1
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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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2
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Cui K, Gao X, Wang B, Wu H, Arulsamy K, Dong Y, Xiao Y, Jiang X, Malovichko MV, Li K, Peng Q, Lu YW, Zhu B, Zheng R, Wong S, Cowan DB, Linton M, Srivastava S, Shi J, Chen K, Chen H. Epsin Nanotherapy Regulates Cholesterol Transport to Fortify Atheroma Regression. Circ Res 2023; 132:e22-e42. [PMID: 36444722 PMCID: PMC9822875 DOI: 10.1161/circresaha.122.321723] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/14/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Excess cholesterol accumulation in lesional macrophages elicits complex responses in atherosclerosis. Epsins, a family of endocytic adaptors, fuel the progression of atherosclerosis; however, the underlying mechanism and therapeutic potential of targeting Epsins remains unknown. In this study, we determined the role of Epsins in macrophage-mediated metabolic regulation. We then developed an innovative method to therapeutically target macrophage Epsins with specially designed S2P-conjugated lipid nanoparticles, which encapsulate small-interfering RNAs to suppress Epsins. METHODS We used single-cell RNA sequencing with our newly developed algorithm MEBOCOST (Metabolite-mediated Cell Communication Modeling by Single Cell Transcriptome) to study cell-cell communications mediated by metabolites from sender cells and sensor proteins on receiver cells. Biomedical, cellular, and molecular approaches were utilized to investigate the role of macrophage Epsins in regulating lipid metabolism and transport. We performed this study using myeloid-specific Epsin double knockout (LysM-DKO) mice and mice with a genetic reduction of ABCG1 (ATP-binding cassette subfamily G member 1; LysM-DKO-ABCG1fl/+). The nanoparticles targeting lesional macrophages were developed to encapsulate interfering RNAs to treat atherosclerosis. RESULTS We revealed that Epsins regulate lipid metabolism and transport in atherosclerotic macrophages. Inhibiting Epsins by nanotherapy halts inflammation and accelerates atheroma resolution. Harnessing lesional macrophage-specific nanoparticle delivery of Epsin small-interfering RNAs, we showed that silencing of macrophage Epsins diminished atherosclerotic plaque size and promoted plaque regression. Mechanistically, we demonstrated that Epsins bound to CD36 to facilitate lipid uptake by enhancing CD36 endocytosis and recycling. Conversely, Epsins promoted ABCG1 degradation via lysosomes and hampered ABCG1-mediated cholesterol efflux and reverse cholesterol transport. In a LysM-DKO-ABCG1fl/+ mouse model, enhanced cholesterol efflux and reverse transport due to Epsin deficiency was suppressed by the reduction of ABCG1. CONCLUSIONS Our findings suggest that targeting Epsins in lesional macrophages may offer therapeutic benefits for advanced atherosclerosis by reducing CD36-mediated lipid uptake and increasing ABCG1-mediated cholesterol efflux.
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Affiliation(s)
- Kui Cui
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Xinlei Gao
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Beibei Wang
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Kulandaisamy Arulsamy
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Yuling Xiao
- Center for Nanomedicine and Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Xingya Jiang
- Center for Nanomedicine and Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Marina V. Malovichko
- Division of Environmental Medicine, University of Louisville, Louisville, KY, 40292, USA
| | - Kathryn Li
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Qianman Peng
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Yao Wei Lu
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Bo Zhu
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Rongbin Zheng
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Scott Wong
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Douglas B. Cowan
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - MacRae Linton
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center; Nashville, TN, 37232, USA
| | - Sanjay Srivastava
- Division of Environmental Medicine, University of Louisville, Louisville, KY, 40292, USA
| | - Jinjun Shi
- Center for Nanomedicine and Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Kaifu Chen
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
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3
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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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4
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Wang B, Tang X, Yao L, Wang Y, Chen Z, Li M, Wu N, Wu D, Dai X, Jiang H, Ai D. Disruption of USP9X in macrophages promotes foam cell formation and atherosclerosis. J Clin Invest 2022; 132:154217. [PMID: 35389885 PMCID: PMC9106359 DOI: 10.1172/jci154217] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 04/01/2022] [Indexed: 11/17/2022] Open
Abstract
Subendothelial macrophage internalization of modified lipids and foam cell formation are hallmarks of atherosclerosis. Deubiquitinating enzymes (DUBs) are involved in various cellular activities; however, their role in foam cell formation is not fully understood. Here, using a loss-of-function lipid accumulation screening, we identified ubiquitin-specific peptidase 9 X-linked (USP9X) as a factor that suppressed lipid uptake in macrophages. We found that USP9X expression in lesional macrophages was reduced during atherosclerosis development in both humans and rodents. Atherosclerotic lesions from macrophage USP9X-deficient mice showed increased macrophage infiltration, lipid deposition, and necrotic core content than control apolipoprotein E–KO (Apoe–/–) mice. Additionally, loss-of-function USP9X exacerbated lipid uptake, foam cell formation, and inflammatory responses in macrophages. Mechanistically, the class A1 scavenger receptor (SR-A1) was identified as a USP9X substrate that removed the K63 polyubiquitin chain at the K27 site. Genetic or pharmacological inhibition of USP9X increased SR-A1 cell surface internalization after binding of oxidized LDL (ox-LDL). The K27R mutation of SR-A1 dramatically attenuated basal and USP9X knockdown–induced ox-LDL uptake. Moreover, blocking binding of USP9X to SR-A1 with a cell-penetrating peptide exacerbated foam cell formation and atherosclerosis. In this study, we identified macrophage USP9X as a beneficial regulator of atherosclerosis and revealed the specific mechanisms for the development of potential therapeutic strategies for atherosclerosis.
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Affiliation(s)
- Biqing Wang
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Xuening Tang
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Liu Yao
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Yuxin Wang
- Key Laboratory of Remodeling-Related Cardiovascular Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhipeng Chen
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
| | - Mengqi Li
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Naishi Wu
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Dawei Wu
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Xiangchen Dai
- Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Hongfeng Jiang
- Key Laboratory of Remodeling-Related Cardiovascular Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Ding Ai
- Department of Physiology and Pathophysiology, Tianjin Medical University, Tianjin, China
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5
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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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6
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Cui K, Dong Y, Wang B, Cowan DB, Chan SL, Shyy J, Chen H. Endocytic Adaptors in Cardiovascular Disease. Front Cell Dev Biol 2020; 8:624159. [PMID: 33363178 PMCID: PMC7759532 DOI: 10.3389/fcell.2020.624159] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Endocytosis is the process of actively transporting materials into a cell by membrane engulfment. Traditionally, endocytosis was divided into three forms: phagocytosis (cell eating), pinocytosis (cell drinking), and the more selective receptor-mediated endocytosis (clathrin-mediated endocytosis); however, other important endocytic pathways (e.g., caveolin-dependent endocytosis) contribute to the uptake of extracellular substances. In each, the plasma membrane changes shape to allow the ingestion and internalization of materials, resulting in the formation of an intracellular vesicle. While receptor-mediated endocytosis remains the best understood pathway, mammalian cells utilize each form of endocytosis to respond to their environment. Receptor-mediated endocytosis permits the internalization of cell surface receptors and their ligands through a complex membrane invagination process that is facilitated by clathrin and adaptor proteins. Internalized vesicles containing these receptor-ligand cargoes fuse with early endosomes, which can then be recycled back to the plasma membrane, delivered to other cellular compartments, or destined for degradation by fusing with lysosomes. These intracellular fates are largely determined by the interaction of specific cargoes with adaptor proteins, such as the epsins, disabled-homolog 2 (Dab2), the stonin proteins, epidermal growth factor receptor substrate 15, and adaptor protein 2 (AP-2). In this review, we focus on the role of epsins and Dab2 in controlling these sorting processes in the context of cardiovascular disease. In particular, we will focus on the function of epsins and Dab2 in inflammation, cholesterol metabolism, and their fundamental contribution to atherogenicity.
