1
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Lu KP, Zhou XZ. Pin1-catalyzed conformational regulation after phosphorylation: A distinct checkpoint in cell signaling and drug discovery. Sci Signal 2024; 17:eadi8743. [PMID: 38889227 PMCID: PMC11409840 DOI: 10.1126/scisignal.adi8743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 05/30/2024] [Indexed: 06/20/2024]
Abstract
Protein phosphorylation is one of the most common mechanisms regulating cellular signaling pathways, and many kinases and phosphatases are proven drug targets. Upon phosphorylation, protein functions can be further regulated by the distinct isomerase Pin1 through cis-trans isomerization. Numerous protein targets and many important roles have now been elucidated for Pin1. However, no tools are available to detect or target cis and trans conformation events in cells. The development of Pin1 inhibitors and stereo- and phospho-specific antibodies has revealed that cis and trans conformations have distinct and often opposing cellular functions. Aberrant conformational changes due to the dysregulation of Pin1 can drive pathogenesis but can be effectively targeted in age-related diseases, including cancers and neurodegenerative disorders. Here, we review advances in understanding the roles of Pin1 signaling in health and disease and highlight conformational regulation as a distinct signal transduction checkpoint in disease development and treatment.
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Affiliation(s)
- Kun Ping Lu
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
- Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
| | - Xiao Zhen Zhou
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
- Lawson Health Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
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2
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Jeong J, Usman M, Li Y, Zhou XZ, Lu KP. Pin1-Catalyzed Conformation Changes Regulate Protein Ubiquitination and Degradation. Cells 2024; 13:731. [PMID: 38727267 PMCID: PMC11083468 DOI: 10.3390/cells13090731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/12/2024] [Accepted: 04/14/2024] [Indexed: 05/13/2024] Open
Abstract
The unique prolyl isomerase Pin1 binds to and catalyzes cis-trans conformational changes of specific Ser/Thr-Pro motifs after phosphorylation, thereby playing a pivotal role in regulating the structure and function of its protein substrates. In particular, Pin1 activity regulates the affinity of a substrate for E3 ubiquitin ligases, thereby modulating the turnover of a subset of proteins and coordinating their activities after phosphorylation in both physiological and disease states. In this review, we highlight recent advancements in Pin1-regulated ubiquitination in the context of cancer and neurodegenerative disease. Specifically, Pin1 promotes cancer progression by increasing the stabilities of numerous oncoproteins and decreasing the stabilities of many tumor suppressors. Meanwhile, Pin1 plays a critical role in different neurodegenerative disorders via the regulation of protein turnover. Finally, we propose a novel therapeutic approach wherein the ubiquitin-proteasome system can be leveraged for therapy by targeting pathogenic intracellular targets for TRIM21-dependent degradation using stereospecific antibodies.
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Affiliation(s)
- Jessica Jeong
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Muhammad Usman
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Yitong Li
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
| | - Xiao Zhen Zhou
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Department of Pathology and Laboratory Medicine, and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada
- Lawson Health Research Institute, Western University, London, ON N6C 2R5, Canada
| | - Kun Ping Lu
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 5C1, Canada; (J.J.)
- Robarts Research Institute, Western University, London, ON N6A 5B7, Canada
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3
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Deritei D, Inuzuka H, Castaldi PJ, Yun JH, Xu Z, Anamika WJ, Asara JM, Guo F, Zhou X, Glass K, Wei W, Silverman EK. HHIP protein interactions in lung cells provide insight into COPD pathogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.01.586839. [PMID: 38617310 PMCID: PMC11014494 DOI: 10.1101/2024.04.01.586839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. The primary causes of COPD are environmental, including cigarette smoking; however, genetic susceptibility also contributes to COPD risk. Genome-Wide Association Studies (GWASes) have revealed more than 80 genetic loci associated with COPD, leading to the identification of multiple COPD GWAS genes. However, the biological relationships between the identified COPD susceptibility genes are largely unknown. Genes associated with a complex disease are often in close network proximity, i.e. their protein products often interact directly with each other and/or similar proteins. In this study, we use affinity purification mass spectrometry (AP-MS) to identify protein interactions with HHIP , a well-established COPD GWAS gene which is part of the sonic hedgehog pathway, in two disease-relevant lung cell lines (IMR90 and 16HBE). To better understand the network neighborhood of HHIP , its proximity to the protein products of other COPD GWAS genes, and its functional role in COPD pathogenesis, we create HUBRIS, a protein-protein interaction network compiled from 8 publicly available databases. We identified both common and cell type-specific protein-protein interactors of HHIP. We find that our newly identified interactions shorten the network distance between HHIP and the protein products of several COPD GWAS genes, including DSP, MFAP2, TET2 , and FBLN5 . These new shorter paths include proteins that are encoded by genes involved in extracellular matrix and tissue organization. We found and validated interactions to proteins that provide new insights into COPD pathobiology, including CAVIN1 (IMR90) and TP53 (16HBE). The newly discovered HHIP interactions with CAVIN1 and TP53 implicate HHIP in response to oxidative stress.
