1
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Khedri A, Guo S, Ramar V, Hudson B, Liu M. FOSL1's Oncogene Roles in Glioma/Glioma Stem Cells and Tumorigenesis: A Comprehensive Review. Int J Mol Sci 2024; 25:5362. [PMID: 38791400 PMCID: PMC11121637 DOI: 10.3390/ijms25105362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/10/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024] Open
Abstract
This review specifically examines the important function of the oncoprotein FOSL1 in the dimeric AP-1 transcription factor, which consists of FOS-related components. FOSL1 is identified as a crucial controller of invasion and metastatic dissemination, making it a potential target for therapeutic treatment in cancer patients. The review offers a thorough examination of the regulatory systems that govern the influence exerted on FOSL1. These include a range of changes that occur throughout the process of transcription and after the translation of proteins. We have discovered that several non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play a significant role in regulating FOSL1 expression by directly interacting with its mRNA transcripts. Moreover, an investigation into the functional aspects of FOSL1 reveals its involvement in apoptosis, proliferation, and migration. This work involves a comprehensive analysis of the complex signaling pathways that support these diverse activities. Furthermore, particular importance is given to the function of FOSL1 in coordinating the activation of several cytokines, such as TGF-beta, and the commencement of IL-6 and VEGF production in tumor-associated macrophages (TAMs) that migrate into the tumor microenvironment. There is a specific emphasis on evaluating the predictive consequences linked to FOSL1. Insights are now emerging on the developing roles of FOSL1 in relation to the processes that drive resistance and reliance on specific treatment methods. Targeting FOSL1 has a strong inhibitory effect on the formation and spread of specific types of cancers. Despite extensive endeavors, no drugs targeting AP-1 or FOSL1 for cancer treatment have been approved for clinical use. Hence, it is imperative to implement innovative approaches and conduct additional verifications.
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Affiliation(s)
- Azam Khedri
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Shanchun Guo
- RCMI Cancer Research Center, Department of Chemistry, New Orleans, LA 70125, USA
| | - Vanajothi Ramar
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - BreAnna Hudson
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Mingli Liu
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
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2
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Song D, Lian Y, Zhang L. The potential of activator protein 1 (AP-1) in cancer targeted therapy. Front Immunol 2023; 14:1224892. [PMID: 37483616 PMCID: PMC10361657 DOI: 10.3389/fimmu.2023.1224892] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
Activator protein-1 (AP-1) is a transcription factor that consists of a diverse group of members including Jun, Fos, Maf, and ATF. AP-1 involves a number of processes such as proliferation, migration, and invasion in cells. Dysfunctional AP-1 activity is associated with cancer initiation, development, invasion, migration and drug resistance. Therefore, AP-1 is a potential target for cancer targeted therapy. Currently, some small molecule inhibitors targeting AP-1 have been developed and tested, showing some anticancer effects. However, AP-1 is complex and diverse in its structure and function, and different dimers may play different roles in different type of cancers. Therefore, more research is needed to reveal the specific mechanisms of AP-1 in cancer, and how to select appropriate inhibitors and treatment strategies. Ultimately, this review summarizes the potential of combination therapy for cancer.
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Affiliation(s)
- Dandan Song
- Clinical Medical Research Center for Women and Children Diseases, Key Laboratory of Birth Defect Prevention and Genetic Medicine of Shandong Health Commission, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, China
| | - Yan Lian
- Department of Obstetrics, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, China
| | - Lin Zhang
- Clinical Medical Research Center for Women and Children Diseases, Key Laboratory of Birth Defect Prevention and Genetic Medicine of Shandong Health Commission, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, China
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3
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Makaros Y, Raiff A, Timms RT, Wagh AR, Gueta MI, Bekturova A, Guez-Haddad J, Brodsky S, Opatowsky Y, Glickman MH, Elledge SJ, Koren I. Ubiquitin-independent proteasomal degradation driven by C-degron pathways. Mol Cell 2023; 83:1921-1935.e7. [PMID: 37201526 PMCID: PMC10237035 DOI: 10.1016/j.molcel.2023.04.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 03/13/2023] [Accepted: 04/25/2023] [Indexed: 05/20/2023]
Abstract
Although most eukaryotic proteins are targeted for proteasomal degradation by ubiquitination, a subset have been demonstrated to undergo ubiquitin-independent proteasomal degradation (UbInPD). However, little is known about the molecular mechanisms driving UbInPD and the degrons involved. Utilizing the GPS-peptidome approach, a systematic method for degron discovery, we found thousands of sequences that promote UbInPD; thus, UbInPD is more prevalent than currently appreciated. Furthermore, mutagenesis experiments revealed specific C-terminal degrons required for UbInPD. Stability profiling of a genome-wide collection of human open reading frames identified 69 full-length proteins subject to UbInPD. These included REC8 and CDCA4, proteins which control proliferation and survival, as well as mislocalized secretory proteins, suggesting that UbInPD performs both regulatory and protein quality control functions. In the context of full-length proteins, C termini also play a role in promoting UbInPD. Finally, we found that Ubiquilin family proteins mediate the proteasomal targeting of a subset of UbInPD substrates.
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Affiliation(s)
- Yaara Makaros
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Anat Raiff
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Richard T Timms
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, Cambridgeshire CB2 0AW, UK
| | - Ajay R Wagh
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Mor Israel Gueta
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Aizat Bekturova
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Julia Guez-Haddad
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Sagie Brodsky
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yarden Opatowsky
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Michael H Glickman
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3525433, Israel
| | - Stephen J Elledge
- Department of Genetics, Harvard Medical School, Division of Genetics, Brigham and Women's Hospital, Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Itay Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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4
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Zhao W, Yu D, Zhai Y, Sun SY. ALK inhibitors downregulate the expression of death receptor 4 in ALK-mutant lung cancer cells via facilitating Fra-1 and c-Jun degradation and subsequent AP-1 suppression. Neoplasia 2023; 42:100908. [PMID: 37192591 DOI: 10.1016/j.neo.2023.100908] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/18/2023]
Abstract
The successful treatment of patients with advanced non-small cell lung cancer (NSCLC) harboring chromosomal rearrangements of anaplastic lymphoma kinase (ALK) with ALK tyrosine kinase inhibitors (ALK-TKIs) represents a promising targeted therapy. As a result, various ALK-TKIs have been rapidly developed, some of which are approved while some are being tested in clinical trials. Death receptor 4 (DR4; also called TNFRSF10A or TRAIL-R1) is a cell surface protein, which functions as a pro-apoptotic protein that transduces TRAIL death signaling to trigger apoptosis. DR4 expression is positively regulated by MEK/ERK signaling and thus can be downregulated by MEK/ERK inhibition. This study thus focused on determining the effects of AKL-TKIs on DR4 expression and the underlying mechanisms. Three tested ALK-TKIs including APG-2449, brigatinib and alectinib effectively and preferentially inhibited Akt/mTOR as well as MEK/ERK signaling and decreased cell survival in ALK-mutant (ALKm) NSCLC cells with induction of apoptosis. This was also true for DR4 downregulation, which occurred even at 2 h post treatment. These ALK-TKIs did not affect DR4 protein stability, rather decreased DR4 mRNA expression. In parallel, they promoted degradation and reduced the levels of Fra-1 and c-Jun, two critical components of AP-1, and suppressed AP-1 (Fra-1/c-Jun)-dependent transcription/expression of DR4. Hence, it appears that ALK-TKIs downregulate DR4 expression in ALKm NSCLC cells via facilitating Fra-1 and c-Jun degradation and subsequent AP-1 suppression. Our findings thus warrant further investigation of the biological significance of DR4 downregulation in ALK-targeted cancer therapy.
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Affiliation(s)
- Wen Zhao
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA
| | - Danlei Yu
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA
| | - Yifan Zhai
- Ascentage Pharma (Suzhou) Co., Ltd, Suzhou, Jiangsu, China
| | - Shi-Yong Sun
- Department of Hematology and Medical Oncology, Emory University School of Medicine and Winship Cancer Institute, Atlanta, GA, USA.