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Affiliation(s)
- Kui Cui
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - Beibei Wang
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - Douglas B Cowan
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States.,Department of Cardiology, Boston Children's Hospital, Boston, MA, United States
| | - Siu-Lung Chan
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
| | - John Shyy
- Division of Cardiology, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Boston, MA, United States.,Department of Surgery, Harvard Medical School, Boston, MA, United States
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7
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Joseph JG, Osorio C, Yee V, Agrawal A, Liu AP. Complimentary action of structured and unstructured domains of epsin supports clathrin-mediated endocytosis at high tension. Commun Biol 2020; 3:743. [PMID: 33293652 PMCID: PMC7722716 DOI: 10.1038/s42003-020-01471-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
Membrane tension plays an inhibitory role in clathrin-mediated endocytosis (CME) by impeding the transition of flat plasma membrane to hemispherical clathrin-coated structures (CCSs). Membrane tension also impedes the transition of hemispherical domes to omega-shaped CCSs. However, CME is not completely halted in cells under high tension conditions. Here we find that epsin, a membrane bending protein which inserts its N-terminus H0 helix into lipid bilayer, supports flat-to-dome transition of a CCS and stabilizes its curvature at high tension. This discovery is supported by molecular dynamic simulation of the epsin N-terminal homology (ENTH) domain that becomes more structured when embedded in a lipid bilayer. In addition, epsin has an intrinsically disordered protein (IDP) C-terminus domain which induces membrane curvature via steric repulsion. Insertion of H0 helix into lipid bilayer is not sufficient for stable epsin recruitment. Epsin's binding to adaptor protein 2 and clathrin is critical for epsin's association with CCSs under high tension conditions, supporting the importance of multivalent interactions in CCSs. Together, our results support a model where the ENTH and unstructured IDP region of epsin have complementary roles to ensure CME initiation and CCS maturation are unimpeded under high tension environments.
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Affiliation(s)
- Jophin G Joseph
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Carlos Osorio
- Department of Mechanical Engineering, University of Houston, Houston, TX, USA
| | - Vivian Yee
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX, USA
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.
- Department of Biophysics, University of Michigan, Ann Arbor, MI, USA.
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8
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Bhattacharjee S, Lee Y, Zhu B, Wu H, Chen Y, Chen H. Epsins in vascular development, function and disease. Cell Mol Life Sci 2020; 78:833-842. [PMID: 32930806 DOI: 10.1007/s00018-020-03642-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/14/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022]
Abstract
Epsins are a family of adaptor proteins involved in clathrin-dependent endocytosis. In the vasculature, epsins 1 and 2 are functionally redundant members of this family that are expressed in the endothelial cells of blood vessels and the lymphatic system throughout development and adulthood. These proteins contain a number of peptide motifs that allow them to interact with lipid moieties and a variety of proteins. These interactions facilitate the regulation of a wide range of cell signaling pathways. In this review, we focus on the involvement of epsins 1 and 2 in controlling vascular endothelial growth factor receptor signaling in angiogenesis and lymphangiogenesis. We also discuss the therapeutic implications of understanding the molecular mechanisms of epsin-mediated regulation in diseases such as atherosclerosis and diabetes.
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Affiliation(s)
- Sudarshan Bhattacharjee
- Vascular Biology Program, Harvard Medical School, Boston Children's Hospital and Department of Surgery, Boston, MA, 02115, USA
| | - Yang Lee
- Vascular Biology Program, Harvard Medical School, Boston Children's Hospital and Department of Surgery, Boston, MA, 02115, USA
| | - Bo Zhu
- Vascular Biology Program, Harvard Medical School, Boston Children's Hospital and Department of Surgery, Boston, MA, 02115, USA
| | - Hao Wu
- Vascular Biology Program, Harvard Medical School, Boston Children's Hospital and Department of Surgery, Boston, MA, 02115, USA
| | - Yabing Chen
- Department of Pathology, Birmingham Veterans Affairs Medical Center, University of Alabama at Birmingham and Research Department, Birmingham, AL, 35294, USA
| | - Hong Chen
- Vascular Biology Program, Harvard Medical School, Boston Children's Hospital and Department of Surgery, Boston, MA, 02115, USA.
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9
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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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10
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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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11
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Brophy ML, Dong Y, Tao H, Yancey PG, Song K, Zhang K, Wen A, Wu H, Lee Y, Malovichko MV, Sithu SD, Wong S, Yu L, Kocher O, Bischoff J, Srivastava S, Linton MF, Ley K, Chen H. Myeloid-Specific Deletion of Epsins 1 and 2 Reduces Atherosclerosis by Preventing LRP-1 Downregulation. Circ Res 2019; 124:e6-e19. [PMID: 30595089 DOI: 10.1161/circresaha.118.313028] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE Atherosclerosis is, in part, caused by immune and inflammatory cell infiltration into the vascular wall, leading to enhanced inflammation and lipid accumulation in the aortic endothelium. Understanding the molecular mechanisms underlying this disease is critical for the development of new therapies. Our recent studies demonstrate that epsins, a family of ubiquitin-binding endocytic adaptors, are critical regulators of atherogenicity. Given the fundamental contribution lesion macrophages make to fuel atherosclerosis, whether and how myeloid-specific epsins promote atherogenesis is an open and significant question. OBJECTIVE We will determine the role of myeloid-specific epsins in regulating lesion macrophage function during atherosclerosis. METHODS AND RESULTS We engineered myeloid cell-specific epsins double knockout mice (LysM-DKO) on an ApoE-/- background. On Western diet, these mice exhibited marked decrease in atherosclerotic lesion formation, diminished immune and inflammatory cell content in aortas, and reduced necrotic core content but increased smooth muscle cell content in aortic root sections. Epsins deficiency hindered foam cell formation and suppressed proinflammatory macrophage phenotype but increased efferocytosis and anti-inflammatory macrophage phenotype in primary macrophages. Mechanistically, we show that epsin loss specifically increased total and surface levels of LRP-1 (LDLR [low-density lipoprotein receptor]-related protein 1), an efferocytosis receptor with antiatherosclerotic properties. We further show that epsin and LRP-1 interact via epsin's ubiquitin-interacting motif domain. ox-LDL (oxidized LDL) treatment increased LRP-1 ubiquitination, subsequent binding to epsin, and its internalization from the cell surface, suggesting that epsins promote the ubiquitin-dependent internalization and downregulation of LRP-1. Crossing ApoE-/-/LysM-DKO mice onto an LRP-1 heterozygous background restored, in part, atherosclerosis, suggesting that epsin-mediated LRP-1 downregulation in macrophages plays a pivotal role in propelling atherogenesis. CONCLUSIONS Myeloid epsins promote atherogenesis by facilitating proinflammatory macrophage recruitment and inhibiting efferocytosis in part by downregulating LRP-1, implicating that targeting epsins in macrophages may serve as a novel therapeutic strategy to treat atherosclerosis.
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Affiliation(s)
- Megan L Brophy
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA.,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center (M.L.B.)
| | - Yunzhou Dong
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Huan Tao
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (H.T., P.G.Y., M.F.L.)
| | - Patricia G Yancey
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (H.T., P.G.Y., M.F.L.)
| | - Kai Song
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Kun Zhang
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA.,Department of Cardiology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China (K.Z.)
| | - Aiyun Wen
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Hao Wu
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Yang Lee
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Marina V Malovichko
- Division of Cardiovascular Medicine, Department of Medicine, University of Louisville, KY (M.V.M., S.D.S., S.S.)
| | - Srinivas D Sithu
- Division of Cardiovascular Medicine, Department of Medicine, University of Louisville, KY (M.V.M., S.D.S., S.S.)
| | - Scott Wong
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Lili Yu
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Olivier Kocher
- Department of Pathology and Center for Vascular Biology Research, Beth Israel Medical Deaconess Medical Center (O.K.), Harvard Medical School, MA
| | - Joyce Bischoff
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
| | - Sanjay Srivastava
- Division of Cardiovascular Medicine, Department of Medicine, University of Louisville, KY (M.V.M., S.D.S., S.S.)
| | - MacRae F Linton
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (H.T., P.G.Y., M.F.L.)
| | - Klaus Ley
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, CA (K.L.)
| | - Hong Chen
- From the Vascular Biology Program and Department of Surgery, Boston Children's Hospital (M.L.B., Y.D., K.S., K.Z., A.W., H.W., Y.L., S.W., L.Y., J.B., H.C.), Harvard Medical School, MA
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12
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Traub LM. A nanobody-based molecular toolkit provides new mechanistic insight into clathrin-coat initiation. eLife 2019; 8:41768. [PMID: 31038455 PMCID: PMC6524969 DOI: 10.7554/elife.41768] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 04/24/2019] [Indexed: 12/21/2022] Open
Abstract
Besides AP-2 and clathrin triskelia, clathrin coat inception depends on a group of early-arriving proteins including Fcho1/2 and Eps15/R. Using genome-edited cells, we described the role of the unstructured Fcho linker in stable AP-2 membrane deposition. Here, expanding this strategy in combination with a new set of llama nanobodies against EPS15 shows an FCHO1/2–EPS15/R partnership plays a decisive role in coat initiation. A nanobody containing an Asn-Pro-Phe peptide within the complementarity-determining region 3 loop is a function-blocking pseudoligand for tandem EPS15/R EH domains. Yet, in living cells, EH domains gathered at clathrin-coated structures are poorly accessible, indicating residence by endogenous NPF-bearing partners. Forcibly sequestering cytosolic EPS15 in genome-edited cells with nanobodies tethered to early endosomes or mitochondria changes the subcellular location and availability of EPS15. This combined approach has strong effects on clathrin coat structure and function by dictating the stability of AP-2 assemblies at the plasma membrane.