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4
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Yan D, Hua L. Nucleolar stress: Friend or foe in cardiac function? Front Cardiovasc Med 2022; 9:1045455. [PMID: 36386352 PMCID: PMC9659567 DOI: 10.3389/fcvm.2022.1045455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 10/17/2022] [Indexed: 03/14/2024] Open
Abstract
Studies in the past decades have uncovered an emerging role of the nucleolus in stress response and human disease progression. The disruption of ribosome biogenesis in the nucleolus causes aberrant nucleolar architecture and function, termed nucleolar stress, to initiate stress-responsive pathways via nucleolar release sequestration of various proteins. While data obtained from both clinical and basic investigations have faithfully demonstrated an involvement of nucleolar stress in the pathogenesis of cardiomyopathy, much remains unclear regarding its precise role in the progression of cardiac diseases. On the one hand, the initiation of nucleolar stress following acute myocardial damage leads to the upregulation of various cardioprotective nucleolar proteins, including nucleostemin (NS), nucleophosmin (NPM) and nucleolin (NCL). As a result, nucleolar stress plays an important role in facilitating the survival and repair of cardiomyocytes. On the other hand, abnormalities in nucleolar architecture and function are correlated with the deterioration of cardiac diseases. Notably, the cardiomyocytes of advanced ischemic and dilated cardiomyopathy display impaired silver-stained nucleolar organiser regions (AgNORs) and enlarged nucleoli, resembling the characteristics of tissue aging. Collectively, nucleolar abnormalities are critically involved in the development of cardiac diseases.
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Affiliation(s)
- Daliang Yan
- Department of Cardiovascular Surgery, Taizhou People’s Hospital, Taizhou, China
| | - Lu Hua
- Department of Oncology, Taizhou People’s Hospital, Taizhou, China
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5
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Nucleolus and Nucleolar Stress: From Cell Fate Decision to Disease Development. Cells 2022; 11:cells11193017. [PMID: 36230979 PMCID: PMC9563748 DOI: 10.3390/cells11193017] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 11/30/2022] Open
Abstract
Besides the canonical function in ribosome biogenesis, there have been significant recent advances towards the fascinating roles of the nucleolus in stress response, cell destiny decision and disease progression. Nucleolar stress, an emerging concept describing aberrant nucleolar structure and function as a result of impaired rRNA synthesis and ribosome biogenesis under stress conditions, has been linked to a variety of signaling transductions, including but not limited to Mdm2-p53, NF-κB and HIF-1α pathways. Studies have uncovered that nucleolus is a stress sensor and signaling hub when cells encounter various stress conditions, such as nutrient deprivation, DNA damage and oxidative and thermal stress. Consequently, nucleolar stress plays a pivotal role in the determination of cell fate, such as apoptosis, senescence, autophagy and differentiation, in response to stress-induced damage. Nucleolar homeostasis has been involved in the pathogenesis of various chronic diseases, particularly tumorigenesis, neurodegenerative diseases and metabolic disorders. Mechanistic insights have revealed the indispensable role of nucleolus-initiated signaling in the progression of these diseases. Accordingly, the intervention of nucleolar stress may pave the path for developing novel therapies against these diseases. In this review, we systemically summarize recent findings linking the nucleolus to stress responses, signaling transduction and cell-fate decision, set the spotlight on the mechanisms by which nucleolar stress drives disease progression, and highlight the merit of the intervening nucleolus in disease treatment.
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6
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Gorski JW, Ueland FR, Kolesar JM. CCNE1 Amplification as a Predictive Biomarker of Chemotherapy Resistance in Epithelial Ovarian Cancer. Diagnostics (Basel) 2020; 10:diagnostics10050279. [PMID: 32380689 PMCID: PMC7277958 DOI: 10.3390/diagnostics10050279] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 04/28/2020] [Accepted: 05/03/2020] [Indexed: 12/15/2022] Open
Abstract
Ovarian cancer is the most-deadly gynecologic malignancy, with greater than 14,000 women expected to succumb to the disease this year in the United States alone. In the front-line setting, patients are treated with a platinum and taxane doublet. Although 40–60% of patients achieve complete clinical response to first-line chemotherapy, 25% are inherently platinum-resistant or refractory with a median overall survival of about one year. More than 80% of women afflicted with ovarian cancer will recur. Many attempts have been made to understand the mechanism of platinum and taxane based chemotherapy resistance. However, despite decades of research, few predictive markers of chemotherapy resistance have been identified. Here, we review the current understanding of one of the most common genetic alterations in epithelial ovarian cancer, CCNE1 (cyclin E1) amplification, and its role as a potential predictive marker of cytotoxic chemotherapy resistance. CCNE1 amplification has been identified as a primary oncogenic driver in a subset of high grade serous ovarian cancer that have an unmet clinical need. Understanding the interplay between cyclin E1 amplification and other common ovarian cancer genetic alterations provides the basis for chemotherapeutic resistance in CCNE1 amplified disease. Exploration of the effect of cyclin E1 amplification on the cellular machinery that causes dysregulated proliferation in cancer cells has allowed investigators to explore promising targeted therapies that provide the basis for emerging clinical trials.
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Affiliation(s)
- Justin W. Gorski
- Division of Gynecologic Oncology, Department of Obstetrics & Gynecology, University of Kentucky Chandler Medical Center, 800 Rose Street, Lexington, KY 40536-0263, USA;
- Correspondence:
| | - Frederick R. Ueland
- Division of Gynecologic Oncology, Department of Obstetrics & Gynecology, University of Kentucky Chandler Medical Center, 800 Rose Street, Lexington, KY 40536-0263, USA;
| | - Jill M. Kolesar
- Department of Pharmacy Practice & Science, University of Kentucky College of Pharmacy, 567 TODD Building, 789 South Limestone Street, Lexington, KY 40539-0596, USA;
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7
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Pu W, Zheng Y, Peng Y. Prolyl Isomerase Pin1 in Human Cancer: Function, Mechanism, and Significance. Front Cell Dev Biol 2020; 8:168. [PMID: 32296699 PMCID: PMC7136398 DOI: 10.3389/fcell.2020.00168] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 02/29/2020] [Indexed: 02/05/2023] Open
Abstract
Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is an evolutionally conserved and unique enzyme that specifically catalyzes the cis-trans isomerization of phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif and, subsequently, induces the conformational change of its substrates. Mounting evidence has demonstrated that Pin1 is widely overexpressed and/or overactivated in cancer, exerting a critical influence on tumor initiation and progression via regulation of the biological activity, protein degradation, or nucleus-cytoplasmic distribution of its substrates. Moreover, Pin1 participates in the cancer hallmarks through activating some oncogenes and growth enhancers, or inactivating some tumor suppressors and growth inhibitors, suggesting that Pin1 could be an attractive target for cancer therapy. In this review, we summarize the findings on the dysregulation, mechanisms, and biological functions of Pin1 in cancer cells, and also discuss the significance and potential applications of Pin1 dysregulation in human cancer.
