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Kozak M, Kaksonen M. Condensation of Ede1 promotes the initiation of endocytosis. eLife 2022; 11:72865. [PMID: 35412456 PMCID: PMC9064294 DOI: 10.7554/elife.72865] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 04/01/2022] [Indexed: 11/27/2022] Open
Abstract
Clathrin-mediated endocytosis is initiated by a network of weakly interacting proteins through a poorly understood mechanism. Ede1, the yeast homolog of mammalian Eps15, is an early-arriving endocytic protein and a key initiation factor. In the absence of Ede1, most other early endocytic proteins lose their punctate localization and endocytic uptake is decreased. We show that in yeast cells, cytosolic concentration of Ede1 is buffered at a critical level. Excess amounts of Ede1 form large condensates which recruit other endocytic proteins and exhibit properties of phase-separated liquid droplets. We demonstrate that the central region of Ede1, containing a coiled-coil and a prion-like region, is essential for both the condensate formation and the function of Ede1 in endocytosis. The functionality of Ede1 mutants lacking the central region can be partially rescued by an insertion of heterologous prion-like domains. Conversely, fusion of a heterologous lipid-binding domain with the central region of Ede1 can promote clustering into stable plasma membrane domains. We propose that the ability of Ede1 to form condensed networks supports the clustering of early endocytic proteins and promotes the initiation of endocytosis.
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Affiliation(s)
- Mateusz Kozak
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Marko Kaksonen
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
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2
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Endocytic Adaptor Proteins in Health and Disease: Lessons from Model Organisms and Human Mutations. Cells 2019; 8:cells8111345. [PMID: 31671891 PMCID: PMC6912373 DOI: 10.3390/cells8111345] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 12/11/2022] Open
Abstract
Cells need to exchange material and information with their environment. This is largely achieved via cell-surface receptors which mediate processes ranging from nutrient uptake to signaling responses. Consequently, their surface levels have to be dynamically controlled. Endocytosis constitutes a powerful mechanism to regulate the surface proteome and to recycle vesicular transmembrane proteins that strand at the plasma membrane after exocytosis. For efficient internalization, the cargo proteins need to be linked to the endocytic machinery via adaptor proteins such as the heterotetrameric endocytic adaptor complex AP-2 and a variety of mostly monomeric endocytic adaptors. In line with the importance of endocytosis for nutrient uptake, cell signaling and neurotransmission, animal models and human mutations have revealed that defects in these adaptors are associated with several diseases ranging from metabolic disorders to encephalopathies. This review will discuss the physiological functions of the so far known adaptor proteins and will provide a comprehensive overview of their links to human diseases.
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3
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Rosen EY, Schram AM, Young RJ, Schreyer MW, Hechtman JF, Shu CA, Ku NC, Hyman DM, Drilon A. Larotrectinib Demonstrates CNS Efficacy in TRK Fusion-Positive Solid Tumors. JCO Precis Oncol 2019; 3:PO.19.00009. [PMID: 32914009 PMCID: PMC7446323 DOI: 10.1200/po.19.00009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2019] [Indexed: 12/01/2022] Open
Affiliation(s)
- Ezra Y. Rosen
- Memorial Sloan Kettering Cancer Center, New York, NY
| | - Alison M. Schram
- Memorial Sloan Kettering Cancer Center, New York, NY
- Weill Cornell Medical College, New York, NY
| | | | | | | | | | | | - David M. Hyman
- Memorial Sloan Kettering Cancer Center, New York, NY
- Weill Cornell Medical College, New York, NY
| | - Alexander Drilon
- Memorial Sloan Kettering Cancer Center, New York, NY
- Weill Cornell Medical College, New York, NY
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4
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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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Dergai M, Iershov A, Novokhatska O, Pankivskyi S, Rynditch A. Evolutionary Changes on the Way to Clathrin-Mediated Endocytosis in Animals. Genome Biol Evol 2016; 8:588-606. [PMID: 26872775 PMCID: PMC4824007 DOI: 10.1093/gbe/evw028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Endocytic pathways constitute an evolutionarily ancient system that significantly contributed to the eukaryotic cell architecture and to the diversity of cell type-specific functions and signaling cascades, in particular of metazoans. Here we used comparative proteomic studies to analyze the universal internalization route in eukaryotes, clathrin-mediated endocytosis (CME), to address the issues of how this system evolved and what are its specific features. Among 35 proteins crucially required for animal CME, we identified a subset of 22 proteins common to major eukaryotic branches and 13 gradually acquired during evolution. Based on exploration of structure-function relationship between conserved homologs in sister, distantly related and early diverged branches, we identified novel features acquired during evolution of endocytic proteins on the way to animals: Elaborated way of cargo recruitment by multiple sorting proteins, structural changes in the core endocytic complex AP2, the emergence of the Fer/Cip4 homology domain-only protein/epidermal growth factor receptor substrate 15/intersectin functional complex as an additional interaction hub and activator of AP2, as well as changes in late endocytic stages due to recruitment of dynamin/sorting nexin 9 complex and involvement of the actin polymerization machinery. The evolutionary reconstruction showed the basis of the CME process and its subsequent step-by-step development. Documented changes imply more precise regulation of the pathway, as well as CME specialization for the uptake of specific cargoes and cell type-specific functions.
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Affiliation(s)
- Mykola Dergai
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine
| | - Anton Iershov
- Department of Biosynthesis of Nucleic Acids, Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine
| | - Olga Novokhatska
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine
| | - Serhii Pankivskyi
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine
| | - Alla Rynditch
- Department of Functional Genomics, Institute of Molecular Biology and Genetics, NASU, Kyiv, Ukraine
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6
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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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7
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Moore FB, Baleja JD. Molecular remodeling mechanisms of the neural somatodendritic compartment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1720-30. [PMID: 22705351 DOI: 10.1016/j.bbamcr.2012.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/06/2012] [Accepted: 06/07/2012] [Indexed: 12/28/2022]
Abstract
Neuronal cells use the process of vesicle trafficking to manipulate the populations of neurotransmitter receptors and other membrane proteins. Long term potentiation (LTP) is a long-lived increase in synaptic strength between neurons and increases postsynaptic dendritic spine size and the concentration of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate-type glutamate receptor (AMPAR) located in the postsynaptic density. AMPAR is removed from the cell surface via clathrin-mediated endocytosis. While the adaptor protein 2 (AP2) complex of endocytosis seems to have the components needed to allow temporal and spatial regulations of internalization, many accessory proteins are involved, such as epidermal growth factor receptor phosphorylation substrate 15 (Eps15). A sequence of repeats in the Eps15 protein is known as the Eps15 homology (EH) domain. It has affinity for asparagine-proline-phenylalanine (NPF) sequences that are contained within vesicle trafficking proteins such as epsin, Rab11 family interacting protein 2 (Rab11-FIP2), and Numb. After endocytosis, a pool of AMPAR is stored in the endosomal recycling compartment that can be transported to the dendritic spine surface upon stimulation during LTP for lateral diffusion into the postsynaptic density. Rab11 and the Eps15 homologue EHD1 are involved in receptor recycling. EHD family members are also involved in transcytosis of the neuronal cell adhesion molecule neuron-glia cell adhesion molecule (NgCAM) from the somatodendritic compartment to the axon. Neurons have a unique morphology comprising many projections of membrane that is constructed in part by the effects of the Eps15 homologue, intersectin. Morphogenesis in the somatodendritic compartment is becoming better understood, but there is still much exciting territory to explore, especially regarding the roles of various EH domain-NPF interactions in endocytic and recycling processes.
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Affiliation(s)
- Fletcher B Moore
- Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA
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8
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Wong KA, Wilson J, Russo A, Wang L, Okur MN, Wang X, Martin NP, Scappini E, Carnegie GK, O'Bryan JP. Intersectin (ITSN) family of scaffolds function as molecular hubs in protein interaction networks. PLoS One 2012; 7:e36023. [PMID: 22558309 PMCID: PMC3338775 DOI: 10.1371/journal.pone.0036023] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 03/28/2012] [Indexed: 11/29/2022] Open
Abstract
Members of the intersectin (ITSN) family of scaffold proteins consist of multiple modular domains, each with distinct ligand preferences. Although ITSNs were initially implicated in the regulation of endocytosis, subsequent studies have revealed a more complex role for these scaffold proteins in regulation of additional biochemical pathways. In this study, we performed a high throughput yeast two-hybrid screen to identify additional pathways regulated by these scaffolds. Although several known ITSN binding partners were identified, we isolated more than 100 new targets for the two mammalian ITSN proteins, ITSN1 and ITSN2. We present the characterization of several of these new targets which implicate ITSNs in the regulation of the Rab and Arf GTPase pathways as well as regulation of the disrupted in schizophrenia 1 (DISC1) interactome. In addition, we demonstrate that ITSN proteins form homomeric and heteromeric complexes with each other revealing an added level of complexity in the function of these evolutionarily conserved scaffolds.
