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Xue Y, Xue C, Song W. Emerging roles of deubiquitinating enzymes in actin cytoskeleton and tumor metastasis. Cell Oncol (Dordr) 2024:10.1007/s13402-024-00923-z. [PMID: 38324230 DOI: 10.1007/s13402-024-00923-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2024] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Metastasis accounts for the majority of cancer-related deaths. Actin dynamics and actin-based cell migration and invasion are important factors in cancer metastasis. Metastasis is characterized by actin polymerization and depolymerization, which are precisely regulated by molecular changes involving a plethora of actin regulators, including actin-binding proteins (ABPs) and signalling pathways, that enable cancer cell dissemination from the primary tumour. Research on deubiquitinating enzymes (DUBs) has revealed their vital roles in actin dynamics and actin-based migration and invasion during cancer metastasis. CONCLUSION Here, we review how DUBs drive tumour metastasis by participating in actin rearrangement and actin-based migration and invasion. We summarize the well-characterized and essential actin cytoskeleton signalling molecules related to DUBs, including Rho GTPases, Src kinases, and ABPs such as cofilin and cortactin. Other DUBs that modulate actin-based migration signalling pathways are also discussed. Finally, we discuss and address therapeutic opportunities and ongoing challenges related to DUBs with respect to actin dynamics.
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Affiliation(s)
- Ying Xue
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, 250021, PR China.
| | - Cong Xue
- School of Stomatology, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, 250117, PR China
| | - Wei Song
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, 250021, PR China.
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2
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Abstract
The Ras homologous (Rho) protein family of GTPases (RhoA, RhoB and RhoC) are the members of the Ras superfamily and regulate cellular processes such as cell migration, proliferation, polarization, adhesion, gene transcription and cytoskeletal structure. Rho GTPases function as molecular switches that cycle between GTP-bound (active state) and GDP-bound (inactive state) forms. Leukaemia-associated RhoGEF (LARG) is a guanine nucleotide exchange factor (GEF) that activates RhoA subfamily GTPases by promoting the exchange of GDP for GTP. LARG is selective for RhoA subfamily GTPases and is an essential regulator of cell migration and invasion. Here, we describe the mechanisms by which LARG is regulated to facilitate the understanding of how LARG mediates functions like cell motility and to provide insight for better therapeutic targeting of these functions.
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Affiliation(s)
- Neda Z. Ghanem
- Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, USA,Molecular Biosciences and BioEngineering Graduate Program, University of Hawaii at Mānoa, Honolulu, USA
| | - Michelle L. Matter
- Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, USA,Molecular Biosciences and BioEngineering Graduate Program, University of Hawaii at Mānoa, Honolulu, USA
| | - Joe W. Ramos
- Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Mānoa, Honolulu, USA,Molecular Biosciences and BioEngineering Graduate Program, University of Hawaii at Mānoa, Honolulu, USA,CONTACT Joe W. Ramos Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, USA
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3
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Kovačević I, Sakaue T, Majoleé J, Pronk MC, Maekawa M, Geerts D, Fernandez-Borja M, Higashiyama S, Hordijk PL. The Cullin-3-Rbx1-KCTD10 complex controls endothelial barrier function via K63 ubiquitination of RhoB. J Cell Biol 2018; 217:1015-1032. [PMID: 29358211 PMCID: PMC5839774 DOI: 10.1083/jcb.201606055] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 04/04/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022] Open
Abstract
The RhoA GTPase controls endothelial cell migration, adhesion, and barrier formation but the role of RhoB is unclear. Kovačević et al. now discover that RhoB is ubiquitinated by the CUL3–Rbx1–KCTD10 complex and that this is a prerequisite for lysosomal degradation of RhoB and the maintenance of endothelial barrier integrity. RhoGTPases control endothelial cell (EC) migration, adhesion, and barrier formation. Whereas the relevance of RhoA for endothelial barrier function is widely accepted, the role of the RhoA homologue RhoB is poorly defined. RhoB and RhoA are 85% identical, but RhoB’s subcellular localization and half-life are uniquely different. Here, we studied the role of ubiquitination for the function and stability of RhoB in primary human ECs. We show that the K63 polyubiquitination at lysine 162 and 181 of RhoB targets the protein to lysosomes. Moreover, we identified the RING E3 ligase complex Cullin-3–Rbx1–KCTD10 as key modulator of endothelial barrier integrity via its regulation of the ubiquitination, localization, and activity of RhoB. In conclusion, our data show that ubiquitination controls the subcellular localization and lysosomal degradation of RhoB and thereby regulates the stability of the endothelial barrier through control of RhoB-mediated EC contraction.
