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Viral and Host Factors Regulating HIV-1 Envelope Protein Trafficking and Particle Incorporation. Viruses 2022; 14:v14081729. [PMID: 36016351 PMCID: PMC9415270 DOI: 10.3390/v14081729] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/25/2022] [Accepted: 08/02/2022] [Indexed: 11/17/2022] Open
Abstract
The HIV-1 envelope glycoprotein (Env) is an essential structural component of the virus, serving as the receptor-binding protein and principal neutralizing determinant. Env trimers are incorporated into developing particles at the plasma membrane of infected cells. Incorporation of HIV-1 Env into particles in T cells and macrophages is regulated by the long Env cytoplasmic tail (CT) and the matrix region of Gag. The CT incorporates motifs that interact with cellular factors involved in endosomal trafficking. Env follows an unusual pathway to arrive at the site of particle assembly, first traversing the secretory pathway to the plasma membrane (PM), then undergoing endocytosis, followed by directed sorting to the site of particle assembly on the PM. Many aspects of Env trafficking remain to be defined, including the sequential events that occur following endocytosis, leading to productive recycling and particle incorporation. This review focuses on the host factors and pathways involved in Env trafficking, and discusses leading models of Env incorporation into particles.
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2
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Dumont V, Lehtonen S. PACSIN proteins in vivo: Roles in development and physiology. Acta Physiol (Oxf) 2022; 234:e13783. [PMID: 34990060 PMCID: PMC9285741 DOI: 10.1111/apha.13783] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/15/2021] [Accepted: 01/01/2022] [Indexed: 12/22/2022]
Abstract
Protein kinase C and casein kinase substrate in neurons (PACSINs), or syndapins (synaptic dynamin‐associated proteins), are a family of proteins involved in the regulation of cell cytoskeleton, intracellular trafficking and signalling. Over the last twenty years, PACSINs have been mostly studied in the in vitro and ex vivo settings, and only in the last decade reports on their function in vivo have emerged. We first summarize the identification, structure and cellular functions of PACSINs, and then focus on the relevance of PACSINs in vivo. During development in various model organisms, PACSINs participate in diverse processes, such as neural crest cell development, gastrulation, laterality development and neuromuscular junction formation. In mouse, PACSIN2 regulates angiogenesis during retinal development and in human, PACSIN2 associates with monosomy and embryonic implantation. In adulthood, PACSIN1 has been extensively studied in the brain and shown to regulate neuromorphogenesis, receptor trafficking and synaptic plasticity. Several genetic studies suggest a role for PACSIN1 in the development of schizophrenia, which is also supported by the phenotype of mice depleted of PACSIN1. PACSIN2 plays an essential role in the maintenance of intestinal homeostasis and participates in kidney repair processes after injury. PACSIN3 is abundant in muscle tissue and necessary for caveolar biogenesis to create membrane reservoirs, thus controlling muscle function, and has been linked to certain genetic muscular disorders. The above examples illustrate the importance of PACSINs in diverse physiological or tissue repair processes in various organs, and associations to diseases when their functions are disturbed.
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Affiliation(s)
- Vincent Dumont
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
| | - Sanna Lehtonen
- Department of Pathology and Research Program for Clinical and Molecular Metabolism Faculty of Medicine University of Helsinki Helsinki Finland
- Department of Pathology University of Helsinki Helsinki Finland
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3
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Lucken-Ardjomande Häsler S, Vallis Y, Pasche M, McMahon HT. GRAF2, WDR44, and MICAL1 mediate Rab8/10/11-dependent export of E-cadherin, MMP14, and CFTR ΔF508. J Cell Biol 2021; 219:151714. [PMID: 32344433 PMCID: PMC7199855 DOI: 10.1083/jcb.201811014] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/07/2019] [Accepted: 02/26/2020] [Indexed: 02/07/2023] Open
Abstract
In addition to the classical pathway of secretion, some transmembrane proteins reach the plasma membrane through alternative routes. Several proteins transit through endosomes and are exported in a Rab8-, Rab10-, and/or Rab11-dependent manner. GRAFs are membrane-binding proteins associated with tubules and vesicles. We found extensive colocalization of GRAF1b/2 with Rab8a/b and partial with Rab10. We identified MICAL1 and WDR44 as direct GRAF-binding partners. MICAL1 links GRAF1b/2 to Rab8a/b and Rab10, and WDR44 binds Rab11. Endogenous WDR44 labels a subset of tubular endosomes, which are closely aligned with the ER via binding to VAPA/B. With its BAR domain, GRAF2 can tubulate membranes, and in its absence WDR44 tubules are not observed. We show that GRAF2 and WDR44 are essential for the export of neosynthesized E-cadherin, MMP14, and CFTR ΔF508, three proteins whose exocytosis is sensitive to ER stress. Overexpression of dominant negative mutants of GRAF1/2, WDR44, and MICAL1 also interferes with it, facilitating future studies of Rab8/10/11-dependent exocytic pathways of central importance in biology.
