonged to the prodirected (52.9%), basic (20.4%), acidic (16.6%), and Tyr-directed (1.7%) motif categories. The regional differentially expressed phosphoproteins included zonula occludens 2, sorting nexin 12, and protein kinase C, which are mainly associated with developmental processes, intracellular transport, vesicle-mediated transport, and immune system process. They are enriched in the endocytosis, tight junction, insulin signaling, and focal adhesion pathways. The temporal differentially expressed phosphoproteins included occludin, epsin 1, and bridging integrator 1, which were mainly associated with macromolecule metabolic process, cell adhesion, and growth. They were enriched in the spliceosomes, adherens junctions, and tight junctions. The observed changes in the phosphoproteins in the tissues of small intestine suggest the protein phosphorylation plays an important role in nutrient transport and immune response of calves during early life, which needs to be confirmed in a larger study.
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Affiliation(s)
- X W Zhao
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - H L Zhu
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Y X Qi
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - T Wu
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - D W Huang
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - G L Cheng
- Anhui Key Laboratory of Animal and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China
| | - Y X Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China.
| | - D P Bu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences of Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - H Hu
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
| | - L F Meng
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing 100093, China
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5
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Langridge PD, Garcia Diaz A, Chan JY, Greenwald I, Struhl G. Evolutionary plasticity in the requirement for force exerted by ligand endocytosis to activate C. elegans Notch proteins. Curr Biol 2022; 32:2263-2271.e6. [PMID: 35349791 PMCID: PMC9133158 DOI: 10.1016/j.cub.2022.03.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/28/2022] [Accepted: 03/08/2022] [Indexed: 10/18/2022]
Abstract
The conserved transmembrane receptor Notch has diverse and profound roles in controlling cell fate during animal development. In the absence of ligand, a negative regulatory region (NRR) in the Notch ectodomain adopts an autoinhibited confirmation, masking an ADAM protease cleavage site;1,2 ligand binding induces cleavage of the NRR, leading to Notch ectodomain shedding as the first step of signal transduction.3,4 In Drosophila and vertebrates, recruitment of transmembrane Delta/Serrate/LAG-2 (DSL) ligands by the endocytic adaptor Epsin, and their subsequent internalization by Clathrin-mediated endocytosis, exerts a "pulling force" on Notch that is essential to expose the cleavage site in the NRR.4-6 Here, we show that Epsin-mediated endocytosis of transmembrane ligands is not essential to activate the two C. elegans Notch proteins, LIN-12 and GLP-1. Using an in vivo force sensing assay in Drosophila,6 we present evidence (1) that the LIN-12 and GLP-1 NRRs are tuned to lower force thresholds than the NRR of Drosophila Notch, and (2) that this difference depends on the absence of a "leucine plug" that occludes the cleavage site in the Drosophila and vertebrate Notch NRRs.1,2 Our results thus establish an unexpected evolutionary plasticity in the force-dependent mechanism of Notch activation and implicate a specific structural element, the leucine plug, as a determinant.
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Affiliation(s)
- Paul D Langridge
- Department of Genetics and Development, Columbia University, New York, NY 10027, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY 10027, USA.
| | | | - Jessica Yu Chan
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Iva Greenwald
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - Gary Struhl
- Department of Genetics and Development, Columbia University, New York, NY 10027, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY 10027, USA.
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6
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Song K, Cai X, Dong Y, Wu H, Wei Y, Shankavaram UT, Cui K, Lee Y, Zhu B, Bhattacharjee S, Wang B, Zhang K, Wen A, Wong S, Yu L, Xia L, Welm AL, Bielenberg DR, Camphausen KA, Kang Y, Chen H. Epsins 1 and 2 promote NEMO linear ubiquitination via LUBAC to drive breast cancer development. J Clin Invest 2021; 131:129374. [PMID: 32960814 DOI: 10.1172/jci129374] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/17/2020] [Indexed: 12/14/2022] Open
Abstract
Estrogen receptor-negative (ER-negative) breast cancer is thought to be more malignant and devastating than ER-positive breast cancer. ER-negative breast cancer exhibits elevated NF-κB activity, but how this abnormally high NF-κB activity is maintained is poorly understood. The importance of linear ubiquitination, which is generated by the linear ubiquitin chain assembly complex (LUBAC), is increasingly appreciated in NF-κB signaling, which regulates cell activation and death. Here, we showed that epsin proteins, a family of ubiquitin-binding endocytic adaptors, interacted with LUBAC via its ubiquitin-interacting motif and bound LUBAC's bona fide substrate NEMO via its N-terminal homolog (ENTH) domain. Furthermore, epsins promoted NF-κB essential modulator (NEMO) linear ubiquitination and served as scaffolds for recruiting other components of the IκB kinase (IKK) complex, resulting in the heightened IKK activation and sustained NF-κB signaling essential for the development of ER-negative breast cancer. Heightened epsin levels in ER-negative human breast cancer are associated with poor relapse-free survival. We showed that transgenic and pharmacological approaches eliminating epsins potently impeded breast cancer development in both spontaneous and patient-derived xenograft breast cancer mouse models. Our findings established the pivotal role epsins played in promoting breast cancer. Thus, targeting epsins may represent a strategy to restrain NF-κB signaling and provide an important perspective into ER-negative breast cancer treatment.
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Affiliation(s)
- Kai Song
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Xiaofeng Cai
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.,Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yong Wei
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA.,Cancer Metabolism and Growth Program, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - Uma T Shankavaram
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland, USA
| | - Kui Cui
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yang Lee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bo Zhu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sudarshan Bhattacharjee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Beibei Wang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kun Zhang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Aiyun Wen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Scott Wong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lili Yu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Lijun Xia
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Alana L Welm
- Department of Oncological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Diane R Bielenberg
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kevin A Camphausen
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland, USA
| | - Yibin Kang
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA.,Cancer Metabolism and Growth Program, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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7
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Dissecting the structural features of β-arrestins as multifunctional proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140603. [PMID: 33421644 DOI: 10.1016/j.bbapap.2021.140603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/21/2020] [Accepted: 01/04/2021] [Indexed: 02/08/2023]
Abstract
β-arrestins bind active G protein-coupled receptors (GPCRs) and play a crucial role in receptor desensitization and internalization. The classical paradigm of arrestin function has been expanded with the identification of many non-receptor-binding partners, which indicated the multifunctional role of β-arrestins in cellular functions. To elucidate the molecular mechanism of β-arrestin-mediated signaling, the structural features of β-arrestins were investigated using X-ray crystallography and cryogenic electron microscopy (cryo-EM). However, the intrinsic conformational flexibility of β-arrestins hampers the elucidation of structural interactions between β-arrestins and their binding partners using conventional structure determination tools. Therefore, structural information obtained using complementary structure analysis techniques would be necessary in combination with X-ray crystallography and cryo-EM data. In this review, we describe how β-arrestins interact with their binding partners from a structural point of view, as elucidated by both traditional methods (X-ray crystallography and cryo-EM) and complementary structure analysis techniques.
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8
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Wang Y, Pedigo CE, Inoue K, Tian X, Cross E, Ebenezer K, Li W, Wang Z, Shin JW, Schwartze E, Groener M, Ishibe S. Murine Epsins Play an Integral Role in Podocyte Function. J Am Soc Nephrol 2020; 31:2870-2886. [PMID: 33051360 PMCID: PMC7790213 DOI: 10.1681/asn.2020050691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/30/2020] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Epsins, a family of evolutionarily conserved membrane proteins, play an essential role in endocytosis and signaling in podocytes. METHODS Podocyte-specific Epn1, Epn2, Epn3 triple-knockout mice were generated to examine downstream regulation of serum response factor (SRF) by cell division control protein 42 homolog (Cdc42). RESULTS Podocyte-specific loss of epsins resulted in increased albuminuria and foot process effacement. Primary podocytes isolated from these knockout mice exhibited abnormalities in cell adhesion and spreading, which may be attributed to reduced activation of cell division control protein Cdc42 and SRF, resulting in diminished β1 integrin expression. In addition, podocyte-specific loss of Srf resulted in severe albuminuria and foot process effacement, and defects in cell adhesion and spreading, along with decreased β1 integrin expression. CONCLUSIONS Epsins play an indispensable role in maintaining properly functioning podocytes through the regulation of Cdc42 and SRF-dependent β1 integrin expression.
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Affiliation(s)
- Ying Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
- Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Chaoyang District, Beijing, 100029, China
| | - Christopher E Pedigo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Kazunori Inoue
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Xuefei Tian
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Elizabeth Cross
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Karen Ebenezer
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Wei Li
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Zhen Wang
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Jee Won Shin
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Eike Schwartze
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Marwin Groener
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Shuta Ishibe
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
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9
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The Path towards Predicting Evolution as Illustrated in Yeast Cell Polarity. Cells 2020; 9:cells9122534. [PMID: 33255231 PMCID: PMC7760196 DOI: 10.3390/cells9122534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 01/14/2023] Open
Abstract
A bottom-up route towards predicting evolution relies on a deep understanding of the complex network that proteins form inside cells. In a rapidly expanding panorama of experimental possibilities, the most difficult question is how to conceptually approach the disentangling of such complex networks. These can exhibit varying degrees of hierarchy and modularity, which obfuscate certain protein functions that may prove pivotal for adaptation. Using the well-established polarity network in budding yeast as a case study, we first organize current literature to highlight protein entrenchments inside polarity. Following three examples, we see how alternating between experimental novelties and subsequent emerging design strategies can construct a layered understanding, potent enough to reveal evolutionary targets. We show that if you want to understand a cell’s evolutionary capacity, such as possible future evolutionary paths, seemingly unimportant proteins need to be mapped and studied. Finally, we generalize this research structure to be applicable to other systems of interest.