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Affiliation(s)
- Wenchen Pu
- Laboratory of Molecular Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Collaborative Innovation Center of Biotherapy, Chengdu, China
| | - Yuanyuan Zheng
- Laboratory of Molecular Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Collaborative Innovation Center of Biotherapy, Chengdu, China
| | - Yong Peng
- Laboratory of Molecular Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Collaborative Innovation Center of Biotherapy, Chengdu, China
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8
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Yu JH, Im CY, Min SH. Function of PIN1 in Cancer Development and Its Inhibitors as Cancer Therapeutics. Front Cell Dev Biol 2020; 8:120. [PMID: 32258027 PMCID: PMC7089927 DOI: 10.3389/fcell.2020.00120] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 02/11/2020] [Indexed: 12/15/2022] Open
Abstract
Peptidyl-prolyl isomerase (PIN1) specifically binds and isomerizes the phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif, which results in the alteration of protein structure, function, and stability. The altered structure and function of these phosphorylated proteins regulated by PIN1 are closely related to cancer development. PIN1 is highly expressed in human cancers and promotes cancer as well as cancer stem cells by breaking the balance of oncogenes and tumor suppressors. In this review, we discuss the roles of PIN1 in cancer and PIN1-targeted small-molecule compounds.
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Affiliation(s)
- Ji Hoon Yu
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu, South Korea
| | - Chun Young Im
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu, South Korea
| | - Sang-Hyun Min
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu, South Korea
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9
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Davidge B, Rebola KGDO, Agbor LN, Sigmund CD, Singer JD. Cul3 regulates cyclin E1 protein abundance via a degron located within the N-terminal region of cyclin E. J Cell Sci 2019; 132:jcs233049. [PMID: 31636116 PMCID: PMC6857591 DOI: 10.1242/jcs.233049] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Cyclin E and its binding partner Cdk2 control the G1/S transition in mammalian cells. Increased levels of cyclin E are found in some cancers. Additionally, proteolytic removal of the cyclin E N-terminus occurs in some cancers and is associated with increased cyclin E-Cdk2 activity and poor clinical prognosis. Cyclin E levels are tightly regulated and controlled in part through ubiquitin-mediated degradation initiated by one of two E3 ligases, Cul1 and Cul3. Cul1 ubiquitylates phosphorylated cyclin E, but the mechanism through which Cul3 ubiquitylates cyclin E is poorly understood. In experiments to ascertain how Cul3 mediates cyclin E destruction, we identified a degron on cyclin E that Cul3 targets for ubiquitylation. Recognition of the degron and binding of Cul3 does not require a BTB domain-containing adaptor protein. Additionally, this degron is lacking in N-terminally truncated cyclin E. Our results describe a mechanism whereby N-terminally truncated cyclin E can avoid the Cul3-mediated degradation pathway. This mechanism helps to explain the increased activity that is associated with the truncated cyclin E variants that occurs in some cancers.
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Affiliation(s)
- Brittney Davidge
- Department of Biology, Portland State University, Portland, OR 97201, USA
| | | | - Larry N Agbor
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226-0509, USA
| | - Curt D Sigmund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226-0509, USA
| | - Jeffrey D Singer
- Department of Biology, Portland State University, Portland, OR 97201, USA
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10
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SPOP suppresses prostate cancer through regulation of CYCLIN E1 stability. Cell Death Differ 2018; 26:1156-1168. [PMID: 30237511 PMCID: PMC6748103 DOI: 10.1038/s41418-018-0198-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/25/2018] [Accepted: 08/27/2018] [Indexed: 11/18/2022] Open
Abstract
SPOP is one of the important subunits for CUL3/SPOP/RBX1 complex tightly connected with tumorigenesis. However, its exact roles in different cancers remain debatable. Here, we identify CYCLIN E1, as a novel substrate for SPOP. SPOP directly interacts with CYCLIN E1 and specific regulates its stability in prostate cancer cell lines. SPOP/CUL3/RBX1 complex regulates CYCLIN E1 stability through poly-ubiquitination. CDK2 competes with SPOP for CYCLIN E1 interaction, suggesting that SPOP probably regulates the stability of CDK2-free CYCLIN E1. CYCLIN E1 expression rescued proliferation, migration, and tumor formation of prostate cancer cell suppressed by SPOP. Furthermore, we found SPOP selectively regulates the substrates’ stability and signaling pathways in prostate cancer and CCRC cell lines, suggesting that complicated mechanisms exist for SPOP to regulate substrate specificity. Altogether, we have revealed a novel mechanism for SPOP in suppressing prostate cancer and provided evidence to show SPOP has dual functions in prostate cancer and CCRC.
