The Experts below are selected from a list of 399 Experts worldwide ranked by ideXlab platform
Axel T. Brunger - One of the best experts on this subject based on the ideXlab platform.
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Brief Report Epsin 1 Undergoes Nucleocytosolic Shuttling and its Eps15 Interactor NH 2-terminal Homology (ENTH) Domain, Structurally Similar to Armadillo and HEAT Repeats, Interacts with the Transcription Factor Promyelocytic Leukemia Zn 2 � Finger P
2013Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Abstract. Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH 2-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH 2-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 Å resolution. This Domain is structurally similar to armadillo and Heat repeats of �-catenin and karyopherin-�, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn 2 � finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function. Key words: clathrin • Eps15 homology Domain • catenin • karyopherin • endocytosi
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The ENTH Domain.
FEBS letters, 2002Co-Authors: Pietro De Camilli, Hong Chen, Joel M. Hyman, Ezequiel Panepucci, Alex Bateman, Axel T. BrungerAbstract:The epsin NH2-terminal homology (ENTH) Domain is a membrane interacting module composed by a superhelix of α-helices. It is present at the NH2-terminus of proteins that often contain consensus sequences for binding to clathrin coat components and their accessory factors, and therefore function as endocytic adaptors. ENTH Domain containing proteins have additional roles in signaling and actin regulation and may have yet other actions in the nucleus. The ENTH Domain is structurally similar to the VHS Domain. These Domains define two families of adaptor proteins which function in membrane traffic and whose interaction with membranes is regulated, in part, by phosphoinositides.
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Epsin 1 Undergoes Nucleocytosolic Shuttling and Its Eps15 Interactor Nh2-Terminal Homology (ENTH) Domain, Structurally Similar to Armadillo and Heat Repeats, Interacts with the Transcription Factor Promyelocytic Leukemia Zn2+ Finger Protein (Plzf)
The Journal of cell biology, 2000Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH2-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH2-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 A resolution. This Domain is structurally similar to armadillo and Heat repeats of β-catenin and karyopherin-β, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn2+ finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1- dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function.
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Epsin 1 undergoes nucleocytosolic shuttling and its eps15 interactor NH(2)-terminal homology (ENTH) Domain, structurally similar to Armadillo and HEAT repeats, interacts with the transcription factor promyelocytic leukemia Zn(2)+ finger protein (PLZF
'Rockefeller University Press', 2000Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH(2)-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH(2)-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 A resolution. This Domain is structurally similar to armadillo and Heat repeats of beta-catenin and karyopherin-beta, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn(2)+ finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1- dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function
Inhwan Hwang - One of the best experts on this subject based on the ideXlab platform.
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The A/ENTH Domain-Containing Protein AtECA4 Is an Adaptor Protein Involved in Cargo Recycling from the trans-Golgi Network/Early Endosome to the Plasma Membrane
Molecular plant, 2018Co-Authors: Hong Hanh Nguyen, Kyungyoung Song, Myoung Hui Lee, Gyeongik Ahn, Jihyeong Lee, Inhwan HwangAbstract:Endocytosis and subsequent trafficking pathways are crucial for regulating the activity of plasma membrane-localized proteins. Depending on cellular and physiological conditions, the internalized cargoes are sorted at (and transported from) the trans-Golgi network/early endosome (TGN/EE) to the vacuole for degradation or recycled back to the plasma membrane. How this occurs at the molecular level remains largely elusive. Here, we provide evidence that the ENTH Domain-containing protein AtECA4 plays a crucial role in recycling cargoes from the TGN/EE to the plasma membrane in Arabidopsis thaliana. AtECA4:sGFP primarily localized to the TGN/EE and plasma membrane (at low levels). Upon NaCl or mannitol treatment, AtECA4:sGFP accumulated at the TGN/EE at an early time point but was released from the TGN/EE to the cytosol at later time points. The ateca4 mutant showed higher resistance to osmotic stress and more sensitive to exogenous abscisic acid (ABA) than the wild type, as well as increased expression of ABA-inducible genes RD29A and RD29B. Consistently, ABCG25, a plasma membrane-localized ABA exporter, accumulated at the prevacuolar compartment in ateca4, indicating a defect in recycling to the plasma membrane. However, the role of AtECA4 in cargo recycling is not specific to ABCG25, as it also functions in the recycling of BRI1. These results suggest that AtECA4 plays a crucial role in the recycling of endocytosed cargoes from the TGN/EE to the plasma membrane.