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Affiliation(s)
| | - Yvonne Vallis
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Mathias Pasche
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Harvey T McMahon
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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4
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Potential role of diacylglycerol kinases in immune-mediated diseases. Clin Sci (Lond) 2021; 134:1637-1658. [PMID: 32608491 DOI: 10.1042/cs20200389] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/08/2020] [Accepted: 06/22/2020] [Indexed: 02/07/2023]
Abstract
The mechanism promoting exacerbated immune responses in allergy and autoimmunity as well as those blunting the immune control of cancer cells are of primary interest in medicine. Diacylglycerol kinases (DGKs) are key modulators of signal transduction, which blunt diacylglycerol (DAG) signals and produce phosphatidic acid (PA). By modulating lipid second messengers, DGK modulate the activity of downstream signaling proteins, vesicle trafficking and membrane shape. The biological role of the DGK α and ζ isoforms in immune cells differentiation and effector function was subjected to in deep investigations. DGK α and ζ resulted in negatively regulating synergistic way basal and receptor induced DAG signals in T cells as well as leukocytes. In this way, they contributed to keep under control the immune response but also downmodulate immune response against tumors. Alteration in DGKα activity is also implicated in the pathogenesis of genetic perturbations of the immune function such as the X-linked lymphoproliferative disease 1 and localized juvenile periodontitis. These findings suggested a participation of DGK to the pathogenetic mechanisms underlying several immune-mediated diseases and prompted several researches aiming to target DGK with pharmacologic and molecular strategies. Those findings are discussed inhere together with experimental applications in tumors as well as in other immune-mediated diseases such as asthma.
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5
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Beyond Lipid Signaling: Pleiotropic Effects of Diacylglycerol Kinases in Cellular Signaling. Int J Mol Sci 2020; 21:ijms21186861. [PMID: 32962151 PMCID: PMC7554708 DOI: 10.3390/ijms21186861] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
The diacylglycerol kinase family, which can attenuate diacylglycerol signaling and activate phosphatidic acid signaling, regulates various signaling transductions in the mammalian cells. Studies on the regulation of diacylglycerol and phosphatidic acid levels by various enzymes, the identification and characterization of various diacylglycerol and phosphatidic acid-regulated proteins, and the overlap of different diacylglycerol and phosphatidic acid metabolic and signaling processes have revealed the complex and non-redundant roles of diacylglycerol kinases in regulating multiple biochemical and biological networks. In this review article, we summarized recent progress in the complex and non-redundant roles of diacylglycerol kinases, which is expected to aid in restoring dysregulated biochemical and biological networks in various pathological conditions at the bed side.
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6
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DGKα in Neutrophil Biology and Its Implications for Respiratory Diseases. Int J Mol Sci 2019; 20:ijms20225673. [PMID: 31766109 PMCID: PMC6887790 DOI: 10.3390/ijms20225673] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/21/2022] Open
Abstract
Diacylglycerol kinases (DGKs) play a key role in phosphoinositide signaling by removing diacylglycerol and generating phosphatidic acid. Besides the well-documented role of DGKα and DGKζ as negative regulators of lymphocyte responses, a robust body of literature points to those enzymes, and specifically DGKα, as crucial regulators of leukocyte function. Upon neutrophil stimulation, DGKα activation is necessary for migration and a productive response. The role of DGKα in neutrophils is evidenced by its aberrant behavior in juvenile periodontitis patients, which express an inactive DGKα transcript. Together with in vitro experiments, this suggests that DGKs may represent potential therapeutic targets for disorders where inflammation, and neutrophils in particular, plays a major role. In this paper we focus on obstructive respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), but also rare genetic diseases such as alpha-1-antitrypsin deficiency. Indeed, the biological role of DGKα is understudied outside the T lymphocyte field. The recent wave of research aiming to develop novel and specific inhibitors as well as KO mice will allow a better understanding of DGK's role in neutrophilic inflammation. Better knowledge and pharmacologic tools may also allow DGK to move from the laboratory bench to clinical trials.
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7
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Montealegre S, van Endert PM. Endocytic Recycling of MHC Class I Molecules in Non-professional Antigen Presenting and Dendritic Cells. Front Immunol 2019; 9:3098. [PMID: 30666258 PMCID: PMC6330327 DOI: 10.3389/fimmu.2018.03098] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/13/2018] [Indexed: 12/14/2022] Open
Abstract
Major histocompatibility complex class I (MHC I) molecules are glycoproteins that display peptide epitopes at the cell surface of nucleated cells for recognition by CD8+ T cells. Like other cell surface receptors, MHC class I molecules are continuously removed from the surface followed by intracellular degradation or recycling to the cell surface, in a process likely involving active quality control the mechanism of which remains unknown. The molecular players and pathways involved in internalization and recycling have previously been studied in model cell lines such as HeLa. However, dendritic cells (DCs), which rely on a specialized endocytic machinery that confers them the unique ability to “cross”-present antigens acquired by internalization, may use distinct MHC I recycling pathways and quality control mechanisms. By providing MHC I molecules cross-presenting antigens, these pathways may play an important role in one of the key functions of DCs, priming of T cell responses against pathogens and tumors. In this review, we will focus on endocytic recycling of MHC I molecules in various experimental conditions and cell types. We discuss the organization of the recycling pathway in model cell lines compared to DCs, highlighting the differences in the recycling rates and pathways of MHC I molecules between various cell types, and their putative functional consequences. Reviewing the literature, we find that conclusive evidence for significant recycling of MHC I molecules in primary DCs has yet to be demonstrated. We conclude that endocytic trafficking of MHC class I in DCs remains poorly understood and should be further studied because of its likely role in antigen cross-presentation.