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11
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Brun S, Abella N, Berciano MT, Tapia O, Jaumot M, Freire R, Lafarga M, Agell N. SUMO regulates p21Cip1 intracellular distribution and with p21Cip1 facilitates multiprotein complex formation in the nucleolus upon DNA damage. PLoS One 2017; 12:e0178925. [PMID: 28582471 PMCID: PMC5459497 DOI: 10.1371/journal.pone.0178925] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/22/2017] [Indexed: 01/06/2023] Open
Abstract
We previously showed that p21Cip1 transits through the nucleolus on its way from the nucleus to the cytoplasm and that DNA damage inhibits this transit and induces the formation of p21Cip1-containing intranucleolar bodies (INoBs). Here, we demonstrate that these INoBs also contain SUMO-1 and UBC9, the E2 SUMO-conjugating enzyme. Furthermore, whereas wild type SUMO-1 localized in INoBs, a SUMO-1 mutant, which is unable to conjugate with proteins, does not, suggesting the presence of SUMOylated proteins at INoBs. Moreover, depletion of the SUMO-conjugating enzyme UBC9 or the sumo hydrolase SENP2 changed p21Cip1 intracellular distribution. In addition to SUMO-1 and p21Cip1, cell cycle regulators and DNA damage checkpoint proteins, including Cdk2, Cyclin E, PCNA, p53 and Mdm2, and PML were also detected in INoBs. Importantly, depletion of UBC9 or p21Cip1 impacted INoB biogenesis and the nucleolar accumulation of the cell cycle regulators and DNA damage checkpoint proteins following DNA damage. The impact of p21Cip1 and SUMO-1 on the accumulation of proteins in INoBs extends also to CRM1, a nuclear exportin that is also important for protein translocation from the cytoplasm to the nucleolus. Thus, SUMO and p21Cip1 regulate the transit of proteins through the nucleolus, and that disruption of nucleolar export by DNA damage induces SUMO and p21Cip1 to act as hub proteins to form a multiprotein complex in the nucleolus.
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Affiliation(s)
- Sonia Brun
- Departament Biomedicina, Universitat de Barcelona, IDIBAPS, Barcelona, Spain
| | - Neus Abella
- Departament Biomedicina, Universitat de Barcelona, IDIBAPS, Barcelona, Spain
| | - Maria T. Berciano
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - Olga Tapia
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - Montserrat Jaumot
- Departament Biomedicina, Universitat de Barcelona, IDIBAPS, Barcelona, Spain
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Tenerife, Spain
| | - Miguel Lafarga
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria-IDIVAL, Santander, Spain
| | - Neus Agell
- Departament Biomedicina, Universitat de Barcelona, IDIBAPS, Barcelona, Spain
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12
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The role of Pin1 in the development and treatment of cancer. Arch Pharm Res 2016; 39:1609-1620. [PMID: 27572155 DOI: 10.1007/s12272-016-0821-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 08/18/2016] [Indexed: 12/16/2022]
Abstract
Protein phosphorylation and post-phosphorylation events regulate many cellular signaling pathways. Peptidyl-prolyl isomerase (Pin1) is the only peptidyl-prolyl cis/trans isomerase that interacts with numerous oncogenic or tumor suppressive phosphorylated proteins, causes conformational changes in target proteins, and eventually regulates the activities of such proteins. These alterations in activity play a pivotal role in tumorigenesis. Since Pin1 is overexpressed and/or activated in various types of cancers, and the dysregulation of proline-directed phosphorylation contributes to tumorigenesis, Pin1 represents an attractive target for cancer therapy. This review will describe the role of Pin1 in cancer and the current status of Pin1 inhibitor development.
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13
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Zheng N, Zhou Q, Wang Z, Wei W. Recent advances in SCF ubiquitin ligase complex: Clinical implications. Biochim Biophys Acta Rev Cancer 2016; 1866:12-22. [PMID: 27156687 DOI: 10.1016/j.bbcan.2016.05.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/09/2022]
Abstract
F-box proteins, which are subunit recruiting modules of SCF (SKP1-Cullin 1-F-box protein) E3 ligase complexes, play critical roles in the development and progression of human malignancies through governing multiple cellular processes including cell proliferation, apoptosis, invasion and metastasis. Moreover, there are emerging studies that lead to the development of F-box proteins inhibitors with promising therapeutic potential. In this article, we describe how F-box proteins including but not restricted to well-established Fbw7, Skp2 and β-TRCP, are involved in tumorigenesis. However, in-depth investigation is required to further explore the mechanism and the physiological contribution of undetermined F-box proteins in carcinogenesis. Lastly, we suggest that targeting F-box proteins could possibly open new avenues for the treatment and prevention of human cancers.
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Affiliation(s)
- Nana Zheng
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Quansheng Zhou
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China
| | - Zhiwei Wang
- The Cyrus Tang Hematology Center and Collaborative Innovation Center of Hematology, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou 215123, China; Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA 02215, USA.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA 02215, USA.
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14
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Uddin S, Bhat AA, Krishnankutty R, Mir F, Kulinski M, Mohammad RM. Involvement of F-BOX proteins in progression and development of human malignancies. Semin Cancer Biol 2016; 36:18-32. [PMID: 26410033 DOI: 10.1016/j.semcancer.2015.09.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 09/15/2015] [Accepted: 09/15/2015] [Indexed: 12/13/2022]
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15
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The relationship between the nucleolus and cancer: Current evidence and emerging paradigms. Semin Cancer Biol 2015; 37-38:36-50. [PMID: 26721423 DOI: 10.1016/j.semcancer.2015.12.004] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/15/2015] [Accepted: 12/19/2015] [Indexed: 12/13/2022]
Abstract
The nucleolus is the most prominent nuclear substructure assigned to produce ribosomes; molecular machines that are responsible for carrying out protein synthesis. To meet the increased demand for proteins during cell growth and proliferation the cell must increase protein synthetic capacity by upregulating ribosome biogenesis. While larger nucleolar size and number have been recognized as hallmark features of many tumor types, recent evidence has suggested that, in addition to overproduction of ribosomes, decreased ribosome biogenesis as well as qualitative changes in this process could also contribute to tumor initiation and cancer progression. Furthermore, the nucleolus has become the focus of intense attention for its involvement in processes that are clearly unrelated to ribosome biogenesis such as sensing and responding to endogenous and exogenous stressors, maintenance of genome stability, regulation of cell-cycle progression, cellular senescence, telomere function, chromatin structure, establishment of nuclear architecture, global regulation of gene expression and biogenesis of multiple ribonucleoprotein particles. The fact that dysregulation of many of these fundamental cellular processes may contribute to the malignant phenotype suggests that normal functioning of the nucleolus safeguards against the development of cancer and indicates its potential as a therapeutic approach. Here we review the recent advances made toward understanding these newly-recognized nucleolar functions and their roles in normal and cancer cells, and discuss possible future research directions.