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An A/ENTH Domain-Containing Protein Functions as an Adaptor for Clathrin-Coated Vesicles on the Growing Cell Plate in Arabidopsis Root Cells
Plant Physiology, 2012Co-Authors: Kyungyoung Song, Mihue Jang, Inhwan HwangAbstract:Cytokinesis is the process of partitioning the cytoplasm of a dividing cell, thereby completing mitosis. Cytokinesis in the plant cell is achieved by the formation of a new cell wall between daughter nuclei using components carried in Golgi-derived vesicles that accumulate at the midplane of the phragmoplast and fuse to form the cell plate. Proteins that play major roles in the development of the cell plate in plant cells are not well defined. Here, we report that an AP180 amino-terminal homology/epsin amino-terminal homology Domain-containing protein from Arabidopsis (Arabidopsis thaliana) is involved in clathrin-coated vesicle formation from the cell plate. Arabidopsis Epsin-like Clathrin Adaptor1 (AtECA1; At2g01600) and its homologous proteins AtECA2 and AtECA4 localize to the growing cell plate in cells undergoing cytokinesis and also to the plasma membrane and endosomes in nondividing cells. AtECA1 (At2g01600) does not localize to nascent cell plates but localizes at higher levels to expanding cell plates even after the cell plate fuses with the parental plasma membrane. The temporal and spatial localization patterns of AtECA1 overlap most closely with those of the clathrin light chain. In vitro protein interaction assays revealed that AtECA1 binds to the clathrin H chain via its carboxyl-terminal Domain. These results suggest that these AP180 amino-terminal homology/epsin amino-terminal homology Domain-containing proteins, AtECA1, AtECA2, and AtECA4, may function as adaptors of clathrin-coated vesicles budding from the cell plate.
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EpsinR2 interacts with clathrin, adaptor protein-3, AtVTI12, and phosphatidylinositol-3-phosphate. Implications for EpsinR2 function in protein trafficking in plant cells.
Plant physiology, 2007Co-Authors: Gil-je Lee, Hyeran Kim, Hyangju Kang, Meehee Jang, Dong-wook Lee, Sookjin Lee, Inhwan HwangAbstract:Members of the epsin family of proteins (epsins) are characterized by the presence of an epsin N-terminal homology (ENTH) Domain. Epsins have been implicated in various protein-trafficking pathways in animal and yeast (Saccharomyces cerevisiae) cells. Plant cells also contain multiple epsin-related proteins. In Arabidopsis (Arabidopsis thaliana), EPSIN1 is involved in vacuolar trafficking of soluble proteins. In this study, we investigated the role of Arabidopsis EpsinR2 in protein trafficking in plant cells. EpsinR2 contains a highly conserved ENTH Domain but a fairly divergent C-terminal sequence. We found that the N-terminal ENTH Domain specifically binds to phosphatidylinositol-3-P in vitro and has a critical role in the targeting of EpsinR2. Upon transient expression in protoplasts, hemagglutinin epitope-tagged EpsinR2 was translocated primarily to a novel cellular compartment, while a minor portion localized to the Golgi complex. Protein-binding experiments showed that EpsinR2 interacts with clathrin, AtVTI12, and the Arabidopsis homologs of adaptor protein-3 δ-adaptin and adaptor protein-2 α-adaptin. Localization experiments revealed that hemagglutinin epitope-tagged EpsinR2 colocalizes primarily with δ-adaptin and partially colocalizes with clathrin and AtVTI12. Based on these findings, we propose that EpsinR2 plays an important role in protein trafficking through interactions with δ-adaptin, AtVTI12, clathrin, and phosphatidylinositol-3-P.
