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Jolly LA, Kumar R, Penzes P, Piper M, Gecz J. The DUB Club: Deubiquitinating Enzymes and Neurodevelopmental Disorders. Biol Psychiatry 2022; 92:614-625. [PMID: 35662507 PMCID: PMC10084722 DOI: 10.1016/j.biopsych.2022.03.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/28/2022] [Accepted: 03/28/2022] [Indexed: 02/08/2023]
Abstract
Protein ubiquitination is a widespread, multifunctional, posttranslational protein modification, best known for its ability to direct protein degradation via the ubiquitin proteasome system (UPS). Ubiquitination is also reversible, and the human genome encodes over 90 deubiquitinating enzymes (DUBs), many of which appear to target specific subsets of ubiquitinated proteins. This review focuses on the roles of DUBs in neurodevelopmental disorders (NDDs). We present the current genetic evidence connecting 12 DUBs to a range of NDDs and the functional studies implicating at least 19 additional DUBs as candidate NDD genes. We highlight how the study of DUBs in NDDs offers critical insights into the role of protein degradation during brain development. Because one of the major known functions of a DUB is to antagonize the UPS, loss of function of DUB genes has been shown to culminate in loss of abundance of its protein substrates. The identification and study of NDD DUB substrates in the developing brain is revealing that they regulate networks of proteins that themselves are encoded by NDD genes. We describe the new technologies that are enabling the full resolution of DUB protein networks in the developing brain, with the view that this knowledge can direct the development of new therapeutic paradigms. The fact that the abundance of many NDD proteins is regulated by the UPS presents an exciting opportunity to combat NDDs caused by haploinsufficiency, because the loss of abundance of NDD proteins can be potentially rectified by antagonizing their UPS-based degradation.
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Affiliation(s)
- Lachlan A Jolly
- University of Adelaide and Robinson Research Institute, Adelaide, South Australia, Australia.
| | - Raman Kumar
- University of Adelaide and Robinson Research Institute, Adelaide, South Australia, Australia
| | - Peter Penzes
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Michael Piper
- School of Biomedical Sciences and Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Jozef Gecz
- University of Adelaide and Robinson Research Institute, Adelaide, South Australia, Australia; South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
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2
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Atif M, Alsrhani A, Naz F, Ullah MI, Alameen AAM, Imran M, Ejaz H. Adenosine A 2A receptor as a potential target for improving cancer immunotherapy. Mol Biol Rep 2022; 49:10677-10687. [PMID: 35752699 DOI: 10.1007/s11033-022-07685-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/07/2022] [Indexed: 11/29/2022]
Abstract
The adenosine nucleoside performs a wide range of actions on various human tissues by activating four cell surface receptors. Adenosine A2A receptors (A2ARs) are widely expressed in the striatum, olfactory bulb, platelets, leukocytes, spleen, and thymus. They promote vasodilatation, platelet antiaggregatory effect, protection from ischemic damage, and regulation of sensorimotor neurons in basal ganglia. Adenosine signaling plays a vital part in modulating in vivo pathophysiological responses. A2ARs are potent negative regulators of the antitumor and proinflammatory actions of activated T cells. This axis offers several therapeutic targets, the most important of which are A2ARs, HIF-1α, and CD39/CD73. Downregulation of this axis increases the effectiveness of modern immunotherapeutic approaches against cancer, such as αCTLA-4/αPD-1. These discoveries have led to a promising novel role of antagonists of A2AR in blocking angiogenesis in immunotherapy of cancer. A small molecule, AZD4635, strongly inhibits A2AR, lowering cancer volume and increasing anticancer immunity. Deletion of A2AR with CRISPR/Cas9 in both human and murine CAR T cells produces a substantial increase in the efficiency of these cells. This review asserts that inhibition of the adenosinergic pathway can boost antitumor immunity, and this axis should be a target for future immunotherapeutic strategies.
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Affiliation(s)
- Muhammad Atif
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Abdullah Alsrhani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Farrah Naz
- Department of Pathology, Institute of Public Health, Lahore, Pakistan
| | - Muhammad Ikram Ullah
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Ayman Ali Mohammed Alameen
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia
| | - Muhammad Imran
- Department of Food Science and Technology, University of Narowal, Narowal, Pakistan
| | - Hasan Ejaz
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Al Jouf, 72388, Saudi Arabia.
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3
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Luo Y, Takagi J, Claus LAN, Zhang C, Yasuda S, Hasegawa Y, Yamaguchi J, Shan L, Russinova E, Sato T. Deubiquitinating enzymes UBP12 and UBP13 stabilize the brassinosteroid receptor BRI1. EMBO Rep 2022; 23:e53354. [PMID: 35166439 PMCID: PMC8982535 DOI: 10.15252/embr.202153354] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 01/24/2023] Open
Abstract
Protein ubiquitination is a dynamic and reversible post-translational modification that controls diverse cellular processes in eukaryotes. Ubiquitin-dependent internalization, recycling, and degradation are important mechanisms that regulate the activity and the abundance of plasma membrane (PM)-localized proteins. In plants, although several ubiquitin ligases are implicated in these processes, no deubiquitinating enzymes (DUBs), have been identified that directly remove ubiquitin from membrane proteins and limit their vacuolar degradation. Here, we discover two DUB proteins, UBP12 and UBP13, that directly target the PM-localized brassinosteroid (BR) receptor BR INSENSITIVE1 (BRI1) in Arabidopsis. BRI1 protein abundance is decreased in the ubp12i/ubp13 double mutant that displayed severe growth defects and reduced sensitivity to BRs. UBP13 directly interacts with and effectively removes K63-linked polyubiquitin chains from BRI1, thereby negatively modulating its vacuolar targeting and degradation. Our study reveals that UBP12 and UBP13 play crucial roles in governing BRI1 abundance and BR signaling activity to regulate plant growth.
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Affiliation(s)
- Yongming Luo
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Junpei Takagi
- Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Lucas Alves Neubus Claus
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Chao Zhang
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX, USA
| | | | - Yoko Hasegawa
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | | | - Libo Shan
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX, USA
| | - Eugenia Russinova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Takeo Sato
- Faculty of Science, Hokkaido University, Sapporo, Japan
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4
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Snyder NA, Silva GM. Deubiquitinating enzymes (DUBs): Regulation, homeostasis, and oxidative stress response. J Biol Chem 2021; 297:101077. [PMID: 34391779 PMCID: PMC8424594 DOI: 10.1016/j.jbc.2021.101077] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 12/17/2022] Open
Abstract
Ubiquitin signaling is a conserved, widespread, and dynamic process in which protein substrates are rapidly modified by ubiquitin to impact protein activity, localization, or stability. To regulate this process, deubiquitinating enzymes (DUBs) counter the signal induced by ubiquitin conjugases and ligases by removing ubiquitin from these substrates. Many DUBs selectively regulate physiological pathways employing conserved mechanisms of ubiquitin bond cleavage. DUB activity is highly regulated in dynamic environments through protein-protein interaction, posttranslational modification, and relocalization. The largest family of DUBs, cysteine proteases, are also sensitive to regulation by oxidative stress, as reactive oxygen species (ROS) directly modify the catalytic cysteine required for their enzymatic activity. Current research has implicated DUB activity in human diseases, including various cancers and neurodegenerative disorders. Due to their selectivity and functional roles, DUBs have become important targets for therapeutic development to treat these conditions. This review will discuss the main classes of DUBs and their regulatory mechanisms with a particular focus on DUB redox regulation and its physiological impact during oxidative stress.
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Affiliation(s)
- Nathan A Snyder
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Gustavo M Silva
- Department of Biology, Duke University, Durham, North Carolina, USA.
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Estadella I, Pedrós-Gámez O, Colomer-Molera M, Bosch M, Sorkin A, Felipe A. Endocytosis: A Turnover Mechanism Controlling Ion Channel Function. Cells 2020; 9:E1833. [PMID: 32759790 PMCID: PMC7463639 DOI: 10.3390/cells9081833] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/30/2020] [Accepted: 08/02/2020] [Indexed: 01/08/2023] Open
Abstract
Ion channels (IChs) are transmembrane proteins that selectively drive ions across membranes. The function of IChs partially relies on their abundance and proper location in the cell, fine-tuned by the delicate balance between secretory, endocytic, and degradative pathways. The disruption of this balance is associated with several diseases, such as Liddle's and long QT syndromes. Because of the vital role of these proteins in human health and disease, knowledge of ICh turnover is essential. Clathrin-dependent and -independent mechanisms have been the primary mechanisms identified with ICh endocytosis and degradation. Several molecular determinants recognized by the cellular internalization machinery have been discovered. Moreover, specific conditions can trigger the endocytosis of many IChs, such as the activation of certain receptors, hypokalemia, and some drugs. Ligand-dependent receptor activation primarily results in the posttranslational modification of IChs and the recruitment of important mediators, such as β-arrestins and ubiquitin ligases. However, endocytosis is not a final fate. Once internalized into endosomes, IChs are either sorted to lysosomes for degradation or recycled back to the plasma membrane. Rab proteins are crucial participants during these turnover steps. In this review, we describe the major ICh endocytic pathways, the signaling inputs triggering ICh internalization, and the key mediators of this essential cellular process.
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Affiliation(s)
- Irene Estadella
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (I.E.); (O.P.-G.); (M.C.-M.); (M.B.)
| | - Oriol Pedrós-Gámez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (I.E.); (O.P.-G.); (M.C.-M.); (M.B.)
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (I.E.); (O.P.-G.); (M.C.-M.); (M.B.)
| | - Manel Bosch
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (I.E.); (O.P.-G.); (M.C.-M.); (M.B.)
- Centres Científics i Tecnològics de la Universitat de Barcelona (CCiTUB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Alexander Sorkin
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (I.E.); (O.P.-G.); (M.C.-M.); (M.B.)
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Bustamante HA, Cereceda K, González AE, Valenzuela GE, Cheuquemilla Y, Hernández S, Arias-Muñoz E, Cerda-Troncoso C, Bandau S, Soza A, Kausel G, Kerr B, Mardones GA, Cancino J, Hay RT, Rojas-Fernandez A, Burgos PV. The Proteasomal Deubiquitinating Enzyme PSMD14 Regulates Macroautophagy by Controlling Golgi-to-ER Retrograde Transport. Cells 2020; 9:E777. [PMID: 32210007 PMCID: PMC7140897 DOI: 10.3390/cells9030777] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 12/15/2022] Open
Abstract
Ubiquitination regulates several biological processes, however the role of specific members of the ubiquitinome on intracellular membrane trafficking is not yet fully understood. Here, we search for ubiquitin-related genes implicated in protein membrane trafficking performing a High-Content siRNA Screening including 1187 genes of the human "ubiquitinome" using amyloid precursor protein (APP) as a reporter. We identified the deubiquitinating enzyme PSMD14, a subunit of the 19S regulatory particle of the proteasome, specific for K63-Ub chains in cells, as a novel regulator of Golgi-to-endoplasmic reticulum (ER) retrograde transport. Silencing or pharmacological inhibition of PSMD14 with Capzimin (CZM) caused a robust increase in APP levels at the Golgi apparatus and the swelling of this organelle. We showed that this phenotype is the result of rapid inhibition of Golgi-to-ER retrograde transport, a pathway implicated in the early steps of the autophagosomal formation. Indeed, we observed that inhibition of PSMD14 with CZM acts as a potent blocker of macroautophagy by a mechanism related to the retention of Atg9A and Rab1A at the Golgi apparatus. As pharmacological inhibition of the proteolytic core of the 20S proteasome did not recapitulate these effects, we concluded that PSMD14, and the K63-Ub chains, act as a crucial regulatory factor for macroautophagy by controlling Golgi-to-ER retrograde transport.