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Affiliation(s)
- Sebastian Montealegre
- Institut National de la Santé et de la Recherche Médicale, Unité 1151, Paris, France.,Université Paris Descartes, Faculté de Médecine, Paris, France.,Centre National de la Recherche Scientifique, UMR8253, Paris, France
| | - Peter M van Endert
- Institut National de la Santé et de la Recherche Médicale, Unité 1151, Paris, France.,Université Paris Descartes, Faculté de Médecine, Paris, France.,Centre National de la Recherche Scientifique, UMR8253, Paris, France
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8
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Iwabuchi E, Miki Y, Kanai A, Miyashita M, Kijima G, Hirakawa H, Suzuki T, Ishida T, Sasano H. The interaction between carcinoembryonic antigen-related cell adhesion molecule 6 and human epidermal growth factor receptor 2 is associated with therapeutic efficacy of trastuzumab in breast cancer. J Pathol 2018; 246:379-389. [PMID: 30058236 DOI: 10.1002/path.5148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/10/2018] [Accepted: 07/26/2018] [Indexed: 12/12/2022]
Abstract
Human epidermal growth factor receptor 2 (HER2) is a target of the HER2 inhibitor trastuzumab, which has been administered to HER2-positive breast cancer patients. However, the therapeutic effects of HER2 inhibitor monotherapy are not always clinically effective as compared with cotreatment with chemotherapy. Therefore, it has become pivotal to predict the therapeutic efficacy of trastuzumab monotherapy prior to administration. Recently, carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) has been reported to be a HER2-related factor. The aim of the present study was to explore the therapeutic mechanism of trastuzumab, including the relevance of CEACAM6 expression. CEACAM6/HER2-double-positive human breast carcinoma cell lines BT-474, HCC-1419 and MDA-MB-361 were used in this study. CEACAM6 knockdown decreased the inhibitory effects of trastuzumab in the trastuzumab-sensitive BT-474 and HCC-1419 cells, but not in the trastuzumab-resistant MDA-MB-361 cells. We examined the interaction between CEACAM6 and HER2 by using a proximity ligation assay (PLA). The interaction was detected in BT-474 and HCC-1419 cells, but not in MDA-MB-361 cells, and was significantly associated with in vitro trastuzumab therapeutic sensitivity. We further analysed the status of CEACAM6 and HER2 and their interaction in archival pathology specimens, also using PLA. The interaction was detected only in CEACAM6/HER2-double-positive breast cancer cases, and their PLA score was significantly associated with the efficacy of trastuzumab treatment. Therefore, evaluation of the CEACAM6-HER2 interaction could serve as a marker to predict the efficacy of trastuzumab monotherapy in breast cancer patients. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Erina Iwabuchi
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yasuhiro Miki
- Department of Disaster Obstetrics and Gynaecology, International Research Institute of Disaster Science (IRIDes), Tohoku University, Sendai, Japan
| | - Ayako Kanai
- Department of Breast and Endocrine Surgical Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Minoru Miyashita
- Department of Breast and Endocrine Surgical Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | | | - Takashi Suzuki
- Department of Pathology and Histotechnology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Takanori Ishida
- Department of Breast and Endocrine Surgical Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hironobu Sasano
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Japan
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9
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Arranz-Nicolás J, Ogando J, Soutar D, Arcos-Pérez R, Meraviglia-Crivelli D, Mañes S, Mérida I, Ávila-Flores A. Diacylglycerol kinase α inactivation is an integral component of the costimulatory pathway that amplifies TCR signals. Cancer Immunol Immunother 2018; 67:965-980. [PMID: 29572701 PMCID: PMC11028345 DOI: 10.1007/s00262-018-2154-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 03/19/2018] [Indexed: 12/18/2022]
Abstract
The arsenal of cancer therapies has evolved to target T lymphocytes and restore their capacity to destroy tumor cells. T cells rely on diacylglycerol (DAG) to carry out their functions. DAG availability and signaling are regulated by the enzymes diacylglycerol kinase (DGK) α and ζ, whose excess function drives T cells into hyporesponsive states. Targeting DGKα is a promising strategy for coping with cancer; its blockade could reinstate T-cell attack on tumors while limiting tumor growth, due to positive DGKα functions in several oncogenic pathways. Here, we made a side-by-side comparison of the effects of commercial pharmacological DGK inhibitors on T-cell responses with those promoted by DGKα and DGKζ genetic deletion or silencing. We show the specificity for DGKα of DGK inhibitors I and II and the structurally similar compound ritanserin. Inhibitor treatment promoted Ras/ERK (extracellular signal-regulated kinase) signaling and AP-1 (Activator protein-1) transcription, facilitated DGKα membrane localization, reduced the requirement for costimulation, and cooperated with enhanced activation following DGKζ silencing/deletion. DGKiII and ritanserin had similar effects on TCR proximal signaling, but ritanserin counteracted long-term T-cell activation, an effect that was potentiated in DGKα-/- cells. In contrast with enhanced activation triggered by pharmacological inhibition, DGKα silencing/genetic deletion led to impaired Lck (lymphocyte-specific protein tyrosine kinase) activation and limited costimulation responses. Our results demonstrate that pharmacological inhibition of DGKα downstream of the TCR provides a gain-of-function effect that amplifies the DAG-dependent signaling cascade, an ability that could be exploited therapeutically to reinvigorate T cells to attack tumors.