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Affiliation(s)
- Linton M Traub
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, United States
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13
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Wu H, Rahman HA, Dong Y, Liu X, Lee Y, Wen A, To KH, Xiao L, Birsner AE, Bazinet L, Wong S, Song K, Brophy ML, Mahamud MR, Chang B, Cai X, Pasula S, Kwak S, Yang W, Bischoff J, Xu J, Bielenberg DR, Dixon JB, D’Amato RJ, Srinivasan RS, Chen H. Epsin deficiency promotes lymphangiogenesis through regulation of VEGFR3 degradation in diabetes. J Clin Invest 2018; 128:4025-4043. [PMID: 30102256 PMCID: PMC6118634 DOI: 10.1172/jci96063] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 06/26/2018] [Indexed: 12/18/2022] Open
Abstract
Impaired lymphangiogenesis is a complication of chronic complex diseases, including diabetes. VEGF-C/VEGFR3 signaling promotes lymphangiogenesis, but how this pathway is affected in diabetes remains poorly understood. We previously demonstrated that loss of epsins 1 and 2 in lymphatic endothelial cells (LECs) prevented VEGF-C-induced VEGFR3 from endocytosis and degradation. Here, we report that diabetes attenuated VEGF-C-induced lymphangiogenesis in corneal micropocket and Matrigel plug assays in WT mice but not in mice with inducible lymphatic-specific deficiency of epsins 1 and 2 (LEC-iDKO). Consistently, LECs isolated from diabetic LEC-iDKO mice elevated in vitro proliferation, migration, and tube formation in response to VEGF-C over diabetic WT mice. Mechanistically, ROS produced in diabetes induced c-Src-dependent but VEGF-C-independent VEGFR3 phosphorylation, and upregulated epsins through the activation of transcription factor AP-1. Augmented epsins bound to and promoted degradation of newly synthesized VEGFR3 in the Golgi, resulting in reduced availability of VEGFR3 at the cell surface. Preclinically, the loss of lymphatic-specific epsins alleviated insufficient lymphangiogenesis and accelerated the resolution of tail edema in diabetic mice. Collectively, our studies indicate that inhibiting expression of epsins in diabetes protects VEGFR3 against degradation and ameliorates diabetes-triggered inhibition of lymphangiogenesis, thereby providing a novel potential therapeutic strategy to treat diabetic complications.
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Affiliation(s)
- Hao Wu
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - H.N. Ashiqur Rahman
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Yunzhou Dong
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Xiaolei Liu
- Center for Vascular and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yang Lee
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Aiyun Wen
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Kim H.T. To
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Li Xiao
- Department of Nephrology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Amy E. Birsner
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Lauren Bazinet
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Scott Wong
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Kai Song
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Megan L. Brophy
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, USA
| | - M. Riaj Mahamud
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Baojun Chang
- Vascular Medicine Institute, Pulmonary, Allergy and Critical Care Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Xiaofeng Cai
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Satish Pasula
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Sukyoung Kwak
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Wenxia Yang
- Department of Nephrology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Joyce Bischoff
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Jian Xu
- Department of Medicine, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma, USA
| | - Diane R. Bielenberg
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - J. Brandon Dixon
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Robert J. D’Amato
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - R. Sathish Srinivasan
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Hong Chen
- Vascular Biology Program, Harvard Medical School, Boston Children’s Hospital, Boston, Massachusetts, USA
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14
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Cheng X, Zheng J, Li G, Göbel V, Zhang H. Degradation for better survival? Role of ubiquitination in epithelial morphogenesis. Biol Rev Camb Philos Soc 2018; 93:1438-1460. [PMID: 29493067 DOI: 10.1111/brv.12404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 01/31/2018] [Accepted: 02/05/2018] [Indexed: 02/06/2023]
Abstract
As a prevalent post-translational modification, ubiquitination is essential for many developmental processes. Once covalently attached to the small and conserved polypeptide ubiquitin (Ub), a substrate protein can be directed to perform specific biological functions via its Ub-modified form. Three sequential catalytic reactions contribute to this process, among which E3 ligases serve to identify target substrates and promote the activated Ub to conjugate to substrate proteins. Ubiquitination has great plasticity, with diverse numbers, topologies and modifications of Ub chains conjugated at different substrate residues adding a layer of complexity that facilitates a huge range of cellular functions. Herein, we highlight key advances in the understanding of ubiquitination in epithelial morphogenesis, with an emphasis on the latest insights into its roles in cellular events involved in polarized epithelial tissue, including cell adhesion, asymmetric localization of polarity determinants and cytoskeletal organization. In addition, the physiological roles of ubiquitination are discussed for typical examples of epithelial morphogenesis, such as lung branching, vascular development and synaptic formation and plasticity. Our increased understanding of ubiquitination in epithelial morphogenesis may provide novel insights into the molecular mechanisms underlying epithelial regeneration and maintenance.
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Affiliation(s)
- Xiaoxiang Cheng
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China
| | - Jun Zheng
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China
| | - Gang Li
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China
| | - Verena Göbel
- Department of Pediatrics, Mucosal Immunology and Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114,, U.S.A
| | - Hongjie Zhang
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau 999078, China
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15
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Dong Y, Wu H, Dong J, Song K, Rahman HA, Towner R, Chen H. Mimetic peptide of ubiquitin-interacting motif of epsin as a cancer therapeutic-perspective in brain tumor therapy through regulating VEGFR2 signaling. VESSEL PLUS 2017; 1:3-11. [PMID: 29905336 PMCID: PMC5997290 DOI: 10.20517/2574-1209.2016.01] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Epsins, endocytic adaptor proteins required for internalization of ubiquitylated receptors, are generally upregulated in human cancers. It has been characterized that mice deficient of epsins in the endothelium inhibit tumor growth by dysregulating vascular endothelial growth factor receptor-2 (VEGFR2) signaling and non-productive tumor angiogenesis. Binding of the epsin ubiquitin (Ub)-interacting motif (UIM) with ubiquitylated VEGFR2 is a critical mechanism for epsin-dependent VEGFR2 endocytosis and degradation, indicative of epsin UIM as a potential therapeutic target. A Computer Assisted Drug Design approach was utilized to create the UIM mimetic peptides for the functional competition of epsin binding sites in ubiquitylated VEGFR2 in vivo. Specifically targeting VEGFR2 in the tumor vasculature, the chemically synthesized chimeric UIM peptide, UPI, causes non-functional tumor angiogenesis, retards tumor growth, and increases survival rates in several tumor models. The authors showed that UPI binds ubiquitylated VEGFR2 to form a supercomplex in an Ub-dependent fashion. Collectively, the UPI targeting strategy offers a potentially novel treatment for cancer patients who are resistant to current anti-angiogenic therapies. In this review, the authors outline the main points of this research specifically as a potential application for glioma tumor therapy.
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Affiliation(s)
- Yunzhou Dong
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hao Wu
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jerry Dong
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Kai Song
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Habibunnabi Ashiqur Rahman
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Hong Chen
- Vascular Biology Program, Department of Surgery, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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16
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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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17
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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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18
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Kalaidzidis I, Miaczynska M, Brewińska-Olchowik M, Hupalowska A, Ferguson C, Parton RG, Kalaidzidis Y, Zerial M. APPL endosomes are not obligatory endocytic intermediates but act as stable cargo-sorting compartments. J Cell Biol 2016; 211:123-44. [PMID: 26459602 PMCID: PMC4602042 DOI: 10.1083/jcb.201311117] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Endocytosis allows cargo to enter a series of specialized endosomal compartments, beginning with early endosomes harboring Rab5 and its effector EEA1. There are, however, additional structures labeled by the Rab5 effector APPL1 whose role in endocytic transport remains unclear. It has been proposed that APPL1 vesicles are transport intermediates that convert into EEA1 endosomes. Here, we tested this model by analyzing the ultrastructural morphology, kinetics of cargo transport, and stability of the APPL1 compartment over time. We found that APPL1 resides on a tubulo-vesicular compartment that is capable of sorting cargo for recycling or degradation and that displays long lifetimes, all features typical of early endosomes. Fitting mathematical models to experimental data rules out maturation of APPL1 vesicles into EEA1 endosomes as a primary mechanism for cargo transport. Our data suggest instead that APPL1 endosomes represent a distinct population of Rab5-positive sorting endosomes, thus providing important insights into the compartmental organization of the early endocytic pathway.