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16
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Zhou Z, He C, Wang J. Regulation mechanism of Fbxw7-related signaling pathways (Review). Oncol Rep 2015; 34:2215-24. [PMID: 26324296 DOI: 10.3892/or.2015.4227] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/29/2015] [Indexed: 11/05/2022] Open
Abstract
F-box and WD repeat domain-containing 7 (Fbxw7), the substrate-recognition component of SCFFbxw7 complex, is thought to be a tumor suppressor involved in cell growth, proliferation, differentiation and survival. Although an increasing number of ubiquitin substrates of Fbxw7 have been identified, the best characterized substrates are cyclin E and c-Myc. Fbxw7/cyclin E and Fbxw7/c-Myc pathways are tightly regulated by multiple regulators. Fbxw7 has been identified as a tumor suppressor in hepatocellular carcinoma. This review focused on the regulation of Fbxw7/cyclin E and Fbxw7/c-Myc pathways and discussed findings to gain a better understanding of the role of Fbxw7 in hepatocellular carcinoma.
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Affiliation(s)
- Zhenyu Zhou
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Chuanchao He
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Jie Wang
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Sun Yat‑sen University, Guangzhou, Guangdong 510120, P.R. China
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17
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Maskey D, Marlin MC, Kim S, Kim S, Ong EC, Li G, Tsiokas L. Cell cycle-dependent ubiquitylation and destruction of NDE1 by CDK5-FBW7 regulates ciliary length. EMBO J 2015. [PMID: 26206584 DOI: 10.15252/embj.201490831] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Primary cilia start forming within the G1 phase of the cell cycle and continue to grow as cells exit the cell cycle (G0). They start resorbing when cells re-enter the cell cycle (S phase) and are practically invisible in mitosis. The mechanisms by which cilium biogenesis and disassembly are coupled to the cell cycle are complex and not well understood. We previously identified the centrosomal phosphoprotein NDE1 as a negative regulator of ciliary length and showed that its levels inversely correlate with ciliogenesis. Here, we identify the tumor suppressor FBW7 (also known as FBXW7, CDC4, AGO, or SEL-10) as the E3 ligase that mediates the destruction of NDE1 upon entry into G1. CDK5, a kinase active in G1/G0, primes NDE1 for FBW7-mediated recognition. Cells depleted of FBW7 or CDK5 show enhanced levels of NDE1 and a reduction in ciliary length, which is corrected in cells depleted of both FBW7 or CDK5 and NDE1. These data show that cell cycle-dependent mechanisms can control ciliary length through a CDK5-FBW7-NDE1 pathway.
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Affiliation(s)
- Dipak Maskey
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Matthew Caleb Marlin
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Seokho Kim
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Sehyun Kim
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - E-Ching Ong
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Guangpu Li
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Leonidas Tsiokas
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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18
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Machado-Oliveira G, Guerreiro E, Matias AC, Facucho-Oliveira J, Pacheco-Leyva I, Bragança J. FBXL5 modulates HIF-1α transcriptional activity by degradation of CITED2. Arch Biochem Biophys 2015; 576:61-72. [PMID: 25956243 DOI: 10.1016/j.abb.2015.04.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 04/24/2015] [Accepted: 04/28/2015] [Indexed: 02/07/2023]
Abstract
CITED2 is a ubiquitously expressed nuclear protein exhibiting a high affinity for the cysteine-histidine-rich domain 1 (CH1) of the transcriptional co-activators CBP/p300. CITED2 is particularly efficient in the inhibition of the hypoxia-inducible factor-1α (HIF-1α) dependent transcription by competing with it for the interaction with the CH1 domain. Here we report a direct and specific interaction between CITED2 and the F-box and leucine rich repeat protein 5 (FBXL5), a substrate adaptor protein which is part of E3 ubiquitin ligase complexes mediating protein degradation by the proteasome. We demonstrated that depletion of FBXL5 by RNA interference led to an increase of CITED2 protein levels. Conversely, overexpression of FBXL5 caused the decrease of CITED2 protein levels in a proteasome-dependent manner, and impaired the interaction between CITED2 and the CH1 domain of p300 in living cells. In undifferentiated mouse embryonic stem cells, the overexpression of FBXL5 also reduced Cited2 protein levels. Finally, we evidenced that FBXL5 overexpression and the consequent degradation of CITED2 enabled the transcriptional activity of the N-terminal transactivation domain of HIF-1α. Collectively, our results highlighted a novel molecular interaction between CITED2 and FBXL5, which might regulate the steady state CITED2 protein levels and contribute to the modulation of gene expression by HIF-1α.
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Affiliation(s)
- Gisela Machado-Oliveira
- Department of Biomedical Sciences and Medicine, University of Algarve, Portugal; CBMR - Centre for Biomedical Research, University of Algarve, Campus of Gambelas, 8005-139 Faro, Portugal
| | - Eduarda Guerreiro
- Department of Biomedical Sciences and Medicine, University of Algarve, Portugal; CBMR - Centre for Biomedical Research, University of Algarve, Campus of Gambelas, 8005-139 Faro, Portugal
| | - Ana Catarina Matias
- Department of Biomedical Sciences and Medicine, University of Algarve, Portugal; CBMR - Centre for Biomedical Research, University of Algarve, Campus of Gambelas, 8005-139 Faro, Portugal
| | | | - Ivette Pacheco-Leyva
- Department of Biomedical Sciences and Medicine, University of Algarve, Portugal; CBMR - Centre for Biomedical Research, University of Algarve, Campus of Gambelas, 8005-139 Faro, Portugal
| | - José Bragança
- Department of Biomedical Sciences and Medicine, University of Algarve, Portugal; CBMR - Centre for Biomedical Research, University of Algarve, Campus of Gambelas, 8005-139 Faro, Portugal.