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5
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He YY, Zhou HF, Chen L, Wang YT, Xie WL, Xu ZZ, Xiong Y, Feng YQ, Liu GY, Li X, Liu J, Wu QP. The Fra-1: Novel role in regulating extensive immune cell states and affecting inflammatory diseases. Front Immunol 2022; 13:954744. [PMID: 36032067 PMCID: PMC9404335 DOI: 10.3389/fimmu.2022.954744] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Fra-1(Fos-related antigen1), a member of transcription factor activator protein (AP-1), plays an important role in cell proliferation, apoptosis, differentiation, inflammation, oncogenesis and tumor metastasis. Accumulating evidence suggest that the malignancy and invasive ability of tumors can be significantly changed by directly targeting Fra-1. Besides, the effects of Fra-1 are gradually revealed in immune and inflammatory settings, such as arthritis, pneumonia, psoriasis and cardiovascular disease. These regulatory mechanisms that orchestrate immune and non-immune cells underlie Fra-1 as a potential therapeutic target for a variety of human diseases. In this review, we focus on the current knowledge of Fra-1 in immune system, highlighting its unique importance in regulating tissue homeostasis. In addition, we also discuss the possible critical intervention strategy in diseases, which also outline future research and development avenues.
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Zeng F, He J, Jin X, Liao Q, Chen Z, Peng H, Zhou Y. FRA-1: A key factor regulating signal transduction of tumor cells and a potential target molecule for tumor therapy. Biomed Pharmacother 2022; 150:113037. [PMID: 35658206 DOI: 10.1016/j.biopha.2022.113037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 11/19/2022] Open
Abstract
Fos-related antigen-1 (FRA-1) is a member of activator protein-1 (AP-1) transcription factor superfamily, and FRA-1 is highly expressed in colon cancer, breast cancer, gastric cancer, lung cancer, bladder cancer, and other tumors. The expression level of FRA-1 is closely related to the processes of tumor cell proliferation, apoptosis, transformation, migration, and invasion, which is a potential therapeutic target and prognostic factor for many tumors. Clarifying the detailed mechanism of action of FRA-1 could provide the theoretical basis for tumor diagnosis, treatment, and prognosis, and is of great significance for the study of tumor etiology and pathogenesis. In this paper, the expression levels and influencing factors of FRA-1 in various tumor tissues and cells are summarized, as well as the effect of FRA-1 expression level on the biological behavior of tumor cells and the signal transduction mechanism. At the same time, the signal transduction mechanism of FRA-1 in inflammation was expounded. In addition, the related metabolites, drugs and non-coding RNA that affect the expression and function of FRA-1 were summarized. Finally, it illustrates that FRA-1 may be taken as a key factor for tumor prognosis and a potential therapeutic target. This review provides a theoretical basis for the systematic understanding of the relationship between FRA-1 and tumors, its function, and possible mechanism.
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Affiliation(s)
- Feng Zeng
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China
| | - Junyu He
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China
| | - Xi Jin
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China
| | - Qianjin Liao
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China
| | - Zhifang Chen
- Department of Gynecology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China
| | - Honghua Peng
- Department of The Oncology, Third Xianya Hospital, Xiangya School of Medicine, Central South University, 138 Tongzipo Road, Changsha, Hunan 410013, China.
| | - Yanhong Zhou
- NHC Key Laboratory of Carcinogenesis and Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China.
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7
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Casalino L, Talotta F, Cimmino A, Verde P. The Fra-1/AP-1 Oncoprotein: From the "Undruggable" Transcription Factor to Therapeutic Targeting. Cancers (Basel) 2022; 14:cancers14061480. [PMID: 35326630 PMCID: PMC8946526 DOI: 10.3390/cancers14061480] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/04/2022] [Accepted: 03/10/2022] [Indexed: 02/06/2023] Open
Abstract
The genetic and epigenetic changes affecting transcription factors, coactivators, and chromatin modifiers are key determinants of the hallmarks of cancer. The acquired dependence on oncogenic transcriptional regulators, representing a major determinant of cancer cell vulnerability, points to transcription factors as ideal therapeutic targets. However, given the unavailability of catalytic activities or binding pockets for small-molecule inhibitors, transcription factors are generally regarded as undruggable proteins. Among components of the AP-1 complex, the FOS-family transcription factor Fra-1, encoded by FOSL1, has emerged as a prominent therapeutic target. Fra-1 is overexpressed in most solid tumors, in response to the BRAF-MAPK, Wnt-beta-catenin, Hippo-YAP, IL-6-Stat3, and other major oncogenic pathways. In vitro functional analyses, validated in onco-mouse models and corroborated by prognostic correlations, show that Fra-1-containing dimers control tumor growth and disease progression. Fra-1 participates in key mechanisms of cancer cell invasion, Epithelial-to-Mesenchymal Transition, and metastatic spreading, by driving the expression of EMT-inducing transcription factors, cytokines, and microRNAs. Here we survey various strategies aimed at inhibiting tumor growth, metastatic dissemination, and drug resistance by interfering with Fra-1 expression, stability, and transcriptional activity. We summarize several tools aimed at the design and tumor-specific delivery of Fra-1/AP-1-specific drugs. Along with RNA-based therapeutics targeting the FOSL1 gene, its mRNA, or cognate regulatory circRNAs, we will examine the exploitation of blocking peptides, small molecule inhibitors, and innovative Fra-1 protein degraders. We also consider the possible caveats concerning Fra-1 inhibition in specific therapeutic contexts. Finally, we discuss a recent suicide gene therapy-based approach, aimed at selectively killing the Fra-1-overexpressing neoplastic cells.
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Affiliation(s)
- Laura Casalino
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”, Consiglio Nazionale dele Ricerche (CNR), 80131 Naples, Italy;
- Correspondence: (L.C.); (P.V.)
| | | | - Amelia Cimmino
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”, Consiglio Nazionale dele Ricerche (CNR), 80131 Naples, Italy;
| | - Pasquale Verde
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”, Consiglio Nazionale dele Ricerche (CNR), 80131 Naples, Italy;
- Correspondence: (L.C.); (P.V.)
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8
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Jab1 promotes gastric cancer tumorigenesis via non-ubiquitin proteasomal degradation of p14ARF. Gastric Cancer 2020; 23:1003-1017. [PMID: 32458234 DOI: 10.1007/s10120-020-01087-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/16/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Jab1 has been reported to regulate various proteins in signal transduction pathways and be implicated in carcinogenesis or tumor progression. However, the precise role and molecular mechanism of Jab1 in gastric tumorigenesis have not yet been fully elucidated. METHODS Jab1 staining in gastric cancer tissues and paired non-cancerous tissues was measured using tissue microarray (TMA) technology. The impact of Jab1 on tumor growth in vivo was analyzed using xenotransplantation experiments in Balb/c mice. The expression of Jab1 and p14ARF in gastric cancer cells was analyzed by western blot and confocal immunofluorescence. CCK-8 and cell cycle experiment were used to evaluate the cell proliferation. Ubiquitination assay was performed to validate whether ubiquitination is involved in Jab1-mediated p14ARF degradation. RESULTS The expression level of protein p14ARF was inversely correlated with the protein level of Jab1. Then, we investigated the mechanism that how Jab1 induced p14ARF depletion. Mechanistic studies showed that Jab1 induced ubiquitin-independent proteasomal p14ARF degradation in gastric cancer cells. Our data demonstrated that Jab1 protein was a vital upstream negative modulation factor of p14ARF, and Jab1 could promote cell proliferation and tumor growth via inhibiting the expression of p14ARF in vivo and in vitro. Moreover, silencing Jab1 protein expression declined tumor growth and further increased the apoptosis rate of gastric cancer cells. In further studies of gastric cancer specimens, we found the increased level of Jab1 protein shortened the overall survival. CONCLUSION Jab1 is upstream of p14ARF and promote gastric cancer cell proliferation in vitro and in vivo. Furthermore, Jab1 decreased the expression of p14ARF though ubiquitination independent proteasomal degradation. Therefore, the connection of Jab1 and p14ARF may provide new methods for the treatment of gastric cancer.
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9
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Yun SI, Hong HK, Yeo SY, Kim SH, Cho YB, Kim KK. Ubiquitin-Specific Protease 21 Promotes Colorectal Cancer Metastasis by Acting as a Fra-1 Deubiquitinase. Cancers (Basel) 2020; 12:cancers12010207. [PMID: 31947604 PMCID: PMC7017141 DOI: 10.3390/cancers12010207] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/02/2020] [Accepted: 01/04/2020] [Indexed: 12/22/2022] Open
Abstract
Fos-related-antigen-1 (Fra-1), a member of the activator protein-1 (AP-1) transcription factor superfamily, has an essential role in cancer progress and metastasis and Fra-1 is considered a therapeutic target in metastatic cancer including metastatic colorectal cancer (mCRC). However, its regulation at protein level has not yet been clearly elucidated. We found that ubiquitin-specific protease 21 (USP21) increases Fra-1 stability by deubiquitinating Fra-1 and enhances the expression of Fra-1 target genes in colon cancer cells. We also showed that USP21 controlled Fra-1-dependent migration and invasion activities. The oncogenic property of USP21 was confirmed by a significant reduction in liver metastasis when USP21-knockdown cancer cells were injected intrasplenically into mice. Consistently, clinicopathological analysis of colorectal cancer patients revealed a correlation of USP21 expression with high-grade carcinoma and life span. These results demonstrate that USP21 enhances Fra-1 stability and AP-1 target gene expression by deubiquitinating Fra-1. Therefore, USP21 is considered an attractive therapeutic target in mCRC with high Fra-1 expression.