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Affiliation(s)
- Hianara A Bustamante
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5110566, Chile; (H.A.B.); (A.E.G.); (G.A.M.)
| | - Karina Cereceda
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Alexis E González
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5110566, Chile; (H.A.B.); (A.E.G.); (G.A.M.)
| | - Guillermo E Valenzuela
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5110566, Chile; (G.E.V.); (G.K.)
- Instituto de Medicina & Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile;
| | - Yorka Cheuquemilla
- Instituto de Medicina & Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile;
| | - Sergio Hernández
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Eloisa Arias-Muñoz
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Cristóbal Cerda-Troncoso
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Susanne Bandau
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, DD1 4HN, Dundee DD1 4HN UK; (S.B.); (R.T.H.)
| | - Andrea Soza
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Gudrun Kausel
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia 5110566, Chile; (G.E.V.); (G.K.)
| | - Bredford Kerr
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Gonzalo A Mardones
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia 5110566, Chile; (H.A.B.); (A.E.G.); (G.A.M.)
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Jorge Cancino
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
| | - Ronald T Hay
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, DD1 4HN, Dundee DD1 4HN UK; (S.B.); (R.T.H.)
| | - Alejandro Rojas-Fernandez
- Instituto de Medicina & Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia 5110566, Chile;
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, DD1 4HN, Dundee DD1 4HN UK; (S.B.); (R.T.H.)
| | - Patricia V Burgos
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile; (K.C.); (S.H.); (E.A.-M.); (C.C.-T.); (A.S.); (B.K.); (J.C.)
- Centro de Envejecimiento y Regeneración (CARE-UC), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 83330023, Chile
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Lee BSL, Devor DC, Hamilton KL. Modulation of Retrograde Trafficking of KCa3.1 in a Polarized Epithelium. Front Physiol 2017; 8:489. [PMID: 28769813 PMCID: PMC5513911 DOI: 10.3389/fphys.2017.00489] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/26/2017] [Indexed: 12/14/2022] Open
Abstract
In epithelia, the intermediate conductance, Ca2+-activated K+ channel (KCa3.1) is targeted to the basolateral membrane (BLM) where this channel plays numerous roles in absorption and secretion. A growing body of research suggests that the membrane resident population of KCa3.1 may be critical in clinical manifestation of diseases. In this study, we investigated the key molecular components that regulate the degradation of KCa3.1 using a Fisher rat thyroid cell line stably expressing KCa3.1. Using immunoblot, Ussing chamber, and pharmacological approaches, we demonstrated that KCa3.1 is targeted exclusively to the BLM, provided a complete time course of degradation of KCa3.1 and degradation time courses of the channel in the presence of pharmacological inhibitors of ubiquitylation and deubiquitylation to advance our understanding of the retrograde trafficking of KCa3.1. We provide a complete degradation profile of KCa3.1 and that the degradation is via an ubiquitin-dependent pathway. Inhibition of E1 ubiquitin activating enzyme by UBEI-41 crippled the ability of the cells to internalize the channel, shown by the increased BLM surface expression resulting in an increased function of the channel as measured by a DCEBIO sensitive K+ current. Additionally, the involvement of deubiquitylases and degradation by the lysosome were also confirmed by treating the cells with PR-619 or leupeptin/pepstatin, respectively; which significantly decreased the degradation rate of membrane KCa3.1. Additionally, we provided the first evidence that KCa3.1 channels were not deubiquitylated at the BLM. These data further define the retrograde trafficking of KCa3.1, and may provide an avenue for therapeutic approach for treatment of disease.
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Affiliation(s)
- Bob Shih-Liang Lee
- Department of Physiology, School of Biomedical Sciences, University of OtagoDunedin, New Zealand
| | - Daniel C Devor
- Department of Cell Biology, University of Pittsburgh School of MedicinePittsburgh, PA, United States
| | - Kirk L Hamilton
- Department of Physiology, School of Biomedical Sciences, University of OtagoDunedin, New Zealand
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8
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Deubiquitylating enzymes in receptor endocytosis and trafficking. Biochem J 2017; 473:4507-4525. [PMID: 27941029 DOI: 10.1042/bcj20160826] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 09/15/2016] [Accepted: 09/16/2016] [Indexed: 12/25/2022]
Abstract
In recent times, our knowledge of the roles ubiquitin plays in multiple cellular processes has expanded exponentially, with one example being the role of ubiquitin in receptor endocytosis and trafficking. This has prompted a multitude of studies examining how the different machinery involved in the addition and removal of ubiquitin can influence this process. Multiple deubiquitylating enzymes (DUBs) have been implicated either in facilitating receptor endocytosis and lysosomal degradation or in rescuing receptor levels by preventing endocytosis and/or promoting recycling to the plasma membrane. In this review, we will discuss in detail what is currently known about the role of DUBs in regulating the endocytosis of various transmembrane receptors and ion channels. We will also expand upon the role DUBs play in receptor sorting at the multivesicular body to determine whether a receptor is recycled or trafficked to the lysosome for degradation. Finally, we will briefly discuss how the DUBs implicated in these processes may contribute to the pathogenesis of a range of diseases, and thus the potential these have as therapeutic targets.
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9
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Datta G, Hossain ME, Asad M, Rathore S, Mohmmed A. Plasmodium falciparum OTU-like cysteine protease (PfOTU) is essential for apicoplast homeostasis and associates with noncanonical role of Atg8. Cell Microbiol 2017; 19. [PMID: 28423214 DOI: 10.1111/cmi.12748] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 03/12/2017] [Accepted: 04/05/2017] [Indexed: 12/19/2022]
Abstract
The metabolic pathways associated with the mitochondrion and the apicoplast in Plasmodium, 2 parasite organelles of prokaryotic origin, are considered as suitable drug targets. In the present study, we have identified functional role of a novel ovarian tumour unit (OTU) domain-containing cysteine protease of Plasmodium falciparum (PfOTU). A C-terminal regulatable fluorescent affinity tag on native protein was utilised for its localization and functional characterization. Detailed studies showed vesicular localization of PfOTU and its association with the apicoplast. Degradation-tag mediated knockdown of PfOTU resulted in abnormal apicoplast development and blocked development of parasites beyond early-schizont stages in subsequent cell cycle; downregulation of PfOTU hindered apicoplast protein import. Further, the isoprenoid precursor-mediated parasite growth-rescue experiments confirmed that PfOTU knockdown specifically effect development of functional apicoplast. We also provide evidence for a possible biological function of PfOTU in membrane deconjugation of Atg8, which may be linked with the apicoplast protein import. Overall, our results show that the PfOTU is involved in apicoplast homeostasis and associates with the noncanonical function of Atg8 in maintenance of parasite apicoplast.
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Affiliation(s)
- Gaurav Datta
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Mohammad E Hossain
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Mohd Asad
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Sumit Rathore
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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10
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Leznicki P, Kulathu Y. Mechanisms of regulation and diversification of deubiquitylating enzyme function. J Cell Sci 2017; 130:1997-2006. [PMID: 28476940 DOI: 10.1242/jcs.201855] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Deubiquitylating (or deubiquitinating) enzymes (DUBs) are proteases that reverse protein ubiquitylation and therefore modulate the outcome of this post-translational modification. DUBs regulate a variety of intracellular processes, including protein turnover, signalling pathways and the DNA damage response. They have also been linked to a number of human diseases, such as cancer, and inflammatory and neurodegenerative disorders. Although we are beginning to better appreciate the role of DUBs in basic cell biology and their importance for human health, there are still many unknowns. Central among these is the conundrum of how the small number of ∼100 DUBs encoded in the human genome is capable of regulating the thousands of ubiquitin modification sites detected in human cells. This Commentary addresses the biological mechanisms employed to modulate and expand the functions of DUBs, and sets directions for future research aimed at elucidating the details of these fascinating processes.This article is part of a Minifocus on Ubiquitin Regulation and Function. For further reading, please see related articles: 'Exploitation of the host cell ubiquitin machinery by microbial effector proteins' by Yi-Han Lin and Matthias P. Machner (J. Cell Sci.130, 1985-1996). 'Cell scientist to watch - Mads Gyrd-Hansen' (J. Cell Sci.130, 1981-1983).
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Affiliation(s)
- Pawel Leznicki
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Yogesh Kulathu
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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11
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Romani L, Oikonomou V, Moretti S, Iannitti RG, D'Adamo MC, Villella VR, Pariano M, Sforna L, Borghi M, Bellet MM, Fallarino F, Pallotta MT, Servillo G, Ferrari E, Puccetti P, Kroemer G, Pessia M, Maiuri L, Goldstein AL, Garaci E. Thymosin α1 represents a potential potent single-molecule-based therapy for cystic fibrosis. Nat Med 2017; 23:590-600. [PMID: 28394330 PMCID: PMC5420451 DOI: 10.1038/nm.4305] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 02/17/2017] [Indexed: 12/17/2022]
Abstract
Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) that compromise its chloride-channel activity. The most common mutation, p.Phe508del, results in the production of a misfolded CFTR protein, which has residual channel activity but is prematurely degraded. Because of the inherent complexity of the pathogenetic mechanisms involved in CF —which include impaired chloride permeability and persistent lung inflammation—a multidrug approach is required for efficacious CF therapy. To date, no individual, drug with pleiotropic beneficial effects for CF is available. Here we report on the ability of thymosin alpha 1 (Tα1)—a naturally occurring polypeptide with an excellent safety profile in the clinic when used as an adjuvant or an immunotherapeutic agent—to rectify the multiple tissue defects in CF mice as well as in cells from subjects with the p.Phe508del mutation. Tα1 displayed two combined properties that favorably opposed CF symptomatology; namely, it reduced inflammation and increased CFTR maturation, stability and activity. By virtue of this two-pronged action, Tα1 offers a strong potential to be an efficacious single molecule-based therapeutic agent in CF.