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10
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Balaji Ragunathrao VA, Anwar M, Akhter MZ, Chavez A, Mao DY, Natarajan V, Lakshmikanthan S, Chrzanowska-Wodnicka M, Dudek AZ, Claesson-Welsh L, Kitajewski JK, Wary KK, Malik AB, Mehta D. Sphingosine-1-Phosphate Receptor 1 Activity Promotes Tumor Growth by Amplifying VEGF-VEGFR2 Angiogenic Signaling. Cell Rep 2020; 29:3472-3487.e4. [PMID: 31825830 PMCID: PMC6927555 DOI: 10.1016/j.celrep.2019.11.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/06/2019] [Accepted: 11/07/2019] [Indexed: 12/24/2022] Open
Abstract
The vascular endothelial growth factor-A (VEGF-A)-VEGFR2 pathway drives tumor vascularization by activating proangiogenic signaling in endothelial cells (ECs). Here, we show that EC-sphingosine-1-phosphate receptor 1 (S1PR1) amplifies VEGFR2-mediated angiogenic signaling to enhance tumor growth. We show that cancer cells induce S1PR1 activity in ECs, and thereby, conditional deletion of S1PR1 in ECs (EC-S1pr1−/− mice) impairs tumor vascularization and growth. Mechanistically, we show that S1PR1 engages the heterotrimeric G-protein Gi, which amplifies VEGF-VEGFR2 signaling due to an increase in the activity of the tyrosine kinase c-Abl1. c-Abl1, by phosphorylating VEGFR2 at tyrosine-951, prolongs VEGFR2 retention on the plasmalemma to sustain Rac1 activity and EC migration. Thus, S1PR1 or VEGFR2 antagonists, alone or in combination, reverse the tumor growth in control mice to the level seen in EC-S1pr1−/− mice. Our findings suggest that blocking S1PR1 activity in ECs has the potential to suppress tumor growth by preventing amplification of VEGF-VEGFR2 signaling. Vijay Avin et al. demonstrate an essential role of endothelial cell (EC)-S1PR1 signaling in amplifying VEGFR2-mediated tumor growth. S1PR1 by Gi and c-Abl1 phosphorylates VEGFR2 at Y951, which retains VEGFR2 at EC plasmalemma, thus enabling EC migration, tumor angiogenesis, and growth.
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Affiliation(s)
- Vijay Avin Balaji Ragunathrao
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Mumtaz Anwar
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Md Zahid Akhter
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Alejandra Chavez
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - De Yu Mao
- Department of Physiology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Viswanathan Natarajan
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA; Department of Medicine, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | | | | | - Arkadiusz Z Dudek
- Department of Medicine, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Lena Claesson-Welsh
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Science for Life Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Jan K Kitajewski
- Department of Physiology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Kishore K Wary
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Asrar B Malik
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Dolly Mehta
- Department of Pharmacology and The Center for Lung and Vascular Biology, The University of Illinois College of Medicine, Chicago, IL 60612, USA.
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11
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Dong Y, Lee Y, Cui K, He M, Wang B, Bhattacharjee S, Zhu B, Yago T, Zhang K, Deng L, Ouyang K, Wen A, Cowan DB, Song K, Yu L, Brophy ML, Liu X, Wylie-Sears J, Wu H, Wong S, Cui G, Kawashima Y, Matsumoto H, Kodera Y, Wojcikiewicz RJH, Srivastava S, Bischoff J, Wang DZ, Ley K, Chen H. Epsin-mediated degradation of IP3R1 fuels atherosclerosis. Nat Commun 2020; 11:3984. [PMID: 32770009 PMCID: PMC7414107 DOI: 10.1038/s41467-020-17848-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 07/15/2020] [Indexed: 12/18/2022] Open
Abstract
The epsin family of endocytic adapter proteins are widely expressed, and interact with both proteins and lipids to regulate a variety of cell functions. However, the role of epsins in atherosclerosis is poorly understood. Here, we show that deletion of endothelial epsin proteins reduces inflammation and attenuates atherosclerosis using both cell culture and mouse models of this disease. In atherogenic cholesterol-treated murine aortic endothelial cells, epsins interact with the ubiquitinated endoplasmic reticulum protein inositol 1,4,5-trisphosphate receptor type 1 (IP3R1), which triggers proteasomal degradation of this calcium release channel. Epsins potentiate its degradation via this interaction. Genetic reduction of endothelial IP3R1 accelerates atherosclerosis, whereas deletion of endothelial epsins stabilizes IP3R1 and mitigates inflammation. Reduction of IP3R1 in epsin-deficient mice restores atherosclerotic progression. Taken together, epsin-mediated degradation of IP3R1 represents a previously undiscovered biological role for epsin proteins and may provide new therapeutic targets for the treatment of atherosclerosis and other diseases. Endothelial cell (EC) dysfunction and inflammation contribute to plaque destabilization in atherosclerosis, increasing the risk of thrombotic events. Here, the authors show that epsin promotes EC inflammation via a mechanism involving IP3R1 degradation, and that deletion of epsin in the endothelium prevents EC dysfunctoin and atherosclerosis in mice.
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Affiliation(s)
- Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Yang Lee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kui Cui
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Ming He
- Department of Medicine, University of California, San Diego, San Diego, CA, 92093, USA
| | - Beibei Wang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Sudarshan Bhattacharjee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Bo Zhu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Tadayuki Yago
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Kun Zhang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lin Deng
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Kunfu Ouyang
- Department of Medicine, University of California, San Diego, San Diego, CA, 92093, USA
| | - Aiyun Wen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Douglas B Cowan
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.,Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kai Song
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lili Yu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Megan L Brophy
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Xiaolei Liu
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Jill Wylie-Sears
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Scott Wong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Guanglin Cui
- Department of Nutrition and Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Yusuke Kawashima
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hiroyuki Matsumoto
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Yoshio Kodera
- Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | | | - Sanjay Srivastava
- Department of Medicine, Division of Cardiovascular Medicine, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Joyce Bischoff
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Da-Zhi Wang
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Klaus Ley
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
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12
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A self-sustaining endocytic-based loop promotes breast cancer plasticity leading to aggressiveness and pro-metastatic behavior. Nat Commun 2020; 11:3020. [PMID: 32541686 PMCID: PMC7296024 DOI: 10.1038/s41467-020-16836-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 05/27/2020] [Indexed: 02/06/2023] Open
Abstract
The subversion of endocytic routes leads to malignant transformation and has been implicated in human cancers. However, there is scarce evidence for genetic alterations of endocytic proteins as causative in high incidence human cancers. Here, we report that Epsin 3 (EPN3) is an oncogene with prognostic and therapeutic relevance in breast cancer. Mechanistically, EPN3 drives breast tumorigenesis by increasing E-cadherin endocytosis, followed by the activation of a β-catenin/TCF4-dependent partial epithelial-to-mesenchymal transition (EMT), followed by the establishment of a TGFβ-dependent autocrine loop that sustains EMT. EPN3-induced partial EMT is instrumental for the transition from in situ to invasive breast carcinoma, and, accordingly, high EPN3 levels are detected at the invasive front of human breast cancers and independently predict metastatic rather than loco-regional recurrence. Thus, we uncover an endocytic-based mechanism able to generate TGFβ-dependent regulatory loops conferring cellular plasticity and invasive behavior.
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13
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Rópolo AS, Feliziani C, Touz MC. Unusual proteins in Giardia duodenalis and their role in survival. ADVANCES IN PARASITOLOGY 2019; 106:1-50. [PMID: 31630755 DOI: 10.1016/bs.apar.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The capacity of the parasite Giardia duodenalis to perform complex functions with minimal amounts of proteins and organelles has attracted increasing numbers of scientists worldwide, trying to explain how this parasite adapts to internal and external changes to survive. One explanation could be that G. duodenalis evolved from a structurally complex ancestor by reductive evolution, resulting in adaptation to its parasitic lifestyle. Reductive evolution involves the loss of genes, organelles, and functions that commonly occur in many parasites, by which the host renders some structures and functions redundant. However, there is increasing data that Giardia possesses proteins able to perform more than one function. During recent decades, the concept of moonlighting was described for multitasking proteins, which involves only proteins with an extra independent function(s). In this chapter, we provide an overview of unusual proteins in Giardia that present multifunctional properties depending on the location and/or parasite requirement. We also discuss experimental evidence that may allow some giardial proteins to be classified as moonlighting proteins by examining the properties of moonlighting proteins in general. Up to date, Giardia does not seem to require the numerous redundant proteins present in other organisms to accomplish its normal functions, and thus this parasite may be an appropriate model for understanding different aspects of moonlighting proteins, which may be helpful in the design of drug targets.
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Affiliation(s)
- Andrea S Rópolo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Constanza Feliziani
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María C Touz
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.
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14
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Remodeling Membrane Binding by Mono-Ubiquitylation. Biomolecules 2019; 9:biom9080325. [PMID: 31370222 PMCID: PMC6723200 DOI: 10.3390/biom9080325] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 07/22/2019] [Accepted: 07/29/2019] [Indexed: 01/17/2023] Open
Abstract
Ubiquitin (Ub) receptors respond to ubiquitylation signals. They bind ubiquitylated substrates and exert their activity in situ. Intriguingly, Ub receptors themselves undergo rapid ubiquitylation and deubiquitylation. Here we asked what is the function of ubiquitylation of Ub receptors? We focused on yeast epsin, a Ub receptor that decodes the ubiquitylation signal of plasma membrane proteins into an endocytosis response. Using mass spectrometry, we identified lysine-3 as the major ubiquitylation site in the epsin plasma membrane binding domain. By projecting this ubiquitylation site onto our crystal structure, we hypothesized that this modification would compete with phosphatidylinositol-4,5-bisphosphate (PIP2) binding and dissociate epsin from the membrane. Using an E. coli-based expression of an authentic ubiquitylation apparatus, we purified ubiquitylated epsin. We demonstrated in vitro that in contrast to apo epsin, the ubiquitylated epsin does not bind to either immobilized PIPs or PIP2-enriched liposomes. To test this hypothesis in vivo, we mimicked ubiquitylation by the fusion of Ub at the ubiquitylation site. Live cell imaging demonstrated that the mimicked ubiquitylated epsin dissociates from the membrane. Our findings suggest that ubiquitylation of the Ub receptors dissociates them from their products to allow binding to a new ubiquitylated substrates, consequently promoting cyclic activity of the Ub receptors.