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19
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Trausch-Azar JS, Abed M, Orian A, Schwartz AL. Isoform-specific SCF(Fbw7) ubiquitination mediates differential regulation of PGC-1α. J Cell Physiol 2015; 230:842-52. [PMID: 25204433 DOI: 10.1002/jcp.24812] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/05/2014] [Indexed: 12/20/2022]
Abstract
The E3 ubiquitin ligase and tumor suppressor SCF(Fbw7) exists as three isoforms that govern the degradation of a host of critical cell regulators, including c-Myc, cyclin E, and PGC-1α. Peroxisome proliferator activated receptor-gamma coactivator 1α (PGC-1α) is a transcriptional coactivator with broad effects on cellular energy metabolism. Cellular PGC-1α levels are tightly controlled in a dynamic state by the balance of synthesis and rapid degradation via the ubiquitin-proteasome system. Isoform-specific functions of SCF(Fbw7) are yet to be determined. Here, we show that the E3 ubiquitin ligase, SCF(Fbw7), regulates cellular PGC-1α levels via two independent, isoform-specific, mechanisms. The cytoplasmic isoform (SCF(Fbw7β)) reduces cellular PGC-1α levels via accelerated ubiquitin-proteasome degradation. In contrast, the nuclear isoform (SCF(Fbw7α)) increases cellular PGC-1α levels and protein stability via inhibition of ubiquitin-proteasomal degradation. When nuclear Fbw7α proteins are redirected to the cytoplasm, cellular PGC-1α protein levels are reduced through accelerated ubiquitin-proteasomal degradation. We find that SCF(Fbw7β) catalyzes high molecular weight PGC-1α-ubiquitin conjugation, whereas SCF(Fbw7α) produces low molecular weight PGC-1α-ubiquitin conjugates that are not effective degradation signals. Thus, selective ubiquitination by specific Fbw7 isoforms represents a novel mechanism that tightly regulates cellular PGC-1α levels. Fbw7 isoforms mediate degradation of a host of regulatory proteins. The E3 ubiquitin ligase, Fbw7, mediates PGC-1α levels via selective isoform-specific ubiquitination. Fbw7β reduces cellular PGC-1α via ubiquitin-mediated degradation, whereas Fbw7α increases cellular PGC-1α via ubiquitin-mediated stabilization.
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Affiliation(s)
- Julie S Trausch-Azar
- Department of Pediatrics, Washington University School of Medicine, St. Louis Children's Hospital, St. Louis, Missouri
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20
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The nucleolar ubiquitin-specific protease USP36 deubiquitinates and stabilizes c-Myc. Proc Natl Acad Sci U S A 2015; 112:3734-9. [PMID: 25775507 DOI: 10.1073/pnas.1411713112] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
c-Myc protein stability and activity are tightly regulated by the ubiquitin-proteasome system. Aberrant stabilization of c-Myc contributes to many human cancers. c-Myc is ubiquitinated by SCF(Fbw7) (a SKP1-cullin-1-F-box complex that contains the F-box and WD repeat domain-containing 7, Fbw7, as the F-box protein) and several other ubiquitin ligases, whereas it is deubiquitinated and stabilized by ubiquitin-specific protease (USP) 28. The bulk of c-Myc degradation appears to occur in the nucleolus. However, whether c-Myc is regulated by deubiquitination in the nucleolus is not known. Here, we report that the nucleolar deubiquitinating enzyme USP36 is a novel c-Myc deubiquitinase. USP36 interacts with and deubiquitinates c-Myc in cells and in vitro, leading to the stabilization of c-Myc. This USP36 regulation of c-Myc occurs in the nucleolus. Interestingly, USP36 interacts with the nucleolar Fbw7γ but not the nucleoplasmic Fbw7α. However, it abolished c-Myc degradation mediated both by Fbw7γ and by Fbw7α. Consistently, knockdown of USP36 reduces the levels of c-Myc and suppresses cell proliferation. We further show that USP36 itself is a c-Myc target gene, suggesting that USP36 and c-Myc form a positive feedback regulatory loop. High expression levels of USP36 are found in a subset of human breast and lung cancers. Altogether, these results identified USP36 as a crucial and bono fide deubiquitinating enzyme controlling c-Myc's nucleolar degradation pathway.
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21
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Bielskienė K, Bagdonienė L, Mozūraitienė J, Kazbarienė B, Janulionis E. E3 ubiquitin ligases as drug targets and prognostic biomarkers in melanoma. MEDICINA-LITHUANIA 2015; 51:1-9. [PMID: 25744769 DOI: 10.1016/j.medici.2015.01.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 01/18/2015] [Indexed: 12/30/2022]
Abstract
Melanomas are highly proliferative and invasive, and are most frequently metastatic. Despite many advances in cancer treatment over the last several decades, the prognosis for patients with advanced melanoma remains poor. New treatment methods and strategies are necessary. The main hallmark of cancer is uncontrolled cellular proliferation with alterations in the expression of proteins. Ubiquitin and ubiquitin-related proteins posttranslationally modify proteins and thereby alter their functions. The ubiquitination process is involved in various physiological responses, including cell growth, cell death, and DNA damage repair. E3 ligases, the most specific enzymes of ubiquitination system, participate in the turnover of many key regulatory proteins and in the development of cancer. E3 ligases are of interest as drug targets for their ability to regulate proteins stability and functions. Compared to the general proteasome inhibitor bortezomib, which blocks the entire protein degradation, drugs that target a particular E3 ligase are expected to have better selectivity with less associated toxicity. Components of different E3 ligases complexes (FBW7, MDM2, RBX1/ROC1, RBX2/ROC2, cullins and many others) are known as oncogenes or tumor suppressors in melanomagenesis. These proteins participate in regulation of different cellular pathways and such important proteins in cancer development as p53 and Notch. In this review we summarized published data on the role of known E3 ligases in the development of melanoma and discuss the inhibitors of E3 ligases as a novel approach for the treatment of malignant melanomas.