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Affiliation(s)
- Luigina Romani
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Vasilis Oikonomou
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Silvia Moretti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Rossana G Iannitti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Maria Cristina D'Adamo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Valeria R Villella
- European Institute for Research in Cystic Fibrosis, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Marilena Pariano
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luigi Sforna
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Monica Borghi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Marina M Bellet
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | | | | | - Giuseppe Servillo
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Eleonora Ferrari
- European Institute for Research in Cystic Fibrosis, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Paolo Puccetti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, INSERM U1138, Université Paris Descartes, Paris, France.,Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France.,Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.,Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden
| | - Mauro Pessia
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Luigi Maiuri
- European Institute for Research in Cystic Fibrosis, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Department of Health Sciences, University of Piemonte Orientale, Novara, Italy
| | - Allan L Goldstein
- Department of Biochemistry and Molecular Medicine, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
| | - Enrico Garaci
- University San Raffaele and IRCCS San Raffaele, Rome, Italy
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12
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Ho HC, MacGurn JA, Emr SD. Deubiquitinating enzymes Ubp2 and Ubp15 regulate endocytosis by limiting ubiquitination and degradation of ARTs. Mol Biol Cell 2017; 28:1271-1283. [PMID: 28298493 PMCID: PMC5415021 DOI: 10.1091/mbc.e17-01-0008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 12/18/2022] Open
Abstract
Endocytic down-regulation of cell-surface proteins is a fundamental cellular process for cell survival and adaptation to environmental stimuli. Ubiquitination of cargo proteins serves as the sorting signal for downstream trafficking and relies on the arrestin-related trafficking adaptor (ART)-Rsp5 ubiquitin ligase adaptor network in yeast. Hence proper regulation of the abundance and activity of these ligase-adaptor complexes is critical for main-tenance of optimal plasma membrane protein composition. Here we report that the stability of ARTs is regulated by the deubiquitinating enzymes (DUBs) Ubp2 and Ubp15. By counteracting the E3 ubiquitin ligase Rsp5, Ubp2 and Ubp15 prevent hyperubiquitination and proteasomal degradation of ARTs. Specifically, we show that loss of both Ubp2 and Ubp15 results in a defect in Hxt6 endocytosis associated with Art4 instability. Our results uncover a novel function for DUBs in the endocytic pathway by which Ubp2 and Ubp15 positively regulate the ART-Rsp5 network.
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Affiliation(s)
- Hsuan-Chung Ho
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240
| | - Scott D Emr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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13
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Sachser RM, Haubrich J, Lunardi PS, de Oliveira Alvares L. Forgetting of what was once learned: Exploring the role of postsynaptic ionotropic glutamate receptors on memory formation, maintenance, and decay. Neuropharmacology 2016; 112:94-103. [PMID: 27425202 DOI: 10.1016/j.neuropharm.2016.07.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 12/26/2022]
Abstract
Over the past years, extensive research in experimental cognitive neuroscience has provided a comprehensive understanding about the role of ionotropic glutamate receptor (IGluR)-dependent signaling underpinning postsynaptic plasticity induced by long-term potentiation (LTP), the leading cellular basis of long-term memory (LTM). However, despite the fact that iGluR-mediated postsynaptic plasticity regulates the formation and persistence of LTP and LTM, here we discuss the state-of-the-art regarding the mechanisms underpinning both LTP and LTM decay. First, we review the crucial roles that iGluRs play on memory encoding and stabilization. Second, we discuss the latest findings in forgetting considering hippocampal GluA2-AMPAR trafficking at postsynaptic sites as well as dendritic spine remodeling possibly involved in LTP decay. Third, on the role of retrieving consolidated LTMs, we discuss the mechanisms involved in memory destabilization that occurs followed reactivation that share striking similarities with the neurobiological basis of forgetting. Fourth, since different AMPAR subunits as well as postsynaptic scaffolding proteins undergo ubiquitination, the ubiquitin-proteasome system (UPS) is discussed in light of memory decay. In conclusion, we provide an integrated overview revealing some of the mechanisms determining memory forgetting that are mediated by iGluRs. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.
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Affiliation(s)
- Ricardo Marcelo Sachser
- Neurobiology of Memory Lab, Biophysics Department, Bioscience Institute, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Neuroscience, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Josué Haubrich
- Psychobiology and Neurocomputation Lab, Biophysics Department, Bioscience Institute, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Neuroscience, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Paula Santana Lunardi
- Neurobiology of Memory Lab, Biophysics Department, Bioscience Institute, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Neuroscience, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Lucas de Oliveira Alvares
- Neurobiology of Memory Lab, Biophysics Department, Bioscience Institute, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Neuroscience, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
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14
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Zhang M, Hu C, Tong D, Xiang S, Williams K, Bai W, Li GM, Bepler G, Zhang X. Ubiquitin-specific Peptidase 10 (USP10) Deubiquitinates and Stabilizes MutS Homolog 2 (MSH2) to Regulate Cellular Sensitivity to DNA Damage. J Biol Chem 2016; 291:10783-91. [PMID: 26975374 DOI: 10.1074/jbc.m115.700047] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Indexed: 11/06/2022] Open
Abstract
MSH2 is a key DNA mismatch repair protein, which plays an important role in genomic stability. In addition to its DNA repair function, MSH2 serves as a sensor for DNA base analogs-provoked DNA replication errors and binds to various DNA damage-induced adducts to trigger cell cycle arrest or apoptosis. Loss or depletion of MSH2 from cells renders resistance to certain DNA-damaging agents. Therefore, the level of MSH2 determines DNA damage response. Previous studies showed that the level of MSH2 protein is modulated by the ubiquitin-proteasome pathway, and histone deacetylase 6 (HDAC6) serves as an ubiquitin E3 ligase. However, the deubiquitinating enzymes, which regulate MSH2 remain unknown. Here we report that ubiquitin-specific peptidase 10 (USP10) interacts with and stabilizes MSH2. USP10 deubiquitinates MSH2 in vitro and in vivo Moreover, the protein level of MSH2 is positively correlated with the USP10 protein level in a panel of lung cancer cell lines. Knockdown of USP10 in lung cancer cells exhibits increased cell survival and decreased apoptosis upon the treatment of DNA-methylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and antimetabolite 6-thioguanine (6-TG). The above phenotypes can be rescued by ectopic expression of MSH2. In addition, knockdown of MSH2 decreases the cellular mismatch repair activity. Overall, our results suggest a novel USP10-MSH2 pathway regulating DNA damage response and DNA mismatch repair.
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Affiliation(s)
- Mu Zhang
- From the Department of Pathology and Cell Biology, Morsani College of Medicine, Tampa, Florida 33612
| | - Chen Hu
- From the Department of Pathology and Cell Biology, Morsani College of Medicine, Tampa, Florida 33612
| | - Dan Tong
- Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Shengyan Xiang
- From the Department of Pathology and Cell Biology, Morsani College of Medicine, Tampa, Florida 33612
| | - Kendra Williams
- From the Department of Pathology and Cell Biology, Morsani College of Medicine, Tampa, Florida 33612
| | - Wenlong Bai
- From the Department of Pathology and Cell Biology, Morsani College of Medicine, Tampa, Florida 33612, Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, and
| | - Guo-Min Li
- Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Gerold Bepler
- Molecular Therapeutics Program, Karmanos Cancer Institute, Detroit, Michigan 48201
| | - Xiaohong Zhang
- From the Department of Pathology and Cell Biology, Morsani College of Medicine, Tampa, Florida 33612, Cancer Biology and Evolution Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, and
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15
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Farshi P, Deshmukh RR, Nwankwo JO, Arkwright RT, Cvek B, Liu J, Dou QP. Deubiquitinases (DUBs) and DUB inhibitors: a patent review. Expert Opin Ther Pat 2015; 25:1191-1208. [PMID: 26077642 DOI: 10.1517/13543776.2015.1056737] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Deubiquitinating-enzymes (DUBs) are key components of the ubiquitin-proteasome system (UPS). The fundamental role of DUBs is specific removal of ubiquitin from substrates. DUBs contribute to activation/deactivation, recycling and localization of numerous regulatory proteins, and thus play major roles in diverse cellular processes. Altered DUB activity is associated with a multitudes of pathologies including cancer. Therefore, DUBs represent novel candidates for target-directed drug development. AREAS COVERED The article is a thorough review/accounting of patented compounds targeting DUBs and stratifying/classifying the patented compounds based on: chemical-structures, nucleic-acid compositions, modes-of-action, and targeting sites. The review provides a brief background on the UPS and the involvement of DUBs. Furthermore, methods for assessing efficacy and potential pharmacological utility of DUB inhibitor (DUBi) are discussed. EXPERT OPINION The FDA's approval of the 20S proteasome inhibitors (PIs): bortezomib and carfilzomib for treatment of hematological malignancies established the UPS as an anti-cancer target. Unfortunately, many patients are inherently resistant or develop resistance to PIs. One potential strategy to combat PI resistance is targeting upstream components of the UPS such as DUBs. DUBs represent a promising potential therapeutic target due to their critical roles in various cellular processes including protein turnover, localization and cellular homeostasis. While considerable efforts have been undertaken to develop DUB modulators, significant advancements are necessary to move DUBis into the clinic.
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Affiliation(s)
- Pershang Farshi
- Barbara Ann Karmanos Cancer Institute, School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Rahul R Deshmukh
- Barbara Ann Karmanos Cancer Institute, School of Medicine, Wayne State University, Detroit, Michigan, USA.,Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Joseph O Nwankwo
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, Federal University, Ndufu-Alike Ikwo, Ebonyi State, Nigeria
| | - Richard T Arkwright
- Barbara Ann Karmanos Cancer Institute, School of Medicine, Wayne State University, Detroit, Michigan, USA.,Department of Oncology, School of Medicine, Wayne State University, Detroit, Michigan, USA
| | - Boris Cvek
- Department of Cell Biology & Genetics, Palacky University, Slechtitelu 11, Olomouc 78371, Czech Republic
| | - Jinbao Liu
- State Key Lab of Respiratory Disease, Protein Modification and Degradation Lab, Department of Pathophysiology, Guangzhou Medical University, Guangdong 510182, China
| | - Q Ping Dou
- Barbara Ann Karmanos Cancer Institute, School of Medicine, Wayne State University, Detroit, Michigan, USA.,Department of Oncology, School of Medicine, Wayne State University, Detroit, Michigan, USA.,Department of Pharmacology, School of Medicine, Wayne State University, Detroit, Michigan, USA.,Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan, USA
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16
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Murtaza M, Jolly LA, Gecz J, Wood SA. La FAM fatale: USP9X in development and disease. Cell Mol Life Sci 2015; 72:2075-89. [PMID: 25672900 PMCID: PMC4427618 DOI: 10.1007/s00018-015-1851-0] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/02/2015] [Accepted: 02/04/2015] [Indexed: 11/12/2022]
Abstract
Deubiquitylating enzymes (DUBs), act downstream of ubiquitylation. As such, these post-post-translational modifiers function as the final arbitrators of a protein substrate’s ubiquitylation status, thus regulating its fate. In most instances, DUBs moderate the absolute level of a substrate, its locality or activity, rather than being an “all-or-none” phenomenon. Yet, disruption of this quantitative regulation can produce dramatic qualitative differences. The ubiquitin-specific protease 9X (USP9X/FAM) is a substrate-specific DUB, which displays an extraordinarily high level of sequence conservation from Drosophila to mammals. It is primarily the recent revelations of USP9X’s pivotal role in human cancers, both as oncogene or tumour suppressor, in developmental disorders including intellectual disability, epilepsy, autism and developmental delay that has led to a subsequent re-examination of its molecular and cellular functions. Results from experimental animal models have implicated USP9X in neurodegeneration, including Parkinson’s and Alzheimer’s disease, as well as autoimmune diseases. In this review, we describe the current and accumulated knowledge on the molecular, cellular and developmental aspects of USP9X function within the context of the biological consequences during normal development and disease.