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15
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Nepal B, Leveritt J, Lazaridis T. Membrane Curvature Sensing by Amphipathic Helices: Insights from Implicit Membrane Modeling. Biophys J 2019; 114:2128-2141. [PMID: 29742406 DOI: 10.1016/j.bpj.2018.03.030] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/24/2018] [Accepted: 03/14/2018] [Indexed: 01/09/2023] Open
Abstract
Sensing and generation of lipid membrane curvature, mediated by the binding of specific proteins onto the membrane surface, play crucial roles in cell biology. A number of mechanisms have been proposed, but the molecular understanding of these processes is incomplete. All-atom molecular dynamics simulations have offered valuable insights but are extremely demanding computationally. Implicit membrane simulations could provide a viable alternative, but current models apply only to planar membranes. In this work, the implicit membrane model 1 is extended to spherical and tubular membranes. The geometric change from planar to curved shapes is straightforward but insufficient for capturing the full curvature effect, which includes changes in lipid packing. Here, these packing effects are taken into account via the lateral pressure profile. The extended implicit membrane model 1 is tested on the wild-types and mutants of the antimicrobial peptide magainin, the ALPS motif of arfgap1, α-synuclein, and an ENTH domain. In these systems, the model is in qualitative agreement with experiments. We confirm that favorable electrostatic interactions tend to weaken curvature sensitivity in the presence of strong hydrophobic interactions but may actually have a positive effect when those are weak. We also find that binding to vesicles is more favorable than binding to tubes of the same diameter and that the long helix of α-synuclein tends to orient along the axis of tubes, whereas shorter helices tend to orient perpendicular to it. Adoption of a specific orientation could provide a mechanism for coupling protein oligomerization to tubule formation.
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Affiliation(s)
- Binod Nepal
- Department of Chemistry, City College of New York, New York, New York
| | - John Leveritt
- Department of Chemistry, Newman University, Wichita, Kansas
| | - Themis Lazaridis
- Department of Chemistry, City College of New York, New York, New York; Graduate Programs in Chemistry, Biochemistry, and Physics, The Graduate Center, City University of New York, New York, New York.
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16
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A Flow Cytometry-Based Phenotypic Screen To Identify Novel Endocytic Factors in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2018. [PMID: 29540444 PMCID: PMC5940143 DOI: 10.1534/g3.118.200102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Endocytosis is a fundamental process for internalizing material from the plasma membrane, including many transmembrane proteins that are selectively internalized depending on environmental conditions. In most cells, the main route of entry is clathrin-mediated endocytosis (CME), a process that involves the coordinated activity of over 60 proteins; however, there are likely as-yet unidentified proteins involved in cargo selection and/or regulation of endocytosis. We performed a mutagenic screen to identify novel endocytic genes in Saccharomyces cerevisiae expressing the methionine permease Mup1 tagged with pHluorin (pHl), a pH-sensitive GFP variant whose fluorescence is quenched upon delivery to the acidic vacuole lumen. We used fluorescence-activated cell sorting to isolate mutagenized cells with elevated fluorescence, resulting from failure to traffic Mup1-pHl cargo to the vacuole, and further assessed subcellular localization of Mup1-pHl to characterize the endocytic defects in 256 mutants. A subset of mutant strains was classified as having general endocytic defects based on mislocalization of additional cargo proteins. Within this group, we identified mutations in four genes encoding proteins with known roles in endocytosis: the endocytic coat components SLA2, SLA1, and EDE1, and the ARP3 gene, whose product is involved in nucleating actin filaments to form branched networks. All four mutants demonstrated aberrant dynamics of the endocytic machinery at sites of CME; moreover, the arp3R346H mutation showed reduced actin nucleation activity in vitro. Finally, whole genome sequencing of two general endocytic mutants identified mutations in conserved genes not previously implicated in endocytosis, KRE33 and IQG1, demonstrating that our screening approach can be used to identify new components involved in endocytosis.
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17
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Nguyen HH, Lee MH, Song K, Ahn G, Lee J, Hwang I. The A/ENTH Domain-Containing Protein AtECA4 Is an Adaptor Protein Involved in Cargo Recycling from the trans-Golgi Network/Early Endosome to the Plasma Membrane. MOLECULAR PLANT 2018; 11:568-583. [PMID: 29317286 DOI: 10.1016/j.molp.2018.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/03/2017] [Accepted: 01/03/2018] [Indexed: 05/05/2023]
Abstract
Endocytosis and subsequent trafficking pathways are crucial for regulating the activity of plasma membrane-localized proteins. Depending on cellular and physiological conditions, the internalized cargoes are sorted at (and transported from) the trans-Golgi network/early endosome (TGN/EE) to the vacuole for degradation or recycled back to the plasma membrane. How this occurs at the molecular level remains largely elusive. Here, we provide evidence that the ENTH domain-containing protein AtECA4 plays a crucial role in recycling cargoes from the TGN/EE to the plasma membrane in Arabidopsis thaliana. AtECA4:sGFP primarily localized to the TGN/EE and plasma membrane (at low levels). Upon NaCl or mannitol treatment, AtECA4:sGFP accumulated at the TGN/EE at an early time point but was released from the TGN/EE to the cytosol at later time points. The ateca4 mutant showed higher resistance to osmotic stress and more sensitive to exogenous abscisic acid (ABA) than the wild type, as well as increased expression of ABA-inducible genes RD29A and RD29B. Consistently, ABCG25, a plasma membrane-localized ABA exporter, accumulated at the prevacuolar compartment in ateca4, indicating a defect in recycling to the plasma membrane. However, the role of AtECA4 in cargo recycling is not specific to ABCG25, as it also functions in the recycling of BRI1. These results suggest that AtECA4 plays a crucial role in the recycling of endocytosed cargoes from the TGN/EE to the plasma membrane.
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Affiliation(s)
- Hong Hanh Nguyen
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Myoung Hui Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Kyungyoung Song
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Gyeongik Ahn
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Jihyeong Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Inhwan Hwang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea; Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
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18
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Epsin-Dependent Ligand Endocytosis Activates Notch by Force. Cell 2017; 171:1383-1396.e12. [PMID: 29195077 DOI: 10.1016/j.cell.2017.10.048] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/30/2017] [Accepted: 09/28/2017] [Indexed: 01/09/2023]
Abstract
DSL ligands activate Notch by inducing proteolytic cleavage of the receptor ectodomain, an event that requires ligand to be endocytosed in signal-sending cells by the adaptor protein Epsin. Two classes of explanation for this unusual requirement are (1) recycling models, in which the ligand must be endocytosed to be modified or repositioned before it binds Notch and (2) pulling models, in which the ligand must be endocytosed after it binds Notch to exert force that exposes an otherwise buried site for cleavage. We demonstrate in vivo that ligands that cannot enter the Epsin pathway nevertheless bind Notch but fail to activate the receptor because they cannot exert sufficient force. This argues against recycling models and in favor of pulling models. Our results also suggest that once ligand binds receptor, activation depends on a competition between Epsin-mediated ligand endocytosis, which induces cleavage, and transendocytosis of the ligand by the receptor, which aborts the incipient signal.
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19
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Waller JA, Nygaard SH, Li Y, du Jardin KG, Tamm JA, Abdourahman A, Elfving B, Pehrson AL, Sánchez C, Wernersson R. Neuroplasticity pathways and protein-interaction networks are modulated by vortioxetine in rodents. BMC Neurosci 2017; 18:56. [PMID: 28778148 PMCID: PMC5543755 DOI: 10.1186/s12868-017-0376-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/21/2017] [Indexed: 01/29/2023] Open
Abstract
Background The identification of biomarkers that predict susceptibility to major depressive disorder and treatment response to antidepressants is a major challenge. Vortioxetine is a novel multimodal antidepressant that possesses pro-cognitive properties and differentiates from other conventional antidepressants on various cognitive and plasticity measures. The aim of the present study was to identify biological systems rather than single biomarkers that may underlie vortioxetine’s treatment effects. Results We show that the biological systems regulated by vortioxetine are overlapping between mouse and rat in response to distinct treatment regimens and in different brain regions. Furthermore, analysis of complexes of physically-interacting proteins reveal that biomarkers involved in transcriptional regulation, neurodevelopment, neuroplasticity, and endocytosis are modulated by vortioxetine. A subsequent qPCR study examining the expression of targets in the protein–protein interactome space in response to chronic vortioxetine treatment over a range of doses provides further biological validation that vortioxetine engages neuroplasticity networks. Thus, the same biology is regulated in different species and sexes, different brain regions, and in response to distinct routes of administration and regimens. Conclusions A recurring theme, based on the present study as well as previous findings, is that networks related to synaptic plasticity, synaptic transmission, signal transduction, and neurodevelopment are modulated in response to vortioxetine treatment. Regulation of these signaling pathways by vortioxetine may underlie vortioxetine’s cognitive-enhancing properties. Electronic supplementary material The online version of this article (doi:10.1186/s12868-017-0376-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jessica A Waller
- External Sourcing and Scientific Excellence, Lundbeck Research U.S.A., Paramus, NJ, 07652, USA
| | | | - Yan Li
- External Sourcing and Scientific Excellence, Lundbeck Research U.S.A., Paramus, NJ, 07652, USA
| | | | - Joseph A Tamm
- In Vitro Biology, Lundbeck Research U.S.A., Paramus, NJ, 07652, USA
| | | | - Betina Elfving
- Translational Neuropsychiatry Unit, Aarhus University, 8240, Risskov, Denmark
| | - Alan L Pehrson
- External Sourcing and Scientific Excellence, Lundbeck Research U.S.A., Paramus, NJ, 07652, USA
| | - Connie Sánchez
- External Sourcing and Scientific Excellence, Lundbeck Research U.S.A., Paramus, NJ, 07652, USA.
| | - Rasmus Wernersson
- Intomics A/S, Diplomvej 377, 2800, Lyngby, Denmark. .,Center for Biological Sequence Analysis, Technical University of Denmark, 2800, Lyngby, Denmark.