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Affiliation(s)
- Igor Kovačević
- Department of Molecular Cell Biology, Sanquin Research, Amsterdam, Netherlands.,Department of Physiology, Vrije Universiteit University Medical Center, Amsterdam, Netherlands
| | - Tomohisa Sakaue
- Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Ehime, Japan.,Department of Cardiovascular and Thoracic Surgery, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.,Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Jisca Majoleé
- Department of Molecular Cell Biology, Sanquin Research, Amsterdam, Netherlands
| | - Manon C Pronk
- Department of Physiology, Vrije Universiteit University Medical Center, Amsterdam, Netherlands
| | - Masashi Maekawa
- Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Ehime, Japan.,Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Mar Fernandez-Borja
- Department of Molecular Cell Biology, Sanquin Research, Amsterdam, Netherlands
| | - Shigeki Higashiyama
- Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Ehime, Japan .,Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Peter L Hordijk
- Department of Physiology, Vrije Universiteit University Medical Center, Amsterdam, Netherlands
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4
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Abstract
Rho GTPases regulate cytoskeletal and cell adhesion dynamics and thereby coordinate a wide range of cellular processes, including cell migration, cell polarity and cell cycle progression. Most Rho GTPases cycle between a GTP-bound active conformation and a GDP-bound inactive conformation to regulate their ability to activate effector proteins and to elicit cellular responses. However, it has become apparent that Rho GTPases are regulated by post-translational modifications and the formation of specific protein complexes, in addition to GTP-GDP cycling. The canonical regulators of Rho GTPases - guanine nucleotide exchange factors, GTPase-activating proteins and guanine nucleotide dissociation inhibitors - are regulated similarly, creating a complex network of interactions to determine the precise spatiotemporal activation of Rho GTPases.
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Affiliation(s)
- Richard G Hodge
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | - Anne J Ridley
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
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5
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Yang Y, Zhou J. CYLD - a deubiquitylase that acts to fine-tune microtubule properties and functions. J Cell Sci 2016; 129:2289-95. [PMID: 27173491 DOI: 10.1242/jcs.183319] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Microtubules are dynamic structures that are crucially involved in a variety of cellular activities. The dynamic properties and functions of microtubules are regulated by various factors, such as tubulin isotype composition and microtubule-binding proteins. Initially identified as a deubiquitylase with tumor-suppressing functions, the protein cylindromatosis (CYLD) has recently been revealed to interact with microtubules, modulate microtubule dynamics, and participate in the regulation of cell migration, cell cycle progression, chemotherapeutic drug sensitivity and ciliogenesis. These findings have greatly enriched our understanding of the roles of CYLD in physiological and pathological conditions. Here, we focus on recent literature that shows how CYLD impacts on microtubule properties and functions in various biological processes, and discuss the challenges we face when interpreting results obtained from different experimental systems.
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Affiliation(s)
- Yunfan Yang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jun Zhou
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance of Shandong Province, Key Laboratory of Molecular and Nano Probes of the Ministry of Education, Shandong Normal University, Jinan 250014, China
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6
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Mathis BJ, Lai Y, Qu C, Janicki JS, Cui T. CYLD-mediated signaling and diseases. Curr Drug Targets 2016; 16:284-94. [PMID: 25342597 DOI: 10.2174/1389450115666141024152421] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/26/2014] [Accepted: 10/03/2014] [Indexed: 02/07/2023]
Abstract
The conserved cylindromatosis (CYLD) codes for a deubiquitinating enzyme and is a crucial regulator of diverse cellular processes such as immune responses, inflammation, death, and proliferation. It directly regulates multiple key signaling cascades, such as the Nuclear Factor kappa B [NFkB] and the Mitogen-Activated Protein Kinase (MAPK) pathways, by its catalytic activity on polyubiquitinated key intermediates. Several lines of emerging evidence have linked CYLD to the pathogenesis of various maladies, including cancer, poor infection control, lung fibrosis, neural development, and now cardiovascular dysfunction. While CYLD-mediated signaling is cell type and stimuli specific, the activity of CYLD is tightly controlled by phosphorylation and other regulators such as Snail. This review explores a broad selection of current and past literature regarding CYLD's expression, function and regulation with emerging reports on its role in cardiovascular disease.