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Affiliation(s)
| | - Lida Bagdonienė
- Department of Biochemistry and Molecular Biology, Vilnius University, Vilnius, Lithuania.
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22
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Diesch J, Hannan RD, Sanij E. Perturbations at the ribosomal genes loci are at the centre of cellular dysfunction and human disease. Cell Biosci 2014; 4:43. [PMID: 25949792 PMCID: PMC4422213 DOI: 10.1186/2045-3701-4-43] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 07/27/2014] [Indexed: 01/05/2023] Open
Abstract
Ribosomal RNA (rRNA) gene (rDNA) transcription by RNA Polymerase I (Pol I) drives cell growth and underlies nucleolar structure and function, indirectly coordinating many fundamental cellular processes. The importance of keeping rDNA transcription under tight control is reflected by the fact that deranged Pol I transcription is a feature of cancer and other human disorders. In this review, we discuss multiple aspects of rDNA function including the relationship between Pol I transcription and proliferative capacity, the role of Pol I transcription in mediating nucleolar structure and integrity, and rDNA/nucleolar interactions with the genome and their influence on heterochromatin and global genome stability. Furthermore, we discuss how perturbations in the structure of the rDNA loci might contribute to human disease, in some cases independent of effects on ribosome biogenesis.
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Affiliation(s)
- Jeannine Diesch
- Growth Control Laboratory, Research Division, Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, Victoria 3002, Australia ; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ross D Hannan
- Growth Control Laboratory, Research Division, Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, Victoria 3002, Australia ; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia ; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia ; Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia ; Division of Cancer Medicine, Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, Victoria 3002, Australia ; School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elaine Sanij
- Growth Control Laboratory, Research Division, Peter MacCallum Cancer Centre, St. Andrews Place, East Melbourne, Victoria 3002, Australia ; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia ; Department of Pathology, University of Melbourne, Parkville, Victoria 3010, Australia
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23
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Genome-wide RNAi screen identifies the Parkinson disease GWAS risk locus SREBF1 as a regulator of mitophagy. Proc Natl Acad Sci U S A 2014; 111:8494-9. [PMID: 24912190 DOI: 10.1073/pnas.1321207111] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Genetic analysis of Parkinson disease (PD) has identified several genes whose mutation causes inherited parkinsonism, as well as risk loci for sporadic PD. PTEN-induced kinase 1 (PINK1) and parkin, linked to autosomal recessive PD, act in a common genetic pathway regulating the autophagic degradation of mitochondria, termed mitophagy. We undertook a genome-wide RNAi screen as an unbiased approach to identify genes regulating the PINK1/Parkin pathway. We identified several genes that have a conserved function in promoting mitochondrial translocation of Parkin and subsequent mitophagy, most notably sterol regulatory element binding transcription factor 1 (SREBF1), F-box and WD40 domain protein 7 (FBXW7), and other components of the lipogenesis pathway. The relevance of mechanisms of autosomal recessive parkinsonism to sporadic PD has long been debated. However, with the recent identification of SREBF1 as a risk locus for sporadic PD, our findings suggest a common mechanistic link between autosomal recessive and sporadic PD, and underscore the importance of mitochondrial homeostasis.
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24
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A CULLINary ride across the secretory pathway: more than just secretion. Trends Cell Biol 2014; 24:389-99. [PMID: 24630736 DOI: 10.1016/j.tcb.2014.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/07/2014] [Accepted: 02/10/2014] [Indexed: 12/14/2022]
Abstract
Mulitmeric cullin-RING ubiquitin ligases (CRLs) represent the largest class of ubiquitin ligases in eukaryotes. However, most CRL ubiquitylation pathways remain uncharacterized. CRLs control a myriad of functions by catalyzing mono- or poly-ubiquitylation of target proteins. Recently, novel CRLs have been identified along the secretory pathway where they modify substrates involved in diverse cellular processes such as vesicle coat assembly and cell cycle progression. This review discusses our current understanding of CRL ubiquitylation within the secretory pathway, with special emphasis on the emerging role of the Golgi as a ubiquitylation platform. CRLs are also implicated in endosome function, where their specific roles are less well understood.
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25
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Quin JE, Devlin JR, Cameron D, Hannan KM, Pearson RB, Hannan RD. Targeting the nucleolus for cancer intervention. Biochim Biophys Acta Mol Basis Dis 2014; 1842:802-16. [PMID: 24389329 DOI: 10.1016/j.bbadis.2013.12.009] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/17/2013] [Indexed: 12/17/2022]
Abstract
The contribution of the nucleolus to cancer is well established with respect to its traditional role in facilitating ribosome biogenesis and proliferative capacity. More contemporary studies however, infer that nucleoli contribute a much broader role in malignant transformation. Specifically, extra-ribosomal functions of the nucleolus position it as a central integrator of cellular proliferation and stress signaling, and are emerging as important mechanisms for modulating how oncogenes and tumor suppressors operate in normal and malignant cells. The dependence of certain tumor cells to co-opt nucleolar processes to maintain their cancer phenotypes has now clearly been demonstrated by the application of small molecule inhibitors of RNA Polymerase I to block ribosomal DNA transcription and disrupt nucleolar function (Bywater et al., 2012 [1]). These drugs, which selectively kill tumor cells in vivo while sparing normal cells, have now progressed to clinical trials. It is likely that we have only just begun to scratch the surface of the potential of the nucleolus as a new target for cancer therapy, with "suppression of nucleolar stress" representing an emerging "hallmark" of cancer. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.