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Affiliation(s)
- Javier Arranz-Nicolás
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Jesús Ogando
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Denise Soutar
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Raquel Arcos-Pérez
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Daniel Meraviglia-Crivelli
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Santos Mañes
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain
| | - Isabel Mérida
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain.
| | - Antonia Ávila-Flores
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, UAM Campus de Cantoblanco, 28049, Madrid, Spain.
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Abstract
Antigen cross-presentation is an adaptation of the cellular process of loading MHC-I molecules with endogenous peptides during their biosynthesis within the endoplasmic reticulum. Cross-presented peptides derive from internalized proteins, microbial pathogens, and transformed or dying cells. The physical separation of internalized cargo from the endoplasmic reticulum, where the machinery for assembling peptide-MHC-I complexes resides, poses a challenge. To solve this problem, deliberate rewiring of organelle communication within cells is necessary to prepare for cross-presentation, and different endocytic receptors and vesicular traffic patterns customize the emergent cross-presentation compartment to the nature of the peptide source. Three distinct pathways of vesicular traffic converge to form the ideal cross-presentation compartment, each regulated differently to supply a unique component that enables cross-presentation of a diverse repertoire of peptides. Delivery of centerpiece MHC-I molecules is the critical step regulated by microbe-sensitive Toll-like receptors. Defining the subcellular sources of MHC-I and identifying sites of peptide loading during cross-presentation remain key challenges.
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Affiliation(s)
- J Magarian Blander
- Jill Roberts Institute for Research in Inflammatory Bowel Disease, Weill Cornell Medicine, Cornell University, New York, NY 10021, USA; .,Joan and Sanford I. Weill Department of Medicine, Department of Microbiology and Immunology, and Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA
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11
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Blander JM. The comings and goings of MHC class I molecules herald a new dawn in cross-presentation. Immunol Rev 2017; 272:65-79. [PMID: 27319343 DOI: 10.1111/imr.12428] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
MHC class I (MHC-I) molecules are the centerpieces of cross-presentation. They are loaded with peptides derived from exogenous sources and displayed on the plasma membrane to communicate with CD8 T cells, relaying a message of tolerance or attack. The study of cross-presentation has been focused on the relative contributions of the vacuolar versus cytosolic pathways of antigen processing and the location where MHC-I molecules are loaded. While vacuolar processing generates peptides loaded onto vacuolar MHC-I molecules, how and where exogenous peptides generated by the proteasome and transported by TAP meet MHC-I molecules for loading has been a matter of debate. The source and trafficking of MHC-I molecules in dendritic cells have largely been ignored under the expectation that these molecules came from the Endoplasmic reticulum (ER) or the plasma membrane. New studies reveal a concentrated pool of MHC-I molecules in the endocytic recycling compartment (ERC). These pools are rapidly mobilized to phagosomes carrying microbial antigens, and in a signal-dependent manner under the control of Toll-like receptors. The phagosome becomes a dynamic hub receiving traffic from multiple sources, the ER-Golgi intermediate compartment for delivering the peptide-loading machinery and the ERC for deploying MHC-I molecules that alert CD8 T cells of infection.
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Affiliation(s)
- J Magarian Blander
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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12
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Iwabuchi E, Miki Y, Ono K, Onodera Y, Sasano H. In Situ Evaluation of Estrogen Receptor Dimers in Breast Carcinoma Cells: Visualization of Protein-Protein Interactions. Acta Histochem Cytochem 2017; 50:85-93. [PMID: 28522883 PMCID: PMC5433938 DOI: 10.1267/ahc.17011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 03/17/2017] [Indexed: 12/26/2022] Open
Abstract
The estrogen receptor (ER) functions as a dimer and is involved in several different biological functions. However ER dimeric proteins have not been identified by in situ methodologies. Structured illumination microscopy (SIM) has been recently developed, which enabled the localization of protein and protein interaction. Therefore, in this study, we firstly demonstrated that ERs formed both homodimers and heterodimers in breast carcinoma cell lines using Nikon’s SIM (N-SIM). ERα/α homodimers were detected in the nuclei of both ERα-positive MCF-7 and T-47D cells; 23.0% and 13.4% of ERα proteins formed ERα/α homodimers, respectively. ERα/β heterodimers were also detected in MCF-7 and T-47D. Approximately 6.6% of both ERα and ERβ1 proteins formed ERα/β1 heterodimers in MCF-7. In addition, 18.1% and 22.4% of ERα and ERβ proteins formed ERα/β2 heterodimers and ERα/β5 heterodimers in MCF-7, respectively. In addition, by using proximity ligation assay (PLA) in MCF-7, estradiol-induced ERα/α homodimers and ERα/β1 heterodimers were both detected after 15 to 45 min of treatment and at 15 min, respectively. The percentage of total ER proteins could also be determined using N-SIM. By using both methods, it has become possible to evaluate precise localization and ratio of ER dimers among different cell types.