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Affiliation(s)
| | | | | | | | - Taixing Cui
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29209, USA.
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Zhou P, Hao Z, Wang X, Gao J, Li D, Xie S, Zhang TC. UV Irradiation Triggers Cylindromatosis Translocation, Modification, and Degradation in a Proteasome-Independent Manner. DNA Cell Biol 2015; 35:140-5. [PMID: 26717101 DOI: 10.1089/dna.2015.3061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The tumor suppressor, cylindromatosis (CYLD), is a negative regulator of NF-κB signaling by removing lysine 63-linked ubiquitin chains from multiple NF-κB signaling components, including TRAF2, TRAF6, and NEMO. How CYLD itself is regulated, however, remains yet to be characterized. In this study, we present the first evidence that UV irradiation is able to induce CYLD translocation from the cytoplasm to microtubules and that the cytoskeleton-associated CYLD is subject to posttranslational modification and degradation in a proteasome-independent manner. By immunostaining, we found that CYLD displayed microtubule-like filament localization under ultraviolet (UV) irradiation. Further studies revealed that the cytoskeleton-associated CYLD underwent posttranslational modification, which in turn contributed to CYLD degradation in an unknown manner, distinct from proteasome-mediated degradation under normal conditions. Collectively, our data suggest that UV-induced CYLD degradation might serve as an underlying mechanism for UV-induced NF-κB pathway activation.
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Affiliation(s)
- Ping Zhou
- 1 Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Ministry of Education and Tianjin, Tianjin University of Science and Technology , Tianjin, China
| | - Ziwei Hao
- 2 State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University , Tianjin, China
| | - Xincheng Wang
- 2 State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University , Tianjin, China
| | - Jinmin Gao
- 2 State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University , Tianjin, China
| | - Dengwen Li
- 2 State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University , Tianjin, China
| | - Songbo Xie
- 2 State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University , Tianjin, China
| | - Tong-Cun Zhang
- 1 Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Ministry of Education and Tianjin, Tianjin University of Science and Technology , Tianjin, China .,3 Institute of Biology and Medicine, Wuhan University of Science and Technology , Wuhan, China
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8
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Yang Y, Ran J, Sun L, Sun X, Luo Y, Yan B, Tala, Liu M, Li D, Zhang L, Bao G, Zhou J. CYLD Regulates Noscapine Activity in Acute Lymphoblastic Leukemia via a Microtubule-Dependent Mechanism. Am J Cancer Res 2015; 5:656-66. [PMID: 25897332 PMCID: PMC4402491 DOI: 10.7150/thno.10844] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/29/2015] [Indexed: 01/26/2023] Open
Abstract
Noscapine is an orally administrable drug used worldwide for cough suppression and has recently been demonstrated to disrupt microtubule dynamics and possess anticancer activity. However, the molecular mechanisms regulating noscapine activity remain poorly defined. Here we demonstrate that cylindromatosis (CYLD), a microtubule-associated tumor suppressor protein, modulates the activity of noscapine both in cell lines and in primary cells of acute lymphoblastic leukemia (ALL). Flow cytometry and immunofluorescence microscopy reveal that CYLD increases the ability of noscapine to induce mitotic arrest and apoptosis. Examination of cellular microtubules as well as in vitro assembled microtubules shows that CYLD enhances the effect of noscapine on microtubule polymerization. Microtubule cosedimentation and fluorescence titration assays further reveal that CYLD interacts with microtubule outer surface and promotes noscapine binding to microtubules. These findings thus demonstrate CYLD as a critical regulator of noscapine activity and have important implications for ALL treatment.