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Affiliation(s)
- Sun-Il Yun
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon 16419, Korea;
| | - Hye Kyung Hong
- Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06531, Korea;
| | - So-Young Yeo
- Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06531, Korea;
| | - Seok-Hyung Kim
- Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06531, Korea;
- Samsung Medical Center, Department of Health Science and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University School of Medicine, Seoul 06531, Korea
- Correspondence: (S.-H.K.); (Y.B.C.); (K.K.K.); Tel.: +82-02-3410-2898 (S.-H.K.); +82-02-3410-0217 (Y.B.C.); +82-031-299-6136 (K.K.K.)
| | - Yong Beom Cho
- Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06531, Korea;
- Samsung Medical Center, Department of Health Science and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University School of Medicine, Seoul 06531, Korea
- Correspondence: (S.-H.K.); (Y.B.C.); (K.K.K.); Tel.: +82-02-3410-2898 (S.-H.K.); +82-02-3410-0217 (Y.B.C.); +82-031-299-6136 (K.K.K.)
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon 16419, Korea;
- Samsung Medical Center, Department of Health Science and Technology, Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University School of Medicine, Seoul 06531, Korea
- Correspondence: (S.-H.K.); (Y.B.C.); (K.K.K.); Tel.: +82-02-3410-2898 (S.-H.K.); +82-02-3410-0217 (Y.B.C.); +82-031-299-6136 (K.K.K.)
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10
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Expression and function of FRA1 protein in tumors. Mol Biol Rep 2019; 47:737-752. [PMID: 31612408 DOI: 10.1007/s11033-019-05123-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 10/09/2019] [Indexed: 12/24/2022]
Abstract
AP-1 is a dimeric complex that is composed of JUN, FOS, ATF and MAF protein families. FOS-related antigen 1 (FRA1) which encoded by FOSL1 gene, belongs to the FOS protein family, and mainly forms an AP-1 complex with the protein of the JUN family to exert an effect. Regulation of FRA1 occurs at levels of transcription and post-translational modification, and phosphorylation is the major post-translational modification. FRA1 is mainly regulated by the mitogen-activated protein kinases signaling pathway and is degraded by ubiquitin-independent proteasomes. FRA1 can affect biological functions, such as tumor proliferation, differentiation, invasion and apoptosis. Studies have demonstrated that FRA1 is abnormally expressed in many tumors and plays a relevant role, but the specific condition varies from the target organs. FRA1 is overexpressed in breast cancer, lung cancer, colorectal cancer, prostate cancer, nasopharyngeal cancer, thyroid cancer and other tumors. However, the expression of FRA1 is decreased in cervical cancer, and the expression of FRA1 in ovarian cancer and oral squamous cell carcinoma is still controversial. In this review, we present a detailed description of the regulatory factors and functions of FRA1, also, the expression of FRA1 in various tumors and its function in relative tumor.
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11
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Chowdhury A, Caroni P. Time units for learning involving maintenance of system-wide cFos expression in neuronal assemblies. Nat Commun 2018; 9:4122. [PMID: 30297716 PMCID: PMC6175937 DOI: 10.1038/s41467-018-06516-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 09/10/2018] [Indexed: 02/01/2023] Open
Abstract
Repeated experiences may be integrated in succession during a learning process, or they may be combined as a whole within dedicated time windows to possibly promote quality control. Here we show that in Pavlovian, incremental and incidental learning, related information acquired within time windows of 5 h is combined to determine what mice learn. Trials required for learning had to occur within 5 h, when learning-related shared cues could produce association and interference. Upon acquisition, cFos expression was elevated during 5 h throughout specific system-wide neuronal assemblies. Time window function depended on network activity and cFos expression. Local cFos activity was required for distant assembly recruitment through network activity and distant BDNF. Activation of learning-related cFos assemblies was sufficient and necessary for time window function. Therefore, learning processes consist of dedicated 5 h time windows (time units for learning), involving maintenance of system-wide neuronal assemblies through network activity and cFos expression. Learning often involves multiple exposures and trials, but it is not known whether those are treated independently, or integrated during dedicated time windows. Here, Chowdhury and Caroni show mice learn new associations during 5 h time windows, where related experiences are integrated in a process requiring coordinated cFos-activated neuronal assemblies.
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Affiliation(s)
- Ananya Chowdhury
- Friedrich Miescher Institut, Maulbeerstrasse 66, CH-4058, Basel, Switzerland.,Depts. of Neurobiology, Psychology, Psychiatry and Biobehavioral Sciences; Integrative Center for Learning and Memory; Brain Research Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Pico Caroni
- Friedrich Miescher Institut, Maulbeerstrasse 66, CH-4058, Basel, Switzerland.
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12
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Njomen E, Osmulski PA, Jones CL, Gaczynska M, Tepe JJ. Small Molecule Modulation of Proteasome Assembly. Biochemistry 2018; 57:4214-4224. [PMID: 29897236 DOI: 10.1021/acs.biochem.8b00579] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The 20S proteasome is the main protease that directly targets intrinsically disordered proteins (IDPs) for proteolytic degradation. Mutations, oxidative stress, or aging can induce the buildup of IDPs resulting in incorrect signaling or aggregation, associated with the pathogenesis of many cancers and neurodegenerative diseases. Drugs that facilitate 20S-mediated proteolysis therefore have many potential therapeutic applications. We report herein the modulation of proteasome assembly by the small molecule TCH-165, resulting in an increase in 20S levels. The increase in the level of free 20S corresponds to enhanced proteolysis of IDPs, including α-synuclein, tau, ornithine decarboxylase, and c-Fos, but not structured proteins. Clearance of ubiquitinated protein was largely maintained by single capped proteasome complexes (19S-20S), but accumulation occurs when all 19S capped proteasome complexes are depleted. This study illustrates the first example of a small molecule capable of targeting disordered proteins for degradation by regulating the dynamic equilibrium between different proteasome complexes.
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Affiliation(s)
- Evert Njomen
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Pawel A Osmulski
- Institute of Biotechnology , University of Texas Health Science Center at San Antonio , 15355 Lambda Drive , San Antonio , Texas 78245 , United States
| | - Corey L Jones
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Maria Gaczynska
- Institute of Biotechnology , University of Texas Health Science Center at San Antonio , 15355 Lambda Drive , San Antonio , Texas 78245 , United States
| | - Jetze J Tepe
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
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Endo S, Fujita M, Yamada S, Imadome K, Nakayama F, Isozaki T, Yasuda T, Imai T, Matsubara H. Fra‑1 enhances the radioresistance of colon cancer cells to X‑ray or C‑ion radiation. Oncol Rep 2018; 39:1112-1118. [PMID: 29399696 PMCID: PMC5802033 DOI: 10.3892/or.2018.6223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/12/2018] [Indexed: 12/14/2022] Open
Abstract
Fos-related antigen 1 (Fra-1) has roles in a variety of cell functions, including cell proliferation, differentiation, transformation, and invasiveness, and it is upregulated in various cancers. We investigated the role of Fra-1 in cellular radioresistance using cells of two human colorectal cancer cell lines, SW620 and SW480. We found that SW620 cells are more sensitive than SW480 cells at doses greater than 6 Gy for X-ray or 3 Gy for carbon-ion (C-ion) radiation. Fra-1 expression tended to be decreased by the radiation in a dose-dependent manner in both cell lines; of note, a greater reduction of Fra-1 expression was observed in SW620 cells, especially at 6 Gy of X-ray or 3 Gy of C-ion irradiation, than in SW480 cells, indicating a possible association between Fra-1 downregulation and cellular radiosensitivity. Knockdown of Fra-1 in SW480 cells significantly increased the radiosensitivity to X-ray or C-ion radiation. On the other hand, overexpression of Fra-1 in SW620 cells significantly enhanced the radioresistance to C-ion radiation, suggesting a role of Fra-1 in radioresistance. Furthermore, we found that downregulation of Fra-1 protein in irradiated SW620 cells was regulated via protein degradation through a proteasome-dependent pathway. Overall, our results indicate a role of Fra-1 in radioresistance to both X-ray and C-ion radiation for colorectal cancer cell lines.