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Affiliation(s)
- Inna Kalaidzidis
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Marta Miaczynska
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Marta Brewińska-Olchowik
- International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Anna Hupalowska
- International Institute of Molecular and Cell Biology, 02-109 Warsaw, Poland
| | - Charles Ferguson
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, University of Queensland St. Lucia, Brisbane, Australia 4072
| | - Robert G Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, University of Queensland St. Lucia, Brisbane, Australia 4072
| | - Yannis Kalaidzidis
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Marino Zerial
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
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19
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Cell Adhesion Molecules and Ubiquitination-Functions and Significance. BIOLOGY 2015; 5:biology5010001. [PMID: 26703751 PMCID: PMC4810158 DOI: 10.3390/biology5010001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/02/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system.
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20
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Dong Y, Wu H, Rahman HNA, Liu Y, Pasula S, Tessneer KL, Cai X, Liu X, Chang B, McManus J, Hahn S, Dong J, Brophy ML, Yu L, Song K, Silasi-Mansat R, Saunders D, Njoku C, Song H, Mehta-D'Souza P, Towner R, Lupu F, McEver RP, Xia L, Boerboom D, Srinivasan RS, Chen H. Motif mimetic of epsin perturbs tumor growth and metastasis. J Clin Invest 2015; 125:4349-64. [PMID: 26571402 DOI: 10.1172/jci80349] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 08/06/2015] [Indexed: 12/14/2022] Open
Abstract
Tumor angiogenesis is critical for cancer progression. In multiple murine models, endothelium-specific epsin deficiency abrogates tumor progression by shifting the balance of VEGFR2 signaling toward uncontrolled tumor angiogenesis, resulting in dysfunctional tumor vasculature. Here, we designed a tumor endothelium-targeting chimeric peptide (UPI) for the purpose of inhibiting endogenous tumor endothelial epsins by competitively binding activated VEGFR2. We determined that the UPI peptide specifically targets tumor endothelial VEGFR2 through an unconventional binding mechanism that is driven by unique residues present only in the epsin ubiquitin-interacting motif (UIM) and the VEGFR2 kinase domain. In murine models of neoangiogenesis, UPI peptide increased VEGF-driven angiogenesis and neovascularization but spared quiescent vascular beds. Further, in tumor-bearing mice, UPI peptide markedly impaired functional tumor angiogenesis, tumor growth, and metastasis, resulting in a notable increase in survival. Coadministration of UPI peptide with cytotoxic chemotherapeutics further sustained tumor inhibition. Equipped with localized tumor endothelium-specific targeting, our UPI peptide provides potential for an effective and alternative cancer therapy.
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MESH Headings
- Adaptor Proteins, Vesicular Transport/genetics
- Adaptor Proteins, Vesicular Transport/metabolism
- Adaptor Proteins, Vesicular Transport/pharmacology
- Amino Acid Motifs
- Animals
- Mice
- Mice, Knockout
- Neoplasm Metastasis
- Neoplasms, Experimental/blood supply
- Neoplasms, Experimental/drug therapy
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Neovascularization, Pathologic/drug therapy
- Neovascularization, Pathologic/genetics
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/pathology
- Peptides/genetics
- Peptides/metabolism
- Peptides/pharmacology
- Protein Structure, Tertiary
- Vascular Endothelial Growth Factor Receptor-2/genetics
- Vascular Endothelial Growth Factor Receptor-2/metabolism
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21
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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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22
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Liu X, Pasula S, Song H, Tessneer KL, Dong Y, Hahn S, Yago T, Brophy ML, Chang B, Cai X, Wu H, McManus J, Ichise H, Georgescu C, Wren JD, Griffin C, Xia L, Srinivasan RS, Chen H. Temporal and spatial regulation of epsin abundance and VEGFR3 signaling are required for lymphatic valve formation and function. Sci Signal 2014; 7:ra97. [PMID: 25314967 DOI: 10.1126/scisignal.2005413] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Lymphatic valves prevent the backflow of the lymph fluid and ensure proper lymphatic drainage throughout the body. Local accumulation of lymphatic fluid in tissues, a condition called lymphedema, is common in individuals with malformed lymphatic valves. The vascular endothelial growth factor receptor 3 (VEGFR3) is required for the development of lymphatic vascular system. The abundance of VEGFR3 in collecting lymphatic trunks is high before valve formation and, except at valve regions, decreases after valve formation. We found that in mesenteric lymphatics, the abundance of epsin 1 and 2, which are ubiquitin-binding adaptor proteins involved in endocytosis, was low at early stages of development. After lymphatic valve formation, the initiation of steady shear flow was associated with an increase in the abundance of epsin 1 and 2 in collecting lymphatic trunks, but not in valve regions. Epsin 1 and 2 bound to VEGFR3 and mediated the internalization and degradation of VEGFR3, resulting in termination of VEGFR3 signaling. Mice with lymphatic endothelial cell-specific deficiency of epsin 1 and 2 had dilated lymphatic capillaries, abnormally high VEGFR3 abundance in collecting lymphatics, immature lymphatic valves, and defective lymph drainage. Deletion of a single Vegfr3 allele or pharmacological suppression of VEGFR3 signaling restored normal lymphatic valve development and lymph drainage in epsin-deficient mice. Our findings establish a critical role for epsins in the temporal and spatial regulation of VEGFR3 abundance and signaling in collecting lymphatic trunks during lymphatic valve formation.
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Affiliation(s)
- Xiaolei Liu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA. Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA
| | - Satish Pasula
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Hoogeun Song
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Kandice L Tessneer
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Yunzhou Dong
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Scott Hahn
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Tadayuki Yago
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Megan L Brophy
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA. Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA
| | - Baojun Chang
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Xiaofeng Cai
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Hao Wu
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - John McManus
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Hirotake Ichise
- Laboratory of Developmental Genetics, Center for Experimental Medicine and Systems Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Constantin Georgescu
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Jonathan D Wren
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA. Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Courtney Griffin
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA. Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, OK 73126, USA
| | - Lijun Xia
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA. Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA
| | - R Sathish Srinivasan
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA
| | - Hong Chen
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma, OK 73104, USA. Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA.
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23
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Gucwa AL, Brown DA. UIM domain-dependent recruitment of the endocytic adaptor protein Eps15 to ubiquitin-enriched endosomes. BMC Cell Biol 2014; 15:34. [PMID: 25260758 PMCID: PMC4181756 DOI: 10.1186/1471-2121-15-34] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 09/22/2014] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Eps15 is an endocytic adaptor protein that stimulates clathrin-mediated endocytosis. Among other interactions, Eps15 binds ubiquitin via UIM domains, recruiting ubiquitinated cargo into clathrin-coated vesicles. In EGF-treated cells, Eps15 also localizes to endosomes. The basis of this localization is not known. RESULTS We show that accumulation of ubiquitinated cargo can recruit Eps15 to endosomes via UIM domain interactions. First, treatment of SK-Br-3 breast cancer cells, which overexpress the EGFR family member ErbB2, with geldanamycin to promote receptor ubiquitination and endosomal transport, recruited FLAG-Eps15 to endosomes. Two in-frame ubiquitin constructs, PM-GFP-Ub (retained in endosomes after endocytosis), and GFP-FYVE-UbΔGG (targeted directly to endosomes) also recruited Eps15 to endosomes, as did slowing endosome maturation with constitutively-active Rab5-Q79L. Endosomal recruitment required the UIM domains, but not the N-terminal EH domains or central coiled-coil domains, of Eps15. Silencing of the endosomal Eps15 binding partner Hrs did not affect recruitment of Eps15 to ubiquitin-enriched endosomes. In fact, Hrs silencing itself modestly recruited Eps15 to endosomes, probably by accumulating endogenous ubiquitinated cargo. Eps15 silencing did not affect lysosomal degradation of ubiquitinated ErbB2; however, GFP-FYVE-UbΔGG overexpression inhibited internalization of EGFR and transferrin receptor. CONCLUSIONS We show for the first time that ubiquitin is sufficient for Eps15 recruitment to endosomes. We speculate that Eps15 recruitment to ubiquitin-rich endosomes may reduce the level of Eps15 at the plasma membrane, slowing endocytosis to allow time for processing of ubiquitinated cargo in endosomes.