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Eguether T, Ermolaeva MA, Zhao Y, Bonnet MC, Jain A, Pasparakis M, Courtois G, Tassin AM. The deubiquitinating enzyme CYLD controls apical docking of basal bodies in ciliated epithelial cells. Nat Commun 2014; 5:4585. [PMID: 25134987 DOI: 10.1038/ncomms5585] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 07/03/2014] [Indexed: 12/20/2022] Open
Abstract
CYLD is a tumour suppressor gene mutated in familial cylindromatosis, a genetic disorder leading to the development of skin appendage tumours. It encodes a deubiquitinating enzyme that removes Lys63- or linear-linked ubiquitin chains. CYLD was shown to regulate cell proliferation, cell survival and inflammatory responses, through various signalling pathways. Here we show that CYLD localizes at centrosomes and basal bodies via interaction with the centrosomal protein CAP350 and demonstrate that CYLD must be both at the centrosome and catalytically active to promote ciliogenesis independently of NF-κB. In transgenic mice engineered to mimic the smallest truncation found in cylindromatosis patients, CYLD interaction with CAP350 is lost disrupting CYLD centrosome localization, which results in cilia formation defects due to impairment of basal body migration and docking. These results point to an undiscovered regulation of ciliogenesis by Lys63 ubiquitination and provide new perspectives regarding CYLD function that should be considered in the context of cylindromatosis.
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Affiliation(s)
- Thibaut Eguether
- 1] Institut Curie/INSERM U759, Campus Universitaire, Bat 112, 91405 Orsay Cedex, France [2] Université Pierre et Marie Curie, 75005 Paris, France [3]
| | - Maria A Ermolaeva
- Institute for Genetics, Center for Molecular Medicine (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany
| | - Yongge Zhao
- Laboratory of Host Defenses, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Marion C Bonnet
- 1] Institute for Genetics, Center for Molecular Medicine (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany [2] Excellence Research Chair, Université Européenne de Bretagne, IRSET/INSERM UMR1085, Faculté de Pharmacie, Université de Rennes 1, 35000 Rennes, France
| | - Ashish Jain
- Laboratory of Host Defenses, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Manolis Pasparakis
- Institute for Genetics, Center for Molecular Medicine (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany
| | - Gilles Courtois
- 1] Université Grenoble Alpes, 38000 Grenoble, France [2] INSERM U1038/BGE/Institut de Recherches en Technologies et Sciences pour le Vivant, CEA, 38054 Grenoble, France
| | - Anne-Marie Tassin
- 1] Institut Curie/INSERM U759, Campus Universitaire, Bat 112, 91405 Orsay Cedex, France [2] CNRS, Centre de Génétique Moléculaire, UPR3404, Avenue de la Terrasse, F-91198 Gif-sur-Yvette, France
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10
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Li D, Gao J, Yang Y, Sun L, Suo S, Luo Y, Shui W, Zhou J, Liu M. CYLD coordinates with EB1 to regulate microtubule dynamics and cell migration. Cell Cycle 2014; 13:974-83. [PMID: 24552808 DOI: 10.4161/cc.27838] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cylindromatosis (CYLD), a deubiquitinase involved in inflammation and tumorigenesis via the modulation of cell signaling, has recently been identified as a critical regulator of microtubule dynamics. CYLD has also been shown to stimulate cell migration and thereby contribute to normal physiological processes. However, it remains elusive how the regulation of microtubule dynamic properties by CYLD is connected to its role in mediating cell migration. In this study, we performed yeast 2-hybrid screening with CYLD as bait and identified 7 CYLD-interacting proteins, including end-binding protein 1 (EB1). The CYLD-EB1 interaction was confirmed both in cells and in vitro, and these 2 proteins colocalized at the plus ends of microtubules. Interestingly, the association of CYLD with EB1 was significantly increased upon the stimulation of cell migration. CYLD coordinated with EB1 to orchestrate tail retraction, centrosome reorientation, and leading-edge microtubule stabilization in migratory cells. In addition, CYLD acted in concert with EB1 to regulate microtubule assembly in vitro, microtubule nucleation at the centrosome, and microtubule growth at the cell periphery. These data provide mechanistic insights into the actions of CYLD in the regulation of microtubule dynamics and cell migration. These findings also support the notion that coordinated actions of microtubule-binding proteins are critical for microtubule-mediated cellular events.