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Affiliation(s)
- Katy A. Wong
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- UIC Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Jessica Wilson
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- UIC Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Angela Russo
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- UIC Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Li Wang
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Mustafa Nazir Okur
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- UIC Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Genetics, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Xuerong Wang
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- UIC Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - Negin P. Martin
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, United States of America
| | - Erica Scappini
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, United States of America
| | - Graeme K. Carnegie
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
| | - John P. O'Bryan
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- Center for Cardiovascular Research, University of Illinois College of Medicine, Chicago, Illinois, United States of America
- UIC Cancer Center, University of Illinois College of Medicine, Chicago, Illinois, United States of America
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Uezu A, Umeda K, Tsujita K, Suetsugu S, Takenawa T, Nakanishi H. Characterization of the EFC/F-BAR domain protein, FCHO2. Genes Cells 2011; 16:868-78. [PMID: 21762413 DOI: 10.1111/j.1365-2443.2011.01536.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We have previously shown that SGIP1α is an endocytic protein specifically expressed in neural tissues. SGIP1α has a lipid-binding domain called the MP domain, which shows no significant homology to any other domains. In this study, we characterized FCHO2, a protein with a high level of homology to SGIP1α. FCHO2 lacks the MP domain but has another lipid-binding domain, the EFC/F-BAR domain. FCHO2 was ubiquitously expressed. The FCHO2 EFC domain bound to phosphatidylserine and phosphoinositides and deformed the plasma membrane and liposomes into narrow tubes. FCHO2 localized to clathrin-coated pits at the plasma membrane and bound to Eps15, an important adaptor protein in clathrin-mediated endocytosis. FCHO2 knockdown reduced transferrin endocytosis. These results suggest that FCHO2 regulates clathrin-mediated endocytosis through its interactions with membranes and Eps15. These properties of FCHO2 are similar to those of SGIP1α. FCHO2 is likely to be a ubiquitous homologue of SGIP1α. We furthermore found that FCHO2 was subjected to monoubiquitination, and gel filtration analysis showed that FCHO2 formed an oligomer. These new properties might also contribute to the role of FCHO2 in clathrin-mediated endocytosis.
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Affiliation(s)
- Akiyoshi Uezu
- Department of Molecular Pharmacology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
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Wang P, Shen G. The endocytic adaptor proteins of pathogenic fungi: charting new and familiar pathways. Med Mycol 2011; 49:449-57. [PMID: 21254965 DOI: 10.3109/13693786.2011.553246] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Intracellular transport is an essential biological process that is highly conserved throughout the eukaryotic organisms. In fungi, adaptor proteins implicated in the endocytic cycle of endocytosis and exocytosis were found to be important for growth, differentiation, and/or virulence. For example, Saccharomyces cerevisiae Pan1 is an endocytic protein that regulates membrane trafficking, the actin cytoskeleton, and signaling. In Cryptococcus neoformans, a multi-modular endocytic protein, Cin1, was recently found to have pleiotropic functions in morphogenesis, endocytosis, exocytosis, and virulence. Interestingly, Cin1 is homologous to human intersectin ITSN1, but homologs of Cin1/ITSN1 were not found in ascomycetous S. cerevisiae and Candida albicans, or zygomycetous fungi. Moreover, an Eps15 protein homologous to S. cerevisiae Pan1/Ede1 and additional relevant protein homologs were identified in C. neoformans, suggesting the existence of either a distinct endocytic pathway mediated by Cin1 or pathways by either Cin1 or/and Pan1/Ede1 homologs. Whether and how the Cin1-mediated endocytic pathway represents a unique role in pathogenesis or reflects a redundancy of a transport apparatus remains an open and challenging question. This review discusses recent findings of endocytic adaptor proteins from pathogenic fungi and provides a perspective for novel endocytic machinery operating in C. neoformans. An understanding of intracellular trafficking mechanisms as they relate to pathogenesis will likely reveal the identity of novel antifungal targets.
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Affiliation(s)
- Ping Wang
- The Research Institute for Children, New Orleans, Louisiana, USA.
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11
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Shinohara A, Ichikawa M, Ueda K, Takahashi T, Hangaishi A, Kurokawa M. A novel MLL-AF1p/Eps15 fusion variant in therapy-related acute lymphoblastic leukemia, lacking the EH-domains. Leuk Res 2010; 34:e62-3. [DOI: 10.1016/j.leukres.2009.07.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 07/14/2009] [Accepted: 07/14/2009] [Indexed: 10/20/2022]
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12
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Chi S, Cao H, Chen J, McNiven MA. Eps15 mediates vesicle trafficking from the trans-Golgi network via an interaction with the clathrin adaptor AP-1. Mol Biol Cell 2008; 19:3564-75. [PMID: 18524853 PMCID: PMC2488291 DOI: 10.1091/mbc.e07-10-0997] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 05/21/2008] [Accepted: 05/22/2008] [Indexed: 11/11/2022] Open
Abstract
Eps15 (EGFR pathway substrate clone 15) is well known for its role in clathrin-coated vesicle formation at the plasma membrane through interactions with other clathrin adaptor proteins such as AP-2. Interestingly, we observed that in addition to its plasma membrane localization, Eps15 is also present at the trans-Golgi network (TGN). Therefore, we predicted that Eps15 might associate with clathrin adaptor proteins at the TGN and thereby mediate the formation of Golgi-derived vesicles. Indeed, we have found that Eps15 and the TGN clathrin adaptor AP-1 coimmunoprecipitate from rat liver Golgi fractions. Furthermore, we have identified a 14-amino acid motif near the AP-2-binding domain of Eps15 that is required for binding to AP-1, but not AP-2. Disruption of the Eps15-AP-1 interaction via siRNA knockdown of AP-1 or expression of mutant Eps15 protein, which lacks a 14-amino acid motif representing the AP-1 binding site of Eps15, significantly reduced the exit of secretory proteins from the TGN. Together, these findings indicate that Eps15 plays an important role in clathrin-coated vesicle formation not only at the plasma membrane but also at the TGN during the secretory process.
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Affiliation(s)
- Susan Chi
- Mayo Clinic College of Medicine, Department of Biochemistry and Molecular Biology, and the Miles and Shirley Fiterman Center for Digestive Diseases, Rochester, MN 55905
| | - Hong Cao
- Mayo Clinic College of Medicine, Department of Biochemistry and Molecular Biology, and the Miles and Shirley Fiterman Center for Digestive Diseases, Rochester, MN 55905
| | - Jing Chen
- Mayo Clinic College of Medicine, Department of Biochemistry and Molecular Biology, and the Miles and Shirley Fiterman Center for Digestive Diseases, Rochester, MN 55905
| | - Mark A. McNiven
- Mayo Clinic College of Medicine, Department of Biochemistry and Molecular Biology, and the Miles and Shirley Fiterman Center for Digestive Diseases, Rochester, MN 55905
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Roxrud I, Raiborg C, Pedersen NM, Stang E, Stenmark H. An endosomally localized isoform of Eps15 interacts with Hrs to mediate degradation of epidermal growth factor receptor. ACTA ACUST UNITED AC 2008; 180:1205-18. [PMID: 18362181 PMCID: PMC2373575 DOI: 10.1083/jcb.200708115] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Down-regulation of activated and ubiquitinated growth factor (GF) receptors by endocytosis and subsequent lysosomal degradation ensures attenuation of GF signaling. The ubiquitin-binding adaptor protein Eps15 (epidermal growth factor receptor [EGFR] pathway substrate 15) functions in endocytosis of such receptors. Here, we identify an Eps15 isoform, Eps15b, and demonstrate its expression in human cells and conservation across vertebrate species. Although both Eps15 and Eps15b interact with the endosomal sorting protein Hrs (hepatocyte growth factor–regulated tyrosine kinase substrate) in vitro, we find that Hrs specifically binds Eps15b in vivo (whereas adaptor protein 2 preferentially interacts with Eps15). Although Eps15 mainly localizes to clathrin-coated pits at the plasma membrane, Eps15b localizes to Hrs-positive microdomains on endosomes. Eps15b overexpression, similarly to Hrs overexpression, inhibits ligand-mediated degradation of EGFR, whereas Eps15 is without effect. Similarly, depletion of Eps15b but not Eps15 delays degradation and promotes recycling of EGFR. These results indicate that Eps15b is an endosomally localized isoform of Eps15 that is present in the Hrs complex via direct Hrs interaction and important for the sorting function of this complex.
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Affiliation(s)
- Ingrid Roxrud
- Centre for Cancer Biomedicine, University of Oslo and the Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway
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14
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Structure of the Eps15-stonin2 complex provides a molecular explanation for EH-domain ligand specificity. EMBO J 2008; 27:558-69. [PMID: 18200045 DOI: 10.1038/sj.emboj.7601980] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Accepted: 12/17/2007] [Indexed: 11/09/2022] Open
Abstract
Eps15 homology (EH) domain-containing proteins play a key regulatory role in intracellular membrane trafficking and cell signalling. EH domains serve as interaction platforms for short peptide motifs comprising the residues NPF within natively unstructured regions of accessory proteins. The EH-NPF interactions described thus far are of very low affinity and specificity. Here, we identify the presynaptic endocytic sorting adaptor stonin2 as a high-affinity ligand for the second EH domain (EH2) of the clathrin accessory protein Eps15. Calorimetric data indicate that both NPF motifs within stonin2 interact with EH2 simultaneously and with sub-micromolar affinity. The solution structure of this complex reveals that the first NPF motif binds to the conserved site on the EH domain, whereas the second motif inserts into a novel hydrophobic pocket. Our data show how combination of two EH-attachment sites provides a means for modulating specificity and allows discrimination from a large pool of potential binding partners containing NPF motifs.