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Affiliation(s)
- Mariyam Murtaza
- The Eskitis Institute for Drug Discovery, Griffith University, Brisbane, QLD, Australia
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17
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Bertuccio CA, Lee SL, Wu G, Butterworth MB, Hamilton KL, Devor DC. Anterograde trafficking of KCa3.1 in polarized epithelia is Rab1- and Rab8-dependent and recycling endosome-independent. PLoS One 2014; 9:e92013. [PMID: 24632741 PMCID: PMC3954861 DOI: 10.1371/journal.pone.0092013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/16/2014] [Indexed: 02/01/2023] Open
Abstract
The intermediate conductance, Ca2+-activated K+ channel (KCa3.1) targets to the basolateral (BL) membrane in polarized epithelia where it plays a key role in transepithelial ion transport. However, there are no studies defining the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia. Herein, we utilize Biotin Ligase Acceptor Peptide (BLAP)-tagged KCa3.1 to address these trafficking steps in polarized epithelia, using MDCK, Caco-2 and FRT cells. We demonstrate that KCa3.1 is exclusively targeted to the BL membrane in these cells when grown on filter supports. Following endocytosis, KCa3.1 degradation is prevented by inhibition of lysosomal/proteosomal pathways. Further, the ubiquitylation of KCa3.1 is increased following endocytosis from the BL membrane and PR-619, a deubiquitylase inhibitor, prevents degradation, indicating KCa3.1 is targeted for degradation by ubiquitylation. We demonstrate that KCa3.1 is targeted to the BL membrane in polarized LLC-PK1 cells which lack the μ1B subunit of the AP-1 complex, indicating BL targeting of KCa3.1 is independent of μ1B. As Rabs 1, 2, 6 and 8 play roles in ER/Golgi exit and trafficking of proteins to the BL membrane, we evaluated the role of these Rabs in the trafficking of KCa3.1. In the presence of dominant negative Rab1 or Rab8, KCa3.1 cell surface expression was significantly reduced, whereas Rabs 2 and 6 had no effect. We also co-immunoprecipitated KCa3.1 with both Rab1 and Rab8. These results suggest these Rabs are necessary for the anterograde trafficking of KCa3.1. Finally, we determined whether KCa3.1 traffics directly to the BL membrane or through recycling endosomes in MDCK cells. For these studies, we used either recycling endosome ablation or dominant negative RME-1 constructs and determined that KCa3.1 is trafficked directly to the BL membrane rather than via recycling endosomes. These results are the first to describe the anterograde and retrograde trafficking of KCa3.1 in polarized epithelia cells.
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Affiliation(s)
- Claudia A. Bertuccio
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shih-Liang Lee
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
| | - Michael B. Butterworth
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Kirk L. Hamilton
- Department of Physiology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand
- * E-mail: (DCD); (KLH)
| | - Daniel C. Devor
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (DCD); (KLH)
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18
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Loss of Usp9x disrupts cortical architecture, hippocampal development and TGFβ-mediated axonogenesis. PLoS One 2013; 8:e68287. [PMID: 23861879 PMCID: PMC3702552 DOI: 10.1371/journal.pone.0068287] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 05/28/2013] [Indexed: 01/17/2023] Open
Abstract
The deubiquitylating enzyme Usp9x is highly expressed in the developing mouse brain, and increased Usp9x expression enhances the self-renewal of neural progenitors in vitro. USP9X is a candidate gene for human neurodevelopmental disorders, including lissencephaly, epilepsy and X-linked intellectual disability. To determine if Usp9x is critical to mammalian brain development we conditionally deleted the gene from neural progenitors, and their subsequent progeny. Mating Usp9xloxP/loxP mice with mice expressing Cre recombinase from the Nestin promoter deleted Usp9x throughout the entire brain, and resulted in early postnatal lethality. Although the overall brain architecture was intact, loss of Usp9x disrupted the cellular organization of the ventricular and sub-ventricular zones, and cortical plate. Usp9x absence also led to dramatic reductions in axonal length, in vivo and in vitro, which could in part be explained by a failure in Tgf-β signaling. Deletion of Usp9x from the dorsal telencephalon only, by mating with Emx1-cre mice, was compatible with survival to adulthood but resulted in reduction or loss of the corpus callosum, a dramatic decrease in hippocampal size, and disorganization of the hippocampal CA3 region. This latter phenotypic aspect resembled that observed in Doublecortin knock-out mice, which is an Usp9x interacting protein. This study establishes that Usp9x is critical for several aspects of CNS development, and suggests that its regulation of Tgf-β signaling extends to neurons.
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19
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The ubiquitin/proteasome system-dependent control of mitochondrial steps in apoptosis. Semin Cell Dev Biol 2012; 23:499-508. [DOI: 10.1016/j.semcdb.2012.03.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/24/2012] [Accepted: 03/28/2012] [Indexed: 12/31/2022]
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20
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Clarke KJ, Adams AE, Manzke LH, Pearson TW, Borchers CH, Porter RK. A role for ubiquitinylation and the cytosolic proteasome in turnover of mitochondrial uncoupling protein 1 (UCP1). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1759-67. [PMID: 22531154 DOI: 10.1016/j.bbabio.2012.03.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/23/2012] [Accepted: 03/29/2012] [Indexed: 11/19/2022]
Abstract
In this study we show that mitochondrial uncoupling protein 1 (UCP1) in brown adipose tissue (BAT) and thymus mitochondria can be ubiquitinylated and degraded by the cytosolic proteasome. Using a ubiquitin conjugating system, we show that UCP1 can be ubiquitinylated in vitro. We demonstrate that UCP1 is ubiquitinylated in vivo using isolated mitochondria from brown adipose tissue, thymus and whole brown adipocytes. Using an in vitro ubiquitin conjugating-proteasome degradation system, we show that the cytosolic proteasome can degrade UCP1 at a rate commensurate with the half-life of UCP1 (i.e. 30-72h in brown adipocytes and ~3h, in thymocytes). In addition, we demonstrate that the cytoplasmic proteasome is required for UCP1 degradation from mitochondria that the process is inhibited by the proteasome inhibitor MG132 and that dissipation of the mitochondrial membrane potential inhibits degradation of UCP1. There also appears to be a greater amount of ubiquitinylated UCP1 associated with BAT mitochondria from cold-acclimated animals. We have also identified (using immunoprecipitation coupled with mass spectrometry) ubiquitinylated proteins with molecular masses greater than 32kDa, as being UCP1. We conclude that there is a role for ubiquitinylation and the cytosolic proteasome in turnover of mitochondrial UCP1. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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Affiliation(s)
- Kieran J Clarke
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
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21
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Zymophagy: selective autophagy of secretory granules. Int J Cell Biol 2012; 2012:396705. [PMID: 22550490 PMCID: PMC3329151 DOI: 10.1155/2012/396705] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/06/2012] [Accepted: 02/06/2012] [Indexed: 02/08/2023] Open
Abstract
Timing is everything. That's especially true when it comes to the activation of enzymes created by the pancreas to break down food. Pancreatic enzymes are packed in secretory granules as precursor molecules called zymogens. In physiological conditions, those zymogens are activated only when they reach the gut, where they get to work releasing and distributing nutrients that we need to survive. If this process fails and the enzymes are prematurely activated within the pancreatic cell, before they are released from the gland, they break down the pancreas itself causing acute pancreatitis. This is a painful disease that ranges from a mild and autolimited process to a severe and lethal condition. Recently, we demonstrated that the pancreatic acinar cell is able to switch on a refined mechanism that could explain the autolimited form of the disease. This is a novel selective form of autophagy named zymophagy, a cellular process to specifically detect and degrade secretory granules containing activated enzymes before they can digest the organ. In this work, we revise the molecules and mechanisms that mediate zymophagy, a selective autophagy of secretory granules.
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22
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Bomberger JM, Coutermarsh BA, Barnaby RL, Stanton BA. Arsenic promotes ubiquitinylation and lysosomal degradation of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels in human airway epithelial cells. J Biol Chem 2012; 287:17130-17139. [PMID: 22467879 DOI: 10.1074/jbc.m111.338855] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Arsenic exposure significantly increases respiratory bacterial infections and reduces the ability of the innate immune system to eliminate bacterial infections. Recently, we observed in the gill of killifish, an environmental model organism, that arsenic exposure induced the ubiquitinylation and degradation of cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel that is essential for the mucociliary clearance of respiratory pathogens in humans. Accordingly, in this study, we tested the hypothesis that low dose arsenic exposure reduces the abundance and function of CFTR in human airway epithelial cells. Arsenic induced a time- and dose-dependent increase in multiubiquitinylated CFTR, which led to its lysosomal degradation, and a decrease in CFTR-mediated chloride secretion. Although arsenic had no effect on the abundance or activity of USP10, a deubiquitinylating enzyme, siRNA-mediated knockdown of c-Cbl, an E3 ubiquitin ligase, abolished the arsenic-stimulated degradation of CFTR. Arsenic enhanced the degradation of CFTR by increasing phosphorylated c-Cbl, which increased its interaction with CFTR, and subsequent ubiquitinylation of CFTR. Because epidemiological studies have shown that arsenic increases the incidence of respiratory infections, this study suggests that one potential mechanism of this effect involves arsenic-induced ubiquitinylation and degradation of CFTR, which decreases chloride secretion and airway surface liquid volume, effects that would be proposed to reduce mucociliary clearance of respiratory pathogens.
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Affiliation(s)
- Jennifer M Bomberger
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219 and
| | - Bonita A Coutermarsh
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Roxanna L Barnaby
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Bruce A Stanton
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755.
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23
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Balut CM, Loch CM, Devor DC. Role of ubiquitylation and USP8-dependent deubiquitylation in the endocytosis and lysosomal targeting of plasma membrane KCa3.1. FASEB J 2011; 25:3938-48. [PMID: 21828287 DOI: 10.1096/fj.11-187005] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We recently demonstrated that plasma membrane KCa3.1 is rapidly endocytosed and targeted for lysosomal degradation via a Rab7- and ESCRT-dependent pathway. Herein, we assess the role of ubiquitylation in this process. Using a biotin ligase acceptor peptide (BLAP)-tagged KCa3.1, in combination with tandem ubiquitin binding entities (TUBEs), we demonstrate that KCa3.1 is polyubiquitylated following endocytosis. Hypertonic sucrose inhibited KCa3.1 endocytosis and resulted in a significant decrease in channel ubiquitylation. Inhibition of the ubiquitin-activating enzyme (E1) with UBEI-41 resulted in reduced KCa3.1 ubiquitylation and internalization. The general deubiquitylase (DUB) inhibitor, PR-619 attenuated KCa3.1 degradation, indicative of deubiquitylation being required for lysosomal delivery. Using the DUB Chip, a protein microarray containing 35 DUBs, we demonstrate a time-dependent association between KCa3.1 and USP8 following endocytosis, which was confirmed by coimmunoprecipitation. Further, overexpression of wild-type USP8 accelerates channel deubiquitylation, while either a catalytically inactive mutant USP8 or siRNA-mediated knockdown of USP8 enhanced accumulation of ubiquitylated KCa3.1, thereby inhibiting channel degradation. In summary, by combining BLAP-tagged KCa3.1 with TUBEs and DUB Chip methodologies, we demonstrate that polyubiquitylation mediates the targeting of membrane KCa3.1 to the lysosomes and also that USP8 regulates the rate of KCa3.1 degradation by deubiquitylating KCa3.1 prior to lysosomal delivery.