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Affiliation(s)
- Satoshi Endo
- Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba 260‑8670, Japan
| | - Mayumi Fujita
- Department of Basic Medical Sciences for Radiation Damage, National Institutes for Quantum and Radiological Science and Technology, Japan
| | - Shigeru Yamada
- Hospital of The National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Japan
| | - Kaori Imadome
- Department of Basic Medical Sciences for Radiation Damage, National Institutes for Quantum and Radiological Science and Technology, Japan
| | - Fumiaki Nakayama
- Department of Basic Medical Sciences for Radiation Damage, National Institutes for Quantum and Radiological Science and Technology, Japan
| | - Tetsuro Isozaki
- Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba 260‑8670, Japan
| | - Takeshi Yasuda
- Department of Basic Medical Sciences for Radiation Damage, National Institutes for Quantum and Radiological Science and Technology, Japan
| | - Takashi Imai
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Japan
| | - Hisahiro Matsubara
- Department of Frontier Surgery, Chiba University Graduate School of Medicine, Chiba 260‑8670, Japan
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Hao Y, Zhu L, Yan L, Liu J, Liu D, Gao N, Tan M, Gao S, Lin B. c-Fos mediates α1, 2-fucosyltransferase 1 and Lewis y expression in response to TGF-β1 in ovarian cancer. Oncol Rep 2017; 38:3355-3366. [PMID: 29130097 PMCID: PMC5783580 DOI: 10.3892/or.2017.6052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 10/06/2017] [Indexed: 12/16/2022] Open
Abstract
FUT1 is a key rate-limiting enzyme in the synthesis of Lewis y, a membrane-associated carbohydrate antigen. The aberrant upregulation of FUT1 and Lewis y antigen is related to proliferation, invasion and prognosis in malignant epithelial tumors. A c-Fos/activator protein-1 (AP-1) binding site was found in the FUT1 promoter. However, the mechanisms of transcriptional regulation of FUT1 remain poorly understood. TGF-β1 is positively correlated to Lewis y. In the present study, we investigated the molecular mechanism of FUT1 gene expression in response to TGF-β1. We demonstrated that c-Fos was highly expressed in 77.50% of ovarian epithelial carcinoma cases and was significantly correlated with Lewis y. Using luciferase activity and chromatin immunoprecipitation (ChIP) assay, we further revealed that c-Fos interacted with the FUT1 promoter in ovarian cancer cells and transcriptional capacity of the heterodimer formed by c-Fos and c-Jun was stronger than that of the c-Fos or c-Jun homodimers. Then, we demonstrated that TGF-β1 induced dose-dependent c-Fos expression, which was involved in TGF-β1-induced ovarian cancer cell proliferation. In addition, inhibition of MAPK activation or TGF-β1 receptor by pharmacological agents prevented TGF-β1-induced c-Fos and Lewis y expression. Silencing of c-Fos prevented TGF-β1-induced Lewis y expression. Collectively, the results of these studies demonstrated that TGF-β1 regulated FUT1 and Lewis y expression by activating the MAPK/c-Fos pathway.
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Affiliation(s)
- Yingying Hao
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Liancheng Zhu
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Limei Yan
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Juanjuan Liu
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Dawo Liu
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Na Gao
- Department of Obstetrics and Gynecology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Mingzi Tan
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Song Gao
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Bei Lin
- Department of Obstetrics and Gynecology, Shengjing Hospital Affiliated to China Medical University, Shenyang, Liaoning 110004, P.R. China
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15
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Shikama Y, Cao M, Ono T, Feng X, Noji H, Kimura H, Ogawa K, Suzuki Y, Ikeda K, Takeishi Y, Kimura J. Reduction of c-Fos via Overexpression of miR-34a Results in Enhancement of TNF- Production by LPS in Neutrophils from Myelodysplastic Syndrome Patients. PLoS One 2016; 11:e0158527. [PMID: 27513856 PMCID: PMC4981319 DOI: 10.1371/journal.pone.0158527] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/16/2016] [Indexed: 02/07/2023] Open
Abstract
Although increased TNF-α has been considered to cause ineffective hematopoiesis in myelodysplastic syndromes (MDS), the mechanisms of TNF-α elevation are not known. We recently found that c-Fos mRNA stabilization under translation-inhibiting stimuli was impaired in MDS-derived neutrophilic granulocytes. In the current study, we identified overexpression of c-Fos-targeting miR-34a and miR-155 as the cause of impairment. Expression levels of miR-34a but not miR-155 inversely correlated with ratios of c-Fos-positive cells in MDS-derived CD16+ neutrophils (r = -0.618, P<0.05), which were analyzed by flow cytometry. Among the seventeen patients, c-Fos was detectable in less than 60% of CD16+ cells in eight patients (Group A), while five (Group B) expressed c-Fos in more than 80% of CD16+ cells, which was consistent with the controls (88.6 ± 7.8%). Group A-derived granulocytes secreted more TNF-α in response to 1 μM LPS for 3 hours (735.4 ± 237.5 pg/mL) than Group B (143.5 ± 65.7 pg/mL, P<0.05) and healthy controls (150.8 ± 91.5 pg/mL, P<0.05). Knockdown of c-Fos in neutrophil-like differentiated HL60 increased the binding of NF-κB p65 to the promoter region of TNF-α DNA. Thus, c-Fos reduction via overexpression of miR-34a contributes to TNF-α overproduction under inflammatory stimuli in MDS.
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Affiliation(s)
- Yayoi Shikama
- Department of Pharmacology, Fukushima Medical University, Fukushima, Japan
- * E-mail:
| | - Meiwan Cao
- Department of Pharmacology, Fukushima Medical University, Fukushima, Japan
| | - Tomoyuki Ono
- Department of Pharmacology, Fukushima Medical University, Fukushima, Japan
| | - Xiaomin Feng
- Department of Pharmacology, Fukushima Medical University, Fukushima, Japan
| | - Hideyoshi Noji
- Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Hideo Kimura
- Department of Hematology, Kita Fukushima Medical Center, Date, Japan
| | - Kazuei Ogawa
- Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Yuko Suzuki
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University, Fukushima, Japan
| | - Kazuhiko Ikeda
- Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
- Department of Blood Transfusion and Transplantation Immunology, Fukushima Medical University, Fukushima, Japan
| | - Yasuchika Takeishi
- Department of Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Junko Kimura
- Department of Pharmacology, Fukushima Medical University, Fukushima, Japan
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16
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Takasugi T, Minegishi S, Asada A, Saito T, Kawahara H, Hisanaga SI. Two Degradation Pathways of the p35 Cdk5 (Cyclin-dependent Kinase) Activation Subunit, Dependent and Independent of Ubiquitination. J Biol Chem 2015; 291:4649-57. [PMID: 26631721 DOI: 10.1074/jbc.m115.692871] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 12/24/2022] Open
Abstract
Cdk5 is a versatile protein kinase that is involved in various neuronal activities, such as the migration of newborn neurons, neurite outgrowth, synaptic regulation, and neurodegenerative diseases. Cdk5 requires the p35 regulatory subunit for activation. Because Cdk5 is more abundantly expressed in neurons compared with p35, the p35 protein levels determine the kinase activity of Cdk5. p35 is a protein with a short half-life that is degraded by proteasomes. Although ubiquitination of p35 has been previously reported, the degradation mechanism of p35 is not yet known. Here, we intended to identify the ubiquitination site(s) in p35. Because p35 is myristoylated at the N-terminal glycine, the possible ubiquitination sites are the lysine residues in p35. We mutated all 23 Lys residues to Arg (p35 23R), but p35 23R was still rapidly degraded by proteasomes at a rate similar to wild-type p35. The degradation of p35 23R in primary neurons and the Cdk5 activation ability of p35 23R suggested the occurrence of ubiquitin-independent degradation of p35 in physiological conditions. We found that p35 has the amino acid sequence similar to the ubiquitin-independent degron in the NKX3.1 homeodomain transcription factor. An Ala mutation at Pro-247 in the degron-like sequence made p35 stable. These results suggest that p35 can be degraded by two degradation pathways: ubiquitin-dependent and ubiquitin-independent. The rapid degradation of p35 by two different methods would be a mechanism to suppress the production of p25, which overactivates Cdk5 to induce neuronal cell death.