Pietro De Camilli - One of the best experts on this subject based on the ideXlab platform.
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Brief Report Epsin 1 Undergoes Nucleocytosolic Shuttling and its Eps15 Interactor NH 2-terminal Homology (ENTH) Domain, Structurally Similar to Armadillo and HEAT Repeats, Interacts with the Transcription Factor Promyelocytic Leukemia Zn 2 � Finger P
2013Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Abstract. Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH 2-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH 2-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 Å resolution. This Domain is structurally similar to armadillo and Heat repeats of �-catenin and karyopherin-�, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn 2 � finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function. Key words: clathrin • Eps15 homology Domain • catenin • karyopherin • endocytosi
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The ENTH Domain.
FEBS letters, 2002Co-Authors: Pietro De Camilli, Hong Chen, Joel M. Hyman, Ezequiel Panepucci, Alex Bateman, Axel T. BrungerAbstract:The epsin NH2-terminal homology (ENTH) Domain is a membrane interacting module composed by a superhelix of α-helices. It is present at the NH2-terminus of proteins that often contain consensus sequences for binding to clathrin coat components and their accessory factors, and therefore function as endocytic adaptors. ENTH Domain containing proteins have additional roles in signaling and actin regulation and may have yet other actions in the nucleus. The ENTH Domain is structurally similar to the VHS Domain. These Domains define two families of adaptor proteins which function in membrane traffic and whose interaction with membranes is regulated, in part, by phosphoinositides.
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Epsin 1 Undergoes Nucleocytosolic Shuttling and Its Eps15 Interactor Nh2-Terminal Homology (ENTH) Domain, Structurally Similar to Armadillo and Heat Repeats, Interacts with the Transcription Factor Promyelocytic Leukemia Zn2+ Finger Protein (Plzf)
The Journal of cell biology, 2000Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH2-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH2-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 A resolution. This Domain is structurally similar to armadillo and Heat repeats of β-catenin and karyopherin-β, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn2+ finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1- dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function.
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Epsin 1 undergoes nucleocytosolic shuttling and its eps15 interactor NH(2)-terminal homology (ENTH) Domain, structurally similar to Armadillo and HEAT repeats, interacts with the transcription factor promyelocytic leukemia Zn(2)+ finger protein (PLZF
'Rockefeller University Press', 2000Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH(2)-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH(2)-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 A resolution. This Domain is structurally similar to armadillo and Heat repeats of beta-catenin and karyopherin-beta, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn(2)+ finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1- dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function
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the epsins define a family of proteins that interact with components of the clathrin coat and contain a new protein module
Journal of Biological Chemistry, 1999Co-Authors: J A Rosenthal, Hong Chen, Vladimir I Slepnev, Lorenzo Pellegrini, Anna Elisabetta Salcini, P P Di Fiore, Pietro De CamilliAbstract:Abstract Epsin (epsin 1) is an interacting partner for the EH Domain-containing region of Eps15 and has been implicated in conjunction with Eps15 in clathrin-mediated endocytosis. We report here the characterization of a similar protein (epsin 2), which we have cloned from human and rat brain libraries. Epsin 1 and 2 are most similar in their NH2-terminal region, which represents a module (epsin NH2 terminal homology Domain, ENTH Domain) found in a variety of other proteins of the data base. The multiple DPW motifs, typical of the central region of epsin 1, are only partially conserved in epsin 2. Both proteins, however, interact through this central region with the clathrin adaptor AP-2. In addition, we show here that both epsin 1 and 2 interact with clathrin. The three NPF motifs of the COOH-terminal region of epsin 1 are conserved in the corresponding region of epsin 2, consistent with the binding of both proteins to Eps15. Epsin 2, like epsin 1, is enriched in brain, is present in a brain-derived clathrin-coated vesicle fraction, is concentrated in the peri-Golgi region and at the cell periphery of transfected cells, and partially colocalizes with clathrin. High overexpression of green fluorescent protein-epsin 2 mislocalizes components of the clathrin coat and inhibits clathrin-mediated endocytosis. The epsins define a new protein family implicated in membrane dynamics at the cell surface.