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Affiliation(s)
- Corina M Balut
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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Bomberger JM, Barnaby RL, Stanton BA. The deubiquitinating enzyme USP10 regulates the endocytic recycling of CFTR in airway epithelial cells. Channels (Austin) 2011; 4:150-4. [PMID: 20215869 DOI: 10.4161/chan.4.3.11223] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a cyclic AMP-regulated chloride channel that plays an important role in regulating the volume of the lung airway surface liquid, and thereby mucociliary clearance and elimination of pathogens from the lung. In epithelial cells, cell surface CFTR abundance is determined in part by regulating both CFTR endocytosis from the apical plasma membrane and recycling back to the plasma membrane. We recently reported, using an activity-based chemical screen to identify active deubiquitinating enzymes (DUBs) in human airway epithelial cells, that Ubiquitin Specific Protease-10 (USP10) is located and active in the early endosomal compartment and regulates the deubiquitination of CFTR and thereby promotes its endocytic recycling. siRNA-mediated knockdown of USP10 increased the multi-ubiquitination and lysosomal degradation of CFTR and decreased the endocytic recycling and the half-life of CFTR in the apical membrane, as well as CFTR-mediated chloride secretion. Overexpression of wild-type USP10 reduced CFTR multi-ubiquitination and degradation, while overexpression of a dominant-negative USP10 promoted increased multi-ubiquitination and lysosomal degradation of CFTR. In the current study, we show localization and activity of USP10 in the early endosomal compartment of primary bronchial epithelial cells, as well as an interaction between CFTR and USP10 in this compartment. These studies demonstrate a novel function for USP10 in facilitating the deubiquitination of CFTR in early endosomes, thereby enhancing the endocytic recycling and cell surface expression of CFTR.
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25
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Pervin S, Tran A, Tran L, Urman R, Braga M, Chaudhuri G, Singh R. Reduced association of anti-apoptotic protein Mcl-1 with E3 ligase Mule increases the stability of Mcl-1 in breast cancer cells. Br J Cancer 2011; 105:428-37. [PMID: 21730980 PMCID: PMC3172901 DOI: 10.1038/bjc.2011.242] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background: Mechanisms that increase resistance to apoptosis help promote cellular transformation. Cancer cells have deregulated apoptotic pathways, where increased expression and stability of anti-apoptotic proteins Mcl-1 and Bcl-2 increases resistance to apoptosis. Pathways that increase the stability of proteins in cancer cells remain poorly understood. Methods: Using human mammary epithelial and established breast cancer cell lines, we assessed the mechanisms that increase the stability of anti-apoptotic proteins in breast cancer cells by caspase assay, western blot, small-inhibitory RNA treatment and immunoprecipitation. Results: While breast cancer cells were resistant to de novo inhibition of protein synthesis, a rapid proteosome-mediated degradation of Mcl-1 and Bcl-2 induced apoptosis in mammary epithelial cells. Although Mule, an E3 ligase that targets Mcl-1 for degradation was expressed in mammary epithelial and breast cancer cell lines, rapid increase of polyubiquitinated Mcl-1 and Bcl-2 was detected only in mammary epithelial cells. Only transient formation of the Mule–Mcl-1 complex was detected in breast cancer cells. Downregulation of pERK1/2 in breast cancer cells reduced Mcl-1 levels and increased Mcl-1/Mule complex. Conclusion: Our findings suggest that reduced Mule/Mcl-1 complex has a significant role in increasing the stability of Mcl-1 in breast cancer cells and increased resistance to apoptosis.
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Affiliation(s)
- S Pervin
- Department of Internal Medicine, Charles Drew University of Medicine and Science, 3084 Hawkins Building, 1731 East 120th Street, Los Angeles, CA 90059, USA.
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26
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Gu Y, Innes RW. The KEEP ON GOING protein of Arabidopsis recruits the ENHANCED DISEASE RESISTANCE1 protein to trans-Golgi network/early endosome vesicles. PLANT PHYSIOLOGY 2011; 155:1827-38. [PMID: 21343429 PMCID: PMC3091131 DOI: 10.1104/pp.110.171785] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 02/18/2011] [Indexed: 05/20/2023]
Abstract
Loss-of-function mutations in the Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced resistance to powdery mildew infection, enhanced senescence, and enhanced programmed cell death under both abiotic and biotic stress conditions. All edr1-mediated phenotypes can be suppressed by a specific missense mutation (keg-4) in the KEEP ON GOING (KEG) gene, which encodes a multidomain protein that includes a RING E3 ligase domain, a kinase domain, ankyrin repeats, and HERC2-like (for HECT and RCC1-like) repeats. The molecular and cellular mechanisms underlying this suppression are poorly understood. Using confocal laser scanning microscopy and fluorescent protein fusions, we determined that KEG localizes to trans-Golgi network/early endosome (TGN/EE) vesicles. Both the keg-4 mutation, which is located in the carboxyl-terminal HERC2-like repeats, and deletion of the entire HERC2-like repeats reduced endosomal localization of KEG and increased localization to the endoplasmic reticulum and cytosol, indicating that the HERC2-like repeats facilitate the TGN/EE targeting of KEG. EDR1 colocalized with KEG to the TGN/EE when coexpressed but localized primarily to the endoplasmic reticulum when expressed alone. Yeast two-hybrid and coimmunoprecipitation analyses revealed that EDR1 and KEG physically interact. Deletion of the HERC2-like repeats abolished the interaction between KEG and EDR1 as well as the KEG-induced TGN/EE localization of EDR1, indicating that the recruitment of EDR1 to the TGN/EE is based on a direct interaction between EDR1 and KEG mediated by the HERC2-like repeats. Collectively, these data suggest that EDR1 and KEG function together to regulate endocytic trafficking and/or the formation of signaling complexes on TGN/EE vesicles during stress responses.
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Affiliation(s)
| | - Roger W. Innes
- Department of Biology, Indiana University, Bloomington, Indiana 47405–7107
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Luise C, Capra M, Donzelli M, Mazzarol G, Jodice MG, Nuciforo P, Viale G, Di Fiore PP, Confalonieri S. An atlas of altered expression of deubiquitinating enzymes in human cancer. PLoS One 2011; 6:e15891. [PMID: 21283576 PMCID: PMC3026797 DOI: 10.1371/journal.pone.0015891] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Accepted: 11/29/2010] [Indexed: 12/04/2022] Open
Abstract
Background Deubiquitinating enzymes (DUBs) are proteases that process ubiquitin (Ub) or ubiquitin-like gene products, remodel polyubiquitin(-like) chains on target proteins, and counteract protein ubiquitination exerted by E3 ubiquitin-ligases. A wealth of studies has established the relevance of DUBs to the control of physiological processes whose subversion is known to cause cellular transformation, including cell cycle progression, DNA repair, endocytosis and signal transduction. Altered expression of DUBs might, therefore, subvert both the proteolytic and signaling functions of the Ub system. Methodology/Principal Findings In this study, we report the first comprehensive screening of DUB dysregulation in human cancers by in situ hybridization on tissue microarrays (ISH-TMA). ISH-TMA has proven to be a reliable methodology to conduct this kind of study, particularly because it allows the precise identification of the cellular origin of the signals. Thus, signals associated with the tumor component can be distinguished from those associated with the tumor microenvironment. Specimens derived from various normal and malignant tumor tissues were analyzed, and the “normal” samples were derived, whenever possible, from the same patients from whom tumors were obtained. Of the ∼90 DUBs encoded by the human genome, 33 were found to be expressed in at least one of the analyzed tissues, of which 22 were altered in cancers. Selected DUBs were subjected to further validation, by analyzing their expression in large cohorts of tumor samples. This analysis unveiled significant correlations between DUB expression and relevant clinical and pathological parameters, which were in some cases indicative of aggressive disease. Conclusions/Significance The results presented here demonstrate that DUB dysregulation is a frequent event in cancer, and have implications for therapeutic approaches based on DUB inhibition.
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Affiliation(s)
- Chiara Luise
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Maria Capra
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | | | | | | | - Paolo Nuciforo
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Giuseppe Viale
- Istituto Europeo di Oncologia, Milan, Italy
- Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, Milan, Italy
| | - Pier Paolo Di Fiore
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- Istituto Europeo di Oncologia, Milan, Italy
- Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, Milan, Italy
- * E-mail: (PPDF); (SC)
| | - Stefano Confalonieri
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
- * E-mail: (PPDF); (SC)
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Grasso D, Ropolo A, Lo Ré A, Boggio V, Molejón MI, Iovanna JL, Gonzalez CD, Urrutia R, Vaccaro MI. Zymophagy, a novel selective autophagy pathway mediated by VMP1-USP9x-p62, prevents pancreatic cell death. J Biol Chem 2010; 286:8308-8324. [PMID: 21173155 DOI: 10.1074/jbc.m110.197301] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Autophagy has recently elicited significant attention as a mechanism that either protects or promotes cell death, although different autophagy pathways, and the cellular context in which they occur, remain to be elucidated. We report a thorough cellular and biochemical characterization of a novel selective autophagy that works as a protective cell response. This new selective autophagy is activated in pancreatic acinar cells during pancreatitis-induced vesicular transport alteration to sequester and degrade potentially deleterious activated zymogen granules. We have coined the term "zymophagy" to refer to this process. The autophagy-related protein VMP1, the ubiquitin-protease USP9x, and the ubiquitin-binding protein p62 mediate zymophagy. Moreover, VMP1 interacts with USP9x, indicating that there is a close cooperation between the autophagy pathway and the ubiquitin recognition machinery required for selective autophagosome formation. Zymophagy is activated by experimental pancreatitis in genetically engineered mice and cultured pancreatic acinar cells and by acute pancreatitis in humans. Furthermore, zymophagy has pathophysiological relevance by controlling pancreatitis-induced intracellular zymogen activation and helping to prevent cell death. Together, these data reveal a novel selective form of autophagy mediated by the VMP1-USP9x-p62 pathway, as a cellular protective response.
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Affiliation(s)
- Daniel Grasso
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Alejandro Ropolo
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Andrea Lo Ré
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Verónica Boggio
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - María I Molejón
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | | | - Claudio D Gonzalez
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina
| | - Raúl Urrutia
- the Chromatin Dynamics and Epigenetic Laboratory, Mayo Clinic, Rochester, Minnesota 55905
| | - María I Vaccaro
- From the Department of Pathophysiology, School of Pharmacy and Biochemistry, University of Buenos Aires, C1113AAD Buenos Aires, Argentina,.
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Marx C, Held JM, Gibson BW, Benz CC. ErbB2 trafficking and degradation associated with K48 and K63 polyubiquitination. Cancer Res 2010; 70:3709-17. [PMID: 20406983 DOI: 10.1158/0008-5472.can-09-3768] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The overexpressed ErbB2/HER2 receptor is a clinically validated cancer target whose surface localization and internalization mechanisms remain poorly understood. Downregulation of the overexpressed 185-kDa ErbB2 receptor is rapidly (2-6 hours) induced by the HSP90 chaperone inhibitor geldanamycin (GA), whereas its downregulation and lysosomal degradation are more slowly (24 hours) induced by the proteasome inhibitor bortezomib/PS341. In PS341-treated SK-BR-3 cells, overexpressed ErbB2 coprecipitates with the E3 ubiquitin ligase c-Cbl and also with the deubiquitinating enzyme USP9x; moreover, siRNA downregulation of USP9x enhances PS341-induced ErbB2 downregulation. Because polyubiquitin linkages via lysine 48 (K48) or 63 (K63) can differentially address proteins for 26S proteasomal degradation or endosome trafficking to the lysosome, multiple reaction monitoring (MRM)/mass spectrometry (MS) and polyubiquitin linkage-specific antibodies were used to quantitatively track K48-linked and K63-linked ErbB2 polyubiquitination following either GA or PS341 treatment of SK-BR-3 cells. MRM/MS revealed that unlike the rapid, modest (4-fold to 8-fold), and synchronous GA induction of K48 and K63 polyubiquitinated ErbB2, PS341 produces a dramatic (20-fold to 40-fold) sequential increase in polyubiquitinated ErbB2 consistent with K48 polyubiquitination followed by K63 editing. Fluorescence microscopic imaging confirmed that PS341, but not GA, induces colocalization of K48-linked and K63-linked polyubiquitin with perinuclear lysosome-sequestered ErbB2. Thus, ErbB2 surface overexpression and recycling seem to depend on its polyubiquitination and deubiquitination; as well, the contrasting effects of PS341 and GA on ErbB2 receptor localization, polyubiquitination, and degradation point to alternate cytoplasmic trafficking likely regulated by different K48 and K63 polyubiquitin editing mechanisms.