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Affiliation(s)
- Azad L Gucwa
- Department of Biomedical Sciences, Long Island University at Post, Brookville, NY 11548-1300, USA.
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24
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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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25
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Lin A, Man HY. Endocytic adaptor epidermal growth factor receptor substrate 15 (Eps15) is involved in the trafficking of ubiquitinated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. J Biol Chem 2014; 289:24652-64. [PMID: 25023288 DOI: 10.1074/jbc.m114.582114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMPA-type glutamate receptors (AMPARs) play a critical role in mediating fast excitatory synaptic transmission in the brain. Alterations in receptor expression, distribution, and trafficking have been shown to underlie synaptic plasticity and higher brain functions, including learning and memory, as well as brain dysfunctions such as drug addiction and psychological disorders. Therefore, it is essential to elucidate the molecular mechanisms that regulate AMPAR dynamics. We have shown previously that mammalian AMPARs are subject to posttranslational modification by ubiquitin, with AMPAR ubiquitination enhancing receptor internalization and reducing AMPAR cell surface expression. Here we report a crucial role for epidermal growth factor receptor substrate 15 (Eps15), an endocytic adaptor, in ubiquitination-dependent AMPAR internalization. We find that suppression or overexpression of Eps15 results in changes in AMPAR surface expression. Eps15 interacts with AMPARs, which requires Nedd4-mediated GluA1 ubiquitination and the ubiquitin-interacting motif of Eps15. Importantly, we find that Eps15 plays an important role in AMPAR internalization. Knockdown of Eps15 suppresses the internalization of GluA1 but not the mutant GluA1 that lacks ubiquitination sites, indicating a role of Eps15 for the internalization of ubiquitinated AMPARs. These results reveal a novel molecular mechanism employed specifically for the trafficking of the ubiquitin-modified AMPARs.
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Affiliation(s)
- Amy Lin
- From the Department of Biology, Boston University, Boston, Massachusetts 02215
| | - Heng-Ye Man
- From the Department of Biology, Boston University, Boston, Massachusetts 02215
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26
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Chandrasekaran P, Moore V, Buckley M, Spurrier J, Kehrl JH, Venkatesan S. HIV-1 Nef down-modulates C-C and C-X-C chemokine receptors via ubiquitin and ubiquitin-independent mechanism. PLoS One 2014; 9:e86998. [PMID: 24489825 PMCID: PMC3906104 DOI: 10.1371/journal.pone.0086998] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 12/16/2013] [Indexed: 12/29/2022] Open
Abstract
Human and Simian Immunodeficiency virus (HIV-1, HIV-2, and SIV) encode an accessory protein, Nef, which is a pathogenesis and virulence factor. Nef is a multivalent adapter that dysregulates the trafficking of many immune cell receptors, including chemokine receptors (CKRs). Physiological endocytic itinerary of agonist occupied CXCR4 involves ubiquitinylation of the phosphorylated receptor at three critical lysine residues and dynamin-dependent trafficking through the ESCRT pathway into lysosomes for degradation. Likewise, Nef induced CXCR4 degradation was critically dependent on the three lysines in the C-terminal -SSLKILSKGK- motif. Nef directly recruits the HECT domain E3 ligases AIP4 or NEDD4 to CXCR4 in the resting state. This mechanism was confirmed by ternary interactions of Nef, CXCR4 and AIP4 or NEDD4; by reversal of Nef effect by expression of catalytically inactive AIP4-C830A mutant; and siRNA knockdown of AIP4, NEDD4 or some ESCRT-0 adapters. However, ubiquitinylation dependent lysosomal degradation was not the only mechanism by which Nef downregulated CKRs. Agonist and Nef mediated CXCR2 (and CXCR1) degradation was ubiquitinylation independent. Nef also profoundly downregulated the naturally truncated CXCR4 associated with WHIM syndrome and engineered variants of CXCR4 that resist CXCL12 induced internalization via an ubiquitinylation independent mechanism.
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Affiliation(s)
- Prabha Chandrasekaran
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Victoria Moore
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Monica Buckley
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Joshua Spurrier
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John H. Kehrl
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sundararajan Venkatesan
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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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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Role of FAAH-like anandamide transporter in anandamide inactivation. PLoS One 2013; 8:e79355. [PMID: 24223930 PMCID: PMC3817039 DOI: 10.1371/journal.pone.0079355] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/30/2013] [Indexed: 11/19/2022] Open
Abstract
The endocannabinoid system modulates numerous physiological processes including nociception and reproduction. Anandamide (AEA) is an endocannabinoid that is inactivated by cellular uptake followed by intracellular hydrolysis by fatty acid amide hydrolase (FAAH). Recently, FAAH-like anandamide transporter (FLAT), a truncated and catalytically-inactive variant of FAAH, was proposed to function as an intracellular AEA carrier and mediate its delivery to FAAH for hydrolysis. Pharmacological inhibition of FLAT potentiated AEA signaling and produced antinociceptive effects. Given that endocannabinoids produce analgesia through central and peripheral mechanisms, the goal of the current work was to examine the expression of FLAT in the central and peripheral nervous systems. In contrast to the original report characterizing FLAT, expression of FLAT was not observed in any of the tissues examined. To investigate the role of FLAT as a putative AEA binding protein, FLAT was generated from FAAH using polymerase chain reaction and further analyzed. Despite its low cellular expression, FLAT displayed residual catalytic activity that was sensitive to FAAH inhibitors and abolished following mutation of its catalytic serine. Overexpression of FLAT potentiated AEA cellular uptake and this appeared to be dependent upon its catalytic activity. Immunofluorescence revealed that FLAT localizes primarily to intracellular membranes and does not contact the plasma membrane, suggesting that its capability to potentiate AEA uptake may stem from its enzymatic rather than transport activity. Collectively, our data demonstrate that FLAT does not serve as a global intracellular AEA carrier, although a role in mediating localized AEA inactivation in mammalian tissues cannot be ruled out.
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29
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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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30
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Zhang L, Xu M, Scotti E, Chen ZJ, Tontonoz P. Both K63 and K48 ubiquitin linkages signal lysosomal degradation of the LDL receptor. J Lipid Res 2013; 54:1410-20. [PMID: 23419260 PMCID: PMC3653405 DOI: 10.1194/jlr.m035774] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Linkage-specific ubiquitination often leads to distinct cellular events. It has been difficult to establish definitively the requirement for a particular linkage in mammalian degradation pathways due to the inability to deplete endogenous ubiquitin while maintaining cell viability. The E3 ubiquitin ligase inducible degrader of the LDL receptor (IDOL) targets the low density lipoprotein receptor (LDLR) for degradation. The nature of the linkages employed to signal lysosomal degradation of the LDLR, and to signal proteasomal autodegradation of IDOL, have not been determined. We used an inducible RNAi strategy to replace endogenous ubiquitin with mutants lacking K48 or K63. We found that IDOL catalyzes the transfer of ubiquitin chains to itself and to the LDLR that do not contain exclusively K48 or K63 linkages. Thus, LDLR can be targeted to the lysosome by either K48 or K63 linkages. We further demonstrate that although both ubiquitin conjugating enzyme E2 (UBE2)Ds and UBE2N/V1 can catalyze LDLR ubiquitination in a cell-free system, UBE2Ds appear to be the major E2 enzymes employed by IDOL in cells, consistent with their ability to catalyze both K48 and K63 linkages. The results reveal mechanistic insight into the posttranscriptional control of lipoprotein uptake and provide a test of the requirement of linkage-specific ubiquitination for specific lysosomal and proteasomal degradation pathways in mammalian cells.
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Affiliation(s)
- Li Zhang
- Howard Hughes Medical Institute and Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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31
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IDOL stimulates clathrin-independent endocytosis and multivesicular body-mediated lysosomal degradation of the low-density lipoprotein receptor. Mol Cell Biol 2013; 33:1503-14. [PMID: 23382078 DOI: 10.1128/mcb.01716-12] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The low-density lipoprotein receptor (LDLR) is a critical determinant of plasma cholesterol levels that internalizes lipoprotein cargo via clathrin-mediated endocytosis. Here, we show that the E3 ubiquitin ligase IDOL stimulates a previously unrecognized, clathrin-independent pathway for LDLR internalization. Real-time single-particle tracking and electron microscopy reveal that IDOL is recruited to the plasma membrane by LDLR, promotes LDLR internalization in the absence of clathrin or caveolae, and facilitates LDLR degradation by shuttling it into the multivesicular body (MVB) protein-sorting pathway. The IDOL-dependent degradation pathway is distinct from that mediated by PCSK9 as only IDOL employs ESCRT (endosomal-sorting complex required for transport) complexes to recognize and traffic LDLR to lysosomes. Small interfering RNA (siRNA)-mediated knockdown of ESCRT-0 (HGS) or ESCRT-I (TSG101) components prevents IDOL-mediated LDLR degradation. We further show that USP8 acts downstream of IDOL to deubiquitinate LDLR and that USP8 is required for LDLR entry into the MVB pathway. These results provide key mechanistic insights into an evolutionarily conserved pathway for the control of lipoprotein receptor expression and cellular lipid uptake.