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Affiliation(s)
- Erina Iwabuchi
- Department of Pathology, Tohoku University Graduate School of Medicine
| | - Yasuhiro Miki
- Department of Disaster Obstetrics and Gynecology, International Research Institute of Disaster Science (IRIDes), Tohoku University
| | - Katsuhiko Ono
- Department of Pathology, Tohoku University Graduate School of Medicine
| | - Yoshiaki Onodera
- Department of Pathology, Tohoku University Graduate School of Medicine
| | - Hironobu Sasano
- Department of Pathology, Tohoku University Graduate School of Medicine
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13
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Cai Y, Yang L, Niu F, Liao K, Buch S. Role of Sigma-1 Receptor in Cocaine Abuse and Neurodegenerative Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:163-175. [PMID: 28315271 DOI: 10.1007/978-3-319-50174-1_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sigma-1 receptors (Sig-1R) are recognized as a unique class of non-G protein-coupled intracellular protein. Sig-1R binds to its ligand such as cocaine , resulting in dissociation of Sig-1R from mitochondrion-associated ER membrane (MAM) to the endoplasmic reticulum (ER), plasma membrane, and nuclear membrane, regulating function of various proteins. Sig-1R has diverse roles in both physiological as well as in pathogenic processes. The disruption of Sig-1R pathways has been implicated as causative mechanism(s) in the development of both neurodegenerative disorders such as Alzheimer disease (AD ), Parkinson disease (PD ), amyotrophic lateral sclerosis (ALS ) and Huntington Disease (HD ) . Additionally, the interaction of cocaine and Sig-1R has more recently been implicated in potentiating the pathogenesis of HIV-associated neurocognitive disorders (HAND) through impairment of blood-brain barrier (BBB), microglial activation and astrogliosis. On the other hand, restoration of Sig-1R homeostasis has been shown to exert neuroprotective effects. In this review, we provide an overview of how Sig-1R plays a role in the pathogenesis of neurodegenerative disorders and cocaine and implications for future development of therapeutic strategies.
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Affiliation(s)
- Yu Cai
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, DRC 8024, Omaha, NE, 68198-5880, USA
| | - Lu Yang
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, DRC 8024, Omaha, NE, 68198-5880, USA
| | - Fang Niu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, DRC 8024, Omaha, NE, 68198-5880, USA
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, DRC 8024, Omaha, NE, 68198-5880, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, DRC 8024, Omaha, NE, 68198-5880, USA.
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14
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Cai Y, Arikkath J, Yang L, Guo ML, Periyasamy P, Buch S. Interplay of endoplasmic reticulum stress and autophagy in neurodegenerative disorders. Autophagy 2016; 12:225-44. [PMID: 26902584 DOI: 10.1080/15548627.2015.1121360] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The common underlying feature of most neurodegenerative diseases such as Alzheimer disease (AD), prion diseases, Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS) involves accumulation of misfolded proteins leading to initiation of endoplasmic reticulum (ER) stress and stimulation of the unfolded protein response (UPR). Additionally, ER stress more recently has been implicated in the pathogenesis of HIV-associated neurocognitive disorders (HAND). Autophagy plays an essential role in the clearance of aggregated toxic proteins and degradation of the damaged organelles. There is evidence that autophagy ameliorates ER stress by eliminating accumulated misfolded proteins. Both abnormal UPR and impaired autophagy have been implicated as a causative mechanism in the development of various neurodegenerative diseases. This review highlights recent advances in the field on the role of ER stress and autophagy in AD, prion diseases, PD, ALS and HAND with the involvement of key signaling pathways in these processes and implications for future development of therapeutic strategies.
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Affiliation(s)
- Yu Cai
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
| | - Jyothi Arikkath
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA.,b Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center , Omaha , NE , USA
| | - Lu Yang
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
| | - Ming-Lei Guo
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
| | - Palsamy Periyasamy
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
| | - Shilpa Buch
- a Department of Pharmacology and Experimental Neuroscience , University of Nebraska Medical Center , Omaha , NE , USA
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15
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Emerging roles of extracellular vesicles in neurodegenerative disorders: focus on HIV-associated neurological complications. Cell Death Dis 2016; 7:e2481. [PMID: 27882942 PMCID: PMC5260908 DOI: 10.1038/cddis.2016.336] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/12/2016] [Accepted: 09/19/2016] [Indexed: 12/22/2022]
Abstract
Exosomes are membrane-enriched extracellular vesicles with a proposed diameter in the range of 30-100 nm. They are released during both normal homeostasis as well as under pathological conditions by most cell types. In recent years, there has been robust interest in the study of these vesicles as conduits for the delivery of information between cells in both analogous as well as disparate tissues. Their ability to transport specialized cargo including signaling mediators, proteins, messenger RNA and miRNAs characterizes these vesicles as primary facilitators of cell-to-cell communication and regulation. Exosomes have also been demonstrated to have important roles in the field of cancer biology and metastasis. More recently, their role in several neurodegenerative disorders has been gaining increased momentum as these particles have been shown to promote the spread of toxic factors such as amyloid beta and prions, adding further validity to their role as important regulators of disease pathogenesis. This review briefly summarizes current findings and thoughts on exosome biology in the context of neurodegenerative disorders and the manipulation of these particles for the development of potential therapeutic strategies.