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Affiliation(s)
- Corina Marx
- Buck Institute for Age Research, Novato, California 94945, USA
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30
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Butterworth MB. Regulation of the epithelial sodium channel (ENaC) by membrane trafficking. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1166-77. [PMID: 20347969 DOI: 10.1016/j.bbadis.2010.03.010] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 03/15/2010] [Accepted: 03/20/2010] [Indexed: 02/07/2023]
Abstract
The epithelial Na(+) channel (ENaC) is a major regulator of salt and water reabsorption in a number of epithelial tissues. Abnormalities in ENaC function have been directly linked to several human disease states including Liddle syndrome, psuedohypoaldosteronism, and cystic fibrosis and may be implicated in salt-sensitive hypertension. ENaC activity in epithelial cells is regulated both by open probability and channel number. This review focuses on the regulation of ENaC in the cells of the kidney cortical collecting duct by trafficking and recycling. The trafficking of ENaC is discussed in the broader context of epithelial cell vesicle trafficking. Well-characterized pathways and protein interactions elucidated using epithelial model cells are discussed, and the known overlap with ENaC regulation is highlighted. In following the life of ENaC in CCD epithelial cells the apical delivery, internalization, recycling, and destruction of the channel will be discussed. While a number of pathways presented still need to be linked to ENaC regulation and many details of the regulation of ENaC trafficking remain to be elucidated, knowledge of these mechanisms may provide further insights into ENaC activity in normal and disease states.
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Affiliation(s)
- Michael B Butterworth
- Department Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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31
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Théard D, Labarrade F, Partisani M, Milanini J, Sakagami H, Fon EA, Wood SA, Franco M, Luton F. USP9x-mediated deubiquitination of EFA6 regulates de novo tight junction assembly. EMBO J 2010; 29:1499-509. [PMID: 20339350 DOI: 10.1038/emboj.2010.46] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 03/03/2010] [Indexed: 11/09/2022] Open
Abstract
In epithelial cells, the tight junction (TJ) functions as a permeability barrier and is involved in cellular differentiation and proliferation. Although many TJ proteins have been characterized, little is known about the sequence of events and temporal regulation of TJ assembly in response to adhesion cues. We report here that the deubiquitinating enzyme USP9x has a critical function in TJ biogenesis by controlling the levels of the exchange factor for Arf6 (EFA6), a protein shown to facilitate TJ formation, during a narrow temporal window preceding the establishment of cell polarity. At steady state, EFA6 is constitutively ubiquitinated and turned over by the proteasome. However, at newly forming contacts, USP9x-mediated deubiquitination protects EFA6 from proteasomal degradation, leading to a transient increase in EFA6 levels. Consistent with this model, USP9x and EFA6 transiently co-localize at primordial epithelial junctions. Furthermore, knockdown of either EFA6 or USP9x impairs TJ biogenesis and EFA6 overexpression rescues TJ biogenesis in USP9x-knockdown cells. As the loss of cell polarity is a critical event in the metastatic spread of cancer, these findings may help to understand the pathology of human carcinomas.
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Affiliation(s)
- Delphine Théard
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia-Antipolis, Valbonne, France
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Identification of a deubiquitinating enzyme as a novel AGS3-interacting protein. PLoS One 2010; 5:e9725. [PMID: 20305814 PMCID: PMC2840025 DOI: 10.1371/journal.pone.0009725] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 02/22/2010] [Indexed: 11/19/2022] Open
Abstract
Activator of G protein Signaling 3 (AGS3) is a receptor-independent G protein activator that has been implicated in multiple biological events such as brain development, neuroplasticity and addiction, cardiac function, Golgi structure/function, macroautophagy and metabolism. However, how AGS3 is regulated is little known. We demonstrate here that AGS3 interacts with a ubiquitin specific protease USP9x, and this interaction is at least partially mediated through the C-terminal G protein regulatory domain of AGS3. Knockdown of USP9x causes a moderate reduction in the level of AGS3. In contrast, overexpression of either USP9x or its deubiquitinating domain UCH increases the amount of AGS3, whereas expression of the mutant UCH domain that lacks deubiquitinating activity does not have the same effect. As previously observed in AGS3 knockdown cells, the localization of several marker proteins of the late Golgi compartments is disturbed in cells depleted of USP9x. Taken together, our study suggests that USP9x can modulate the level of a subpopulation of AGS3, and this modulation plays a role in regulating the structure of the late Golgi compartments. Finally, we have found that levels of AGS3 and USP9x are co-regulated in the prefrontal cortex of rats withdrawn from repeated cocaine treatment. In conjunction with the above data, this observation indicates a potential role of USP9X in the regulation of the AGS3 level during cocaine-induced neuroplasticity.
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Abstract
Cell signalling and endocytic membrane trafficking have traditionally been viewed as distinct processes. Although our present understanding is incomplete and there are still great controversies, it is now recognized that these processes are intimately and bidirectionally linked in animal cells. Indeed, many recent examples illustrate how endocytosis regulates receptor signalling (including signalling from receptor tyrosine kinases and G protein-coupled receptors) and, conversely, how signalling regulates the endocytic pathway. The mechanistic and functional principles that underlie the relationship between signalling and endocytosis in cell biology are becoming increasingly evident across many systems.
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Knecht E, Aguado C, Cárcel J, Esteban I, Esteve JM, Ghislat G, Moruno JF, Vidal JM, Sáez R. Intracellular protein degradation in mammalian cells: recent developments. Cell Mol Life Sci 2009; 66:2427-43. [PMID: 19399586 PMCID: PMC11115841 DOI: 10.1007/s00018-009-0030-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 04/02/2009] [Indexed: 12/16/2022]
Abstract
In higher organisms, dietary proteins are broken down into amino acids within the digestive tract but outside the cells, which incorporate the resulting amino acids into their metabolism. However, under certain conditions, an organism loses more nitrogen than is assimilated in the diet. This additional loss was found in the past century to come from intracellular proteins and started an intensive research that produced an enormous expansion of the field and a dispersed literature. Therefore, our purpose is to provide an updated summary of the current knowledge on the proteolytic machinery involved in intracellular protein degradation and its physiological and pathological relevance, especially addressed to newcomers in the field who may find further details in more specialized reviews. However, even providing a general overview, this is an extremely wide field and, therefore, we mainly focus on mammalian cells, while other cells will be mentioned only for comparison purposes.
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Affiliation(s)
- Erwin Knecht
- Centro de Investigación Príncipe Felipe, Valencia, Spain.
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UBXD4, a UBX-containing protein, regulates the cell surface number and stability of alpha3-containing nicotinic acetylcholine receptors. J Neurosci 2009; 29:6883-96. [PMID: 19474315 DOI: 10.1523/jneurosci.4723-08.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Adaptor proteins are likely to modulate spatially and temporally the trafficking of a number of membrane proteins, including neuronal nicotinic acetylcholine receptors (nAChRs). A yeast two-hybrid screen identified a novel UBX-containing protein, UBXD4, as one of the cytosolic proteins that interact directly with the alpha3 and alpha4 nAChR subunits. The function of UBX-containing proteins is largely unknown. Immunoprecipitation and confocal microscopy confirmed the interaction of UBXD4 with alpha3-containing nAChRs (alpha3* nAChRs) expressed in HEK293 cells, PC12 cells, and rat cortical neurons. Overexpression of UBXD4 in differentiated PC12 cells (dPC12) increased nAChR cell surface expression, especially that of the alpha3beta2 subtype. These findings were corroborated by electrophysiology, immunofluorescent staining, and biotinylation of surface receptors. Silencing of UBXD4 led to a significant reduction of alpha3* nAChRs in rat cortical neurons and dPC12 cells. Biochemical and immunofluorescence studies of endogenous UBXD4 showed that the protein is located in both the ER and cis-Golgi compartments. Our investigations also showed that the alpha3 subunit is ubiquitinated and that UBXD4 can interfere with its ubiquitination and consequent degradation by the proteasome. Our data suggest that UBXD4 modulates the distribution of alpha3* nAChRs between specialized intracellular compartments and the plasma membrane. This effect is achieved by controlling the stability of the alpha3 subunit and, consequently, the number of receptors at the cell surface.
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36
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Acconcia F, Sigismund S, Polo S. Ubiquitin in trafficking: The network at work. Exp Cell Res 2009; 315:1610-8. [DOI: 10.1016/j.yexcr.2008.10.014] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
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Bomberger JM, Barnaby RL, Stanton BA. The deubiquitinating enzyme USP10 regulates the post-endocytic sorting of cystic fibrosis transmembrane conductance regulator in airway epithelial cells. J Biol Chem 2009; 284:18778-89. [PMID: 19398555 DOI: 10.1074/jbc.m109.001685] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ABC transporter superfamily, is a cyclic AMP-regulated chloride channel and a regulator of other ion channels and transporters. In epithelial cells CFTR is rapidly endocytosed from the apical plasma membrane and efficiently recycles back to the plasma membrane. Because ubiquitination targets endocytosed CFTR for degradation in the lysosome, deubiquitinating enzymes (DUBs) are likely to facilitate CFTR recycling. Accordingly, the aim of this study was to identify DUBs that regulate the post-endocytic sorting of CFTR. Using an activity-based chemical screen to identify active DUBs in human airway epithelial cells, we demonstrated that Ubiquitin Specific Protease-10 (USP10) is located in early endosomes and regulates the deubiquitination of CFTR and its trafficking in the post-endocytic compartment. small interference RNA-mediated knockdown of USP10 increased the amount of ubiquitinated CFTR and its degradation in lysosomes, and reduced both apical membrane CFTR and CFTR-mediated chloride secretion. Moreover, a dominant negative USP10 (USP10-C424A) increased the amount of ubiquitinated CFTR and its degradation, whereas overexpression of wt-USP10 decreased the amount of ubiquitinated CFTR and increased the abundance of CFTR. These studies demonstrate a novel function for USP10 in facilitating the deubiquitination of CFTR in early endosomes and thereby enhancing the endocytic recycling of CFTR.