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Affiliation(s)
| | | | - Akiko Asada
- From the Laboratory of Molecular Neuroscience and
| | - Taro Saito
- From the Laboratory of Molecular Neuroscience and
| | - Hiroyuki Kawahara
- Laboratory of Cellular Biochemistry, Department of Biological Sciences, and Graduate School of Sciences, Tokyo Metropolitan University, Mianami-osawa, Hachioji,Tokyo 192-0397, Japan
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17
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Dhillon AS, Tulchinsky E. FRA-1 as a driver of tumour heterogeneity: a nexus between oncogenes and embryonic signalling pathways in cancer. Oncogene 2015; 34:4421-8. [PMID: 25381818 PMCID: PMC4351906 DOI: 10.1038/onc.2014.374] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 10/02/2014] [Accepted: 10/02/2014] [Indexed: 12/12/2022]
Abstract
Tumour heterogeneity is a major factor undermining the success of therapies targeting metastatic cancer. Two major theories are thought to explain the phenomenon of heterogeneity in cancer--clonal evolution and cell plasticity. In this review, we examine a growing body of work implicating the transcription factor FOS-related antigen 1 (FRA-1) as a central node in tumour cell plasticity networks, and discuss mechanisms regulating its activity in cancer cells. We also discuss evidence from the FRA-1 perspective supporting the notion that clonal selection and cell plasticity represent two sides of the same coin. We propose that FRA-1-overexpressing clones featuring high plasticity undergo positive selection during consecutive stages of multistep tumour progression. This model underscores a potential mechanism through which tumour cells retaining elevated levels of plasticity acquire a selective advantage over other clonal populations within a tumour.
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Affiliation(s)
- A S Dhillon
- Research Division, Peter MacCallum Cancer Center, St Andrews Place, East Melbourne, Melbourne, Victoria 3002, Australia
| | - E Tulchinsky
- Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, UK
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18
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Ji L, Zheng Z, Shi L, Huang Y, Lu B, Wang Z. Andrographolide decreased VEGFD expression in hepatoma cancer cells by inducing ubiquitin/proteasome-mediated cFos protein degradation. Biochim Biophys Acta Gen Subj 2015; 1850:750-8. [DOI: 10.1016/j.bbagen.2015.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 12/24/2014] [Accepted: 01/07/2015] [Indexed: 01/11/2023]
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19
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Caputto BL, Cardozo Gizzi AM, Gil GA. c-Fos: An AP-1 transcription factor with an additional cytoplasmic, non-genomic lipid synthesis activation capacity. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1241-6. [DOI: 10.1016/j.bbalip.2014.05.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/13/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
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20
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Dennissen FJA, Kholod N, van Leeuwen FW. The ubiquitin proteasome system in neurodegenerative diseases: culprit, accomplice or victim? Prog Neurobiol 2012; 96:190-207. [PMID: 22270043 DOI: 10.1016/j.pneurobio.2012.01.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/18/2011] [Accepted: 01/05/2012] [Indexed: 12/14/2022]
Abstract
A shared hallmark for many neurodegenerative disorders is the accumulation of toxic protein species which is assumed to be the cause for these diseases. Since the ubiquitin proteasome system (UPS) is the most important pathway for selective protein degradation it is likely that it is involved in the aetiology neurodegenerative disorders. Indeed, impairment of the UPS has been reported to occur during neurodegeneration. Although accumulation of toxic protein species (amyloid β) are in turn known to impair the UPS the relationship is not necessarily causal. We provide an overview of the most recent insights in the roles the UPS plays in protein degradation and other processes. Additionally, we discuss the role of the UPS in clearance of the toxic proteins known to accumulate in the hallmarks of neurodegenerative diseases. The present paper will focus on critically reviewing the involvement of the UPS in specific neurodegenerative diseases and will discuss if UPS impairment is a cause, a consequence or both of the disease.
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Affiliation(s)
- F J A Dennissen
- Department of Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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21
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Syntenin-mediated regulation of Sox4 proteasomal degradation modulates transcriptional output. Oncogene 2011; 31:2668-79. [PMID: 21986941 DOI: 10.1038/onc.2011.445] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The transcription factor Sox4 is aberrantly expressed in many human tumors and can modulate tumorigenesis and metastases of murine tumors in vivo. However, mechanisms that control Sox4 function remain poorly defined. It has recently been observed that DNA damage increases Sox4 protein expression independently of Sox4 mRNA levels, suggesting an as yet undefined post-transcriptional mechanism regulating Sox4 expression and functionality. Here, we show that Sox4 protein is rapidly degraded by the proteasome as indicated by pharmacological inhibition with Mg132 and epoxymycin. Sox4 half-life was found to be less than 1 h as evident by inhibition of protein synthesis using cycloheximide. Ectopic expression of Sox4 deletion mutants revealed that the C-terminal 33 residues of Sox4 were critical in modulating its degradation in a polyubiquitin-independent manner. Syntenin, a Sox4 binding partner, associates with this domain and was found to stabilize Sox4 expression. Syntenin-induced stabilization of Sox4 correlated with Sox4-syntenin relocalization to the nucleus, where both proteins accumulate. Syntenin overexpression or knockdown in human tumor cell lines was found to reciprocally modulate Sox4 protein expression and transcriptional activity implicating its role as a regulator of Sox4. Taken together, our data demonstrate that the Sox4 C-terminal domain regulates polyubiquitin-independent proteasomal degradation of Sox4 that can be modulated by interaction with syntenin. As aberrant Sox4 expression has been found associated with many human cancers, modulation of Sox4 proteasomal degradation may impact oncogenesis and metastatic properties of tumors.
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22
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Abstract
Remodeling of uterine spiral arteries by trophoblast cells is a requisite process for hemochorial placentation and successful pregnancy. The rat exhibits deep intrauterine trophoblast invasion and accompanying trophoblast-directed vascular modification. The involvement of phosphatidylinositol 3 kinase (PI3K), AKT, and Fos-like antigen 1 (FOSL1) in regulating invasive trophoblast and hemochorial placentation was investigated using Rcho-1 trophoblast stem cells and rat models. Disruption of PI3K/AKT with small-molecule inhibitors interfered with the differentiation-dependent elaboration of a signature invasive-vascular remodeling trophoblast gene expression profile and trophoblast invasion. AKT isoform-specific knockdown also affected the signature invasive-vascular remodeling trophoblast gene expression profile. Nuclear FOSL1 increased during trophoblast cell differentiation in a PI3K/AKT-dependent manner. Knockdown of FOSL1 disrupted the expression of a subset of genes associated with the invasive-vascular remodeling trophoblast phenotype, including the matrix metallopeptidase 9 gene (Mmp9). FOSL1 was shown to occupy regions of the Mmp9 promoter in trophoblast cells critical for the regulation of Mmp9 gene expression. Inhibition of FOSL1 expression also abrogated trophoblast invasion, as assessed in vitro and following in vivo trophoblast-specific lentivirally delivered FOSL1 short hairpin RNA (shRNA). In summary, FOSL1 is a key downstream effector of the PI3K/AKT signaling pathway responsible for development of trophoblast lineages integral to establishing the maternal-fetal interface.
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Melo SP, Barbour KW, Berger FG. Cooperation between an intrinsically disordered region and a helical segment is required for ubiquitin-independent degradation by the proteasome. J Biol Chem 2011; 286:36559-67. [PMID: 21878626 DOI: 10.1074/jbc.m111.274258] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 26 S proteasomal complex, which is responsible for the bulk of protein degradation within the cell, recognizes its target substrates via covalently linked polyubiquitin moieties. However, a small but growing number of proteasomal substrates are degraded without a requirement for ubiquitinylation. One such substrate is the pyrimidine biosynthetic enzyme thymidylate synthase (EC 2.1.1.45), which catalyzes the synthesis of TMP and is the sole de novo source of TTP for DNA replication and repair. Previous work showed that intracellular proteolysis of human thymidylate synthase is directed by a degron at the polypeptide's N-terminal end, composed of an intrinsically disordered region (IDR) followed by a highly conserved amphipathic α-helix (hA). In the present report, we show that the hA helix does not function simply as an extension or scaffold for the IDR; rather, it provides a specific structural component that is necessary for degradation. Furthermore, its helical conformation is required for this function. We demonstrate that small domains from heterologous proteins can substitute for the IDR and the hA helix of human thymidylate synthase, indicating that the degradation-promoting function of these regions is not sequence-specific. The results, in general, indicate that cooperation between intrinsically disordered domains and α-helical segments is required for ubiquitin-independent degradation by the proteasome. There appears to be little sequence constraint on the ability of these regions to function as degron constituents. Rather, it is the overall conformation (or lack thereof) that is critical.