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32
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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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33
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Abstract
As an obligate pathogen, influenza virus requires host cell factors and compartments to mediate productive infection and to produce infectious progeny virus. Recently, several small interfering RNA (siRNA) knockdown screens revealed influenza virus host dependency proteins, all of which identified at least two subunits of the coat protein I (COPI) complex. COPI proteins oligomerize to form coated vesicles that transport contents between the Golgi apparatus and the endoplasmic reticulum, and they have also been reported to mediate endosomal trafficking. However, it remains unclear which steps in the influenza virus infection cycle rely on the COPI complex. Upon systematic dissection of the influenza virus infection cycle, from entry to progeny virion production, we found that prolonged exposure to COPI complex disruption through siRNA depletion resulted in significant defects in virus internalization and trafficking to late endosomes. Acute inhibition of COPI complex recruitment to the Golgi apparatus with pharmacological compounds failed to recapitulate the same entry defects as observed with the COPI-depleted cells but did result in specific decreases in viral membrane protein expression and assembly, leading to defects in progeny virion production. Taken together, our findings suggest that COPI complexes likely function indirectly in influenza virus entry but play direct roles in viral membrane protein expression and assembly.
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34
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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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35
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Dong N, Zhu Y, Lu Q, Hu L, Zheng Y, Shao F. Structurally distinct bacterial TBC-like GAPs link Arf GTPase to Rab1 inactivation to counteract host defenses. Cell 2012; 150:1029-41. [PMID: 22939626 DOI: 10.1016/j.cell.2012.06.050] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 02/15/2012] [Accepted: 06/29/2012] [Indexed: 11/25/2022]
Abstract
Rab GTPases are frequent targets of vacuole-living bacterial pathogens for appropriate trafficking of the vacuole. Here we discover that bacterial effectors including VirA from nonvacuole Shigella flexneri and EspG from extracellular Enteropathogenic Escherichia coli (EPEC) harbor TBC-like dual-finger motifs and exhibits potent RabGAP activities. Specific inactivation of Rab1 by VirA/EspG disrupts ER-to-Golgi trafficking. S. flexneri intracellular persistence requires VirA TBC-like GAP activity that mediates bacterial escape from autophagy-mediated host defense. Rab1 inactivation by EspG severely blocks host secretory pathway, resulting in inhibited interleukin-8 secretion from infected cells. Crystal structures of VirA/EspG-Rab1-GDP-aluminum fluoride complexes highlight TBC-like catalytic role for the arginine and glutamine finger residues and reveal a 3D architecture distinct from that of the TBC domain. Structure of Arf6-EspG-Rab1 ternary complex illustrates a pathogenic signaling complex that rewires host Arf signaling to Rab1 inactivation. Structural distinctions of VirA/EspG further predict a possible extensive presence of TBC-like RabGAP effectors in counteracting various host defenses.
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Affiliation(s)
- Na Dong
- National Institute of Biological Sciences, Beijing 102206, China
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36
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Scheuring D, Künzl F, Viotti C, Yan MSW, Jiang L, Schellmann S, Robinson DG, Pimpl P. Ubiquitin initiates sorting of Golgi and plasma membrane proteins into the vacuolar degradation pathway. BMC PLANT BIOLOGY 2012; 12:164. [PMID: 22970698 PMCID: PMC3534617 DOI: 10.1186/1471-2229-12-164] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 07/13/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND In yeast and mammals, many plasma membrane (PM) proteins destined for degradation are tagged with ubiquitin. These ubiquitinated proteins are internalized into clathrin-coated vesicles and are transported to early endosomal compartments. There, ubiquitinated proteins are sorted by the endosomal sorting complex required for transport (ESCRT) machinery into the intraluminal vesicles of multivesicular endosomes. Degradation of these proteins occurs after endosomes fuse with lysosomes/lytic vacuoles to release their content into the lumen. In plants, some PM proteins, which cycle between the PM and endosomal compartments, have been found to be ubiquitinated, but it is unclear whether ubiquitin is sufficient to mediate internalization and thus acts as a primary sorting signal for the endocytic pathway. To test whether plants use ubiquitin as a signal for the degradation of membrane proteins, we have translationally fused ubiquitin to different fluorescent reporters for the plasma membrane and analyzed their transport. RESULTS Ubiquitin-tagged PM reporters localized to endosomes and to the lumen of the lytic vacuole in tobacco mesophyll protoplasts and in tobacco epidermal cells. The internalization of these reporters was significantly reduced if clathrin-mediated endocytosis was inhibited by the coexpression of a mutant of the clathrin heavy chain, the clathrin hub. Surprisingly, a ubiquitin-tagged reporter for the Golgi was also transported into the lumen of the vacuole. Vacuolar delivery of the reporters was abolished upon inhibition of the ESCRT machinery, indicating that the vacuolar delivery of these reporters occurs via the endocytic transport route. CONCLUSIONS Ubiquitin acts as a sorting signal at different compartments in the endomembrane system to target membrane proteins into the vacuolar degradation pathway: If displayed at the PM, ubiquitin triggers internalization of PM reporters into the endocytic transport route, but it also mediates vacuolar delivery if displayed at the Golgi. In both cases, ubiquitin-tagged proteins travel via early endosomes and multivesicular bodies to the lytic vacuole. This suggests that vacuolar degradation of ubiquitinated proteins is not restricted to PM proteins but might also facilitate the turnover of membrane proteins in the early secretory pathway.
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Affiliation(s)
- David Scheuring
- Department of Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, 69120, Germany
| | - Fabian Künzl
- Department of Developmental Genetics, Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, 72076, Germany
| | - Corrado Viotti
- Department of Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, 69120, Germany
- Plant Developmental Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, 69120, Germany
| | - Melody San Wan Yan
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin NT, Hong Kong, PR China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin NT, Hong Kong, PR China
| | - Swen Schellmann
- Botanical Institute, Biozentrum Köln, University of Cologne, Cologne, 50674, Germany
| | - David G Robinson
- Department of Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, 69120, Germany
| | - Peter Pimpl
- Department of Developmental Genetics, Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, 72076, Germany
- Department of Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, 69120, Germany
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Guo J, Wang T, Li X, Shallow H, Yang T, Li W, Xu J, Fridman MD, Yang X, Zhang S. Cell surface expression of human ether-a-go-go-related gene (hERG) channels is regulated by caveolin-3 protein via the ubiquitin ligase Nedd4-2. J Biol Chem 2012; 287:33132-41. [PMID: 22879586 DOI: 10.1074/jbc.m112.389643] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The human ether-a-go-go-related gene (hERG) encodes the rapidly activating delayed rectifier potassium channel (I(Kr)) which plays an important role in cardiac repolarization. A reduction or increase in hERG current can cause long or short QT syndrome, respectively, leading to fatal cardiac arrhythmias. The channel density in the plasma membrane is a key determinant of the whole cell current amplitude. To gain insight into the molecular mechanisms for the regulation of hERG density at the plasma membrane, we used whole cell voltage clamp, Western blotting, and immunocytochemical methods to investigate the effects of an integral membrane protein, caveolin-3 (Cav3) on hERG expression levels. Our data demonstrate that Cav3, hERG, and ubiquitin-ligase Nedd4-2 interact with each other and form a complex. Expression of Cav3 thus enhances the hERG-Nedd4-2 interaction, leading to an increased ubiquitination and degradation of mature, plasma-membrane localized hERG channels. Disrupting Nedd4-2 interaction with hERG by mutations eliminates the effects of Cav3 on hERG channels. Knockdown of endogenous Cav3 or Nedd4-2 in cultured neonatal rat ventricular myocytes using siRNA led to an increase in native I(Kr). Our data demonstrate that hERG expression in the plasma membrane is regulated by Cav3 via Nedd4-2. These findings extend our understanding of the regulation of hERG channels and cardiac electrophysiology.