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15
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Regan-Klapisz E, Sorokina I, Voortman J, de Keizer P, Roovers RC, Verheesen P, Urbé S, Fallon L, Fon EA, Verkleij A, Benmerah A, van Bergen en Henegouwen PMP. Ubiquilin recruits Eps15 into ubiquitin-rich cytoplasmic aggregates via a UIM-UBL interaction. J Cell Sci 2005; 118:4437-50. [PMID: 16159959 DOI: 10.1242/jcs.02571] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Eps15 and its related protein Eps15R are key components of the clathrin-mediated endocytic pathway. We searched for new binding partners of Eps15 using a yeast two-hybrid screen. We report here that ubiquilin (hPLIC1), a type-2 ubiquitin-like protein containing a ubiquitin-like domain (UBL) and a ubiquitin-associated domain (UBA), interacts with both Eps15 and Eps15R. Using glutathione-S-transferase pull-down experiments, we show that the first ubiquitin-interacting motif of Eps15 (UIM1) interacts directly with the UBL domain of ubiquilin, whereas it does not bind to ubiquitinated proteins. The second UIM of Eps15 (UIM2) binds poorly to the UBL domain but does bind to ubiquitinated proteins. Two other UIM-containing endocytic proteins, Hrs and Hbp, also interact with ubiquilin in a UIM-dependent manner, whereas epsin does not. Immunofluorescence analysis showed that endogenous Eps15 and Hrs, but not epsin, colocalize with green-fluorescent-protein-fused ubiquilin in cytoplasmic aggregates that are not endocytic compartments. We have characterized these green-fluorescent-protein-fused-ubiquilin aggregates as ubiquitin-rich intracytoplasmic inclusions that are recruited to aggresomes upon proteasome inhibition. Moreover, we show that endogenous Eps15 and endogenous ubiquilin colocalize to cytoplasmic aggregates and aggresomes. Finally, we show that the recruitment of Eps15 into ubiquilin-positive aggregates is UIM dependent. Altogether, our data identify ubiquilin as the first common UIM-binding partner of a subset of UIM-containing endocytic proteins. We propose that this UIM/UBL-based interaction is responsible for the sequestration of certain UIM-containing endocytic proteins into cytoplasmic ubiquitin-rich protein aggregates.
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Affiliation(s)
- Elsa Regan-Klapisz
- Molecular Cell Biology, Institute of Biomembranes, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands
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16
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Miliaras NB, Park JH, Wendland B. The function of the endocytic scaffold protein Pan1p depends on multiple domains. Traffic 2005; 5:963-78. [PMID: 15522098 DOI: 10.1111/j.1600-0854.2004.00238.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pan1p is an essential protein of the yeast Saccharomyces cerevisiae that is required for the internalization step of endocytosis and organization of the actin cytoskeleton. Pan1p, which binds several other endocytic proteins, is composed of multiple protein-protein interaction domains including two Eps15 Homology (EH) domains, a coiled-coil domain, an acidic Arp2/3-activating region, and a proline-rich domain. In this study, we have induced high-level expression of various domains of Pan1p in wild-type cells to assess the dominant consequences on viability, endocytosis, and actin organization. We found that the most severe phenotypes, with blocked endocytosis and aggregated actin, required expression of nearly full length Pan1p, and also required the endocytic regulatory protein kinase Prk1p. The central coiled-coil domain was the smallest fragment whose overexpression caused any dominant effects; these effects were more pronounced by inclusion of the second EH domain. Co-overexpressing nonoverlapping amino- and carboxy-terminal fragments did not mimic the effects of the intact protein, whereas fragments that overlapped within the coiled-coil region could. Yeast two-hybrid and in vivo coimmunoprecipitation analyses suggest that Pan1 may form dimers or higher order oligomers. Collectively, our data support a view of Pan1p as a dimeric/oligomeric scaffold whose functions require both the amino- and carboxy-termini, linked by the central region.
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Affiliation(s)
- Nicholas B Miliaras
- Department of Biology, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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17
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Abstract
Exogenously and endogenously originated signals are propagated within the cell by functional and physical networks of proteins, leading to numerous biological outcomes. Many protein-protein interactions take place between binding domains and short peptide motifs. Frequently, these interactions are inducible by upstream signaling events, in which case one of the two binding surfaces may be created by a posttranslational modification. Here, we discuss two protein networks. One, the EH-network, is based on the Eps15 homology (EH) domain, which binds to peptides containing the sequence Asp-Pro-Phe (NPF). The other, which we define as the monoubiquitin (mUb) network, relies on monoubiquitination, which is emerging as an important posttranslational modification that regulates protein function. Both networks were initially implicated in the control of plasma membrane receptor endocytosis and in the regulation of intracellular trafficking routes. The ramifications of these two networks, however, appear to extend into many other aspects of cell physiology as well, such as transcriptional regulation, actin cytoskeleton remodeling, and DNA repair. The focus of this review is to integrate available knowledge of the EH- and mUb networks with predictions of genetic and physical interactions stemming from functional genomics approaches.
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Affiliation(s)
- Simona Polo
- Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
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18
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So CW, Lin M, Ayton PM, Chen EH, Cleary ML. Dimerization contributes to oncogenic activation of MLL chimeras in acute leukemias. Cancer Cell 2003; 4:99-110. [PMID: 12957285 DOI: 10.1016/s1535-6108(03)00188-0] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
MLL is a histone methyltransferase that can be converted into an oncoprotein by acquisition of transcriptional effector domains following heterologous protein fusions with a variety of nuclear transcription factors, cofactors, or chromatin remodeling proteins in acute leukemias. Here we demonstrate an alternative mechanism for activation of MLL following fusions with proteins (AF1p/Eps15 and GAS7) that normally reside in the cytoplasm. The coiled-coil oligomerization domains of these proteins are necessary and sufficient for leukemogenic transformation induced by the respective MLL fusion proteins. Furthermore, homodimerization of MLL by synthetic dimerization modules mimics bona fide MLL fusion proteins resulting in Hox gene activation and enhanced self-renewal of hematopoietic progenitors. Our studies support an oligomerization-dependent mechanism for oncogenic conversion of MLL, presumably in part by recruitment of accessory factors through the dimerized MLL moiety of the chimeric protein.
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Affiliation(s)
- Chi Wai So
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
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19
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Shtiegman K, Yarden Y. The role of ubiquitylation in signaling by growth factors: implications to cancer. Semin Cancer Biol 2003; 13:29-40. [PMID: 12507554 DOI: 10.1016/s1044-579x(02)00097-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cancer cells depend on multiple, locally produced growth factors. Signaling by growth factors entails phosphorylation events, and its termination is determined primarily by endocytosis of growth factor receptor complexes. One group of growth factor receptors frequently implicated in human cancer is the ErbB family of receptor tyrosine kinases. By using ErbB as a prototype, here we review the role of protein ubiquitylation in the process that terminates signaling. Specifically, we concentrate on several adaptor proteins, including c-Cbl and Hgs, to elucidate the complexity of receptor sorting for degradation. Detailed understanding of ubiquitylation control on receptor desensitization may lead to better ways to diagnose and eradicate cancer.
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Affiliation(s)
- Keren Shtiegman
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel
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20
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Klapisz E, Sorokina I, Lemeer S, Pijnenburg M, Verkleij AJ, van Bergen en Henegouwen PMP. A ubiquitin-interacting motif (UIM) is essential for Eps15 and Eps15R ubiquitination. J Biol Chem 2002; 277:30746-53. [PMID: 12072436 DOI: 10.1074/jbc.m203004200] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An important negative control mechanism in the signaling of epidermal growth factor (EGF) is the endocytosis and subsequent degradation of activated EGF receptors. Eps15 and its related partner Eps15R play a key role in clathrin-mediated endocytosis of transmembrane receptors. Upon EGF stimulation of the cell, Eps15 becomes both phosphorylated on tyrosine residues and monoubiquitinated. Although tyrosine phosphorylation of Eps15 has been implicated in EGF receptor internalization, the function of Eps15 ubiquitination is not known. Using a mutational approach, we have found that the second ubiquitin-interacting motif (UIM) of Eps15 and Eps15R is essential for their ubiquitination. This UIM partially overlaps with the recently characterized nuclear export signal in Eps15. We show that these two overlapping motifs have different structural requirements with respect to nuclear export signal versus ubiquitination signal activity. Our data demonstrate that the UIM does not contain the ubiquitin acceptor site but functions as a recruitment site for the ubiquitination machinery leading to the monoubiquitination of both Eps15 and Eps15R.