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20
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A mammalian mirtron miR-1224 promotes tube-formation of human primary endothelial cells by targeting anti-angiogenic factor epsin2. Sci Rep 2017; 7:5541. [PMID: 28717225 PMCID: PMC5514154 DOI: 10.1038/s41598-017-05782-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 06/05/2017] [Indexed: 01/29/2023] Open
Abstract
Angiogenesis, new vessel formation from pre-existing vessels, is a highly conserved event through vertebrates. However, the system for tuning angiogenesis by species-intrinsic factors is totally unknown. miR-1224 is a member of mammal-specific mirtrons, which were identified as non-canonical microRNAs. We found that the expression of miR-1224 was upregulated in capillary-like tube-forming human umbilical vein endothelial cells on Matrigel. Enforced expression of miR-1224 stimulated tube formation, whereas repression of endogenous miR-1224 inhibited formation. Enforced expression of miR-1224 enhanced VEGF signaling and repressed NOTCH signaling. The adaptor protein of clathrin-dependent endocytosis, epsin2, which has been shown to be a suppressor of angiogenesis, was a direct target of miR-1224. Knockdown of EPN2 stimulated tube formation, while overexpression of EPN2 repressed miR-1224-mediated stimulation. Our findings indicate that miR-1224 is a mammal specific modulator of angiogenesis.
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21
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Song K, Wu H, Rahman HNA, Dong Y, Wen A, Brophy ML, Wong S, Kwak S, Bielenberg DR, Chen H. Endothelial epsins as regulators and potential therapeutic targets of tumor angiogenesis. Cell Mol Life Sci 2016; 74:393-398. [PMID: 27572288 DOI: 10.1007/s00018-016-2347-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/17/2016] [Accepted: 08/22/2016] [Indexed: 12/16/2022]
Abstract
VEGF-driven tumor angiogenesis has been validated as a central target in several tumor types deserving of continuous and further considerations to improve the efficacy and selectivity of the current therapeutic paradigms. Epsins, a family of endocytic clathrin adaptors, have been implicated in regulating endothelial cell VEGFR2 signaling, where its inactivation leads to nonproductive leaky neo-angiogenesis and, therefore, impedes tumor development and progression. Targeting endothelial epsins is of special significance due to its lack of affecting other angiogenic-signaling pathways or disrupting normal quiescent vessels, suggesting a selective modulation of tumor angiogenesis. This review highlights seminal findings on the critical role of endothelial epsins in tumor angiogenesis and their underlying molecular events, as well as strategies to prohibit the normal function of endogenous endothelial epsins that capitalize on these newly understood mechanisms.
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Affiliation(s)
- Kai Song
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Hao Wu
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - H N Ashiqur Rahman
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Yunzhou Dong
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Aiyun Wen
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Megan L Brophy
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Scott Wong
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Sukyoung Kwak
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Diane R Bielenberg
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Hong Chen
- Vascular Biology Program, Karp Family Research Laboratory, Department of Surgery, Boston Children's Hospital, Harvard Medical School, 12.214, 300 Longwood Avenue, Boston, MA, 02115, USA.
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22
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Szymanska M, Fosdahl AM, Raiborg C, Dietrich M, Liestøl K, Stang E, Bertelsen V. Interaction with epsin 1 regulates the constitutive clathrin-dependent internalization of ErbB3. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1179-88. [PMID: 26975582 DOI: 10.1016/j.bbamcr.2016.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/24/2016] [Accepted: 03/10/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND In contrast to other members of the EGF receptor family, ErbB3 is constitutively internalized in a clathrin-dependent manner. Previous studies have shown that ErbB3 does not interact with the coated pit localized adaptor complex 2 (AP-2), and that ErbB3 lacks two AP-2 interacting internalization signals identified in the EGF receptor. Several other clathrin-associated sorting proteins which may recruit cargo into coated pits have, however, been identified, and the study was performed to identify adaptors needed for constitutive internalization of ErbB3. METHODS A high-throughput siRNA screen was used to identify adaptor proteins needed for internalization of ErbB3. Upon knock-down of candidate proteins internalization of ErbB3 was identified using an antibody-based internalization assay combined with automatic fluorescence microscopy. RESULTS Among 29 candidates only knock-down of epsin 1 turned out to inhibit ErbB3. Epsin 1 has ubiquitin interacting motifs (UIMs) and we show that ErbB3 interacts with an epsin 1 deletion mutant containing these UIMs. In support of an ErbB3-epsin 1 UIM dependent interaction, we show that ErbB3 is constitutively ubiquitinated, but that both ubiquitination and the ErbB3-epsin 1 interaction increase upon ligand binding. CONCLUSION Altogether the results are consistent with a model whereby both constitutive and ligand-induced internalization of ErbB3 are regulated through interaction with epsin 1. GENERAL SIGNIFICANCE Internalization is an important regulator of growth factor receptor mediated signaling and the current study identify mechanisms regulating plasma membrane turnover of ErbB3.
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Affiliation(s)
- Monika Szymanska
- Department of Pathology, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Anne Marthe Fosdahl
- Department of Pathology, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Camilla Raiborg
- Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway; Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Markus Dietrich
- Department of Pathology, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Knut Liestøl
- Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway; Department of Informatics, University of Oslo, Oslo, Norway
| | - Espen Stang
- Department of Pathology, Oslo University Hospital, Oslo, Norway.
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23
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Rahman HNA, Wu H, Dong Y, Pasula S, Wen A, Sun Y, Brophy ML, Tessneer KL, Cai X, McManus J, Chang B, Kwak S, Rahman NS, Xu W, Fernandes C, Mcdaniel JM, Xia L, Smith L, Srinivasan RS, Chen H. Selective Targeting of a Novel Epsin-VEGFR2 Interaction Promotes VEGF-Mediated Angiogenesis. Circ Res 2016; 118:957-969. [PMID: 26879230 DOI: 10.1161/circresaha.115.307679] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/12/2016] [Indexed: 12/17/2022]
Abstract
RATIONALE We previously reported that vascular endothelial growth factor (VEGF)-induced binding of VEGF receptor 2 (VEGFR2) to epsins 1 and 2 triggers VEGFR2 degradation and attenuates VEGF signaling. The epsin ubiquitin interacting motif (UIM) was shown to be required for the interaction with VEGFR2. However, the molecular determinants that govern how epsin specifically interacts with and regulates VEGFR2 were unknown. OBJECTIVE The goals for the present study were as follows: (1) to identify critical molecular determinants that drive the specificity of the epsin and VEGFR2 interaction and (2) to ascertain whether such determinants were critical for physiological angiogenesis in vivo. METHODS AND RESULTS Structural modeling uncovered 2 novel binding surfaces within VEGFR2 that mediate specific interactions with epsin UIM. Three glutamic acid residues in epsin UIM were found to interact with residues in VEGFR2. Furthermore, we found that the VEGF-induced VEGFR2-epsin interaction promoted casitas B-lineage lymphoma-mediated ubiquitination of epsin, and uncovered a previously unappreciated ubiquitin-binding surface within VEGFR2. Mutational analysis revealed that the VEGFR2-epsin interaction is supported by VEGFR2 interacting specifically with the UIM and with ubiquitinated epsin. An epsin UIM peptide, but not a mutant UIM peptide, potentiated endothelial cell proliferation, migration and angiogenic properties in vitro, increased postnatal retinal angiogenesis, and enhanced VEGF-induced physiological angiogenesis and wound healing. CONCLUSIONS Distinct residues in the epsin UIM and VEGFR2 mediate specific interactions between epsin and VEGFR2, in addition to UIM recognition of ubiquitin moieties on VEGFR2. These novel interactions are critical for pathophysiological angiogenesis, suggesting that these sites could be selectively targeted by therapeutics to modulate angiogenesis.