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Affiliation(s)
- Sandra P Melo
- Department of Biological Sciences and Center for Colon Cancer Research, University of South Carolina, Columbia, South Carolina 29208, USA
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24
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Pakay JL, Diesch J, Gilan O, Yip YY, Sayan E, Kolch W, Mariadason JM, Hannan RD, Tulchinsky E, Dhillon AS. A 19S proteasomal subunit cooperates with an ERK MAPK-regulated degron to regulate accumulation of Fra-1 in tumour cells. Oncogene 2011; 31:1817-24. [DOI: 10.1038/onc.2011.375] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Pérez-Cadahía B, Drobic B, Davie JR. Activation and function of immediate-early genes in the nervous system. Biochem Cell Biol 2011; 89:61-73. [PMID: 21326363 DOI: 10.1139/o10-138] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Immediate-early genes have important roles in processes such as brain development, learning, and responses to drug abuse. Further, immediate-early genes play an essential role in cellular responses that contribute to long-term neuronal plasticity. Neuronal plasticity is a characteristic of the nervous system that is not limited to the first stages of brain development but persists in adulthood and seems to be an inherent feature of everyday brain function. The plasticity refers to the neuron's capability of showing short- or long-lasting phenotypic changes in response to different stimuli and cellular scenarios. In this review, we focus on the immediate-early genes encoding transcription factors (AP-1 and Egr) that are relevant for neuronal responses. Our current understanding of the mechanisms involved in the induction of the immediate-early genes is presented.
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Affiliation(s)
- Beatriz Pérez-Cadahía
- Toxicology Unit, Department of Psychobiology, University of A Coruña, A Coruña, Spain
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27
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Abstract
Human thymidylate synthase (hTS; EC 2.1.1.45) is one of a small group of proteasomal substrates whose intracellular degradation occurs in a ubiquitin-independent manner. Previous studies have shown that proteolytic breakdown of the hTS polypeptide is directed by an intrinsically disordered 27-residue domain at the N-terminal end of the molecule. This domain, in co-operation with an α-helix spanning amino acids 31–45, functions as a degron, in that it has the ability to destabilize a heterologous polypeptide to which it is attached. In the present study, we provide evidence indicating that it is the 26S isoform of the proteasome that is responsible for intracellular degradation of the hTS polypeptide. In addition, we have used targeted in vitro mutagenesis to show that an Arg–Arg motif at residues 10–11 is required for proteolysis, an observation that was confirmed by functional analysis of the TS N-terminus from other mammalian species. The effects of stabilizing mutations on hTS degradation are maintained when the enzyme is provided with an alternative means of proteasome association; thus such mutations perturb one or more post-docking steps in the degradation pathway. Surprisingly, deletion mutants missing large segments of the disordered domain still function as proteasomal substrates; however, degradation of such mutants occurs by a mechanism that is distinct from that for the wild-type protein. Taken together, our results provide information on the roles of specific subregions within the intrinsically disordered N-terminal domain of hTS in regulation of degradation, leading to a deeper understanding of mechanisms underlying the ubiquitin-independent proteasomal degradation pathway.
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Cen J, Qi Y, Tao YF, Deng Y, Fang WR, Li YM, Zhang LY, Huang WL. HZ08, a great regulator to reverse multidrug resistance via cycle arrest and apoptosis sensitization in MCF-7/ADM. Eur J Pharmacol 2010; 647:21-30. [PMID: 20816813 DOI: 10.1016/j.ejphar.2010.08.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Revised: 07/14/2010] [Accepted: 08/21/2010] [Indexed: 11/25/2022]
Abstract
In early studies, it was demonstrated that R-HZ08, S-HZ08 and the racemate had strong reverse efficacy of multidrug resistance in vitro and in vivo (Yan et al., 2008b). The effect was supposed to have direct interaction with multidrug resistance-associated protein (MRP1) in MCF-7/ADM and P-glycoprotein in K562/A02. According to our latest study, we found HZ08 could enhance chemotherapy induced apoptosis by synergistic action on reactive oxygen species generation, GSH depletion, mitochondrial membrane potential depolarization, cytochrome c release and caspase activation. Moreover, the potential selective effect of HZ08 on resistant cells suggested that HZ08 have specific targets for resistance reversal via apoptosis regulation. Therefore, we traced individual influence of HZ08, not only on apoptosis pathway per se but also on apoptosis related intracellular regulation systems. Then we found HZ08 could increase cells in G(0)/G(1) phase and regulate apoptosis related proteins (Bcl-2, Bax) as well as upstream functional molecules (c-Myc and c-Fos), which are usually abnormal in malignancy and responsible for multidrug resistance in MCF-7/ADM. Thereby, chemotherapy induced apoptosis was promoted. R-HZ08 showed better effect than S-HZ08 or the racemate did in most of targets above. Furthermore, HZ08 did not change the concentration of intracellular Ca(2+) which means it would not have side effect as verapamil does. Considering multidrug resistance is multifactorial, HZ08, especially R-HZ08, which could sensitize apoptosis by multiple improvements of upstream malignant characters, will be a promising drug to enhance the effect of chemotherapy in the treatment of multidrug resistant tumor.
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Affiliation(s)
- Juan Cen
- Department of Physiology, China Pharmaceutical University, Nanjing, PR China
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29
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Hrizo SL, Palladino MJ. Hsp70- and Hsp90-mediated proteasomal degradation underlies TPI sugarkill pathogenesis in Drosophila. Neurobiol Dis 2010; 40:676-83. [PMID: 20727972 DOI: 10.1016/j.nbd.2010.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 08/04/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022] Open
Abstract
Triosephosphate isomerase (TPI) deficiency is a severe glycolytic enzymopathy that causes progressive locomotor impairment and neurodegeneration, susceptibility to infection, and premature death. The recessive missense TPI(sugarkill) mutation in Drosophila melanogaster exhibits phenotypes analogous to human TPI deficiency such as progressive locomotor impairment, neurodegeneration, and reduced life span. We have shown that the TPI(sugarkill) protein is an active stable dimer; however, the mutant protein is turned over by the proteasome reducing cellular levels of this glycolytic enzyme. As proteasome function is often coupled with molecular chaperone activity, we hypothesized that TPI(sugarkill) is recognized by molecular chaperones that mediate the proteasomal degradation of the mutant protein. Coimmunoprecipitation data and analyses of TPI(sugarkill) turnover in animals with reduced or enhanced molecular chaperone activity indicate that both Hsp90 and Hsp70 are important for targeting TPI(sugarkill) for degradation. Furthermore, molecular chaperone and proteasome activity modified by pharmacological or genetic manipulations resulted in improved TPI(sugarkill) protein levels and rescue some but not all of the disease phenotypes suggesting that TPI deficiency pathology is complex. Overall, these data demonstrate a surprising role for Hsp70 and Hsp90 in the progression of neural dysfunction associated with TPI deficiency.
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Affiliation(s)
- Stacy L Hrizo
- Deparment of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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30
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c-Fos proteasomal degradation is activated by a default mechanism, and its regulation by NAD(P)H:quinone oxidoreductase 1 determines c-Fos serum response kinetics. Mol Cell Biol 2010; 30:3767-78. [PMID: 20498278 DOI: 10.1128/mcb.00899-09] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The short-lived proto-oncoprotein c-Fos is a component of the activator protein 1 (AP-1) transcription factor. A large region of c-Fos is intrinsically unstructured and susceptible to a recently characterized proteasomal ubiquitin-independent degradation (UID) pathway. UID is active by a default mechanism that is inhibited by NAD(P)H:quinone oxidoreductase 1 (NQO1), a 20S proteasome gatekeeper. Here, we show that NQO1 binds and induces robust c-Fos accumulation by blocking the UID pathway. c-Jun, a partner of c-Fos, also protects c-Fos from proteasomal degradation by default. Our findings suggest that NQO1 protects monomeric c-Fos from proteasomal UID, a function that is fulfilled later by c-Jun. We show that this process regulates c-Fos homeostasis (proteostasis) in response to serum stimulation, phosphorylation, nuclear translocation, and transcription activity. In addition, we show that NQO1 is important to ensure immediate c-Fos accumulation in response to serum, since a delayed response was observed under low NQO1 expression. These data suggest that in vivo, protein unstructured regions determine the kinetics and the homeostasis of regulatory proteins. Our data provide evidence for another layer of regulation of key regulatory proteins that functions at the level of protein degradation and is designed to ensure optimal formation of functional complexes such as AP-1.