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Wang P, Liu H, Wang Y, Liu O, Zhang J, Gleason A, Yang Z, Wang H, Shi A, Grant BD. RAB-10 Promotes EHBP-1 Bridging of Filamentous Actin and Tubular Recycling Endosomes. PLoS Genet 2016; 12:e1006093. [PMID: 27272733 PMCID: PMC4894640 DOI: 10.1371/journal.pgen.1006093] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 05/10/2016] [Indexed: 12/21/2022] Open
Abstract
EHBP-1 (Ehbp1) is a conserved regulator of endocytic recycling, acting as an effector of small GTPases including RAB-10 (Rab10). Here we present evidence that EHBP-1 associates with tubular endosomal phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] enriched membranes through an N-terminal C2-like (NT-C2) domain, and define residues within the NT-C2 domain that mediate membrane interaction. Furthermore, our results indicate that the EHBP-1 central calponin homology (CH) domain binds to actin microfilaments in a reaction that is stimulated by RAB-10(GTP). Loss of any aspect of this RAB-10/EHBP-1 system in the C. elegans intestinal epithelium leads to retention of basolateral recycling cargo in endosomes that have lost their normal tubular endosomal network (TEN) organization. We propose a mechanism whereby RAB-10 promotes the ability of endosome-bound EHBP-1 to also bind to the actin cytoskeleton, thereby promoting endosomal tubulation. Endosomes are intracellular organelles that sort protein and lipid components integral to the membrane, as well as more loosely associated lumenal content, for delivery to distinct intracellular destinations. Endosomes associated with recycling cargo back to the plasma membrane are often tubular in morphology, and this morphology is thought to be essential for recycling function. Our previous work identified a particularly dramatic network of endosomal tubules involved in membrane protein recycling in the basolateral intestinal epithelial cells of C. elegans. Our subsequent genetic analysis of basolateral recycling in this system identified a number of key regulators of these endosomes, including the small GTPase RAB-10 and its effector EHBP-1. Our new work presented here shows that EHBP-1 promotes endosomal tubulation by linking the membrane lipid PI(4,5)P2 to the actin cytoskeleton, and that the linkage of EHBP-1 to actin is enhanced by the interaction of EHBP-1 with RAB-10. This work has broad implications for how endosomal tubulation occurs in all cells, and has specific implications for the role of EHBP-1 in related processes such as insulin-stimulated recycling of glucose transporters in human adipocytes, a process intimately linked to type II diabetes.
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Affiliation(s)
- Peixiang Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hang Liu
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yu Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Ou Liu
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Jing Zhang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Adenrele Gleason
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
| | - Zhenrong Yang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hui Wang
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Anbing Shi
- Department of Medical Genetics, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Institute for Brain Research, Huazhong University of Science and Technology, Wuhan, Hubei, China
- Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
- * E-mail: (AS); (BDG)
| | - Barth D. Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail: (AS); (BDG)
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17
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Enterohaemorrhagic E. coli modulates an ARF6:Rab35 signaling axis to prevent recycling endosome maturation during infection. J Mol Biol 2016; 428:3399-407. [PMID: 27261256 PMCID: PMC5013874 DOI: 10.1016/j.jmb.2016.05.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/19/2016] [Accepted: 05/20/2016] [Indexed: 02/06/2023]
Abstract
Enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC/EHEC) manipulate a plethora of host cell processes to establish infection of the gut mucosa. This manipulation is achieved via the injection of bacterial effector proteins into host cells using a Type III secretion system. We have previously reported that the conserved EHEC and EPEC effector EspG disrupts recycling endosome function, reducing cell surface levels of host receptors through accumulation of recycling cargo within the host cell. Here we report that EspG interacts specifically with the small GTPases ARF6 and Rab35 during infection. These interactions target EspG to endosomes and prevent Rab35-mediated recycling of cargo to the host cell surface. Furthermore, we show that EspG has no effect on Rab35-mediated uncoating of newly formed endosomes, and instead leads to the formation of enlarged EspG/TfR/Rab11 positive, EEA1/Clathrin negative stalled recycling structures. Thus, this paper provides a molecular framework to explain how EspG disrupts recycling whilst also reporting the first known simultaneous targeting of ARF6 and Rab35 by a bacterial pathogen. EHEC delivers effector proteins into host cells to establish infection in the gut The effector EspG interacts with GTP-ARF6 confining EspG to recycling endosomes During infection EspG interacts preferentially with Rab35, not Rab1 Spatial restriction of bacterial effectors during infection determines their function
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18
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Bahl K, Xie S, Spagnol G, Sorgen P, Naslavsky N, Caplan S. EHD3 Protein Is Required for Tubular Recycling Endosome Stabilization, and an Asparagine-Glutamic Acid Residue Pair within Its Eps15 Homology (EH) Domain Dictates Its Selective Binding to NPF Peptides. J Biol Chem 2016; 291:13465-78. [PMID: 27189942 DOI: 10.1074/jbc.m116.716407] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 11/06/2022] Open
Abstract