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Affiliation(s)
- H N Ashiqur Rahman
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Hao Wu
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Yunzhou Dong
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Satish Pasula
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Aiyun Wen
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Ye Sun
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Megan L Brophy
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA.,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA
| | - Kandice L Tessneer
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Xiaofeng Cai
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - John McManus
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Baojun Chang
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Sukyoung Kwak
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - Negar S Rahman
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Wenjia Xu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Conrad Fernandes
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - John Michael Mcdaniel
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Lijun Xia
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Lois Smith
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
| | - R Sathish Srinivasan
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Hong Chen
- Vascular Biology Program, Karp Family Research Labs #12.214, Harvard Medical School, Boston Children's Hospital, 300 Longwood Ave, Boston, MA 02115, USA
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24
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Guo S, Zhang X, Zheng M, Zhang X, Min C, Wang Z, Cheon SH, Oak MH, Nah SY, Kim KM. Selectivity of commonly used inhibitors of clathrin-mediated and caveolae-dependent endocytosis of G protein-coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2101-10. [PMID: 26055893 DOI: 10.1016/j.bbamem.2015.05.024] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 05/23/2015] [Accepted: 05/30/2015] [Indexed: 12/15/2022]
Abstract
Among the multiple G protein-coupled receptor (GPCR) endocytic pathways, clathrin-mediated endocytosis (CME) and caveolar endocytosis are more extensively characterized than other endocytic pathways. A number of endocytic inhibitors have been used to block CME; however, systemic studies to determine the selectivity of these inhibitors are needed. Clathrin heavy chain or caveolin1-knockdown cells have been employed to determine the specificity of various chemical and molecular biological tools for CME and caveolar endocytosis. Sucrose, concanavalin A, and dominant negative mutants of dynamin blocked other endocytic pathways, in addition to CME. In particular, concanavalin A nonspecifically interfered with the signaling of several GPCRs tested in the study. Decreased pH, monodansylcadaverine, and dominant negative mutants of epsin were more specific for CME than other treatments were. A recently introduced CME inhibitor, Pitstop2™, showed only marginal selectivity for CME and interfered with receptor expression on the cell surface. Blockade of receptor endocytosis by epsin mutants and knockdown of the clathrin heavy chain enhanced the β2AR-mediated ERK activation. Overall, our studies show that previous experimental results should be interpreted with discretion if they included the use of endocytic inhibitors that were previously thought to be CME-selective. In addition, our study shows that endocytosis of β2 adrenoceptor through clathrin-mediated pathway has negative effects on ERK activation.
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Affiliation(s)
- Shuohan Guo
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Xiaohan Zhang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Mei Zheng
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Xiaowei Zhang
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Chengchun Min
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Zengtao Wang
- Department of Medicinal Chemistry, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Seung Hoon Cheon
- Department of Medicinal Chemistry, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea
| | - Min-Ho Oak
- College of Pharmacy, Mokpo National University, Muan-gun, Jeollanamdo 534-729, Republic of Korea
| | - Seung-Yeol Nah
- Department of Physiology, College of Veterinary Medicine and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Republic of Korea
| | - Kyeong-Man Kim
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju 500-757, Republic of Korea.
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25
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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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26
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Abstract
Endocytosis, the process whereby the plasma membrane invaginates to form vesicles, is essential for bringing many substances into the cell and for membrane turnover. The mechanism driving clathrin-mediated endocytosis (CME) involves > 50 different protein components assembling at a single location on the plasma membrane in a temporally ordered and hierarchal pathway. These proteins perform precisely choreographed steps that promote receptor recognition and clustering, membrane remodeling, and force-generating actin-filament assembly and turnover to drive membrane invagination and vesicle scission. Many critical aspects of the CME mechanism are conserved from yeast to mammals and were first elucidated in yeast, demonstrating that it is a powerful system for studying endocytosis. In this review, we describe our current mechanistic understanding of each step in the process of yeast CME, and the essential roles played by actin polymerization at these sites, while providing a historical perspective of how the landscape has changed since the preceding version of the YeastBook was published 17 years ago (1997). Finally, we discuss the key unresolved issues and where future studies might be headed.
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Affiliation(s)
- Bruce L Goode
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Julian A Eskin
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Beverly Wendland
- The Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218
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27
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Feliziani C, Zamponi N, Gottig N, Rópolo AS, Lanfredi-Rangel A, Touz MC. The giardial ENTH protein participates in lysosomal protein trafficking and endocytosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:646-59. [PMID: 25576518 DOI: 10.1016/j.bbamcr.2014.12.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/18/2014] [Accepted: 12/30/2014] [Indexed: 12/01/2022]
Abstract
In the protozoa parasite Giardia lamblia, endocytosis and lysosomal protein trafficking are vital parasite-specific processes that involve the action of the adaptor complexes AP-1 and AP-2 and clathrin. In this work, we have identified a single gene in Giardia encoding a protein containing an ENTH domain that defines monomeric adaptor proteins of the epsin family. This domain is present in the epsin or epsin-related (epsinR) adaptor proteins, which are implicated in endocytosis and Golgi-to-endosome protein trafficking, respectively, in other eukaryotic cells. We found that GlENTHp (for G. lamblia ENTH protein) localized in the cytosol, strongly interacted with PI3,4,5P3, was associated with the alpha subunit of AP-2, clathrin and ubiquitin and was involved in receptor-mediated endocytosis. It also bonded PI4P, the gamma subunit of AP-1 and was implicated in ER-to-PV trafficking. Alteration of the GlENTHp function severely affected trophozoite growth showing an unusual accumulation of dense material in the lysosome-like peripheral vacuoles (PVs), indicating that GlENTHp might be implicated in the maintenance of PV homeostasis. In this study, we showed evidence suggesting that GlENTHp might function as a monomeric adaptor protein supporting the findings of other group indicating that GlENTHp might be placed at the beginning of the ENTH family.
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Affiliation(s)
- Constanza Feliziani
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina
| | - Nahuel Zamponi
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina
| | - Natalia Gottig
- Molecular Biology Division, Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Andrea S Rópolo
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina
| | | | - Maria C Touz
- Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC, CONICET, Universidad Nacional de Córdoba, Friuli 2434, Córdoba, Argentina.
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28
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Ramakrishnan N, Radhakrishnan R. Phenomenology based multiscale models as tools to understand cell membrane and organelle morphologies. ACTA ACUST UNITED AC 2015; 22:129-175. [PMID: 27087801 DOI: 10.1016/bs.adplan.2015.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An intriguing question in cell biology is "how do cells regulate their shape?" It is commonly believed that the observed cellular morphologies are a result of the complex interaction among the lipid molecules (constituting the cell membrane), and with a number of other macromolecules, such as proteins. It is also believed that the common biophysical processes essential for the functioning of a cell also play an important role in cellular morphogenesis. At the cellular scale-where typical dimensions are in the order of micrometers-the effects arising from the molecular scale can either be modeled as equilibrium or non-equilibrium processes. In this chapter, we discuss the dynamically triangulated Monte Carlo technique to model and simulate membrane morphologies at the cellular scale, which in turn can be used to investigate several questions related to shape regulation in cells. In particular, we focus on two specific problems within the framework of isotropic and anisotropic elasticity theories: namely, (i) the origin of complex, physiologically relevant, membrane shapes due to the interaction of the membrane with curvature remodeling proteins, and (ii) the genesis of steady state cellular shapes due to the action of non-equilibrium forces that are generated by the fission and fusion of transport vesicles and by the binding and unbinding of proteins from the parent membrane.
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Affiliation(s)
- N Ramakrishnan
- Department of Chemical and Biomolecular Engineering, Department of Bioengineering, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA-19104
| | - Ravi Radhakrishnan
- Department of Chemical and Biomolecular Engineering, Department of Bioengineering, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA-19104
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29
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Ramakrishnan N, Sunil Kumar PB, Radhakrishnan R. Mesoscale computational studies of membrane bilayer remodeling by curvature-inducing proteins. PHYSICS REPORTS 2014; 543:1-60. [PMID: 25484487 PMCID: PMC4251917 DOI: 10.1016/j.physrep.2014.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Biological membranes constitute boundaries of cells and cell organelles. These membranes are soft fluid interfaces whose thermodynamic states are dictated by bending moduli, induced curvature fields, and thermal fluctuations. Recently, there has been a flood of experimental evidence highlighting active roles for these structures in many cellular processes ranging from trafficking of cargo to cell motility. It is believed that the local membrane curvature, which is continuously altered due to its interactions with myriad proteins and other macromolecules attached to its surface, holds the key to the emergent functionality in these cellular processes. Mechanisms at the atomic scale are dictated by protein-lipid interaction strength, lipid composition, lipid distribution in the vicinity of the protein, shape and amino acid composition of the protein, and its amino acid contents. The specificity of molecular interactions together with the cooperativity of multiple proteins induce and stabilize complex membrane shapes at the mesoscale. These shapes span a wide spectrum ranging from the spherical plasma membrane to the complex cisternae of the Golgi apparatus. Mapping the relation between the protein-induced deformations at the molecular scale and the resulting mesoscale morphologies is key to bridging cellular experiments across the various length scales. In this review, we focus on the theoretical and computational methods used to understand the phenomenology underlying protein-driven membrane remodeling. Interactions at the molecular scale can be computationally probed by all atom and coarse grained molecular dynamics (MD, CGMD), as well as dissipative particle dynamics (DPD) simulations, which we only describe in passing. We choose to focus on several continuum approaches extending the Canham - Helfrich elastic energy model for membranes to include the effect of curvature-inducing proteins and explore the conformational phase space of such systems. In this description, the protein is expressed in the form of a spontaneous curvature field. The approaches include field theoretical methods limited to the small deformation regime, triangulated surfaces and particle-based computational models to investigate the large-deformation regimes observed in the natural state of many biological membranes. Applications of these methods to understand the properties of biological membranes in homogeneous and inhomogeneous environments of proteins, whose underlying curvature fields are either isotropic or anisotropic, are discussed. The diversity in the curvature fields elicits a rich variety of morphological states, including tubes, discs, branched tubes, and caveola. Mapping the thermodynamic stability of these states as a function of tuning parameters such as concentration and strength of curvature induction of the proteins is discussed. The relative stabilities of these self-organized shapes are examined through free-energy calculations. The suite of methods discussed here can be tailored to applications in specific cellular settings such as endocytosis during cargo trafficking and tubulation of filopodial structures in migrating cells, which makes these methods a powerful complement to experimental studies.