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31
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Padhan K, Varma R. Immunological synapse: a multi-protein signalling cellular apparatus for controlling gene expression. Immunology 2010; 129:322-8. [PMID: 20409153 DOI: 10.1111/j.1365-2567.2009.03241.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The interaction of T cells with antigen-presenting cells is the hallmark of adaptive immunity. In vitro studies have described the formation of an immunological synapse between these cells, and intra-vital imaging has described in great detail the dynamics of these interactions. The immunological synapse has become a paradigm to study signals exchanged between the two cells. A wealth of information has been amassed regarding the localization of signalling molecules, their kinetics and the transcription factors they activate. We continue to discover mechanisms that cause receptors and signalling molecules to compartmentalize in the cell; however, the emerging challenge lies in understanding how the immunological synapse contributes to differentiation. Here, we review some of the transcription factors activated downstream of T-cell receptor signalling and discuss mechanisms by which antigen dose and affinity may influence differentiation. Antigen affinity might change the kind of transcription factors that are activated whereas antigen dose is likely to influence the temporal dynamics of the transcription factors. The immunological synapse is therefore likely to influence differentiation by modulating the trafficking of transcription factors and by promoting asymmetric cell division, an emerging concept.
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Affiliation(s)
- Kartika Padhan
- Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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32
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Wang Y, Guan X. GLP-2 potentiates L-type Ca2+ channel activity associated with stimulated glucose uptake in hippocampal neurons. Am J Physiol Endocrinol Metab 2010; 298:E156-66. [PMID: 19920220 PMCID: PMC2822481 DOI: 10.1152/ajpendo.00585.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucagon-like peptide-2 (GLP-2) is a neuropeptide secreted from endocrine cells in the gut and neurons in the brain. GLP-2 stimulates intestinal crypt cell proliferation and mucosal blood flow while decreasing gastric emptying and gut motility. However, a GLP-2-mediated signaling network has not been fully established in primary cells. Since the GLP-2 receptor mRNA and protein were highly expressed in the mouse hippocampus, we further characterized that human (125)I-labeled GLP-2(1-33) specifically bound to cultured hippocampal neurons with K(d) = 0.48 nM, and GLP-2 acutely induced subcellular translocalization of the early gene c-Fos. Using the whole cell patch clamp, we recorded barium currents (I(Ba)) flowing through voltage-gated Ca(2+) channels (VGCC) in those neurons in the presence of GLP-2 with and without inhibitors. We showed that GLP-2 (20 nM) enhanced the whole cell I(Ba) mediated by L-type VGCC that was defined using an L-type Ca(2+) channel blocker (nifedipine, 10 microM). Moreover, GLP-2-potentiation of L-type VGCC was abolished in neurons pretreated with a PKA inhibitor (PKI(14-22), 1 microM). Finally, using a fluorescent nonmetabolized glucose analog (6-NBDG) tracing imaging, we showed that glucose was taken up directly by cultured neurons. GLP-2 increased 2-deoxy-d-[(3)H]glucose uptake that was dependent upon dosage, activation of PKA, and potentiation of L-type VGCC. We conclude that GLP-2 potentiates L-type VGCC activity through activating PKA signaling, partially stimulating glucose uptake by primary cultured hippocampal neurons. The potentiation of L-type VGCC may be physiologically relevant to GLP-2-induced neuroendocrine modulation of neurotransmitter release and hormone secretion.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
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33
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Malnou CE, Brockly F, Favard C, Moquet-Torcy G, Piechaczyk M, Jariel-Encontre I. Heterodimerization with different Jun proteins controls c-Fos intranuclear dynamics and distribution. J Biol Chem 2010; 285:6552-62. [PMID: 20053986 DOI: 10.1074/jbc.m109.032680] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The c-Fos proto-oncogenic transcription factor defines a multigene family controlling many processes both at the cell and the whole organism level. To bind to its target AP-1/12-O-tetradecanoylphorbol-13-acetate-responsive element or cAMP-responsive element DNA sequences in gene promoters and exert its transcriptional part, c-Fos must heterodimerize with other bZip proteins, its best studied partners being the Jun proteins (c-Jun, JunB, and JunD). c-Fos expression is regulated at many transcriptional and post-transcriptional levels, yet little is known on how its localization is dynamically regulated in the cell. Here we have investigated its intranuclear mobility using fluorescence recovery after photobleaching, genetic, and biochemical approaches. Whereas monomeric c-Fos is highly mobile and distributed evenly with nucleolar exclusion in the nucleus, heterodimerization with c-Jun entails intranuclear redistribution and dramatic reduction in mobility of c-Fos caused by predominant association with the nuclear matrix independently of any binding to AP-1/12-O-tetradecanoylphorbol-13-acetate-responsive element or cAMP-responsive element sequences. In contrast to c-Jun, dimerization with JunB does not detectably affect c-Fos mobility. However, dimerization with JunB affects intranuclear distribution with significant differences in the localization of c-Fos.c-Jun and c-Fos.JunB dimers. Moreover, c-Jun and JunB exert comparable effects on another Fos family member, Fra-1. Thus, we report a novel regulation, i.e. differentially regulated intranuclear mobility and distribution of Fos proteins by their Jun partners, and suggest the existence of intranuclear storage sites for latent c-Fos.c-Jun AP-1 complexes. This may affect the numerous physiopathological functions these transcription factors control.
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Affiliation(s)
- Cécile E Malnou
- Institut de Génétique Moléculaire de Montpellier, UMR5535, CNRS, 1919 route de Mende, 34293 Montpellier Cedex 5, France
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34
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Abstract
Cooperation among transcription factors is central for their ability to execute specific transcriptional programmes. The AP1 complex exemplifies a network of transcription factors that function in unison under normal circumstances and during the course of tumour development and progression. This Perspective summarizes our current understanding of the changes in members of the AP1 complex and the role of ATF2 as part of this complex in tumorigenesis.
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Affiliation(s)
- Pablo Lopez-Bergami
- Instituto de Biologia y Medicina Experimental, Vuelta de Obligado 2490, Buenos Aires1428, Argentina,
| | - Eric Lau
- Signal Transduction Program, Burnham Institute for Medical Research, La Jolla, CA 92037, USA,
| | - Ze'ev Ronai
- Signal Transduction Program, Burnham Institute for Medical Research, La Jolla, CA 92037, USA
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35
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Bichenkov E, Ellingson JS. Ethanol alters the expressions of c-Fos and myelin basic protein in differentiating oligodendrocytes. Alcohol 2009; 43:627-34. [PMID: 20004340 DOI: 10.1016/j.alcohol.2009.09.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 06/01/2009] [Accepted: 09/15/2009] [Indexed: 10/20/2022]
Abstract
Myelination occurs in the central nervous system of the human fetus, adolescents, and young adults. Ethanol interferes with myelination in part by altering the composition of the myelin sheath. Here we show that ethanol also affected the expression of the transcription factor c-Fos in differentiating oligodendrocytes (OLGs). Central glial-4 OLG progenitors were induced to differentiate in the absence and presence of 100 mM ethanol, and ethanol-caused changes in the levels of c-Fos and myelin basic protein (MBP) were determined by Western blot analysis at selected developmental stages. The relatively high c-Fos level in progenitors did not immediately decrease to a low level at the onset of differentiation but displayed a downregulation at a later developmental stage. Ethanol delayed the developmental c-Fos downregulation maintaining c-Fos at a 45% higher level at 2 days of differentiation (DoD). Ethanol also decreased the rate of the burst of MBP expression that occurred between 1 and 2 DoD, reducing the MBP level by 47% at 2 DoD. The ethanol-caused delays of c-Fos downregulation and MBP upregulation were both blocked by the protein kinase C (PKC) inhibitor bisindolylmaleimide I (BIM). Likewise, treatment of OLGs with a low 5-nM concentration of the PKC activator by 12-O-tetradecanoylphorbol-13-acetate mimicked the ethanol effects on the expression of both proteins, effects that were also counteracted by BIM. The results indicate that ethanol-caused delays of the stage-specific c-Fos downregulation and the inhibition of MBP expression both occur through a PKC-mediated mechanism. The ethanol-caused delay in c-Fos downregulation may disrupt normal timing for expression of genes involved in OLG differentiation, and the inhibited MBP expression may alter the myelin sheath composition.
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36
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Peña MMO, Melo SP, Xing YY, White K, Barbour KW, Berger FG. The intrinsically disordered N-terminal domain of thymidylate synthase targets the enzyme to the ubiquitin-independent proteasomal degradation pathway. J Biol Chem 2009; 284:31597-607. [PMID: 19797058 DOI: 10.1074/jbc.m109.038455] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ubiquitin-independent proteasomal degradation pathway is increasingly being recognized as important in regulation of protein turnover in eukaryotic cells. One substrate of this pathway is the pyrimidine biosynthetic enzyme thymidylate synthase (TS; EC 2.1.1.45), which catalyzes the reductive methylation of dUMP to form dTMP and is essential for DNA replication during cell growth and proliferation. Previous work from our laboratory showed that degradation of TS is ubiquitin-independent and mediated by an intrinsically disordered 27-residue region at the N-terminal end of the molecule. In the current study we show that this region, in cooperation with an alpha-helix formed by the next 15 residues, functions as a degron, i.e. it is capable of destabilizing a heterologous protein to which it is fused. Comparative analysis of the primary sequence of TS from a number of mammalian species revealed that the N-terminal domain is hypervariable among species yet is conserved with regard to its disordered nature, its high Pro content, and the occurrence of Pro at the penultimate site. Characterization of mutant proteins showed that Pro-2 protects the N terminus against N(alpha)-acetylation, a post-translational process that inhibits TS degradation. However, although a free amino group at the N terminus is necessary, it is not sufficient for degradation of the polypeptide. The implications of these findings to the proteasome-targeting function of the N-terminal domain, particularly with regard to its intrinsic flexibility, are discussed.