An elaborate network of dynamic lipid membranes, termed tubular recycling endosomes (TRE), coordinates the process of endocytic recycling in mammalian cells. The C-terminal Eps15 homology domain (EHD)-containing proteins have been implicated in the bending and fission of TRE, thus regulating endocytic recycling. EHD proteins have an EH domain that interacts with proteins containing an NPF motif. We found that NPF-containing EHD1 interaction partners such as molecules interacting with CasL-like1 (MICAL-L1) and Syndapin2 are essential for TRE biogenesis. Also crucial for TRE biogenesis is the generation of phosphatidic acid, an essential lipid component of TRE that serves as a docking point for MICAL-L1 and Syndapin2. EHD1 and EHD3 have 86% amino acid identity; they homo- and heterodimerize and partially co-localize to TRE. Despite their remarkable identity, they have distinct mechanistic functions. EHD1 induces membrane vesiculation, whereas EHD3 supports TRE biogenesis and/or stabilization by an unknown mechanism. While using phospholipase D inhibitors (which block the conversion of glycerophospholipids to phosphatidic acid) to deplete cellular TRE, we observed that, upon inhibitor washout, there was a rapid and dramatic regeneration of MICAL-L1-marked TRE. Using this "synchronized" TRE biogenesis system, we determined that EHD3 is involved in the stabilization of TRE rather than in their biogenesis. Moreover, we identify the residues Ala-519/Asp-520 of EHD1 and Asn-519/Glu-520 of EHD3 as defining the selectivity of these two paralogs for NPF-containing binding partners, and we present a model to explain the atomic mechanism and provide new insight for their differential roles in vesiculation and tubulation, respectively.
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Affiliation(s)
- Kriti Bahl
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Shuwei Xie
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Gaelle Spagnol
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Paul Sorgen
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Naava Naslavsky
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Steve Caplan
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
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19
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Henmi Y, Oe N, Kono N, Taguchi T, Takei K, Tanabe K. Phosphatidic acid induces EHD3-containing membrane tubulation and is required for receptor recycling. Exp Cell Res 2016; 342:1-10. [DOI: 10.1016/j.yexcr.2016.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/22/2015] [Accepted: 02/15/2016] [Indexed: 10/22/2022]
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20
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Xie S, Bahl K, Reinecke JB, Hammond GRV, Naslavsky N, Caplan S. The endocytic recycling compartment maintains cargo segregation acquired upon exit from the sorting endosome. Mol Biol Cell 2015; 27:108-26. [PMID: 26510502 PMCID: PMC4694750 DOI: 10.1091/mbc.e15-07-0514] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/23/2015] [Indexed: 12/22/2022] Open
Abstract
The endocytic recycling compartment (ERC) is a series of perinuclear tubular and vesicular membranes that regulates recycling to the plasma membrane. Despite evidence that cargo is sorted at the early/sorting endosome (SE), whether cargo mixes downstream at the ERC or remains segregated is an unanswered question. Here we use three-dimensional (3D) structured illumination microscopy and dual-channel and 3D direct stochastic optical reconstruction microscopy (dSTORM) to obtain new information about ERC morphology and cargo segregation. We show that cargo internalized either via clathrin-mediated endocytosis (CME) or independently of clathrin (CIE) remains segregated in the ERC, likely on distinct carriers. This suggests that no further sorting occurs upon cargo exit from SE. Moreover, 3D dSTORM data support a model in which some but not all ERC vesicles are tethered by contiguous "membrane bridges." Furthermore, tubular recycling endosomes preferentially traffic CIE cargo and may originate from SE membranes. These findings support a significantly altered model for endocytic recycling in mammalian cells in which sorting occurs in peripheral endosomes and segregation is maintained at the ERC.
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Affiliation(s)
- Shuwei Xie
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870
| | - Kriti Bahl
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870
| | - James B Reinecke
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870
| | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Naava Naslavsky
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870
| | - Steve Caplan
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870
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21
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Xie S, Naslavsky N, Caplan S. Diacylglycerol kinases in membrane trafficking. CELLULAR LOGISTICS 2015; 5:e1078431. [PMID: 27057419 DOI: 10.1080/21592799.2015.1078431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022]
Abstract
Diacylglycerol kinases (DGKs) belong to a family of cytosolic kinases that regulate the phosphorylation of diacylglycerol (DAG), converting it into phosphatidic acid (PA). There are 10 known mammalian DGK isoforms, each with a different tissue distribution and substrate specificity. These differences allow regulation of cellular responses by fine-tuning the delicate balance of cellular DAG and PA. DGK isoforms are best characterized as mediators of signal transduction and immune function. However, since recent studies reveal that DAG and PA are also involved in the regulation of endocytic trafficking, it is therefore anticipated that DGKs also plays an important role in membrane trafficking. In this review, we summarize the literature discussing the role of DGK isoforms at different stages of endocytic trafficking, including endocytosis, exocytosis, endocytic recycling, and transport from/to the Golgi apparatus. Overall, these studies contribute to our understanding of the involvement of PA and DAG in endocytic trafficking, an area of research that is drawing increasing attention in recent years.