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Affiliation(s)
- N. Ramakrishnan
- Department of Chemical and Biomolecular Engineering, Department of Bioengineering, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA-19104
| | - P. B. Sunil Kumar
- Department of Physics, Indian Institute of Technology Madras, Chennai, India - 600036
| | - Ravi Radhakrishnan
- Department of Chemical and Biomolecular Engineering, Department of Bioengineering, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA-19104
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30
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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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31
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Van Roey K, Uyar B, Weatheritt RJ, Dinkel H, Seiler M, Budd A, Gibson TJ, Davey NE. Short Linear Motifs: Ubiquitous and Functionally Diverse Protein Interaction Modules Directing Cell Regulation. Chem Rev 2014; 114:6733-78. [DOI: 10.1021/cr400585q] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kim Van Roey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Robert J. Weatheritt
- MRC
Laboratory of Molecular Biology (LMB), Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Holger Dinkel
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Markus Seiler
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Aidan Budd
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J. Gibson
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Norman E. Davey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department
of Physiology, University of California, San Francisco, San Francisco, California 94143, United States
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32
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Kirchhausen T, Owen D, Harrison SC. Molecular structure, function, and dynamics of clathrin-mediated membrane traffic. Cold Spring Harb Perspect Biol 2014; 6:a016725. [PMID: 24789820 DOI: 10.1101/cshperspect.a016725] [Citation(s) in RCA: 303] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Clathrin is a molecular scaffold for vesicular uptake of cargo at the plasma membrane, where its assembly into cage-like lattices underlies the clathrin-coated pits of classical endocytosis. This review describes the structures of clathrin, major cargo adaptors, and other proteins that participate in forming a clathrin-coated pit, loading its contents, pinching off the membrane as a lattice-enclosed vesicle, and recycling the components. It integrates as much of the structural information as possible at the time of writing into a sketch of the principal steps in coated-pit and coated-vesicle formation.
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Affiliation(s)
- Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School/PCMM, Boston, Massachusetts 02115
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33
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Tessneer KL, Pasula S, Cai X, Dong Y, McManus J, Liu X, Yu L, Hahn S, Chang B, Chen Y, Griffin C, Xia L, Adams RH, Chen H. Genetic reduction of vascular endothelial growth factor receptor 2 rescues aberrant angiogenesis caused by epsin deficiency. Arterioscler Thromb Vasc Biol 2013; 34:331-337. [PMID: 24311377 DOI: 10.1161/atvbaha.113.302586] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE We previously showed that endothelial epsin deficiency caused elevated vascular endothelial growth factor receptor 2 (VEGFR2) and enhanced VEGF signaling, resulting in aberrant tumor angiogenesis and reduced tumor growth in adult mice. However, direct evidence demonstrating that endothelial epsins regulate angiogenesis specifically through VEGFR2 downregulation is still lacking. In addition, whether the lack of epsins causes abnormal angiogenesis during embryonic development remains unclear. APPROACH AND RESULTS A novel strain of endothelial epsin-deleted mice that are heterozygous for VEGFR2 (Epn1(fl/fl); Epn2(-/-); Flk(fl/+); iCDH5 Cre mice) was created. Analysis of embryos at different developmental stages showed that deletion of epsins caused defective embryonic angiogenesis and retarded embryo development. In vitro angiogenesis assays using isolated primary endothelial cells (ECs) from Epn1(fl/fl); Epn2(-/-); iCDH5 Cre (EC-iDKO) and Epn1(fl/fl); Epn2(-/-); Flk(fl/+); iCDH5 Cre (EC-iDKO-Flk(fl/+)) mice demonstrated that VEGFR2 reduction in epsin-depleted cells was sufficient to restore normal VEGF signaling, EC proliferation, EC migration, and EC network formation. These findings were complemented by in vivo wound healing, inflammatory angiogenesis, and tumor angiogenesis assays in which reduction of VEGFR2 was sufficient to rescue abnormal angiogenesis in endothelial epsin-deleted mice. CONCLUSIONS Our results provide the first genetic demonstration that epsins function specifically to downregulate VEGFR2 by mediating activated VEGFR2 internalization and degradation and that genetic reduction of VEGFR2 level protects against excessive angiogenesis caused by epsin loss. Our findings indicate that epsins may be a potential therapeutic target in conditions in which tightly regulated angiogenesis is crucial, such as in diabetic wound healing and tumors.
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Affiliation(s)
- Kandice L Tessneer
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Satish Pasula
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Xiaofeng Cai
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Yunzhou Dong
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - John McManus
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Xiaolei Liu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Biochemistry and Molecular Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Lili Yu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Scott Hahn
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Baojun Chang
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Yiyuan Chen
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Courtney Griffin
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Cell Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Lijun Xia
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Biochemistry and Molecular Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Ralf H Adams
- Max Planck Institute for Molecular Biomedicine, Department of Tissue Morphogenesis, and University of Münster, Faculty of Medicine, Münster, Germany
| | - Hong Chen
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Biochemistry and Molecular Biology Department, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Abstract
Erythropoietin (Epo) binding to the Epo receptor (EpoR) elicits downstream signaling that is essential for red blood cell production. One important negative regulatory mechanism to terminate Epo signaling is Epo-induced EpoR endocytosis and degradation. Defects in this mechanism play a key role in the overproduction of erythrocytes in primary familial and congenital polycythemia (PFCP). Here we have identified a novel mechanism mediating Epo-dependent EpoR internalization. Epo induces Cbl-dependent ubiquitination of the p85 regulatory subunit of PI3K, which binds to phosphotyrosines on EpoR. Ubiquitination allows p85 to interact with the endocytic protein epsin-1, thereby driving EpoR endocytosis. Knockdown of Cbl, expression of its dominant negative forms, or expression of an epsin-1 mutant devoid of ubiquitin-interacting motifs all compromise Epo-induced EpoR internalization. Mutated EpoRs mimicking those from PFCP patients cannot bind p85, co-localize with epsin-1, or internalize on Epo stimulation and exhibit Epo hypersensitivity. Similarly, knockdown of Cbl also causes Epo hypersensitivity in primary erythroid progenitors. Restoring p85 binding to PFCP receptors rescues Epo-induced epsin-1 co-localization and EpoR internalization and normalizes Epo hypersensitivity. Our results uncover a novel Cbl/p85/epsin-1 pathway in EpoR endocytosis and show that defects in this pathway contribute to excessive Epo signaling and erythroid hyperproliferation in PFCP.
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35
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Shen Q, He B, Lu N, Conradt B, Grant BD, Zhou Z. Phagocytic receptor signaling regulates clathrin and epsin-mediated cytoskeletal remodeling during apoptotic cell engulfment in C. elegans. Development 2013; 140:3230-43. [PMID: 23861060 PMCID: PMC3931732 DOI: 10.1242/dev.093732] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The engulfment and subsequent degradation of apoptotic cells by phagocytes is an evolutionarily conserved process that efficiently removes dying cells from animal bodies during development. Here, we report that clathrin heavy chain (CHC-1), a membrane coat protein well known for its role in receptor-mediated endocytosis, and its adaptor epsin (EPN-1) play crucial roles in removing apoptotic cells in Caenorhabditis elegans. Inactivating epn-1 or chc-1 disrupts engulfment by impairing actin polymerization. This defect is partially suppressed by inactivating UNC-60, a cofilin ortholog and actin server/depolymerization protein, further indicating that EPN-1 and CHC-1 regulate actin assembly during pseudopod extension. CHC-1 is enriched on extending pseudopods together with EPN-1, in an EPN-1-dependent manner. Epistasis analysis places epn-1 and chc-1 in the same cell-corpse engulfment pathway as ced-1, ced-6 and dyn-1. CED-1 signaling is necessary for the pseudopod enrichment of EPN-1 and CHC-1. CED-1, CED-6 and DYN-1, like EPN-1 and CHC-1, are essential for the assembly and stability of F-actin underneath pseudopods. We propose that in response to CED-1 signaling, CHC-1 is recruited to the phagocytic cup through EPN-1 and acts as a scaffold protein to organize actin remodeling. Our work reveals novel roles of clathrin and epsin in apoptotic-cell internalization, suggests a Hip1/R-independent mechanism linking clathrin to actin assembly, and ties the CED-1 pathway to cytoskeleton remodeling.
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Affiliation(s)
- Qian Shen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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36
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Humphries AC, Way M. The non-canonical roles of clathrin and actin in pathogen internalization, egress and spread. Nat Rev Microbiol 2013; 11:551-60. [PMID: 24020073 DOI: 10.1038/nrmicro3072] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The role of clathrin in pathogen entry has received much attention and has highlighted the adaptability of clathrin during internalization. Recent studies have now uncovered additional roles for clathrin and have put the spotlight on its role in pathogen spread. Here, we discuss the manipulation of clathrin by pathogens, with specific attention to the processes that occur at the plasma membrane. In the majority of cases, both clathrin and the actin cytoskeleton are hijacked, so we also examine the interplay between these two systems and their role during pathogen internalization, egress and spread.
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Affiliation(s)
- Ashley C Humphries
- Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
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37
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Vanlandingham PA, Fore TR, Chastain LR, Royer SM, Bao H, Reist NE, Zhang B. Epsin 1 Promotes Synaptic Growth by Enhancing BMP Signal Levels in Motoneuron Nuclei. PLoS One 2013; 8:e65997. [PMID: 23840387 PMCID: PMC3686817 DOI: 10.1371/journal.pone.0065997] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/01/2013] [Indexed: 11/19/2022] Open
Abstract
Bone morphogenetic protein (BMP) retrograde signaling is crucial for neuronal development and synaptic plasticity. However, how the BMP effector phospho-Mother against decapentaplegic (pMad) is processed following receptor activation remains poorly understood. Here we show that Drosophila Epsin1/Liquid facets (Lqf) positively regulates synaptic growth through post-endocytotic processing of pMad signaling complex. Lqf and the BMP receptor Wishful thinking (Wit) interact genetically and biochemically. lqf loss of function (LOF) reduces bouton number whereas overexpression of lqf stimulates bouton growth. Lqf-stimulated synaptic overgrowth is suppressed by genetic reduction of wit. Further, synaptic pMad fails to accumulate inside the motoneuron nuclei in lqf mutants and lqf suppresses synaptic overgrowth in spinster (spin) mutants with enhanced BMP signaling by reducing accumulation of nuclear pMad. Interestingly, lqf mutations reduce nuclear pMad levels without causing an apparent blockage of axonal transport itself. Finally, overexpression of Lqf significantly increases the number of multivesicular bodies (MVBs) in the synapse whereas lqf LOF reduces MVB formation, indicating that Lqf may function in signaling endosome recycling or maturation. Based on these observations, we propose that Lqf plays a novel endosomal role to ensure efficient retrograde transport of BMP signaling endosomes into motoneuron nuclei.