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Affiliation(s)
- Maria Marjorette O Peña
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA
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37
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Catalgol B, Ziaja I, Breusing N, Jung T, Höhn A, Alpertunga B, Schroeder P, Chondrogianni N, Gonos ES, Petropoulos I, Friguet B, Klotz LO, Krutmann J, Grune T. The proteasome is an integral part of solar ultraviolet a radiation-induced gene expression. J Biol Chem 2009; 284:30076-86. [PMID: 19690165 DOI: 10.1074/jbc.m109.044503] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Solar ultraviolet (UV) A radiation is a well known trigger of signaling responses in human skin fibroblasts. One important consequence of this stress response is the increased expression of matrix metalloproteinase-1 (MMP-1), which causes extracellular protein degradation and thereby contributes to photoaging of human skin. In the present study we identify the proteasome as an integral part of the UVA-induced, intracellular signaling cascade in human dermal fibroblasts. UVA-induced singlet oxygen formation was accompanied by protein oxidation, the cross-linking of oxidized proteins, and an inhibition of the proteasomal system. This proteasomal inhibition subsequently led to an accumulation of c-Jun and phosphorylated c-Jun and activation of activator protein-1, i.e. transcription factors known to control MMP-1 expression. Increased transcription factor activation was also observed if the proteasome was inhibited by cross-linked proteins or lactacystin, indicating a general mechanism. Most importantly, inhibition of the proteasome was of functional relevance for UVA-induced MMP-1 expression, because overexpression of the proteasome or the protein repair enzyme methionine sulfoxide reductase prevented the UVA-induced induction of MMP-1. These studies show that an environmentally relevant stimulus can trigger a signaling pathway, which links intracellular and extracellular protein degradation. They also identify the proteasome as an integral part of the UVA stress response.
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Affiliation(s)
- Betul Catalgol
- Institute of Biological Chemistry and Nutrition, University of Hohenheim, 70593 Stuttgart, Germany
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38
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Eleuteri AM, Amici M, Bonfili L, Cecarini V, Cuccioloni M, Grimaldi S, Giuliani L, Angeletti M, Fioretti E. 50 Hz extremely low frequency electromagnetic fields enhance protein carbonyl groups content in cancer cells: effects on proteasomal systems. J Biomed Biotechnol 2009; 2009:834239. [PMID: 19672456 PMCID: PMC2722031 DOI: 10.1155/2009/834239] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 05/14/2009] [Accepted: 06/05/2009] [Indexed: 11/17/2022] Open
Abstract
Electromagnetic fields are an assessed cause of prolonging free radicals lifespan. This study was carried out to investigate the influence of extremely low frequency electromagnetic fields on protein oxidation and on the 20S proteasome functionality, the complex responsible for the degradation of oxidized proteins. Caco 2 cells were exposed, for 24-72 hours, to 1 mT, 50 Hz electromagnetic fields. The treatment induced a time-dependent increase both in cell growth and in protein oxidation, more evident in the presence of TPA, while no changes in cell viability were detected. Exposing the cells to 50 Hz electromagnetic fields caused a global activation of the 20S proteasome catalytic components, particularly evident at 72 hours exposure and in the presence of TPA. The finding that EGCG, a natural antioxidant compound, counteracted the field-related pro-oxidant effects demonstrates that the increased proteasome activity was due to an enhancement in intracellular free radicals.
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Affiliation(s)
- A M Eleuteri
- Department of Biology M.C.A., University of Camerino, 62032 Camerino (MC), Italy.
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39
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Baugh JM, Viktorova EG, Pilipenko EV. Proteasomes can degrade a significant proportion of cellular proteins independent of ubiquitination. J Mol Biol 2009; 386:814-27. [PMID: 19162040 DOI: 10.1016/j.jmb.2008.12.081] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 12/29/2008] [Accepted: 12/30/2008] [Indexed: 12/13/2022]
Abstract
The critical role of the ubiquitin-26S proteasome system in regulation of protein homeostasis in eukaryotes is well established. In contrast, the impact of the ubiquitin-independent proteolytic activity of proteasomes is poorly understood. Through biochemical analysis of mammalian lysates, we find that the 20S proteasome, latent in peptide hydrolysis, specifically cleaves more than 20% of all cellular proteins. Thirty intrinsic proteasome substrates (IPSs) were identified and in vitro studies of their processing revealed that cleavage occurs at disordered regions, generating stable products encompassing structured domains. The mechanism of IPS recognition is remarkably well conserved in the eukaryotic kingdom, as mammalian and yeast 20S proteasomes exhibit the same target specificity. Further, 26S proteasomes specifically recognize and cleave IPSs at similar sites, independent of ubiquitination, suggesting that disordered regions likely constitute the universal structural signal for IPS proteolysis by proteasomes. Finally, we show that proteasomes contribute to physiological regulation of IPS levels in living cells and the inactivation of ubiquitin-activating enzyme E1 does not prevent IPS degradation. Collectively, these findings suggest a significant contribution of the ubiquitin-independent proteasome degradation pathway to the regulation of protein homeostasis in eukaryotes.
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Affiliation(s)
- James M Baugh
- Department of Microbiology, University of Chicago, Chicago, IL 60637, USA
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Abstract
JunB is a member of the AP-1 (activator protein-1) family of dimeric transcription factors. It exerts a dual action on the cell cycle. It is best known as a cell proliferation inhibitor, a senescence inducer and a tumour suppressor. As for the molecular mechanisms involved, they largely involve both positive actions on genes such as the p16INK4alpha cyclin-dependent kinase inhibitor and negative effects on genes such as cyclin D1 during the G1-phase of the cell cycle. However, JunB is also endowed with a cell-division-promoting activity, in particular via stimulation of cyclin A2 gene expression during S-phase. Strikingly, its role in G2 and M has received little attention so far despite its possible role in the preparation of mitosis. This review addresses the known and possible mechanisms whereby JunB is implicated in the control of the different phases of the cell cycle.
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41
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Bonfili L, Cecarini V, Amici M, Cuccioloni M, Angeletti M, Keller JN, Eleuteri AM. Natural polyphenols as proteasome modulators and their role as anti-cancer compounds. FEBS J 2008; 275:5512-26. [DOI: 10.1111/j.1742-4658.2008.06696.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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42
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Jariel-Encontre I, Bossis G, Piechaczyk M. Ubiquitin-independent degradation of proteins by the proteasome. Biochim Biophys Acta Rev Cancer 2008; 1786:153-77. [PMID: 18558098 DOI: 10.1016/j.bbcan.2008.05.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 05/15/2008] [Accepted: 05/15/2008] [Indexed: 02/08/2023]
Abstract
The proteasome is the main proteolytic machinery of the cell and constitutes a recognized drugable target, in particular for treating cancer. It is involved in the elimination of misfolded, altered or aged proteins as well as in the generation of antigenic peptides presented by MHC class I molecules. It is also responsible for the proteolytic maturation of diverse polypeptide precursors and for the spatial and temporal regulation of the degradation of many key cell regulators whose destruction is necessary for progression through essential processes, such as cell division, differentiation and, more generally, adaptation to environmental signals. It is generally believed that proteins must undergo prior modification by polyubiquitin chains to be addressed to, and recognized by, the proteasome. In reality, however, there is accumulating evidence that ubiquitin-independent proteasomal degradation may have been largely underestimated. In particular, a number of proto-oncoproteins and oncosuppressive proteins are privileged ubiquitin-independent proteasomal substrates, the altered degradation of which may have tumorigenic consequences. The identification of ubiquitin-independent mechanisms for proteasomal degradation also poses the paramount question of the multiplicity of catabolic pathways targeting each protein substrate. As this may help design novel therapeutic strategies, the underlying mechanisms are critically reviewed here.
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Affiliation(s)
- Isabelle Jariel-Encontre
- Institut de Génétique Moléculaire de Montpellier, CNRS, UMR5535, IFR122, 1919 Route de Mende, Montpellier, F-34293, France
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