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Affiliation(s)
- Dengwen Li
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Jinmin Gao
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Yunfan Yang
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Lei Sun
- Tianjin Key Laboratory of Medical Epigenetics; School of Basic Medical Sciences; Tianjin Medical University; Tianjin, China
| | - Shaojun Suo
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Youguang Luo
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Wenqing Shui
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Jun Zhou
- State Key Laboratory of Medicinal Chemical Biology; College of Life Sciences; Nankai University; Tianjin, China
| | - Min Liu
- Tianjin Key Laboratory of Medical Epigenetics; School of Basic Medical Sciences; Tianjin Medical University; Tianjin, China
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Systematic Analysis of the Functions of Lysine Acetylation in the Regulation of Tat Activity. PLoS One 2013; 8:e67186. [PMID: 23826228 PMCID: PMC3695041 DOI: 10.1371/journal.pone.0067186] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 05/15/2013] [Indexed: 11/28/2022] Open
Abstract
The Tat protein of HIV-1 has several well-known properties, such as nucleocytoplasmic trafficking, transactivation of transcription, interaction with tubulin, regulation of mitotic progression, and induction of apoptosis. Previous studies have identified a couple of lysine residues in Tat that are essential for its functions. In order to analyze the functions of all the lysine residues in Tat, we mutated them individually to alanine, glutamine, and arginine. Through systematic analysis of the lysine mutants, we discovered several previously unidentified characteristics of Tat. We found that lysine acetylation could modulate the subcellular localization of Tat, in addition to the regulation of its transactivation activity. Our data also revealed that lysine mutations had distinct effects on microtubule assembly and Tat binding to bromodomain proteins. By correlation analysis, we further found that the effects of Tat on apoptosis and mitotic progression were not entirely attributed to its effect on microtubule assembly. Our findings suggest that Tat may regulate diverse cellular activities through binding to different proteins and that the acetylation of distinct lysine residues in Tat may modulate its interaction with various partners.
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Hurst JH, Dohlman HG. Dynamic ubiquitination of the mitogen-activated protein kinase kinase (MAPKK) Ste7 determines mitogen-activated protein kinase (MAPK) specificity. J Biol Chem 2013; 288:18660-71. [PMID: 23645675 DOI: 10.1074/jbc.m113.475707] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ubiquitination is a post-translational modification that tags proteins for proteasomal degradation. In addition, there is a growing appreciation that ubiquitination can influence protein activity and localization. Ste7 is a prototype MAPKK in yeast that participates in both the pheromone signaling and nutrient deprivation/invasive growth pathways. We have shown previously that Ste7 is ubiquitinated upon pheromone stimulation. Here, we show that the Skp1/Cullin/F-box ubiquitin ligase SCF(Cdc4) and the ubiquitin protease Ubp3 regulate Ste7 ubiquitination and signal specificity. Using purified components, we demonstrate that SCF(Cdc4) ubiquitinates Ste7 directly. Using gene deletion mutants, we show that SCF(Cdc4) and Ubp3 have opposing effects on Ste7 ubiquitination. Although SCF(Cdc4) is necessary for proper activation of the pheromone MAPK Fus3, Ubp3 is needed to limit activation of the invasive growth MAPK Kss1. Finally, we show that Fus3 phosphorylates Ubp3 directly and that phosphorylation of Ubp3 is necessary to limit Kss1 activation. These results reveal a feedback loop wherein one MAPK limits the ubiquitination of an upstream MAPKK and thereby prevents spurious activation of a second competing MAPK.
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Affiliation(s)
- Jillian H Hurst
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599-7260, USA
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