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Affiliation(s)
| | - Taylor R. Fore
- Department of Biology, University of Oklahoma, Norman, Oklahoma
| | | | - Suzanne M. Royer
- Department of Biomedical Sciences, Molecular, Cellular, and Integrative Neuroscience Program, Colorado State University, Fort Collins, Colorado
| | - Hong Bao
- Department of Biology, University of Oklahoma, Norman, Oklahoma
| | - Noreen E. Reist
- Department of Biomedical Sciences, Molecular, Cellular, and Integrative Neuroscience Program, Colorado State University, Fort Collins, Colorado
| | - Bing Zhang
- Department of Biology, University of Oklahoma, Norman, Oklahoma
- * E-mail:
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38
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Sorrentino V, Nelson JK, Maspero E, Marques ARA, Scheer L, Polo S, Zelcer N. The LXR-IDOL axis defines a clathrin-, caveolae-, and dynamin-independent endocytic route for LDLR internalization and lysosomal degradation. J Lipid Res 2013; 54:2174-2184. [PMID: 23733886 DOI: 10.1194/jlr.m037713] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Low density lipoprotein (LDL) cholesterol is taken up into cells via clathrin-mediated endocytosis of the LDL receptor (LDLR). Following dissociation of the LDLR-LDL complex, LDL is directed to lysosomes whereas the LDLR recycles to the plasma membrane. Activation of the sterol-sensing nuclear receptors liver X receptors (LXRs) enhances degradation of the LDLR. This depends on the LXR target gene inducible degrader of the LDLR (IDOL), an E3-ubiquitin ligase that promotes ubiquitylation and lysosomal degradation of the LDLR. How ubiquitylation of the LDLR by IDOL controls its endocytic trafficking is currently unknown. Using genetic- and pharmacological-based approaches coupled to functional assessment of LDL uptake, we show that the LXR-IDOL axis targets a LDLR pool present in lipid rafts. IDOL-dependent internalization of the LDLR is independent of clathrin, caveolin, macroautophagy, and dynamin. Rather, it depends on the endocytic protein epsin. Consistent with LDLR ubiquitylation acting as a sorting signal, degradation of the receptor can be blocked by perturbing the endosomal sorting complex required for transport (ESCRT) or by USP8, a deubiquitylase implicated in sorting ubiquitylated cargo to multivesicular bodies. In summary, we provide evidence for the existence of an LXR-IDOL-mediated internalization pathway for the LDLR that is distinct from that used for lipoprotein uptake.
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Affiliation(s)
- Vincenzo Sorrentino
- Department of Medical Biochemistry, Academic Medical Center of the University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Jessica K Nelson
- Department of Medical Biochemistry, Academic Medical Center of the University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Elena Maspero
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy; and
| | - André R A Marques
- Department of Medical Biochemistry, Academic Medical Center of the University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Lilith Scheer
- Department of Medical Biochemistry, Academic Medical Center of the University of Amsterdam, 1105AZ Amsterdam, The Netherlands
| | - Simona Polo
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, 20139 Milan, Italy; and; Dipartimento di Scienze della Salute, Universita' degli Studi di Milano, 20122 Milan, Italy
| | - Noam Zelcer
- Department of Medical Biochemistry, Academic Medical Center of the University of Amsterdam, 1105AZ Amsterdam, The Netherlands.
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39
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Endocytic adaptor protein epsin is elevated in prostate cancer and required for cancer progression. ISRN ONCOLOGY 2013; 2013:420597. [PMID: 23691361 PMCID: PMC3649151 DOI: 10.1155/2013/420597] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 02/27/2013] [Indexed: 11/29/2022]
Abstract
Epsins have an important role in mediating clathrin-mediated endocytosis of ubiquitinated cell surface receptors. The potential role for epsins in tumorigenesis and cancer metastasis by regulating intracellular signaling pathways has largely not been explored. Epsins are reportedly upregulated in several types of cancer including human skin, lung, and canine mammary cancers. However, whether their expression is elevated in prostate cancer is unknown. In this study, we investigated the potential role of epsins in prostate tumorigenesis using the wild type or epsin-deficient human prostate cancer cells, LNCaP, in a human xenograft model, and the spontaneous TRAMP mouse model in wild type or epsin-deficient background. Here, we reported that the expression of epsins 1 and 2 is upregulated in both human and mouse prostate cancer cells and cancerous tissues. Consistent with upregulation of epsins in prostate tumors, we discovered that depletion of epsins impaired tumor growth in both the human LNCaP xenograft and the TRAMP mouse prostate. Furthermore, epsin depletion significantly prolonged survival in the TRAMP mouse model. In summary, our findings suggest that epsins may act as oncogenic proteins to promote prostate tumorigenesis and that depletion or inhibition of epsins may provide a novel therapeutic target for future prostate cancer therapies.
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40
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Mutant huntingtin affects endocytosis in striatal cells by altering the binding of AP-2 to membranes. Exp Neurol 2013; 241:75-83. [DOI: 10.1016/j.expneurol.2012.11.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 11/21/2012] [Accepted: 11/26/2012] [Indexed: 11/18/2022]
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41
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Tessneer KL, Cai X, Pasula S, Dong Y, Liu X, Chang B, McManus J, Hahn S, Yu L, Chen H. Epsin Family of Endocytic Adaptor Proteins as Oncogenic Regulators of Cancer Progression. ACTA ACUST UNITED AC 2013; 2:144-150. [PMID: 24501612 PMCID: PMC3911794 DOI: 10.6000/1929-2279.2013.02.03.2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tumor angiogenesis, tumor cell proliferation, and tumor cell migration result from an accumulation of oncogenic mutations that alter protein expression and the regulation of various signaling cascades. Epsins, a small family of clathrin-mediated endocytic adaptor proteins, are reportedly upregulated in a variety of cancers. Importantly, loss of epsins protects against tumorigenesis, thus supporting an oncogenic role for epsins in cancer. Although a clear relationship between epsins and cancer has evolved, the importance of this relationship with regards to cancer progression and anti-cancer therapies remains unclear. In this review, we summarize epsins’ role as endocytic adaptors that modulate VEGF and Notch signaling through the regulated internalization of VEGFR2 and trans-endocytosis of Notch receptors. As both VEGF and Notch signaling have significant implications in angiogenesis, we focus on the newly identified role for epsins in tumor angiogenesis. In addition to epsins’ canonical role in receptor-mediated endocytosis, and the resulting downstream signaling regulation, we discuss the non-canonical role of epsins as regulators of small GTPases and the implications this has on tumor cell proliferation and invasion. Given epsins’ identified roles in tumor angiogenesis, tumor cell proliferation, and tumor cell invasion, we predict that the investigative links between epsins and cancer will provide new insights into the importance of endocytic adaptors and their potential use as future therapeutic targets.
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Affiliation(s)
- Kandice L Tessneer
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Xiaofeng Cai
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Satish Pasula
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Yunzhou Dong
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Xiaolei Liu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA ; Biochemistry and Molecular Biology Department, University of Oklahoma Health Science Center, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
| | - Baojun Chang
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - John McManus
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Scott Hahn
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Lili Yu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA
| | - Hong Chen
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, 825 N.E. 13 Street, Oklahoma City, OK 73104, USA ; Biochemistry and Molecular Biology Department, University of Oklahoma Health Science Center, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104, USA
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42
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Pasula S, Cai X, Dong Y, Messa M, McManus J, Chang B, Liu X, Zhu H, Mansat RS, Yoon SJ, Hahn S, Keeling J, Saunders D, Ko G, Knight J, Newton G, Luscinskas F, Sun X, Towner R, Lupu F, Xia L, Cremona O, De Camilli P, Min W, Chen H. Endothelial epsin deficiency decreases tumor growth by enhancing VEGF signaling. J Clin Invest 2012. [PMID: 23187125 DOI: 10.1172/jci64537] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Epsins are a family of ubiquitin-binding, endocytic clathrin adaptors. Mice lacking both epsins 1 and 2 (Epn1/2) die at embryonic day 10 and exhibit an abnormal vascular phenotype. To examine the angiogenic role of endothelial epsins, we generated mice with constitutive or inducible deletion of Epn1/2 in vascular endothelium. These mice exhibited no abnormal phenotypes under normal conditions, suggesting that lack of endothelial epsins 1 and 2 did not affect normal blood vessels. In tumors, however, loss of epsins 1 and 2 resulted in disorganized vasculature, significantly increased vascular permeability, and markedly retarded tumor growth. Mechanistically, we show that VEGF promoted binding of epsin to ubiquitinated VEGFR2. Loss of epsins 1 and 2 specifically impaired endocytosis and degradation of VEGFR2, which resulted in excessive VEGF signaling that compromised tumor vascular function by exacerbating nonproductive leaky angiogenesis. This suggests that tumor vasculature requires a balance in VEGF signaling to provide sufficient productive angiogenesis for tumor development and that endothelial epsins 1 and 2 negatively regulate the output of VEGF signaling. Promotion of excessive VEGF signaling within tumors via a block of epsin 1 and 2 function may represent a strategy to prevent normal angiogenesis in cancer patients who are resistant to anti-VEGF therapies.