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Affiliation(s)
- Elsa Klapisz
- Molecular Cell Biology, Institute of Biomembranes, Universiteit Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands
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21
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Galperin E, Benjamin S, Rapaport D, Rotem-Yehudar R, Tolchinsky S, Horowitz M. EHD3: a protein that resides in recycling tubular and vesicular membrane structures and interacts with EHD1. Traffic 2002; 3:575-89. [PMID: 12121420 DOI: 10.1034/j.1600-0854.2002.30807.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Here we report the characterization of an eps15 homology (EH) domain containing protein designated EHD3. EHD3 was mapped to human chromosome 2p22-23, while the murine Ehd3 homolog was mapped to chromosome 17p21. Both the human and the mouse genes contain a polymorphic (CA) repeat in their 3'UTR. One 3.6-kb Ehd3 transcript was mainly detected in adult mouse brain and kidney and at day 7 of mouse development. On the other hand, human tissues exhibited two, 4.2- and 3.6-kb, EHD3 RNA species. They were predominantly expressed in heart, brain, placenta, liver, kidney and ovary. EHD3, expressed as a green fluorescent fusion protein was localized to endocytic vesicles and to microtubule-dependent, membrane tubules. There was a clear colocalization of EHD3-positive structures and transferrin-containing recycling vesicles, implying that EHD3 resides within the endocytic recycling compartment. Shuffling the N-terminal domain of EHD1 (previously shown to reside in the transferrin-containing, endocytic recycling compartment) with that of EHD3 resulted in a chimeric EHD protein that was localized mainly to tubules instead of the endocytic vesicles, implicating the N-terminal domain as responsible for the tubular localization of EHD3. Mutant EHD3 forms, missing the N-terminal or the C-terminal domains, lost their tubular localization. Results of two-hybrid analyses indicated that EHD1 and EHD3 interact with each other. In addition, EHD1 and EHD3 could be coimmunoprecipitated from cellular extracts, confirming the interaction implied by two-hybrid analysis. Moreover, coexpression of EHD1 and EHD3 resulted in their colocalization in microtubule-dependent tubules as well as in punctate forms. Based on its specific intracellular localization and its interaction with EHD1, we postulate that EHD3 localizes on endocytic tubular and vesicular structures and regulates their microtubule-dependent movement.
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Affiliation(s)
- Emilia Galperin
- Department of Cell Research and Immunology, Tel-Aviv University, Ramat-Aviv, Israel 69978
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22
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Lindsay AJ, McCaffrey MW. Rab11-FIP2 functions in transferrin recycling and associates with endosomal membranes via its COOH-terminal domain. J Biol Chem 2002; 277:27193-9. [PMID: 11994279 DOI: 10.1074/jbc.m200757200] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Rab11-FIP2 is a recently described member of the Rip11/Rab11-FIP/Rab coupling protein family of Rab11 interacting proteins. Rab11-FIP2 interacts with both Rab11 and myosin Vb and co-localizes with Rab11 in both HeLa and Madin-Darby canine kidney cells (Hales, C. M., Griner, R., Hobdy-Henderson, K. C., Dorn, M. C., Hardy, D., Kumar, R., Navarre, J., Chan, E. K., Lapierre, L. A., and Goldenring, J. R. (2001) J. Biol. Chem. 276, 39067-390751). Here, we characterized the specificity of the interaction between Rab11-FIP2 and Rab11 and report that it does not interact with Rab4, Rab3, Rab5, Rab6, or Rab7. We demonstrate that the COOH-terminal region of Rab11-FIP2, which contains the Rab11 binding domain (RBD), is necessary and sufficient for its early endosomal membrane association. In contrast, the amino-terminal region, which contains a phospholipid binding C2-domain, by itself was insufficient for membrane binding. Expression of a deletion mutant of Rab11-FIP2, containing the RBD, caused tubulation of a transferrin receptor-positive early endosomal compartment in HeLa cells. Endogenous Rab11 was also associated with this compartment. This phenotype cannot be reversed by excess wild-type Rab11, or dominant-positive Rab11 (Rab11Q70L), suggesting that Rab11-FIP2 functions downstream of Rab11 in endosomal trafficking.
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Affiliation(s)
- Andrew J Lindsay
- Cell and Molecular Biology Laboratory, Department of Biochemistry, University College Cork, Lee Maltings, Prospect Row, Cork, Ireland
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23
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Poupon V, Polo S, Vecchi M, Martin G, Dautry-Varsat A, Cerf-Bensussan N, Di Fiore PP, Benmerah A. Differential nucleocytoplasmic trafficking between the related endocytic proteins Eps15 and Eps15R. J Biol Chem 2002; 277:8941-8. [PMID: 11777906 DOI: 10.1074/jbc.m108385200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Eps15 and Eps15R are constitutive components of clathrin-coated pits that are required for clathrin-dependent endocytosis. The most striking difference between these two related proteins is that Eps15R is also found in the nucleus, whereas Eps15 is excluded from this compartment at steady state. To better understand the individual functions of these two proteins, the mechanisms responsible for their different localization were investigated. Interestingly, some mutants of Eps15 were found in the nucleus. This nuclear localization was correlated with the loss of the last approximately 100 amino acids of Eps15, suggesting the presence of a nuclear export signal (NES) within this region. As expected, the last 25 amino acids contain a leucine-rich sequence matching with classical NESs, show a leptomycin B-sensitive nuclear export activity, and bind to the exportin CRM1 in a leucine residue-dependent manner. In contrast, no NES could be found in Eps15R, a result in keeping with its constitutive nuclear localization that appears to be regulated by alternative splicing. Altogether, these results are the first characterization of nucleocytoplasmic shuttling signals for endocytic proteins. They also provide an explanation for the different nuclear localization of Eps15 and Eps15R and further evidence for a possible nuclear function for Eps15 protein family members.
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Affiliation(s)
- Viviane Poupon
- INSERM E9925, Faculté Necker-Enfants Malades, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
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24
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Saito K, Murai J, Kajiho H, Kontani K, Kurosu H, Katada T. A novel binding protein composed of homophilic tetramer exhibits unique properties for the small GTPase Rab5. J Biol Chem 2002; 277:3412-8. [PMID: 11733506 DOI: 10.1074/jbc.m106276200] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The small GTPase Rab family, which cycles between GTP-bound active and GDP-bound inactive states, plays an important role in membrane trafficking. Among them, Rab5 is involved in early endocytic pathway, and several Rab5-binding proteins have been identified as regulators or effectors to coordinate the docking and fusion processes of endocytic vesicles. We describe a novel binding protein exhibiting unique biochemical properties for Rab5. The Rab5-binding protein enhances GDP-GTP exchange reaction on Rab5 but preferentially interacts with its GTP-bound form. Gel filtration and immunoprecipitation analyses indicate that the Rab5-binding protein functions as a tetramer composed of anti-parallel linkage of two parallel dimers. These results suggest that the newly identified protein may function as an upstream activator and/or downstream effector for Rab5 in endocytic pathway. Possible roles of the quaternary structure have been discussed in terms of the Rab5-mediated signaling.
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Affiliation(s)
- Kota Saito
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan
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25
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Kuo HJ, Tran NT, Clary SA, Morris NP, Glanville RW. Characterization of EHD4, an EH domain-containing protein expressed in the extracellular matrix. J Biol Chem 2001; 276:43103-10. [PMID: 11533061 DOI: 10.1074/jbc.m106128200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To identify proteins that promote assembly of type VI collagen tetramers or stabilize type VI collagen filaments, a two-hybrid screen of a human placenta library was used and a new extracellular protein discovered. The cDNA sequence of the new protein encodes 541 amino acid residues. This cDNA sequence is identical to EHD4, a recently described member of the EH domain family of proteins. Two mRNAs of 4.4 and 3.0 kilobases were present in human skin fibroblasts and most tissues tested but were most prevalent in the heart. The chromosomal localization of the gene for this new protein was determined to be at 15q14-q15. Three polyclonal peptide antibodies were made against synthetic EHD4 peptides. The affinity-purified antibodies were used in immunofluorescent staining of developing limbs and matrices produced by human skin fibroblasts and mouse NIH3T3 fibroblasts in culture. Embryonic rat limb cartilage was strongly stained throughout development, and cultured fibroblasts deposited an extracellular filamentous network containing EHD4. In non-denaturing extracts of fetal bovine cartilage and in human skin fibroblast culture media, two components of approximately 220 and 158 kDa were observed, which, after reduction, migrated as a 56-kDa component on SDS-polyacrylamide gel electrophoresis. EHD4 is the first extracellular matrix protein described that contains an EH domain.