Hong Chen - One of the best experts on this subject based on the ideXlab platform.
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Brief Report Epsin 1 Undergoes Nucleocytosolic Shuttling and its Eps15 Interactor NH 2-terminal Homology (ENTH) Domain, Structurally Similar to Armadillo and HEAT Repeats, Interacts with the Transcription Factor Promyelocytic Leukemia Zn 2 � Finger P
2013Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Abstract. Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH 2-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH 2-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 Å resolution. This Domain is structurally similar to armadillo and Heat repeats of �-catenin and karyopherin-�, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn 2 � finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function. Key words: clathrin • Eps15 homology Domain • catenin • karyopherin • endocytosi
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The ENTH Domain.
FEBS letters, 2002Co-Authors: Pietro De Camilli, Hong Chen, Joel M. Hyman, Ezequiel Panepucci, Alex Bateman, Axel T. BrungerAbstract:The epsin NH2-terminal homology (ENTH) Domain is a membrane interacting module composed by a superhelix of α-helices. It is present at the NH2-terminus of proteins that often contain consensus sequences for binding to clathrin coat components and their accessory factors, and therefore function as endocytic adaptors. ENTH Domain containing proteins have additional roles in signaling and actin regulation and may have yet other actions in the nucleus. The ENTH Domain is structurally similar to the VHS Domain. These Domains define two families of adaptor proteins which function in membrane traffic and whose interaction with membranes is regulated, in part, by phosphoinositides.
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Epsin 1 Undergoes Nucleocytosolic Shuttling and Its Eps15 Interactor Nh2-Terminal Homology (ENTH) Domain, Structurally Similar to Armadillo and Heat Repeats, Interacts with the Transcription Factor Promyelocytic Leukemia Zn2+ Finger Protein (Plzf)
The Journal of cell biology, 2000Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH2-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH2-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 A resolution. This Domain is structurally similar to armadillo and Heat repeats of β-catenin and karyopherin-β, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn2+ finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1- dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function.
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Epsin 1 undergoes nucleocytosolic shuttling and its eps15 interactor NH(2)-terminal homology (ENTH) Domain, structurally similar to Armadillo and HEAT repeats, interacts with the transcription factor promyelocytic leukemia Zn(2)+ finger protein (PLZF
'Rockefeller University Press', 2000Co-Authors: Joel Hyman, Pietro De Camilli, Hong Chen, Pier Paolo Di Fiore, Axel T. BrungerAbstract:Epsin (Eps15 interactor) is a cytosolic protein involved in clathrin-mediated endocytosis via its direct interactions with clathrin, the clathrin adaptor AP-2, and Eps15. The NH(2)-terminal portion of epsin contains a phylogenetically conserved module of unknown function, known as the ENTH Domain (epsin NH(2)-terminal homology Domain). We have now solved the crystal structure of rat epsin 1 ENTH Domain to 1.8 A resolution. This Domain is structurally similar to armadillo and Heat repeats of beta-catenin and karyopherin-beta, respectively. We have also identified and characterized the interaction of epsin 1, via the ENTH Domain, with the transcription factor promyelocytic leukemia Zn(2)+ finger protein (PLZF). Leptomycin B, an antifungal antibiotic, which inhibits the Crm1- dependent nuclear export pathway, induces an accumulation of epsin 1 in the nucleus. These findings suggest that epsin 1 may function in a signaling pathway connecting the endocytic machinery to the regulation of nuclear function