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Affiliation(s)
- Shuwei Xie
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center; University of Nebraska Medical Center ; Omaha, NE USA
| | - Naava Naslavsky
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center; University of Nebraska Medical Center ; Omaha, NE USA
| | - Steve Caplan
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center; University of Nebraska Medical Center ; Omaha, NE USA
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22
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Reineke JB, Xie S, Naslavsky N, Caplan S. Qualitative and quantitative analysis of endocytic recycling. Methods Cell Biol 2015; 130:139-55. [PMID: 26360033 DOI: 10.1016/bs.mcb.2015.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Endocytosis, which encompasses the internalization and sorting of plasma membrane (PM) lipids and proteins to distinct membrane-bound intracellular compartments, is a highly regulated and fundamental cellular process by which eukaryotic cells dynamically regulate their PM composition. Indeed, endocytosis is implicated in crucial cellular processes that include proliferation, migration, and cell division as well as maintenance of tissue homeostasis such as apical-basal polarity. Once PM constituents have been taken up into the cell, either via clathrin-dependent endocytosis (CDE) or clathrin-independent endocytosis (CIE), they typically have two fates: degradation through the late-endosomal/lysosomal pathway or returning to the PM via endocytic recycling pathways. In this review, we will detail experimental procedures that allow for both qualitative and quantitative assessment of endocytic recycling of transmembrane proteins internalized by CDE and CIE, using the HeLa cervical cancer cell line as a model system.
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Affiliation(s)
- James B Reineke
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shuwei Xie
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Naava Naslavsky
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Steve Caplan
- Department of Biochemistry and Molecular Biology and the Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
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23
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Goldenring JR. Recycling endosomes. Curr Opin Cell Biol 2015; 35:117-22. [PMID: 26022676 DOI: 10.1016/j.ceb.2015.04.018] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 12/13/2022]
Abstract
The endosomal membrane recycling system represents a dynamic conduit for sorting and re-exporting internalized membrane constituents. The recycling system is composed of multiple tubulovesicular recycling pathways that likely confer distinct trafficking pathways for individual cargoes. In addition, elements of the recycling system are responsible for assembly and maintenance of apical membrane specializations including primary cilia and apical microvilli. The existence of multiple intersecting and diverging recycling tracks likely accounts for specificity in plasma membrane recycling trafficking.
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Affiliation(s)
- James R Goldenring
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; The Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA; The Nashville VA Medical Center, Nashville, TN, USA.
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24
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Merida I, Andrada E, Gharbi SI, Avila-Flores A. Redundant and specialized roles for diacylglycerol kinases and in the control of T cell functions. Sci Signal 2015; 8:re6. [DOI: 10.1126/scisignal.aaa0974] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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25
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Bahl K, Naslavsky N, Caplan S. Role of the EHD2 unstructured loop in dimerization, protein binding and subcellular localization. PLoS One 2015; 10:e0123710. [PMID: 25875965 PMCID: PMC4398442 DOI: 10.1371/journal.pone.0123710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 03/05/2015] [Indexed: 11/20/2022] Open
Abstract
The C-terminal Eps 15 Homology Domain proteins (EHD1-4) play important roles in regulating endocytic trafficking. EHD2 is the only family member whose crystal structure has been solved, and it contains an unstructured loop consisting of two proline-phenylalanine (PF) motifs: KPFRKLNPF. In contrast, despite EHD2 having nearly 70% amino acid identity with its paralogs, EHD1, EHD3 and EHD4, the latter proteins contain a single KPF or RPF motif, but no NPF motif. In this study, we sought to define the precise role of each PF motif in EHD2’s homo-dimerization, binding with the protein partners, and subcellular localization. To test the role of the NPF motif, we generated an EHD2 NPF-to-NAF mutant to mimic the homologous sequences of EHD1 and EHD3. We demonstrated that this mutant lost both its ability to dimerize and bind to Syndapin2. However, it continued to localize primarily to the cytosolic face of the plasma membrane. On the other hand, EHD2 NPF-to-APA mutants displayed normal dimerization and Syndapin2 binding, but exhibited markedly increased nuclear localization and reduced association with the plasma membrane. We then hypothesized that the single PF motif of EHD1 (that aligns with the KPF of EHD2) might be responsible for both binding and localization functions of EHD1. Indeed, the EHD1 RPF motif was required for dimerization, interaction with MICAL-L1 and Syndapin2, as well as localization to tubular recycling endosomes. Moreover, recycling assays demonstrated that EHD1 RPF-to-APA was incapable of supporting normal receptor recycling. Overall, our data suggest that the EHD2 NPF phenylalanine residue is crucial for EHD2 localization to the plasma membrane, whereas the proline residue is essential for EHD2 dimerization and binding. These studies support the recently proposed model in which the EHD2 N-terminal region may regulate the availability of the unstructured loop for interactions with neighboring EHD2 dimers, thus promoting oligomerization.
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Affiliation(s)
- Kriti Bahl
- Department of Biochemistry and Molecular Biology, the Fred and Pamela Buffett Cancer Center, The University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Naava Naslavsky
- Department of Biochemistry and Molecular Biology, the Fred and Pamela Buffett Cancer Center, The University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail: (SC); (NN)
| | - Steve Caplan
- Department of Biochemistry and Molecular Biology, the Fred and Pamela Buffett Cancer Center, The University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail: (SC); (NN)
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