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MESH Headings
- 3T3 Cells
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Western
- Carrier Proteins/chemistry
- Carrier Proteins/physiology
- Cartilage/metabolism
- Cattle
- Cells, Cultured
- Chromosome Mapping
- Chromosomes, Human, Pair 15
- Collagen/metabolism
- Collagen Type IV/metabolism
- DNA, Complementary/metabolism
- DNA-Binding Proteins
- Electrophoresis, Polyacrylamide Gel
- Extracellular Matrix/metabolism
- Extracellular Matrix Proteins/chemistry
- Extracellular Matrix Proteins/physiology
- Fibroblasts/metabolism
- Fluorescent Antibody Technique, Indirect
- Gene Library
- Humans
- Mice
- Models, Genetic
- Molecular Sequence Data
- Nuclear Proteins
- Organ Culture Techniques
- Peptides/chemistry
- Placenta/metabolism
- Protein Binding
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Radiation Hybrid Mapping
- Rats
- Skin/metabolism
- Tissue Distribution
- Two-Hybrid System Techniques
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Affiliation(s)
- H J Kuo
- Shriners Hospital for Children, Portland, Oregon 97201, USA
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26
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Rotem-Yehudar R, Galperin E, Horowitz M. Association of insulin-like growth factor 1 receptor with EHD1 and SNAP29. J Biol Chem 2001; 276:33054-60. [PMID: 11423532 DOI: 10.1074/jbc.m009913200] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ligand-induced receptor-mediated endocytosis plays a central role in regulating signaling conveyed by tyrosine kinase receptors. This process depends on the recruitment of the adaptor protein 2 (AP-2) complex, clathrin, dynamin, and other accessory proteins to the ligand-bound receptor. We show here that besides AP-2 and clathrin, two other proteins participate in the endocytic process of the insulin-like growth factor receptor (IGF-1R); they are EHD1, an Eps15 homology (EH) domain-containing protein 1, and SNAP29, a synaptosomal-associated protein. EHD1 and SNAP29 form complexes with alpha-adaptin of AP-2 and co-localize in endocytic vesicles, indicating a role for them in endocytosis. EHD1 and SNAP29 interact directly with each other and are present in complexes with IGF-1R. After IGF-1 induction, EHD1 and IGF-1R co-localize intracellularly. Overexpression of EHD1 in Chinese hamster ovary cells represses IGF-1-mediated signaling, as measured by mitogen-activated protein kinase phosphorylation and Akt phosphorylation, indicating that EHD1 plays a role as a down-regulator in IGF-1 signaling pathway.
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Affiliation(s)
- R Rotem-Yehudar
- Department of Cell Research and Immunology, Tel-Aviv University, Ramat-Aviv, 69978, Tel-Aviv, Israel
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27
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Salcini AE, Hilliard MA, Croce A, Arbucci S, Luzzi P, Tacchetti C, Daniell L, De Camilli P, Pelicci PG, Di Fiore PP, Bazzicalupo P. The Eps15 C. elegans homologue EHS-1 is implicated in synaptic vesicle recycling. Nat Cell Biol 2001; 3:755-60. [PMID: 11483962 DOI: 10.1038/35087075] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Eps15 represents the prototype of a family of evolutionarily conserved proteins that are characterized by the presence of the EH domain, a protein-protein interaction module, and that are involved in many aspects of intracellular vesicular sorting. Although biochemical and functional studies have implicated Eps15 in endocytosis, its function in the endocytic machinery remains unclear. Here we show that the Caenorhabditis elegans gene, zk1248.3 (ehs-1), is the orthologue of Eps15 in nematodes, and that its product, EHS-1, localizes to synaptic-rich regions. ehs-1-impaired worms showed temperature-dependent depletion of synaptic vesicles and uncoordinated movement. These phenotypes could be correlated with a presynaptic defect in neurotransmission. Impairment of EHS-1 function in dyn-1(ky51) worms, which express a mutant form of dynamin and display a temperature-sensitive locomotion defect, resulted in a worsening of the dyn-1 phenotype and uncoordination at the permissive temperature. Thus, ehs-1 and dyn-1 interact genetically. Moreover, mammalian Eps15 and dynamin protein were shown to interact in vivo. Taken together, our results indicate that EHS-1 acts in synaptic vesicle recycling and that its function might be linked to that of dynamin.
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Affiliation(s)
- A E Salcini
- Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy
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28
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Martina JA, Bonangelino CJ, Aguilar RC, Bonifacino JS. Stonin 2: an adaptor-like protein that interacts with components of the endocytic machinery. J Cell Biol 2001; 153:1111-20. [PMID: 11381094 PMCID: PMC2174325 DOI: 10.1083/jcb.153.5.1111] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endocytosis of cell surface proteins is mediated by a complex molecular machinery that assembles on the inner surface of the plasma membrane. Here, we report the identification of two ubiquitously expressed human proteins, stonin 1 and stonin 2, related to components of the endocytic machinery. The human stonins are homologous to the Drosophila melanogaster stoned B protein and exhibit a modular structure consisting of an NH(2)-terminal proline-rich domain, a central region of homology specific to the stonins, and a COOH-terminal region homologous to the mu subunits of adaptor protein (AP) complexes. Stonin 2, but not stonin 1, interacts with the endocytic machinery proteins Eps15, Eps15R, and intersectin 1. These interactions occur via two NPF motifs in the proline-rich domain of stonin 2 and Eps15 homology domains of Eps15, Eps15R, and intersectin 1. Stonin 2 also interacts indirectly with the adaptor protein complex, AP-2. In addition, stonin 2 binds to the C2B domains of synaptotagmins I and II. Overexpression of GFP-stonin 2 interferes with recruitment of AP-2 to the plasma membrane and impairs internalization of the transferrin, epidermal growth factor, and low density lipoprotein receptors. These observations suggest that stonin 2 is a novel component of the general endocytic machinery.
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Affiliation(s)
- José A. Martina
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Cecilia J. Bonangelino
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Rubén C. Aguilar
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
| | - Juan S. Bonifacino
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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29
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Bean AJ, Davanger S, Chou MF, Gerhardt B, Tsujimoto S, Chang Y. Hrs-2 regulates receptor-mediated endocytosis via interactions with Eps15. J Biol Chem 2000; 275:15271-8. [PMID: 10809762 DOI: 10.1074/jbc.275.20.15271] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hrs-2, via interactions with SNAP-25, plays a regulatory role on the exocytic machinery. We now show that Hrs-2 physically interacts with Eps15, a protein required for receptor-mediated endocytosis. The Hrs-2/Eps15 interaction is calcium dependent, inhibited by SNAP-25 and alpha-adaptin, and results in the inhibition of receptor-mediated endocytosis. Immunoelectron microscopy reveals Hrs-2 localization on the limiting membrane of multivesicular bodies, organelles in the endosomal pathway. These data show that Hrs-2 regulates endocytosis, delineate a biochemical pathway (Hrs-2-Eps15-AP2) in which Hrs-2 functions, and suggest that Hrs-2 acts to provide communication between endo- and exocytic processes.
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Affiliation(s)
- A J Bean
- Department of Neurobiology and Anatomy, and The W. M. Keck Center for the Neurobiology of Learning and Memory, University of Texas Medical School, Houston, Texas 77030, USA
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30
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Enmon JL, de Beer T, Overduin M. Solution structure of Eps15's third EH domain reveals coincident Phe-Trp and Asn-Pro-Phe binding sites. Biochemistry 2000; 39:4309-19. [PMID: 10757979 DOI: 10.1021/bi9927383] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Eps15 homology (EH) domains interact with proteins involved in endocytosis and signal transduction. EH domains bind to Asn-Pro-Phe (NPF) consensus motifs of target proteins. A few EH domains, such as the third EH domain (EH(3)) of human Eps15, prefer to bind Phe-Trp (FW) sequences. The structure of EH(3) has been solved by nuclear magnetic resonance (NMR) spectroscopy and is the first of an FW- and NPF-binding EH domain. Both FW and NPF sequences bind in the same hydrophobic pocket as shown by heteronuclear chemical shift mapping. EH(3) contains the dual EF-hand fold characteristic of the EH domain family, but it binds calcium with high affinity in the first EF-hand rather than the usual coordination in the second EF-hand. Point mutations were designed based on differences in the EH(3) and the second EH domain (EH(2)) of human Eps15 that alter the affinity of the domains for FW or NPF motif peptides. Peptides that mimic binding sites in the potential EH(3) targets Rab, synaptojanin, and the cation-dependent mannose 6-phosphate receptor were used to explore wild-type and mutant affinities. Characterization of the structure and binding properties of an FW- and NPF-binding EH domain and comparison to an NPF-specific EH domain provide important insights into the mechanisms of EH domain ligand recognition.