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the epsins define a family of proteins that interact with components of the clathrin coat and contain a new protein module
Journal of Biological Chemistry, 1999Co-Authors: J A Rosenthal, Hong Chen, Vladimir I Slepnev, Lorenzo Pellegrini, Anna Elisabetta Salcini, P P Di Fiore, Pietro De CamilliAbstract:Abstract Epsin (epsin 1) is an interacting partner for the EH Domain-containing region of Eps15 and has been implicated in conjunction with Eps15 in clathrin-mediated endocytosis. We report here the characterization of a similar protein (epsin 2), which we have cloned from human and rat brain libraries. Epsin 1 and 2 are most similar in their NH2-terminal region, which represents a module (epsin NH2 terminal homology Domain, ENTH Domain) found in a variety of other proteins of the data base. The multiple DPW motifs, typical of the central region of epsin 1, are only partially conserved in epsin 2. Both proteins, however, interact through this central region with the clathrin adaptor AP-2. In addition, we show here that both epsin 1 and 2 interact with clathrin. The three NPF motifs of the COOH-terminal region of epsin 1 are conserved in the corresponding region of epsin 2, consistent with the binding of both proteins to Eps15. Epsin 2, like epsin 1, is enriched in brain, is present in a brain-derived clathrin-coated vesicle fraction, is concentrated in the peri-Golgi region and at the cell periphery of transfected cells, and partially colocalizes with clathrin. High overexpression of green fluorescent protein-epsin 2 mislocalizes components of the clathrin coat and inhibits clathrin-mediated endocytosis. The epsins define a new protein family implicated in membrane dynamics at the cell surface.
Peter S. Mcpherson - One of the best experts on this subject based on the ideXlab platform.
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Liquid facets-related (lqfR) is required for egg chamber morphogenesis during Drosophila oogenesis.
PloS one, 2011Co-Authors: Peter A. Leventis, Peter S. Mcpherson, Sylwia Wasiak, Tanya R. Da Sylva, Nimerta Rajwans, Gabrielle L. BoulianneAbstract:Clathrin interactor 1 [CLINT1] (also called ENTHoprotin/EpsinR) is an Epsin N-terminal homology (ENTH) Domain-containing adaptor protein that functions in anterograde and retrograde clathrin-mediated trafficking between the trans-Golgi network and the endosome. Removal of both Saccharomyces cerevisiae homologs, Ent3p and Ent5p, result in yeast that are viable, but that display a cold-sensitive growth phenotype and mistrafficking of various vacuolar proteins. Similarly, either knock-down or overexpression of vertebrate CLINT1 in cell culture causes mistrafficking of proteins. Here, we have characterized Drosophila CLINT1, liquid-facets Related (lqfR). LqfR is ubiquitously expressed throughout development and is localized to the Golgi and endosome. Strong hypomorphic mutants generated by imprecise P-element excision exhibit extra macrochaetae, rough eyes and are female sterile. Although essentially no eggs are laid, the ovaries do contain late-stage egg chambers that exhibit abnormal morphology. Germline clones reveal that LqfR expression in the somatic follicle cells is sufficient to rescue the oogenesis defects. Clones of mutant lqfR follicle cells have a decreased cell size consistent with a downregulation of Akt1. We find that while total Akt1 levels are increased there is also a significant decrease in activated phosphorylated Akt1. Taken together, these results show that LqfR function is required to regulate follicle cell size and signaling during Drosophila oogenesis.
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There's a GAP in the ENTH Domain.