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Affiliation(s)
- Jun Guo
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
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Schubert KO, Föcking M, Prehn JHM, Cotter DR. Hypothesis review: are clathrin-mediated endocytosis and clathrin-dependent membrane and protein trafficking core pathophysiological processes in schizophrenia and bipolar disorder? Mol Psychiatry 2012; 17:669-81. [PMID: 21986877 DOI: 10.1038/mp.2011.123] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Clathrin-mediated endocytosis (CME) is the best-characterized mechanism governing cellular membrane and protein trafficking. In this hypothesis review, we integrate recent evidence implicating CME and related cellular trafficking mechanisms in the pathophysiology of psychotic disorders such as schizophrenia and bipolar disorder. The evidence includes proteomic and genomic findings implicating proteins and genes of the clathrin interactome. Additionally, several important candidate genes for schizophrenia, such as dysbindin, are involved in processes closely linked to CME and membrane trafficking. We discuss that key aspects of psychosis neuropathology such as synaptic dysfunction, white matter changes and aberrant neurodevelopment are all influenced by clathrin-dependent processes, and that other cellular trafficking mechanisms previously linked to psychoses interact with the clathrin interactome in important ways. Furthermore, many antipsychotic drugs have been shown to affect clathrin-interacting proteins. We propose that the targeted pharmacological manipulation of the clathrin interactome may offer fruitful opportunities for novel treatments of schizophrenia.
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Affiliation(s)
- K O Schubert
- Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Republic of Ireland
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Ji W, Li Y, Wan T, Wang J, Zhang H, Chen H, Min W. Both internalization and AIP1 association are required for tumor necrosis factor receptor 2-mediated JNK signaling. Arterioscler Thromb Vasc Biol 2012; 32:2271-9. [PMID: 22743059 DOI: 10.1161/atvbaha.112.253666] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The proinflammtory cytokine tumor necrosis factor (TNF), primarily via TNF receptor 1 (TNFR1), induces nuclear factor-κB (NF-κB)-dependent cell survival, and c-Jun N-terminal kinase (JNK) and caspase-dependent cell death, regulating vascular endothelial cell (EC) activation and apoptosis. However, signaling by the second receptor, TNFR2, is poorly understood. The goal of this study was to dissect how TNFR2 mediates NF-κB and JNK signaling in vascular EC, and its relevance to in vivo EC function. METHODS AND RESULTS We show that TNFR2 contributes to TNF-induced NF-κB and JNK signaling in EC as TNFR2 deletion or knockdown reduces the TNF responses. To dissect the critical domains of TNFR2 that mediate the TNF responses, we examine the activity of TNFR2 mutant with a specific deletion of the TNFR2 intracellular region, which contains conserved domain I, domain II, domain III, and 2 TNFR-associated factor-2-binding sites. Deletion analyses indicate that different sequences on TNFR2 have distinct roles in NF-κB and JNK activation. Specifically, deletion of the TNFR-associated factor-2-binding sites (TNFR2-59) diminishes the TNFR2-mediated NF-κB, but not JNK activation; whereas, deletion of domain II or domain III blunts TNFR2-mediated JNK but not NF-κB activation. Interestingly, we find that the TNFR-associated factor-2-binding sites ensure TNFR2 on the plasma membrane, but the di-leucine LL motif within the domain II and aa338-355 within the domain III are required for TNFR2 internalization as well as TNFR2-dependent JNK signaling. Moreover, domain III of TNFR2 is responsible for association with ASK1-interacting protein-1, a signaling adaptor critical for TNF-induced JNK signaling. While TNFR2 containing the TNFR-associated factor-2-binding sites prevents EC cell death, a specific activation of JNK without NF-κB activation by TNFR2-59 strongly induces caspase activation and EC apoptosis. CONCLUSIONS Our data reveal that both internalization and ASK1-interacting protein-1 association are required for TNFR2-dependent JNK and apoptotic signaling. Controlling TNFR2-mediated JNK and apoptotic signaling in EC may provide a novel strategy for the treatment of vascular diseases.
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Affiliation(s)
- Weidong Ji
- Interdepartmental Program in Vascular Biology and Therapeutics, Yale University School of Medicine, 10 Amistad St., 401B, New Haven, CT 06520, USA
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40
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Lin AE, Guttman JA. Lack of Tir ubiquitylation contributes to enteropathogenic E. coli remaining extracellular during nonphagocytic cell infections. Anat Rec (Hoboken) 2012; 295:1230-8. [PMID: 22648930 DOI: 10.1002/ar.22503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 05/01/2012] [Accepted: 05/03/2012] [Indexed: 11/07/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) is an extracellular pathogen that alters many host subcellular components during its infectious processes. We have previously shown that EPEC hijacks a large assortment of host cell endocytic components and uses these proteins to form protruding structures called "pedestals" rather than triggering internalization of the bacteria. Other invasive pathogens that also recruit similar endocytic components have been shown to enter their host cells on the ubiquitylation of their host cell receptors. Therefore, we hypothesize that EPEC remains extracellular by maintaining its receptor, translocated intimin receptor (Tir), in an unubiquitylated state. Using immunoprecipitation-Western blots, we demonstrate no association of ubiquitin with Tir. To further elucidate the effect Tir ubiquitylation would have on EPEC during their infections, we engineered Tir-ubiquitin fusion constructs, expressed them in host epithelial cells, and infected them with Δtir EPEC. We found these cells induced a significant increase in EPEC invasion as compared with cells that expressed the Tir construct that lacked ubiquitin conjugation. Our results indicate that the lack of EPEC receptor ubiquitylation is a contributing factor that these microbes use to prevent their internalization into epithelial cells.
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Affiliation(s)
- Ann E Lin
- Department of Biological Sciences, Simon Fraser University, Shrum Science Centre, Burnaby, British Columbia V5A 1S6, Canada
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41
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Meloty-Kapella L, Shergill B, Kuon J, Botvinick E, Weinmaster G. Notch ligand endocytosis generates mechanical pulling force dependent on dynamin, epsins, and actin. Dev Cell 2012; 22:1299-312. [PMID: 22658936 DOI: 10.1016/j.devcel.2012.04.005] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 02/15/2012] [Accepted: 04/04/2012] [Indexed: 12/17/2022]
Abstract
Notch signaling induced by cell surface ligands is critical to development and maintenance of many eukaryotic organisms. Notch and its ligands are integral membrane proteins that facilitate direct cell-cell interactions to activate Notch proteolysis and release the intracellular domain that directs Notch-specific cellular responses. Genetic studies suggest that Notch ligands require endocytosis, ubiquitylation, and epsin endocytic adaptors to activate signaling, but the exact role of ligand endocytosis remains unresolved. Here we characterize a molecularly distinct mode of clathrin-mediated endocytosis requiring ligand ubiquitylation, epsins, and actin for ligand cells to activate signaling in Notch cells. Using a cell-bead optical tweezers system, we obtained evidence for cell-mediated mechanical force dependent on this distinct mode of ligand endocytosis. We propose that the mechanical pulling force produced by endocytosis of Notch-bound ligand drives conformational changes in Notch that permit activating proteolysis.
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Affiliation(s)
- Laurence Meloty-Kapella
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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42
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Pryor S, McCaffrey G, Young LR, Grimes ML. NGF causes TrkA to specifically attract microtubules to lipid rafts. PLoS One 2012; 7:e35163. [PMID: 22496904 PMCID: PMC3319630 DOI: 10.1371/journal.pone.0035163] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/13/2012] [Indexed: 11/18/2022] Open
Abstract
Membrane protein sorting is mediated by interactions between proteins and lipids. One mechanism that contributes to sorting involves patches of lipids, termed lipid rafts, which are different from their surroundings in lipid and protein composition. Although the nerve growth factor (NGF) receptors, TrkA and p75(NTR) collaborate with each other at the plasma membrane to bind NGF, these two receptors are endocytosed separately and activate different cellular responses. We hypothesized that receptor localization in membrane rafts may play a role in endocytic sorting. TrkA and p75(NTR) both reside in detergent-resistant membranes (DRMs), yet they responded differently to a variety of conditions. The ganglioside, GM1, caused increased association of NGF, TrkA, and microtubules with DRMs, but a decrease in p75(NTR). When microtubules were induced to polymerize and attach to DRMs by in vitro reactions, TrkA, but not p75(NTR), was bound to microtubules in DRMs and in a detergent-resistant endosomal fraction. NGF enhanced the interaction between TrkA and microtubules in DRMs, yet tyrosine phosphorylated TrkA was entirely absent in DRMs under conditions where activated TrkA was detected in detergent-sensitive membranes and endosomes. These data indicate that TrkA and p75(NTR) partition into membrane rafts by different mechanisms, and that the fraction of TrkA that associates with DRMs is internalized but does not directly form signaling endosomes. Rather, by attracting microtubules to lipid rafts, TrkA may mediate other processes such as axon guidance.