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Affiliation(s)
- J L Enmon
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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31
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Benmerah A, Poupon V, Cerf-Bensussan N, Dautry-Varsat A. Mapping of Eps15 domains involved in its targeting to clathrin-coated pits. J Biol Chem 2000; 275:3288-95. [PMID: 10652316 DOI: 10.1074/jbc.275.5.3288] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Clathrin-coated pit (CCP) formation occurs as a result of the targeting and assembly of cytosolic coat proteins, mainly the plasma membrane clathrin-associated protein complex (AP-2) and clathrin, to the intracellular face of the plasma membrane. In the present study, the mechanisms by which Eps15, an AP-2-binding protein, is targeted to CCPs was analyzed by following the intracellular localization of Eps15 mutants fused to the green fluorescent protein. Our previous results indicated that the N-terminal Eps15 homology (EH) domains are required for CCP targeting. We now show that EH domains are, however, not sufficient for targeting to CCPs. Similarly, neither the central coiled-coil nor the C-terminal AP-2 binding domains were able to address green fluorescent protein to CCPs. Thus, targeting of Eps15 to CCPs likely results from the collaboration between EH domains and another domain of the protein. An Eps15 mutant lacking the coiled-coil domain localized to CCPs showing that Eps15 dimerization is not strictly required. In contrast, Eps15 mutants lacking all AP-2 binding sites showed a dramatic decrease in plasma membrane staining, showing that AP-2 binding sites, together with EH domains, play an important role in targeting Eps15 into CCPs. Finally, the effect of the Eps15 mutants on clathrin-dependent endocytosis was tested by both immunofluorescence and flow cytometry. The results obtained showed that inhibition of transferrin uptake was observed only with mutants able to interfere with CCP assembly.
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Affiliation(s)
- A Benmerah
- INSERM E9925, Faculté Necker-Enfants Malades, 156 rue de Vaugirard, 75730 Paris, Cedex 15, France.
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32
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Abstract
The EH domain is an evolutionary conserved protein-protein interaction domain present in a growing number of proteins from yeast to mammals. Even though the domain was discovered just 5 years ago, a great deal has been learned regarding its three-dimensional structure and binding specificities. Moreover, a number of cellular ligands of the domain have been identified and demonstrated to define a complex network of protein-protein interactions in the eukaryotic cell. Interestingly, many of the EH-containing and EH-binding proteins display characteristics of endocytic "accessory" proteins, suggesting that the principal function of the EH network is to regulate various steps in endocytosis. In addition, recent evidence suggests that the EH network might work as an "integrator" of signals controlling cellular pathways as diverse as endocytosis, nucleocytosolic export, and ultimately cell proliferation.
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Affiliation(s)
- E Santolini
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
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Poupon V, Bègue B, Gagnon J, Dautry-Varsat A, Cerf-Bensussan N, Benmerah A. Molecular cloning and characterization of MT-ACT48, a novel mitochondrial acyl-CoA thioesterase. J Biol Chem 1999; 274:19188-94. [PMID: 10383425 DOI: 10.1074/jbc.274.27.19188] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
While characterizing Eps15 partners, we identified a 48-kDa polypeptide (p48) which was precipitated by Eps15-derived glutathione S-transferase fusion proteins. A search in a murine expressed sequence tag data base with N-terminal microsequences of p48 led to the identification of two complete cDNA clones encoding two isoforms of a 439-amino acid protein sharing 95% nucleic and amino acid identity. Northern blot and immunoblotting studies showed that p48 was ubiquitously expressed. A significant homology (19% identity and 40% similarity) between p48 and rat brain cytosolic acyl-CoA thioesterase was observed in an 80-amino acid C-terminal domain, retrieved from proteins from human, nematode, and plants. The thioesterase function of p48 was further demonstrated against long chain acyl-CoAs in a spectrophotometric assay. Furthermore, data obtained from sequence analysis showed that p48 contained a mitochondrial targeting signal, cleaved in mature protein as assessed by microsequencing. The mitochondrial localization of both endogenous and transfected p48 was confirmed by confocal microscopy. These results indicate that p48, called MT-ACT48 (mitochondrial acyl-CoA thioesterase of 48 kDa), defines a novel family of mitochondrial long chain acyl-CoA thioesterases.
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Affiliation(s)
- V Poupon
- CJF 97-10 INSERM, Faculté Necker-Enfants Malades, 156 rue de Vaugirard, 75756 Paris Cedex 15, France
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34
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Mintz L, Galperin E, Pasmanik-Chor M, Tulzinsky S, Bromberg Y, Kozak CA, Joyner A, Fein A, Horowitz M. EHD1--an EH-domain-containing protein with a specific expression pattern. Genomics 1999; 59:66-76. [PMID: 10395801 DOI: 10.1006/geno.1999.5800] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A cDNA that is a member of the eps15 homology (EH)-domain-containing family and is expressed differentially in testis was isolated from mouse and human. The corresponding genes map to the centromeric region of mouse chromosome 19 and to the region of conserved synteny on human chromosome 11q13. Northern analysis revealed two RNA species in mouse. In addition to the high levels in testis, expression was noted in kidney, heart, intestine, and brain. In human, three RNA species were evident. The smaller one was predominant in testis, while the largest species was evident in other tissues as well. The predicted protein sequence has an EH domain at its C-terminus, including an EF, a Ca2+ binding motif, and a central coiled-coil structure, as well as a nucleotide binding consensus site at its N-terminus. As such, it is a member of the EH-domain-containing protein family and was designated EHD1 (EH domain-containing 1). In cells in tissue culture, we localized EHD1 as a green fluorescent protein fusion protein, in transferrin-containing, endocytic vesicles. Immunostaining of different adult mouse organs revealed major expression of EHD1 in germ cells in meiosis, in the testes, in adipocytes, and in specific retinal layers. Results of in situ hybridization to whole embryos and immunohistochemical analyses indicated that EHD1 expression was already noted at day 9.5 in the limb buds and pharyngeal arches and at day 10.5 in sclerotomes, at various elements of the branchial apparatus (mandible and hyoid), and in the occipital region. At day 15.5 EHD1 expression peaked in cartilage, preceding hypertrophy and ossification, and at day 17.5 there was no expression in the bones. The EHD1 gene is highly conserved between nematode, Drosophila, mouse, and human. Its predicted protein structure and cellular localization point to the possibility that EHD1 participates in ligand-induced endocytosis.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Northern
- COS Cells
- Carrier Proteins/genetics
- Chromosome Mapping
- Chromosomes/genetics
- Chromosomes, Human, Pair 11/genetics
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Embryo, Mammalian/metabolism
- Embryonic and Fetal Development
- Endocytosis
- Female
- Gene Expression
- Gene Expression Regulation, Developmental
- Green Fluorescent Proteins
- HeLa Cells
- Humans
- In Situ Hybridization
- Luminescent Proteins/genetics
- Male
- Mice
- Mice, Inbred ICR
- Mice, Inbred Strains
- Molecular Sequence Data
- Muridae
- RNA/genetics
- RNA/metabolism
- Recombinant Fusion Proteins/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
- Vesicular Transport Proteins
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Affiliation(s)
- L Mintz
- Department of Cell Research and Immunology, Tel-Aviv University, Ramat-Aviv, 69978, Israel
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35
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Boleti H, Benmerah A, Ojcius DM, Cerf-Bensussan N, Dautry-Varsat A. Chlamydia infection of epithelial cells expressing dynamin and Eps15 mutants: clathrin-independent entry into cells and dynamin-dependent productive growth. J Cell Sci 1999; 112 ( Pt 10):1487-96. [PMID: 10212143 DOI: 10.1242/jcs.112.10.1487] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chlamydiae enter epithelial cells via a mechanism that still remains to be fully elucidated. In this study we investigated the pathway of entry of C. psittaci GPIC and C. trachomatis LGV/L2 into HeLa cells and demonstrated that it does not depend on clathrin coated vesicle formation. We used mutant cell lines defective in clathrin-mediated endocytosis due to overexpression of dominant negative mutants of either dynamin I or Eps15 proteins. When clathrin-dependent endocytosis was inhibited by overexpression of the dynK44A mutant of dynamin I (defective in GTPase activity), Chlamydia entry was not affected. However, in these cells there was a dramatic inhibition in the proliferation of Chlamydia and the growth of the chlamydia vacuole (inclusion). When clathrin-dependent endocytosis was inhibited by overexpression of an Eps15 dominant negative mutant, the entry and growth of Chlamydia was unaltered. These results indicate that the effect on the growth of Chlamydia in the dynK44A cells was not simply due to a deprivation of nutrients taken up by endocytosis. Instead, the dominant-negative mutant of dynamin most likely affects the vesicular traffic between the Chlamydia inclusion and intracellular membrane compartments. In addition, cytochalasin D inhibited Chlamydia entry by more than 90%, indicating that chlamydiae enter epithelial cells by an actin-dependent mechanism resembling phagocytosis. Finally, dynamin is apparently not involved in the formation of phagocytic vesicles containing Chlamydia.
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Affiliation(s)
- H Boleti
- Unité de Biologie des Interactions Cellulaires, Institut Pasteur, URA CNRS 1960, rue du Dr Roux, France.