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Brigitte Ritter, Peter S. McphersonAbstract:Cell polarity, defined by the asymmetric distribution of cellular components, is a fundamental property of virtually all cell types. The yeast Saccharomyces cerevisiae is an important model system to study the molecular mechanisms of polarity, and lessons learned in this organism have proven applicable to more complex species (1). During cell division, S. cerevisiae undergo a stereotypical form of polarized growth that leads to the formation of a daughter cell. In this process, known as budding, cortical cues deposited during previous cycles of cell division lead to activation of the small GTPase Cdc42, which triggers the formation of actin cables that orient toward the plasma membrane (1). These structures guide the segregation of organelles and act as tracks for secretory vesicles that deliver essential components for bud formation. In close proximity to the exocytic sites, the cells organize sites of endocytosis, which are necessary to counter the potential diffusion of membrane-bound proteins away from the site of polarized growth (2). Endocytic sites are composed of patches of actin interacting with a complex series of endocytic regulatory proteins. Several of the endocytic proteins contain independently folded protein modules, such as the epsin N-terminal homology (ENTH) Domain, that interact with phospholipids, including inositol phospholipids, to induce and stabilize membrane curvature (3). Intriguingly, a new study by Aguilar et al. (4) in this issue of PNAS demonstrates that ENTH Domains use a surface patch, distinct from their inositol phospholipid-binding pocket, to interact with GTPase activating proteins (GAPs) for Cdc42. Surprisingly, this leads to activation of Cdc42 signaling pathways, perhaps by acting as a sink to sequester GAP activity from Cdc42. The finding that ENTH Domains interact with GAPs is exciting not only because it reveals an increased complexity of the ENTH module but also because it provides a new and direct link between endocytosis and events downstream of Cdc42 activation, including actin dynamics and cell polarity.
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ENTH/ANTH proteins and clathrin-mediated membrane budding.
Journal of Cell Science, 2004Co-Authors: Valerie Legendre-guillemin, Natasha K. Hussain, Sylwia Wasiak, Annie Angers, Peter S. McphersonAbstract:The epsin N-terminal homology (ENTH) Domain is an evolutionarily conserved protein module found primarily in proteins that participate in clathrin-mediated endocytosis. Structural analyses and ligand-binding studies have shown that a set of proteins previously designated as harboring an ENTH Domain in fact contain a highly similar, yet unique module referred to as an AP180 N-terminal homology (ANTH) Domain. ENTH and ANTH (E/ANTH) Domains bind both inositol phospholipids and proteins and contribute to the nucleation and formation of clathrin coats on membranes. ENTH Domains also function in the development of membrane curvature through lipid remodeling during the formation of clathrin-coated vesicles. E/ANTH-bearing proteins have recently been shown to function with adaptor protein-1 and GGA adaptors at the trans-Golgi network, which suggests that E/ANTH Domains are universal components of the machinery for clathrin-mediated membrane budding.
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a role for epsin n terminal homology ap180 n terminal homology ENTH anth Domains in tubulin binding
Journal of Biological Chemistry, 2003Co-Authors: Natasha K. Hussain, Peter S. Mcpherson, Montarop Yamabhai, Asha L Bhakar, Martina Metzler, Stephen S G Ferguson, Michael R Hayden, Brian K. KayAbstract:The epsin N-terminal homology (ENTH) Domain is a protein module of approximately 150 amino acids found at the N terminus of a variety of proteins identified in yeast, plants, nematode, frog, and mammals. ENTH Domains comprise multiple alpha-helices folded upon each other to form a compact globular structure that has been implicated in interactions with lipids and proteins. In characterizing this evolutionarily conserved Domain, we isolated and identified tubulin as an ENTH Domain-binding partner. The interaction, which is direct and has a dissociation constant of approximately 1 microm, was observed with ENTH Domains of proteins present in various species. Tubulin is co-immunoprecipitated from rat brain extracts with the ENTH Domain-containing proteins, epsins 1 and 2, and punctate epsin staining is observed along the microtubule cytoskeleton of dissociated cortical neurons. Consistent with a role in microtubule processes, the over-expression of epsin ENTH Domain in PC12 cells stimulates neurite outgrowth. These data demonstrate an evolutionarily conserved property of ENTH Domains to interact with tubulin and microtubules.