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Affiliation(s)
- Jennifer M Bomberger
- Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
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38
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Jolly LA, Taylor V, Wood SA. USP9X enhances the polarity and self-renewal of embryonic stem cell-derived neural progenitors. Mol Biol Cell 2009; 20:2015-29. [PMID: 19176755 DOI: 10.1091/mbc.e08-06-0596] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The substrate-specific deubiquitylating enzyme USP9X is a putative "stemness" gene expressed in many progenitor cell populations. To test its function in embryonic stem cell-derived neural progenitor/stem cells, we expressed USP9X from a Nestin promoter. Elevated USP9X levels resulted in two phenomena. First, it produced a dramatically altered cellular architecture wherein the majority (>80%) of neural progenitors was arranged into radial clusters. These progenitors expressed markers of radial glial cells and were highly polarized with adherens junction proteins (N-cadherin, beta-catenin, and AF-6) and apical markers (Prominin1, atypical protein kinase C-zeta) as well as Notch, Numb, and USP9X itself, concentrated at the center. The cluster centers were also devoid of nuclei and so resembled the apical end-feet of radial progenitors in the neural tube. Second, USP9X overexpression caused a fivefold increase in the number of radial progenitors and neurons, in the absence of exogenous growth factors. 5-Bromo-2'-deoxyuridine labeling, as well as the examination of the brain lipid-binding protein:betaIII-tubulin ratio, indicated that nestin-USP9X enhanced the self-renewal of radial progenitors but did not block their subsequent differentiation to neurons and astrocytes. nestin-USP9X radial progenitors reformed clusters after passage as single cells, whereas control cells did not, suggesting it aids the establishment of polarity. We propose that USP9X-induced polarization of these neural progenitors results in their radial arrangement, which provides an environment conducive for self-renewal.
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Affiliation(s)
- Lachlan A Jolly
- Child Health Research Institute, North Adelaide, South Australia 5006, Australia
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39
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Neutzner A, Benard G, Youle RJ, Karbowski M. Role of the ubiquitin conjugation system in the maintenance of mitochondrial homeostasis. Ann N Y Acad Sci 2009; 1147:242-53. [PMID: 19076446 DOI: 10.1196/annals.1427.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondria are essential for a variety of cellular functions, including ATP production, lipid biosynthesis, and calcium homeostasis. Moreover, a number of major cell signaling pathways, including apoptosis, require mitochondria. Consistent with a major role of mitochondria in the control of cell function, defects of these organelles are thought to induce a variety of pathologies ranging from diabetic neuropathies to Parkinson's and Alzheimer's diseases. Here we discuss the role of ubiquitin (Ub) conjugation in the maintenance of mitochondrial function. We found that at least four putative RING finger E3 Ub ligases, the main determinants of substrate specificity in the ubiquitination system, localize to mitochondria. Our data also demonstrate that mitochondrial membrane dynamics is under the regulatory control of the Ub-conjugation system. These and data recently published by others indicate that the Ub-conjugation system and proteasomal degradation of mitochondrial proteins might be vital for the maintenance of mitochondrial homeostasis and lead to cell demise when dysfunctional.
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Affiliation(s)
- Albert Neutzner
- Surgical Neurology Branch/National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
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40
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Liang W, Hoang Q, Clark RB, Fishman PH. Accelerated dephosphorylation of the beta2-adrenergic receptor by mutation of the C-terminal lysines: effects on ubiquitination, intracellular trafficking, and degradation. Biochemistry 2008; 47:11750-62. [PMID: 18841999 DOI: 10.1021/bi800219q] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Agonist-mediated ubiquitination regulates some G protein-coupled receptors by targeting them to lysosomes for degradation. Phosphorylation also regulates receptor endocytosis and trafficking to lysosomes. To explore the roles of the two post-translational modifications, we mutated the three C-terminal lysines to arginines in the human beta 2-adrenergic receptor (beta 2AR) (K348/372/375R). The level of agonist-mediated ubiquitination of the mutant (3K/R) was greatly reduced compared to that of wild-type (WT) beta 2AR in whole cells and in cell-free assays. Downregulation of 3K/R also was attenuated compared to that of the WT, whereas internalization and recycling were more similar. During endocytosis, WT and 3K/R appeared in different vesicles and WT, but not 3K/R, was transported to lysosomes. Both were rapidly phosphorylated in agonist-stimulated cells, but upon agonist removal, the rate of dephosphorylation of 3K/R initially was approximately 5 times faster than that of WT. The increased rate also was observed in a cell-free, soluble assay and, thus, was not due to differences in receptor trafficking. Okadaic acid, a potent phosphatase inhibitor, reduced the level of dephosphorylation and increased the levels of lysosomal targeting and degradation of 3K/R. The reduced level of ubiquitination and rapid dephosphorylation of 3K/R appear to prevent it from being sorted to lysosomes in contrast to the phosphorylated and ubiquitinated WT beta 2AR. Our findings indicate that both phosphorylation and ubiquitination are involved in the intracellular sorting of beta 2AR between pathways of recycling to the plasma membrane and degradation in lysosomes, and that the rate of dephosphorylation may be another mechanism of regulating the sorting.
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Affiliation(s)
- Wei Liang
- Membrane Biochemistry Section, Laboratory of Molecular and Cellular Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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41
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Mo B, Callegari E, Telefont M, Renner KJ. Estrogen regulation of proteins in the rat ventromedial nucleus of the hypothalamus. J Proteome Res 2008; 7:5040-8. [PMID: 18841879 DOI: 10.1021/pr8005974] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The effects of estradiol (E2) on the expression of proteins in the pars lateralis of the ventromedial nucleus of the hypothalamus (VMNpl) in ovariectomized rats was studied using 2-dimensional gel electrophoresis followed by RPLC-nanoESI-MS/MS. E2 treatment resulted in the up-regulation of 29 identified proteins. Many of these proteins are implicated in the promotion of neuronal plasticity and signaling.
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Affiliation(s)
- Bing Mo
- Department of Biology and Neuroscience Group, University of South Dakota, Vermillion, South Daklota 57069, USA
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42
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Butterworth MB, Edinger RS, Frizzell RA, Johnson JP. Regulation of the epithelial sodium channel by membrane trafficking. Am J Physiol Renal Physiol 2008; 296:F10-24. [PMID: 18508877 DOI: 10.1152/ajprenal.90248.2008] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The epithelial Na(+) channel (ENaC) is a major regulator of salt and water reabsorption in a number of epithelial tissues. Abnormalities in ENaC function have been directly linked to several human disease states including Liddle's syndrome, psuedohypoaldosteronism, and cystic fibrosis and may be implicated in states as diverse as salt-sensitive hypertension, nephrosis, and pulmonary edema. ENaC activity in epithelial cells is highly regulated both by open probability and number of channels. Open probability is regulated by a number of factors, including proteolytic processing, while ENaC number is regulated by cellular trafficking. This review discusses current understanding of apical membrane delivery, cell surface stability, endocytosis, retrieval, and recycling of ENaC and the molecular partners that have so far been shown to participate in these processes. We review known sites and mechanisms of hormonal regulation of trafficking by aldosterone, vasopressin, and insulin. While many details of the regulation of ENaC trafficking remain to be elucidated, knowledge of these mechanisms may provide further insights into ENaC activity in normal and disease states.
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Affiliation(s)
- Michael B Butterworth
- Dept. of Cell Biology and Physiology, Univ. of Pittsburgh, S375 BST, 3500 Terrace St., Pittsburgh, PA 15261, USA.
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43
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Wainszelbaum MJ, Charron AJ, Kong C, Kirkpatrick DS, Srikanth P, Barbieri MA, Gygi SP, Stahl PD. The hominoid-specific oncogene TBC1D3 activates Ras and modulates epidermal growth factor receptor signaling and trafficking. J Biol Chem 2008; 283:13233-42. [PMID: 18319245 PMCID: PMC2442359 DOI: 10.1074/jbc.m800234200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 02/12/2008] [Indexed: 11/06/2022] Open
Abstract
Hominoid- and human-specific genes may have evolved to modulate signaling pathways of a higher order of complexity. TBC1D3 is a hominoid-specific oncogene encoded by a cluster of eight paralogs on chromosome 17. Initial work indicates that TBC1D3 is widely expressed in human tissues ( Hodzic, D., Kong, C., Wainszelbaum, M. J., Charron, A. J., Su, X., and Stahl, P. D. (2006) Genomics 88, 731-736 ). In this study, we show that TBC1D3 expression has a powerful effect on cell proliferation that is further enhanced by epidermal growth factor (EGF) in both human and mouse cell lines. EGF activation of the Erk and protein kinase B/Akt pathways is enhanced, both in amplitude and duration, by TBC1D3 expression, whereas RNA interference silencing of TBC1D3 suppresses the activation. Light microscopy and Western blot experiments demonstrate that increased signaling in response to EGF is coupled with a significant delay in EGF receptor (EGFR) trafficking and degradation, which significantly extends the life span of EGFR. Moreover, TBC1D3 suppresses polyubiquitination of the EGFR and the recruitment of c-Cbl. Using the Ras binding domain of Raf1 to monitor GTP-Ras we show that TBC1D3 expression enhances Ras activation in quiescent cells, which is further increased by EGF treatment. We speculate that TBC1D3 may alter Ras GTP loading. We conclude that the expression of TBC1D3 generates a delay in EGFR degradation, a decrease in ubiquitination, and a failure to recruit adapter proteins that ultimately dysregulate EGFR signal transduction and enhance cell proliferation. Altered growth factor receptor trafficking and GTP-Ras turnover may be sites where recently evolved genes such as TBC1D3 selectively modulate signaling in hominoids and humans.
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Affiliation(s)
- Marisa J. Wainszelbaum
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Audra J. Charron
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Chen Kong
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Donald S. Kirkpatrick
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Priya Srikanth
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - M. Alejandro Barbieri
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Steven P. Gygi
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Philip D. Stahl
- Department of Cell Biology and
Physiology, Washington University School of Medicine, St. Louis, Missouri
63110 and the Department of Cell
Biology, Harvard Medical School, Boston, Massachusetts 02115
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44
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Martin SL, Epperson LE, Rose JC, Kurtz CC, Ané C, Carey HV. Proteomic analysis of the winter-protected phenotype of hibernating ground squirrel intestine. Am J Physiol Regul Integr Comp Physiol 2008; 295:R316-28. [PMID: 18434441 DOI: 10.1152/ajpregu.00418.2007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The intestine of hibernating ground squirrels is protected against damage by ischemia-reperfusion (I/R) injury. This resistance does not depend on the low body temperature of torpor; rather, it is exhibited during natural interbout arousals that periodically return hibernating animals to euthermia. Here we use fluorescence two-dimensional difference gel electrophoresis (DIGE) to identify protein spot differences in intestines of 13-lined ground squirrels in the sensitive and protected phases of the circannual hibernation cycle, comparing sham-treated control animals with those exposed to I/R. Protein spot differences distinguished the sham-treated summer and hibernating samples, as well as the response to I/R between summer and hibernating intestines. The majority of protein changes among these groups were attributed to a seasonal difference between summer and winter hibernators. Many of the protein spots that differed were unambiguously identified by high-pressure liquid chromatography followed by tandem mass spectrometry of their constituent peptides. Western blot analysis confirmed significant upregulation for three of the proteins, albumin, apolipoprotein A-I, and ubiquitin hydrolase L1, that were identified in the DIGE analysis as increased in sham-treated hibernating squirrels compared with sham-treated summer squirrels. This study identifies several candidate proteins that may contribute to hibernation-induced protection of the gut during natural torpor-arousal cycles and experimental I/R injury. It also reveals the importance of enterocyte maturation in defining the hibernating gut proteome and the role of changing cell populations for the differences between sham and I/R-treated summer animals.