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36
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Benmerah A, Bayrou M, Cerf-Bensussan N, Dautry-Varsat A. Inhibition of clathrin-coated pit assembly by an Eps15 mutant. J Cell Sci 1999; 112 ( Pt 9):1303-11. [PMID: 10194409 DOI: 10.1242/jcs.112.9.1303] [Citation(s) in RCA: 331] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent data have shown that Eps15, a newly identified component of clathrin-coated pits constitutively associated with the AP-2 complex, is required for receptor-mediated endocytosis. However, its precise function remains unknown. Interestingly, Eps15 contains three EH (Eps15-Homology) domains also found in proteins required for the internalization step of endocytosis in yeast. Results presented here show that EH domains are required for correct coated pit targeting of Eps15. Furthermore, when cells expressed an Eps15 mutant lacking EH domains, the plasma membrane punctate distribution of both AP-2 and clathrin was lost, implying the absence of coated pits. This was further confirmed by the fact that dynamin, a GTPase found in coated pits, was homogeneously redistributed on the plasma membrane and that endocytosis of transferrin, a specific marker of clathrin-dependent endocytosis, was strongly inhibited. Altogether, these results strongly suggest a role for Eps15 in coated pit assembly and more precisely a role for Eps15 in the docking of AP-2 onto the plasma membrane. This hypothesis is supported by the fact that a GFP fusion protein encoding the ear domain of (alpha)-adaptin, the AP-2 binding site for Eps15, was efficiently targeted to plasma membrane coated pits.
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Affiliation(s)
- A Benmerah
- Unité de Biologie des Interactions Cellulaires, URA-CNRS 1960, Institut Pasteur, 75724 Paris Cedex 15, France.
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37
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Sengar AS, Wang W, Bishay J, Cohen S, Egan SE. The EH and SH3 domain Ese proteins regulate endocytosis by linking to dynamin and Eps15. EMBO J 1999; 18:1159-71. [PMID: 10064583 PMCID: PMC1171207 DOI: 10.1093/emboj/18.5.1159] [Citation(s) in RCA: 189] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Clathrin-mediated endocytosis is a multistep process which requires interaction between a number of conserved proteins. We have cloned two mammalian genes which code for a number of endocytic adaptor proteins. Two of these proteins, termed Ese1 and Ese2, contain two N-terminal EH domains, a central coiled-coil domain and five C-terminal SH3 domains. Ese1 is constitutively associated with Eps15 proteins to form a complex with at least 14 protein-protein interaction surfaces. Yeast two-hybrid assays have revealed that Ese1 EH and SH3 domains bind epsin family proteins and dynamin, respectively. Overexpression of Ese1 is sufficient to block clathrin-mediated endocytosis in cultured cells, presumably through disruption of higher order protein complexes, which are assembled on the endogenous Ese1-Eps15 scaffold. The Ese1-Eps15 scaffold therefore links dynamin, epsin and other endocytic pathway components.
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Affiliation(s)
- A S Sengar
- Programs of Cancer and Blood Research, and Developmental Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada.
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38
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Abstract
A number of proteins that have been implicated in endocytosis feature a conserved protein-interaction module known as an EH domain. The three-dimensional structure of an EH domain has recently been solved, and is likely to presage significant advances in understanding molecular mechanisms of endocytosis.
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Affiliation(s)
- B J Mayer
- Howard Hughes Medical Institute, Children's Hospital, Department of Microbiology, Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts, 02115, USA.
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39
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Barth HG, Boyes BE, Jackson C. Size Exclusion Chromatography and Related Separation Techniques. Anal Chem 1998. [DOI: 10.1021/a1980015t] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Howard G. Barth
- Central Research and Development, DuPont Company, Experimental Station, P.O. Box 80228, Wilmington, Delaware 19880-0228, Little Falls Analytical DivisionNewport, Hewlett-Packard Company, 538 First State Boulevard, Newport, Delaware 19804, and Marshall Laboratory, DuPont Automative Products, 3401 Grays Ferry Avenue, Philadelphia, Pennsylvania 19146
| | - Barry E. Boyes
- Central Research and Development, DuPont Company, Experimental Station, P.O. Box 80228, Wilmington, Delaware 19880-0228, Little Falls Analytical DivisionNewport, Hewlett-Packard Company, 538 First State Boulevard, Newport, Delaware 19804, and Marshall Laboratory, DuPont Automative Products, 3401 Grays Ferry Avenue, Philadelphia, Pennsylvania 19146
| | - Christian Jackson
- Central Research and Development, DuPont Company, Experimental Station, P.O. Box 80228, Wilmington, Delaware 19880-0228, Little Falls Analytical DivisionNewport, Hewlett-Packard Company, 538 First State Boulevard, Newport, Delaware 19804, and Marshall Laboratory, DuPont Automative Products, 3401 Grays Ferry Avenue, Philadelphia, Pennsylvania 19146
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40
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Wendland B, Emr SD. Pan1p, yeast eps15, functions as a multivalent adaptor that coordinates protein-protein interactions essential for endocytosis. J Cell Biol 1998; 141:71-84. [PMID: 9531549 PMCID: PMC2132731 DOI: 10.1083/jcb.141.1.71] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A genetic screen for factors required for endocytosis in the budding yeast Saccharomyces cerevisiae previously identified PAN1. Pan1p is a homologue of the mammalian protein eps15, which has been implicated in endocytosis by virtue of its association with the plasma membrane clathrin adaptor complex AP-2. Pan1p contains two eps15 homology (EH) domains, a protein-protein interaction motif also present in other proteins that function in membrane trafficking. To address the role of Pan1p and EH domains in endocytosis, a yeast two-hybrid screen was performed using the EH domain-containing region of Pan1p. This screen identified yAP180A, one of two yeast homologues of a class of clathrin assembly proteins (AP180) that exhibit in vitro clathrin cage assembly activity. In vitro binding studies using GST fusion proteins and yeast extracts defined distinct binding sites on yAP180A for Pan1p and clathrin. yAP180 proteins and Pan1p, like actin, localize to peripheral patches along the plasma membrane. Mammalian synaptojanin, a phosphatidylinositol polyphosphate-5-phosphatase, also has been implicated in endocytosis recently, and three synaptojanin-like genes have been identified in yeast. We observed genetic interactions between the yeast SJL1 gene and PAN1, which suggest a role for phosphoinositide metabolites in Pan1p function. Together with other studies, these findings suggest that Pan1p coordinates regulatory interactions between proteins required for both endocytosis and actin-cytoskeleton organization; these proteins include the yAP180 proteins, clathrin, the ubiquitin-protein ligase Rsp5p, End3p, and synaptojanin. We suggest that Pan1p (and by extension eps15) serves as a multivalent adaptor around which dynamic interactions between structural and regulatory components of the endocytic pathway converge.
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Affiliation(s)
- B Wendland
- Howard Hughes Medical Institute, Division of Cellular and Molecular Medicine, University of California at San Diego, School of Medicine, La Jolla, California 92093-0668, USA.
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41
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McPherson PS, de Heuvel E, Phillie J, Wang W, Sengar A, Egan S. EH domain-dependent interactions between Eps15 and clathrin-coated vesicle protein p95. Biochem Biophys Res Commun 1998; 244:701-5. [PMID: 9535728 DOI: 10.1006/bbrc.1998.8331] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The endocytic protein Eps15 contains three copies of the EH domain, a protein module thought to function in protein-protein interactions. Using overlay assays with an Eps15 EH domain fusion protein, we have now identified a protein of 95 kDa (p95) as a major EH domain-binding partner in a wide variety of tissues. The amino acids asparagine-proline-phenylalanine (NPF) form the core of an EH domain-binding motif and three NPF repeats are found in the endocytic protein synaptojanin-170. We have confirmed previous studies indicating that synaptojanin-170 is an EH domain-binding protein, and have used peptide blocking experiments to demonstrate that the interaction is mediated through the NPF repeats. Interestingly, the same peptide also blocks EH domain-binding to p95. Finally, we have shown that p95 is enriched on clathrin-coated vesicles, suggesting an endocytic role for the protein. These data support an important role for EH domain-NPF motif interactions in endocytosis.
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Affiliation(s)
- P S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Quebec, Canada.
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42
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Benmerah A, Lamaze C, Bègue B, Schmid SL, Dautry-Varsat A, Cerf-Bensussan N. AP-2/Eps15 interaction is required for receptor-mediated endocytosis. J Cell Biol 1998; 140:1055-62. [PMID: 9490719 PMCID: PMC2132690 DOI: 10.1083/jcb.140.5.1055] [Citation(s) in RCA: 301] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We have previously shown that the protein Eps15 is constitutively associated with the plasma membrane adaptor complex, AP-2, suggesting its possible role in endocytosis. To explore the role of Eps15 and the function of AP-2/Eps15 association in endocytosis, the Eps15 binding domain for AP-2 was precisely delineated. The entire COOH-terminal domain of Eps15 or a mutant form lacking all the AP-2-binding sites was fused to the green fluorescent protein (GFP), and these constructs were transiently transfected in HeLa cells. Overexpression of the fusion protein containing the entire COOH-terminal domain of Eps15 strongly inhibited endocytosis of transferrin, whereas the fusion protein in which the AP-2-binding sites had been deleted had no effect. These results were confirmed in a cell-free assay that uses perforated A431 cells to follow the first steps of coated vesicle formation at the plasma membrane. Addition of Eps15-derived glutathione-S-transferase fusion proteins containing the AP-2-binding site in this assay inhibited not only constitutive endocytosis of transferrin but also ligand-induced endocytosis of epidermal growth factor. This inhibition could be ascribed to a competition between the fusion protein and endogenous Eps15 for AP-2 binding. Altogether, these results show that interaction of Eps15 with AP-2 is required for efficient receptor-mediated endocytosis and thus provide the first evidence that Eps15 is involved in the function of plasma membrane-coated pits.