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Affiliation(s)
- Shona Pryor
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Gretchen McCaffrey
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Lindsay R. Young
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Mark L. Grimes
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, United States of America
- * E-mail:
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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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Brankatschk B, Wichert SP, Johnson SD, Schaad O, Rossner MJ, Gruenberg J. Regulation of the EGF transcriptional response by endocytic sorting. Sci Signal 2012; 5:ra21. [PMID: 22416276 DOI: 10.1126/scisignal.2002351] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ligand binding to the epidermal growth factor receptor (EGFR) on the cell surface activates the extracellular signal-regulated kinase (ERK) cascade. Activated, ligand-bound receptors are internalized, and this process may contribute to termination of signaling or enable signaling from intracellular sites. ESCRT (endosomal sorting complex required for transport) complexes may contribute to termination of signaling by sorting receptors into intraluminal vesicles of multivesicular endosomes from which the receptors continue into lysosomes for degradation. We showed that depletion of ESCRTs, which causes the retention of the EGFR in endosomes, increased the activation of the EGFR and its downstream kinases but had little effect on the overall profile and amplitude of the EGF-induced transcriptional response. In contrast, interfering with receptor endocytosis or ubiquitination to keep the EGFR at the cell surface stimulated increases in the abundance of many EGF-induced transcripts, similar to those induced by EGFR overexpression. We also found that the complete EGF transcriptional program was rapidly activated after ligand binding to the receptor. We conclude that the transcriptional response is elicited primarily by receptor molecules at the cell surface.
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Affiliation(s)
- Ben Brankatschk
- Department of Biochemistry, University of Geneva, 30 Quai E. Ansermet, 1211 Geneva 4, Switzerland
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45
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Abstract
From the moment of cotranslational insertion into the lipid bilayer of the endoplasmic reticulum (ER), newly synthesized integral membrane proteins are subject to a complex series of sorting, trafficking, quality control, and quality maintenance systems. Many of these processes are intimately controlled by ubiquitination, a posttranslational modification that directs trafficking decisions related to both the biosynthetic delivery of proteins to the plasma membrane (PM) via the secretory pathway and the removal of proteins from the PM via the endocytic pathway. Ubiquitin modification of integral membrane proteins (or "cargoes") generally acts as a sorting signal, which is recognized, captured, and delivered to a specific cellular destination via specialized trafficking events. By affecting the quality, quantity, and localization of integral membrane proteins in the cell, defects in these processes contribute to human diseases, including cystic fibrosis, circulatory diseases, and various neuropathies. This review summarizes our current understanding of how ubiquitin modification influences cargo trafficking, with a special emphasis on mechanisms of quality control and quality maintenance in the secretory and endocytic pathways.
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Affiliation(s)
- Jason A MacGurn
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA.
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Xie X, Cho B, Fischer JA. Drosophila Epsin's role in Notch ligand cells requires three Epsin protein functions: the lipid binding function of the ENTH domain, a single Ubiquitin interaction motif, and a subset of the C-terminal protein binding modules. Dev Biol 2012; 363:399-412. [PMID: 22265678 DOI: 10.1016/j.ydbio.2012.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 11/16/2022]
Abstract
Epsin is an endocytic protein that binds Clathrin, the plasma membrane, Ubiquitin, and also a variety of other endocytic proteins through well-characterized motifs. Although Epsin is a general endocytic factor, genetic analysis in Drosophila and mice revealed that Epsin is essential specifically for internalization of ubiquitinated transmembrane ligands of the Notch receptor, a process required for Notch activation. Epsin's mechanism of function is complex and context-dependent. Consequently, how Epsin promotes ligand endocytosis and thus Notch signaling is unclear, as is why Notch signaling is uniquely dependent on Epsin. Here, by generating Drosophila lines containing transgenes that express a variety of different Epsin deletion and substitution variants, we tested each of the five protein or lipid interaction modules for a role in Notch activation by each of the two ligands, Serrate and Delta. There are five main results of this work that impact present thinking about the role of Epsin in ligand cells. First, we discovered that deletion or mutation of both UIMs destroyed Epsin's function in Notch signaling and had a greater negative impact on Epsin activity than removal of any other module type. Second, only one of Epsin's two UIMs was essential. Third, the lipid-binding function of the ENTH domain was required only for maximal Epsin activity. Fourth, although the C-terminal Epsin modules that interact with Clathrin, the adapter protein complex AP-2, or endocytic accessory proteins were necessary collectively for Epsin activity, their functions were highly redundant; most unexpected was the finding that Epsin's Clathrin binding motifs were dispensable. Finally, we found that signaling from either ligand, Serrate or Delta, required the same Epsin modules. All of these observations are consistent with a model where Epsin's essential function in ligand cells is to link ubiquitinated Notch ligands to Clathrin-coated vesicles through other Clathrin adapter proteins. We propose that Epsin's specificity for Notch signaling simply reflects its unique ability to interact with the plasma membrane, Ubiquitin, and proteins that bind Clathrin.
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Affiliation(s)
- Xuanhua Xie
- Section of Molecular Cell and Developmental Biology, Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
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47
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Wu M, De Camilli P. Supported native plasma membranes as platforms for the reconstitution and visualization of endocytic membrane budding. Methods Cell Biol 2012; 108:3-18. [PMID: 22325595 DOI: 10.1016/b978-0-12-386487-1.00001-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cell-free assays represent an important complement to studies in living cells for the elucidation of mechanisms underlying the dynamics of biological membranes, such as budding, fission, and fusion reactions. Here we describe a method for the reconstitution of endocytosis, the process through which cells internalize portions of the plasma membrane along with extracellular material, under conditions that allow the visualization of individual budding events with high spatial and temporal resolution. The method, which is based on the generation of planar plasma membrane sheets attached to a glass substrate and their subsequent incubation with a cytosolic extract, results in a very robust formation of endocytic buds, which upon appropriate conditions undergo fission. The synchronization of the endocytic events and the accessibility of the material to a variety of manipulations make this experimental system a powerful tool for the molecular dissection of endocytosis.
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Affiliation(s)
- Min Wu
- Howard Hughes Medical Institute, Department of Cell Biology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
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48
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Pontier SM, Schweisguth F. Glycosphingolipids in signaling and development: From liposomes to model organisms. Dev Dyn 2011; 241:92-106. [DOI: 10.1002/dvdy.22766] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2011] [Indexed: 01/05/2023] Open
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Abstract
In the first volume of Developmental Cell, it was reported that the classic Drosophila neurogenic gene neuralized encodes a ubiquitin ligase that monoubiquitylates the Notch ligand Delta, thus promoting Delta endocytosis. A requirement for ligand internalization by the signal-sending cell, although counterintuitive, remains to date a feature unique to Notch signaling. Ten years and many ubiquitin ligases later, we discuss sequels to these three papers with an eye toward reviewing the development of ideas for how ligand ubiquitylation and endocytosis propel Notch signaling.
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50
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Ramanan V, Agrawal NJ, Liu J, Engles S, Toy R, Radhakrishnan R. Systems biology and physical biology of clathrin-mediated endocytosis. Integr Biol (Camb) 2011; 3:803-15. [PMID: 21792431 PMCID: PMC3153420 DOI: 10.1039/c1ib00036e] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In this review, we describe the application of experimental data and modeling of intracellular endocytic trafficking mechanisms with a focus on the process of clathrin-mediated endocytosis. A detailed parts-list for the protein-protein interactions in clathrin-mediated endocytosis has been available for some time. However, recent experimental, theoretical, and computational tools have proved to be critical in establishing a sequence of events, cooperative dynamics, and energetics of the intracellular process. On the experimental front, total internal reflection fluorescence microscopy, photo-activated localization microscopy, and spinning-disk confocal microscopy have focused on assembly and patterning of endocytic proteins at the membrane, while on the theory front, minimal theoretical models for clathrin nucleation, biophysical models for membrane curvature and bending elasticity, as well as methods from computational structural and systems biology, have proved insightful in describing membrane topologies, curvature mechanisms, and energetics.
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Affiliation(s)
- Vyas Ramanan
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Neeraj J. Agrawal
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Jin Liu
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Sean Engles
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Randall Toy
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Bioengineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 210 South 33rd Street, Philadelphia, PA 19104, USA
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