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Affiliation(s)
- Satish Pasula
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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43
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Abstract
Solid tumor growth requires the formation of new blood vessels to supply nutrients and oxygen to the malignant cells; one approach to cancer therapy is to block this process by inhibiting VEGF signaling. In this issue of the JCI, Pasula et al. demonstrate a surprising role of epsins--proteins involved in endocytosis--in tumor angiogenesis via their modulation of VEGF signaling. Their findings suggest that these proteins might represent a new target for the development of cancer therapeutics.
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Affiliation(s)
- Nancy Klauber-Demore
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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44
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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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45
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Henry A, Hislop J, Grove J, Thorn K, Marsh M, von Zastrow M. Regulation of endocytic clathrin dynamics by cargo ubiquitination. Dev Cell 2012; 23:519-32. [PMID: 22940114 PMCID: PMC3470869 DOI: 10.1016/j.devcel.2012.08.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 06/21/2012] [Accepted: 08/04/2012] [Indexed: 12/21/2022]
Abstract
VIDEO ABSTRACT Some endocytic cargoes control clathrin-coated pit (CCP) maturation, but it is not known how such regulation is communicated. We found that μ-opioid neuropeptide receptors signal to their enclosing CCPs by ubiquitination. Nonubiquitinated receptors delay CCPs at an intermediate stage of maturation, after clathrin lattice assembly is complete but before membrane scission. Receptor ubiquitination relieves this inhibition, effectively triggering CCP scission and producing a receptor-containing endocytic vesicle. The ubiquitin modification that conveys this endocytosis-promoting signal is added to the receptor's first cytoplasmic loop, catalyzed by the Smurf2 ubiquitin ligase, and coordinated with activation-dependent receptor phosphorylation and clustering through Smurf2 recruitment by the endocytic adaptor beta-arrestin. Epsin1 detects the signal at the CCP and is required for ubiquitin-promoted scission. This cargo-to-coat communication system mediates a biochemical checkpoint that ensures appropriate receptor ubiquitination for later trafficking, and it controls specific receptor loading into CCPs by sensing when a sufficient quorum is reached.
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Affiliation(s)
- Anastasia G. Henry
- Program in Cell Biology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - James N. Hislop
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Joe Grove
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Kurt Thorn
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Mark Marsh
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Mark von Zastrow
- Program in Cell Biology, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
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46
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Cho DI, Min C, Jung KS, Cheong SY, Zheng M, Cheong SJ, Oak MH, Cheong JH, Lee BK, Kim KM. The N-terminal region of the dopamine D2 receptor, a rhodopsin-like GPCR, regulates correct integration into the plasma membrane and endocytic routes. Br J Pharmacol 2012; 166:659-75. [PMID: 22117524 DOI: 10.1111/j.1476-5381.2011.01787.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND AND PURPOSE Functional roles of the N-terminal region of rhodopsin-like GPCR family remain unclear. Using dopamine D(2) and D(3) receptors as a model system, we probed the roles of the N-terminal region in the signalling, intracellular trafficking of receptor proteins, and explored the critical factors that determine the functionality of the N-terminal region. EXPERIMENTAL APPROACH The N-terminal region of the D(2) receptor was gradually shortened or switched with that of the D(3) receptor or a non-specific sequence (FLAG), or potential N-terminal glycosylation sites were mutated. Effects of these manipulations on surface expression, internalization, post-endocytic behaviours and signalling were determined. KEY RESULTS Shortening the N-terminal region of the D(2) receptor enhanced receptor internalization and impaired surface expression and signalling; ligand binding, desensitization and down-regulation were not affected but their association with a particular microdomain, caveolae, was disrupted. Replacement of critical residues within the N-terminal region with the FLAG epitope failed to restore surface expression but partially restored the altered internalization and signalling. When the N-terminal regions were switched between D(2) and D(3) receptors, cell surface expression pattern of each receptor was switched. Mutations of potential N-terminal glycosylation sites inhibited surface expression but enhanced internalization of D(2) receptors. CONCLUSIONS AND IMPLICATIONS Shortening of N-terminus or mutation of glycosylation sites located within the N-terminus enhanced receptor internalization but impaired the surface expression of D(2) receptors. The N-terminal region of the D(2) receptor, in a sequence-specific manner, controls the receptor's conformation and integration into the plasma membrane, which determine its subcellular localization, intracellular trafficking and signalling properties.
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Affiliation(s)
- D I Cho
- Department of Pharmacology, College of Pharmacy, Research Institute of Drug Development, Chonnam National University, Gwang-Ju, 500-757 Korea
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Lai CL, Jao CC, Lyman E, Gallop JL, Peter BJ, McMahon HT, Langen R, Voth GA. Membrane binding and self-association of the epsin N-terminal homology domain. J Mol Biol 2012; 423:800-17. [PMID: 22922484 PMCID: PMC3682188 DOI: 10.1016/j.jmb.2012.08.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/13/2012] [Accepted: 08/16/2012] [Indexed: 01/23/2023]
Abstract
Epsin possesses a conserved epsin N-terminal homology (ENTH) domain that acts as a phosphatidylinositol 4,5-bisphosphate‐lipid‐targeting and membrane‐curvature‐generating element. Upon binding phosphatidylinositol 4,5‐bisphosphate, the N-terminal helix (H0) of the ENTH domain becomes structured and aids in the aggregation of ENTH domains, which results in extensive membrane remodeling. In this article, atomistic and coarse-grained (CG) molecular dynamics (MD) simulations are used to investigate the structure and the stability of ENTH domain aggregates on lipid bilayers. EPR experiments are also reported for systems composed of different ENTH-bound membrane morphologies, including membrane vesicles as well as preformed membrane tubules. The EPR data are used to help develop a molecular model of ENTH domain aggregates on preformed lipid tubules that are then studied by CG MD simulation. The combined computational and experimental approach suggests that ENTH domains exist predominantly as monomers on vesiculated structures, while ENTH domains self-associate into dimeric structures and even higher‐order oligomers on the membrane tubes. The results emphasize that the arrangement of ENTH domain aggregates depends strongly on whether the local membrane curvature is isotropic or anisotropic. The molecular mechanism of ENTH‐domain-induced membrane vesiculation and tubulation and the implications of the epsin's role in clathrin-mediated endocytosis resulting from the interplay between ENTH domain membrane binding and ENTH domain self-association are also discussed.
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Affiliation(s)
- Chun-Liang Lai
- Department of Chemistry, Institute of Biophysical Dynamics, James Franck Institute, and Computation Institute, University of Chicago, 5735S Ellis Avenue, Chicago, IL 60637, USA
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48
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Song K, Jang M, Kim SY, Lee G, Lee GJ, Kim DH, Lee Y, Cho W, Hwang I. An A/ENTH domain-containing protein functions as an adaptor for clathrin-coated vesicles on the growing cell plate in Arabidopsis root cells. PLANT PHYSIOLOGY 2012; 159:1013-25. [PMID: 22635117 PMCID: PMC3387690 DOI: 10.1104/pp.112.199380] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 05/21/2012] [Indexed: 05/21/2023]
Abstract
Cytokinesis is the process of partitioning the cytoplasm of a dividing cell, thereby completing mitosis. Cytokinesis in the plant cell is achieved by the formation of a new cell wall between daughter nuclei using components carried in Golgi-derived vesicles that accumulate at the midplane of the phragmoplast and fuse to form the cell plate. Proteins that play major roles in the development of the cell plate in plant cells are not well defined. Here, we report that an AP180 amino-terminal homology/epsin amino-terminal homology domain-containing protein from Arabidopsis (Arabidopsis thaliana) is involved in clathrin-coated vesicle formation from the cell plate. Arabidopsis Epsin-like Clathrin Adaptor1 (AtECA1; At2g01600) and its homologous proteins AtECA2 and AtECA4 localize to the growing cell plate in cells undergoing cytokinesis and also to the plasma membrane and endosomes in nondividing cells. AtECA1 (At2g01600) does not localize to nascent cell plates but localizes at higher levels to expanding cell plates even after the cell plate fuses with the parental plasma membrane. The temporal and spatial localization patterns of AtECA1 overlap most closely with those of the clathrin light chain. In vitro protein interaction assays revealed that AtECA1 binds to the clathrin H chain via its carboxyl-terminal domain. These results suggest that these AP180 amino-terminal homology/epsin amino-terminal homology domain-containing proteins, AtECA1, AtECA2, and AtECA4, may function as adaptors of clathrin-coated vesicles budding from the cell plate.
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49
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Sen A, Madhivanan K, Mukherjee D, Aguilar RC. The epsin protein family: coordinators of endocytosis and signaling. Biomol Concepts 2012; 3:117-126. [PMID: 22942912 DOI: 10.1515/bmc-2011-0060] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The epsins are a conserved family of endocytic adaptors essential for cell viability in yeast and for embryo development in higher eukaryotes. Epsins function as adaptors by recognizing ubiquitinated cargo and as endocytic accessory proteins by contributing to endocytic network stability/regulation and membrane bending. Importantly, epsins play a critical role in signaling by contributing to epidermal growth factor receptor downregulation and the activation of notch and RhoGTPase pathways. In this review, we present an overview of the epsins and emphasize their functional importance as coordinators of endocytosis and signaling.
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Affiliation(s)
- Arpita Sen
- Department of Biological Sciences and Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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50
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Lin AE, Benmerah A, Guttman JA. Eps15 and Epsin1 Are Crucial for Enteropathogenic Escherichia coli Pedestal Formation Despite the Absence of Adaptor Protein 2. J Infect Dis 2011; 204:695-703. [DOI: 10.1093/infdis/jir386] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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