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Affiliation(s)
- Jaclyn E Quin
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Jennifer R Devlin
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Donald Cameron
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Kate M Hannan
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Richard B Pearson
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Ross D Hannan
- Oncogenic Signalling and Growth Control Program, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, The University of Melbourne, Parkville, Victoria, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia; School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia.
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26
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Lu A, Pfeffer SR. Golgi-associated RhoBTB3 targets cyclin E for ubiquitylation and promotes cell cycle progression. ACTA ACUST UNITED AC 2013; 203:233-50. [PMID: 24145166 PMCID: PMC3812982 DOI: 10.1083/jcb.201305158] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Golgi protein RhoBTB3 in complex with CUL3 and RBX1 promotes Cyclin E ubiquitylation to allow its turnover during S phase and progression through the cell cycle. Cyclin E regulates the cell cycle transition from G1 to S phase and is degraded before entry into G2 phase. Here we show that RhoBTB3, a Golgi-associated, Rho-related ATPase, regulates the S/G2 transition of the cell cycle by targeting Cyclin E for ubiquitylation. Depletion of RhoBTB3 arrested cells in S phase, triggered Golgi fragmentation, and elevated Cyclin E levels. On the Golgi, RhoBTB3 bound Cyclin E as part of a Cullin3 (CUL3)-dependent RING–E3 ubiquitin ligase complex comprised of RhoBTB3, CUL3, and RBX1. Golgi association of this complex was required for its ability to catalyze Cyclin E ubiquitylation and allow normal cell cycle progression. These experiments reveal a novel role for a Ras superfamily member in catalyzing Cyclin E turnover during S phase, as well as an unexpected, essential role for the Golgi as a ubiquitylation platform for cell cycle control.
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Affiliation(s)
- Albert Lu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
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27
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Ekholm-Reed S, Goldberg MS, Schlossmacher MG, Reed SI. Parkin-dependent degradation of the F-box protein Fbw7β promotes neuronal survival in response to oxidative stress by stabilizing Mcl-1. Mol Cell Biol 2013; 33:3627-43. [PMID: 23858059 PMCID: PMC3753862 DOI: 10.1128/mcb.00535-13] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/28/2013] [Indexed: 11/20/2022] Open
Abstract
Parkinson's disease (PD) is characterized by progressive loss of midbrain dopaminergic neurons resulting in motor dysfunction. While most PD is sporadic in nature, a significant subset can be linked to either dominant or recessive germ line mutations. PARK2, encoding the ubiquitin ligase parkin, is the most frequently mutated gene in hereditary Parkinson's disease. Here, we present evidence for a neuronal ubiquitin ligase cascade involving parkin and the multisubunit ubiquitin ligase SCF(Fbw7β). Specifically, parkin targets the SCF substrate adapter Fbw7β for proteasomal degradation. Furthermore, we show that the physiological role of parkin-mediated regulation of Fbw7β levels is the stabilization of the mitochondrial prosurvival factor Mcl-1, an SCF(Fbw7β) target in neurons. We show that neurons depleted of parkin become acutely sensitive to oxidative stress due to an inability to maintain adequate levels of Mcl-1. Therefore, loss of parkin function through biallelic mutation of PARK2 may lead to death of dopaminergic neurons through unregulated SCF(Fbw7β)-mediated ubiquitylation-dependent proteolysis of Mcl-1.
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Affiliation(s)
- Susanna Ekholm-Reed
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Matthew S. Goldberg
- Department of Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Michael G. Schlossmacher
- Division of Neuroscience, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Steven I. Reed
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA
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28
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Wang R, Wang Y, Liu N, Ren C, Jiang C, Zhang K, Yu S, Chen Y, Tang H, Deng Q, Fu C, Wang Y, Li R, Liu M, Pan W, Wang P. FBW7 regulates endothelial functions by targeting KLF2 for ubiquitination and degradation. Cell Res 2013; 23:803-19. [PMID: 23507969 DOI: 10.1038/cr.2013.42] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
F-box and WD repeat domain-containing 7 (FBW7), the substrate-binding subunit of E3 ubiquitin ligase SCF(FBW7) (a complex of SKP1, cullin-1 and FBW7), plays important roles in various physiological and pathological processes. Although FBW7 is required for vascular development, its function in the endothelium remains to be investigated. In this study, we show that FBW7 is an important regulator of endothelial functions, including angiogenesis, leukocyte adhesion and the endothelial barrier integrity. Using RNA interference, we found that the depletion of FBW7 markedly impairs angiogenesis in vitro and in vivo. We identified the zinc finger transcription factor Krüppel-like factor 2 (KLF2) as a physiological target of FBW7 in endothelial cells. Knockdown of FBW7 expression resulted in the accumulation of endogenous KLF2 protein in endothelial cells. FBW7-mediated KLF2 destruction was shown to depend on the phosphorylation of KLF2 via glycogen synthase kinase-3 (GSK3) at two conserved phosphodegrons. Mutating these phosphodegron motifs abolished the FBW7-mediated degradation and ubiquitination of KLF2. The siRNA-mediated knockdown of FBW7 showed that KLF2 is an essential target of FBW7 in the regulation of endothelial functions. Moreover, FBW7-mediated KLF2 degradation was shown to be critical for angiogenesis in teratomas and in zebrafish development. Taken together, our study suggests a role for FBW7 in the processes of endothelial cell migration, angiogenesis, inflammation and barrier integrity, and provides novel insights into the regulation of KLF2 stability in vivo.
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Affiliation(s)
- Rui Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
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