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Affiliation(s)
- Sandra L Martin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
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45
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Zezula J, Freissmuth M. The A(2A)-adenosine receptor: a GPCR with unique features? Br J Pharmacol 2008; 153 Suppl 1:S184-90. [PMID: 18246094 DOI: 10.1038/sj.bjp.0707674] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The A(2A)-adenosine receptor is a prototypical G(s)-coupled receptor. However, the A(2A)-receptor has several structural and functional characteristics that make it unique. In contrast to the classical model of collision coupling described for the beta-adrenergic receptors, the A(2A)-receptor couples to adenylyl cyclase by restricted collision coupling and forms a tight complex with G(s). The mechanistic basis for this is not clear; restricted collision coupling may arise from the interaction of the receptor with additional proteins or due to the fact that G protein-coupling is confined to specialized membrane microdomains. The A(2A)-receptor has a long C-terminus (of >120 residues), which is for the most part dispensable for coupling to G(s). It was originally viewed as the docking site for kinases and the beta-arrestin family to initiate receptor desensitization and endocytosis. The A(2A)-receptor is, however, fairly resistant to agonist-induced internalization. Recently, the C-terminus has also been appreciated as a binding site for several additional 'accessory' proteins. Established interaction partners include alpha-actinin, ARNO, USP4 and translin-associated protein-X. In addition, the A(2A)-receptor has also been reported to form a heteromeric complex with the D(2)-dopamine receptor and the metabotropic glutamate receptor-5. It is clear that (i) this list cannot be exhaustive and (ii) that all these proteins cannot bind simultaneously to the receptor. There must be rules of engagement, which allow the receptor to elicit different biological responses, which depend on the cellular context and the nature of the concomitant signal(s). Thus, the receptor may function as a coincidence detector and a signal integrator.
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Affiliation(s)
- J Zezula
- Center of Biomolecular Medicine and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Austria
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46
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Doelling JH, Phillips AR, Soyler-Ogretim G, Wise J, Chandler J, Callis J, Otegui MS, Vierstra RD. The ubiquitin-specific protease subfamily UBP3/UBP4 is essential for pollen development and transmission in Arabidopsis. PLANT PHYSIOLOGY 2007; 145:801-13. [PMID: 17905865 PMCID: PMC2048767 DOI: 10.1104/pp.106.095323] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Accepted: 09/25/2007] [Indexed: 05/17/2023]
Abstract
Deubiquitinating enzymes are essential to the ubiquitin (Ub)/26S proteasome system where they release Ub monomers from the primary translation products of poly-Ub and Ub extension genes, recycle Ubs from polyubiquitinated proteins, and reverse the effects of ubiquitination by releasing bound Ubs from individual targets. The Ub-specific proteases (UBPs) are one large family of deubiquitinating enzymes that bear signature cysteine and histidine motifs. Here, we genetically characterize a UBP subfamily in Arabidopsis (Arabidopsis thaliana) encoded by paralogous UBP3 and UBP4 genes. Whereas homozygous ubp3 and ubp4 single mutants do not display obvious phenotypic abnormalities, double-homozygous mutant individuals could not be created due to a defect in pollen development and/or transmission. This pollen defect was rescued with a transgene encoding wild-type UBP3 or UBP4, but not with a transgene encoding an active-site mutant of UBP3, indicating that deubiquitination activity of UBP3/UBP4 is required. Nuclear DNA staining revealed that ubp3 ubp4 pollen often fail to undergo mitosis II, which generates the two sperm cells needed for double fertilization. Substantial changes in vacuolar morphology were also evident in mutant grains at the time of pollen dehiscence, suggesting defects in vacuole and endomembrane organization. Even though some ubp3 ubp4 pollen could germinate in vitro, they failed to fertilize wild-type ovules even in the absence of competing wild-type pollen. These studies provide additional evidence that the Ub/26S proteasome system is important for male gametogenesis in plants and suggest that deubiquitination of one or more targets by UBP3/UBP4 is critical for the development of functional pollen.
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Affiliation(s)
- Jed H Doelling
- Division of Plant and Soil Sciences , West Virginia University, Morgantown, West Virginia 26506, USA.
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47
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Butterworth MB, Edinger RS, Ovaa H, Burg D, Johnson JP, Frizzell RA. The deubiquitinating enzyme UCH-L3 regulates the apical membrane recycling of the epithelial sodium channel. J Biol Chem 2007; 282:37885-93. [PMID: 17967898 DOI: 10.1074/jbc.m707989200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The epithelial sodium channel (ENaC) is ubiquitinated by the E3 ligase Nedd4-2 at the apical membranes of polarized cortical collecting duct (CCD) epithelial cells. This leads to ENaC endocytosis and possible degradation. Because ENaC is known to recycle at the apical membranes of CCD cells, deubiquitinating enzymes (DUBs) are likely involved in regulating ENaC surface density by facilitating ENaC recycling as opposed to degradation. Using a chemical probe approach to tag active DUBs, we identified ubiquitin C-terminal hydrolase (UCH) isoform L3 as the predominant DUB in endosomal compartments of CCD cells. Blocking UCH-L3 activity or reducing its expression by selective knockdown increased ENaC ubiquitination and resulted in its removal from the apical membranes of CCD cells. Functionally this caused a rapid reduction in transepithelial Na(+) currents across the CCD epithelia. Surface biotinylation demonstrated the loss of ENaC from the apical surface when UCH-L3 was inhibited. Whole cell or apical surface immunoprecipitation demonstrated increased ENaC ubiquitination with UCH-L3 inhibition. This constitutes a novel function for UCH in epithelia and in the regulation of ion channels and demonstrates the dynamic regulation of apically located ENaC by recycling, which is facilitated by this DUB.
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Affiliation(s)
- Michael B Butterworth
- Department of Cell Biology and Physiology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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48
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Toyoshima M, Tanaka N, Aoki J, Tanaka Y, Murata K, Kyuuma M, Kobayashi H, Ishii N, Yaegashi N, Sugamura K. Inhibition of tumor growth and metastasis by depletion of vesicular sorting protein Hrs: its regulatory role on E-cadherin and beta-catenin. Cancer Res 2007; 67:5162-71. [PMID: 17545595 DOI: 10.1158/0008-5472.can-06-2756] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abnormally high signals from receptor tyrosine kinases (RTK) are associated with carcinogenesis, and impaired deactivation of RTKs may also be a mechanism in cancer. Hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) is one of the master regulators that sort activated receptors toward lysosomes and shut down their signals. Hrs contains a ubiquitin-interacting motif and is involved in the endosomal sorting of monoubiquitinated membrane proteins, such as growth factor receptor and E-cadherin. Here, we investigated the role of Hrs in determining the malignancy of cancer cells and discovered that the targeted disruption of Hrs by small interfering RNA effectively attenuated the proliferation, anchorage-independent growth, tumorigenesis, and metastatic potential of HeLa cells in vitro and in vivo. The restoration of Hrs expression increased cell proliferation and anchorage-independent growth in a mouse embryonic fibroblast line established from a Hrs knockout mouse. Further analysis revealed that Hrs depletion was associated with the up-regulation of E-cadherin and reduced beta-catenin signaling. The aberrant accumulation of E-cadherin most likely resulted from impaired E-cadherin degradation in lysosomes. These results suggest that Hrs may play a critical role in determining the malignancy of cancer cells by regulating the degradation of E-cadherin.
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Affiliation(s)
- Masafumi Toyoshima
- Department of Microbiology, Tohoku University Graduate School of Medicine, Sendai, Japan
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49
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Niendorf S, Oksche A, Kisser A, Löhler J, Prinz M, Schorle H, Feller S, Lewitzky M, Horak I, Knobeloch KP. Essential role of ubiquitin-specific protease 8 for receptor tyrosine kinase stability and endocytic trafficking in vivo. Mol Cell Biol 2007; 27:5029-39. [PMID: 17452457 PMCID: PMC1951504 DOI: 10.1128/mcb.01566-06] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Posttranslational modification by ubiquitin controls multiple cellular functions and is counteracted by the activities of deubiquitinating enzymes. UBPy (USP8) is a growth-regulated ubiquitin isopeptidase that interacts with the HRS-STAM complex. Using Cre-loxP-mediated gene targeting in mice, we show that lack of UBPy results in embryonic lethality, whereas its conditional inactivation in adults causes fatal liver failure. The defect is accompanied by a strong reduction or absence of several growth factor receptor tyrosine kinases (RTKs), like epidermal growth factor receptor, hepatocyte growth factor receptor (c-met), and ERBB3. UBPy-deficient cells exhibit aberrantly enlarged early endosomes colocalizing with enhanced ubiquitination and have reduced levels of HRS and STAM2. Congruently immortalized cells gradually stop proliferation upon induced deletion of UBPy. These results unveil a central and nonredundant role of UBPy in growth regulation, endosomal sorting, and the control of RTKs in vivo.
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Affiliation(s)
- Sandra Niendorf
- Leibniz Institut für Molekulare Pharmakologie, Krahmerstr. 6, D-12207 Berlin, Germany
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50
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Ren J, Kee Y, Huibregtse JM, Piper RC. Hse1, a component of the yeast Hrs-STAM ubiquitin-sorting complex, associates with ubiquitin peptidases and a ligase to control sorting efficiency into multivesicular bodies. Mol Biol Cell 2007; 18:324-35. [PMID: 17079730 PMCID: PMC1751313 DOI: 10.1091/mbc.e06-06-0557] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 10/16/2006] [Accepted: 10/19/2006] [Indexed: 11/11/2022] Open
Abstract
Ubiquitinated integral membrane proteins are delivered to the interior of the lysosome/vacuole for degradation. This process relies on specific ubiquitination of potential cargo and recognition of that Ub-cargo by sorting receptors at multiple compartments. We show that the endosomal Hse1-Vps27 sorting receptor binds to ubiquitin peptidases and the ubiquitin ligase Rsp5. Hse1 is linked to Rsp5 directly via a PY element within its C-terminus and through a novel protein Hua1, which recruits a complex of Rsp5, Rup1, and Ubp2. The SH3 domain of Hse1 also binds to the deubiquitinating protein Ubp7. Functional analysis shows that when both modes of Rsp5 association with Hse1 are altered, sorting of cargo that requires efficient ubiquitination for entry into the MVB is blocked, whereas sorting of cargo containing an in-frame addition of ubiquitin is normal. Further deletion of Ubp7 restores sorting of cargo when the Rsp5:Hse1 interaction is compromised suggesting that both ubiquitin ligases and peptidases associate with the Hse1-Vps27 sorting complex to control the ubiquitination status and sorting efficiency of cargo proteins. Additionally, we find that disruption of UBP2 and RUP1 inhibits MVB sorting of some cargos suggesting that Rsp5 requires association with Ubp2 to properly ubiquitinate cargo for efficient MVB sorting.
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Affiliation(s)
- Jihui Ren
- *Department of Physiology and Biophysics, University of Iowa, Iowa City, IA 52242; and
| | - Younghoon Kee
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712
| | - Jon M. Huibregtse
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712
| | - Robert C. Piper
- *Department of Physiology and Biophysics, University of Iowa, Iowa City, IA 52242; and
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