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Affiliation(s)
- A Benmerah
- Developpement Normal et Pathologique du Systeme Immunitaire, Institut National de la Sante et de la Recherche Medicale U 429, Hopital Necker-Enfants Malades, 75743 Paris Cedex 15, France
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43
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Coda L, Salcini AE, Confalonieri S, Pelicci G, Sorkina T, Sorkin A, Pelicci PG, Di Fiore PP. Eps15R is a tyrosine kinase substrate with characteristics of a docking protein possibly involved in coated pits-mediated internalization. J Biol Chem 1998; 273:3003-12. [PMID: 9446614 DOI: 10.1074/jbc.273.5.3003] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
eps15R was identified because of its relatedness to eps15, a gene encoding a tyrosine kinase substrate bearing a novel protein-protein interaction domain, called EH. In this paper, we report a biochemical characterization of the eps15R gene product(s). In NIH-3T3 cells, three proteins of 125, 108, and 76 kDa were specifically recognized by anti-eps15R sera. The 125-kDa species is a bona fide product of the eps15R gene, whereas p108 and p76 are most likely products of alternative splicing events. Eps15R protein(s) are tyrosine-phosphorylated following epidermal growth factor receptor activation in NIH-3T3 cells overexpressing the receptor, even at low levels of receptor occupancy, thus behaving as physiological substrates. A role for eps15R in clathrin-mediated endocytosis is suggested by its localization in plasma membrane-coated pits and in vivo association to the coated pits' adapter protein AP-2. Finally, we demonstrate that a sizable fraction of eps15R exists in the cell as a complex with eps15 and that its EH domains exhibit binding specificities that are partially distinct from those of eps15. We propose that eps15 and eps15R are multifunctional binding proteins that serve pleiotropic functions within the cell.
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Affiliation(s)
- L Coda
- Department of Experimental Oncology, European Institute of Oncology, 20141 Milan, Italy
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44
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Cupers P, Jadhav AP, Kirchhausen T. Assembly of clathrin coats disrupts the association between Eps15 and AP-2 adaptors. J Biol Chem 1998; 273:1847-50. [PMID: 9442014 DOI: 10.1074/jbc.273.4.1847] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Eps15 is a phosphorylation substrate of the epidermal growth factor receptor kinase. In vivo, it is largely found in complex with AP-2, the plasma membrane clathrin adaptor protein complex. Although AP-2 is uniformly distributed across the surface of clathrin-coated pits and vesicles, Eps15 is preferentially found in the rims of endocytic clathrin-coated pits (1). This observation suggests that Eps15 may disengage from AP-2 during coat formation. Here we use two new anti-Eps15 antibodies to show that, contrary to our own earlier suggestion, coated vesicles isolated from brain do not contain detectable amounts of Eps15. Furthermore, when AP-2 complexes that are saturated with Eps15 are used for in vitro assembly of clathrin-AP-2 coats, normal structures are formed that contain the expected amounts of clathrin and AP-2, but the amount of Eps15 present is dramatically lower than that of AP-2. We propose that during coated pit formation, addition of clathrin to the growing edge at the rim of the pit releases Eps15 from AP-2.
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Affiliation(s)
- P Cupers
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
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45
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Zucker S, Drews M, Conner C, Foda HD, DeClerck YA, Langley KE, Bahou WF, Docherty AJ, Cao J. Tissue inhibitor of metalloproteinase-2 (TIMP-2) binds to the catalytic domain of the cell surface receptor, membrane type 1-matrix metalloproteinase 1 (MT1-MMP). J Biol Chem 1998; 273:1216-22. [PMID: 9422789 DOI: 10.1074/jbc.273.2.1216] [Citation(s) in RCA: 233] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It has been proposed that tissue inhibitor of metalloproteinase-2 (TIMP-2), in stoichiometric concentrations, serves as an intermediate in progelatinase A activation by binding to activated membrane type 1-matrix metalloproteinase 1 (MT1-MMP) on the plasma membrane. An MT1-MMP-independent cell surface receptor for TIMP-2 has also been postulated. To clarify TIMP-2 binding, we have performed 125I-TIMP-2 binding studies on transfected COS-1 cells and endothelial cells. Specific receptors for TIMP-2 were identified on COS-1 cells transfected with MT1-MMP cDNA, but not on vector-transfected cells. Treatment of MT1-MMP transfected COS-1 cells with a hydroxamic acid inhibitor of MMPs, CT-1746, but not an inactive stereoisomer, CT-1915, produced dose-dependent inhibition of specific TIMP-2 binding comparable with that noted with excess unlabeled TIMP-2. This result suggests that TIMP-2 binds to the zinc catalytic site of MT1-MMP. As demonstrated by the limited competition for binding of C-terminal deleted TIMP-2, the C-terminal domain of TIMP-2 participates in binding to MT1-MMP. Cross-linking studies followed by immunoprecipitation using antibodies to MT1-MMP were employed to identify 125I-TIMP-2.MT1-MMP complexes in MT1-MMP-transfected COS-1 cell membrane extracts. TIMP-2 receptors were also identified on concanavalin A-treated human umbilical vein endothelial cells; inhibition of TIMP-2 binding with CT-1746 was demonstrated.
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Affiliation(s)
- S Zucker
- Department of Medicine, Department of Veterans Affairs Medical Center, Northport, New York 11768, USA
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46
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Cupers P, ter Haar E, Boll W, Kirchhausen T. Parallel dimers and anti-parallel tetramers formed by epidermal growth factor receptor pathway substrate clone 15. J Biol Chem 1997; 272:33430-4. [PMID: 9407139 DOI: 10.1074/jbc.272.52.33430] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The recently discovered localization of epidermal growth factor receptor pathway substrate clone 15 (Eps15) to plasma membrane clathrin-coated pits and its constitutive association with the endocytic clathrin adaptor protein complex, AP-2, strongly suggest that Eps15 has an important role in the pathway of clathrin-dependent endocytic traffic. We report here that Eps15 forms dimers and tetramers of distinct shape. The Eps15 dimer is an elongated molecule, 32 nm in length. There is a globular "head" at one end of the molecule and an extended "stalk" of 25 nm which is kinked at about 17 nm away from the head. In the Eps15 dimer, two subunits are arranged parallel to each other, so that the head corresponds to two side by side copies of the N-terminal region I, which contains the three Eps15 homology domains. The proximal part of the stalk is the coiled-coil central region II containing 20 heptad repeats. The kink is at the boundary between region II and the C-terminal region III, which contains the AP-2 binding site, 15 aspartic-proline-phenylalanine repeats, and proline-rich Src homology domain ligand sites. The Eps15 tetramer has a "dumbbell" shape, approximately 31 nm in length; it is formed by the anti-parallel association of two Eps15 dimers. Formation of these Eps15 tetramers appears to require contacts between regions I of one dimer and regions III of a second apposing dimer. The extended shapes of the Eps15 dimers and tetramers suggest how Eps15 oligomers are located in the clathrin coat. We discuss the implications for accessibility to partners and for proposed functions of Eps15.
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Affiliation(s)
- P Cupers
- Department of Cell Biology, Harvard Medical School and The Center for Blood Research, Boston, Massachusetts 02115, USA
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47
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Yamaguchi A, Urano T, Goi T, Feig LA. An Eps homology (EH) domain protein that binds to the Ral-GTPase target, RalBP1. J Biol Chem 1997; 272:31230-4. [PMID: 9395447 DOI: 10.1074/jbc.272.50.31230] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Ral proteins constitute a family of small GTPases that can be activated by Ras in cells. In the GTP-bound state, Ral proteins bind to RalBP1, a GTPase-activating protein for CDC42 and Rac GTPases. We have used the two-hybrid system in yeast to clone a cDNA for a novel approximately 85-kDa protein that can bind to an additional site on RalBP1. This newly identified protein contains an Eps homology (EH) domain, which was first detected in the epidermal growth factor (EGF) receptor substrate Eps15. Recently, the EH domain of Eps15 has been shown to bind to proteins containing an asparagine-proline-phenylalanine motif. Moreover, EH domains have been found in proteins involved in endocytosis and/or actin cytoskeleton regulation. The RalBP1 associated Eps-homology domain protein, Reps1, is tyrosine-phosphorylated in response to EGF stimulation of cells. In addition, Reps1 has the capacity to form a complex with the SH3 domains of the adapter proteins Crk and Grb2, which may link Reps1 to an EGF-responsive tyrosine kinase. Thus, Reps1 may coordinate the cellular actions of activated EGF receptors and Ral-GTPases.
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Affiliation(s)
- A Yamaguchi
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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