1
|
William JNG, Dhar R, Gundamaraju R, Sahoo OS, Pethusamy K, Raj AFPAM, Ramasamy S, Alqahtani MS, Abbas M, Karmakar S. SKping cell cycle regulation: role of ubiquitin ligase SKP2 in hematological malignancies. Front Oncol 2024; 14:1288501. [PMID: 38559562 PMCID: PMC10978726 DOI: 10.3389/fonc.2024.1288501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 02/15/2024] [Indexed: 04/04/2024] Open
Abstract
SKP2 (S-phase kinase-associated protein 2) is a member of the F-box family of substrate-recognition subunits in the SCF ubiquitin-protein ligase complexes. It is associated with ubiquitin-mediated degradation in the mammalian cell cycle components and other target proteins involved in cell cycle progression, signal transduction, and transcription. Being an oncogene in solid tumors and hematological malignancies, it is frequently associated with drug resistance and poor disease outcomes. In the current review, we discussed the novel role of SKP2 in different hematological malignancies. Further, we performed a limited in-silico analysis to establish the involvement of SKP2 in a few publicly available cancer datasets. Interestingly, our study identified Skp2 expression to be altered in a cancer-specific manner. While it was found to be overexpressed in several cancer types, few cancer showed a down-regulation in SKP2. Our review provides evidence for developing novel SKP2 inhibitors in hematological malignancies. We also investigated the effect of SKP2 status on survival and disease progression. In addition, the role of miRNA and its associated families in regulating Skp2 expression was explored. Subsequently, we predicted common miRNAs against Skp2 genes by using miRNA-predication tools. Finally, we discussed current approaches and future prospective approaches to target the Skp2 gene by using different drugs and miRNA-based therapeutics applications in translational research.
Collapse
Affiliation(s)
- Jonahunnatha Nesson George William
- Department of Medical, Oral and Biotechnological Sciences (DSMOB), Ageing Research Center and Translational Medicine-CeSI-MeT, “G. d’Annunzio” University Chieti-Pescara, Chieti, Italy
| | - Ruby Dhar
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | - Rohit Gundamaraju
- ER Stress and Intestinal Mucosal Biology Lab, School of Health Sciences, University of Tasmania, Launceston, TAS, Australia
| | - Om Saswat Sahoo
- Department of Biotechnology, National Institute of Technology, Durgapur, India
| | - Karthikeyan Pethusamy
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | | | - Subbiah Ramasamy
- Cardiac Metabolic Disease Laboratory, Department Of Biochemistry, School of Biological Sciences, Madurai Kamaraj University, Madurai, India
| | - Mohammed S. Alqahtani
- Radiological Sciences Department, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
- BioImaging Unit, Space Research Centre, University of Leicester, Leicester, United Kingdom
| | - Mohamed Abbas
- Electrical Engineering Department, College of Engineering, King Khalid University, Abha, Saudi Arabia
| | - Subhradip Karmakar
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| |
Collapse
|
2
|
Canalis E, Yu J, Singh V, Mocarska M, Schilling L. NOTCH2 sensitizes the chondrocyte to the inflammatory response of tumor necrosis factor α. J Biol Chem 2023; 299:105372. [PMID: 37865314 PMCID: PMC10692730 DOI: 10.1016/j.jbc.2023.105372] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/06/2023] [Accepted: 10/15/2023] [Indexed: 10/23/2023] Open
Abstract
Notch regulates the immune and inflammatory response and has been associated with the pathogenesis of osteoarthritis in humans and preclinical models of the disease. Notch2tm1.1Ecan mice harbor a NOTCH2 gain-of-function and are sensitized to osteoarthritis, but the mechanisms have not been explored. We examined the effects of tumor necrosis factor α (TNFα) in chondrocytes from Notch2tm1.1Ecan mice and found that NOTCH2 enhanced the effect of TNFα on Il6 and Il1b expression. Similar results were obtained in cells from a conditional model of NOTCH2 gain-of-function, Notch22.1Ecan mice, and following the expression of the NOTCH2 intracellular domain in vitro. Recombination signal-binding protein for immunoglobulin Kappa J region partners with the NOTCH2 intracellular domain to activate transcription; in the absence of Notch signaling it inhibits transcription, and Rbpj inactivation in chondrocytes resulted in Il6 induction. Although TNFα induced IL6 to a greater extent in the context of NOTCH2 activation, there was a concomitant inhibition of Notch target genes Hes1, Hey1, Hey2, and Heyl. Electrophoretic mobility shift assay demonstrated displacement of recombination signal-binding protein for immunoglobulin Kappa J region from DNA binding sites by TNFα explaining the increased Il6 expression and the concomitant decrease in Notch target genes. NOTCH2 enhanced the effect of TNFα on NF-κB signaling, and RNA-Seq revealed increased expression of pathways associated with inflammation and the phagosome in NOTCH2 overexpressing cells in the absence and presence of TNFα. Collectively, NOTCH2 has important interactions with TNFα resulting in the enhanced expression of Il6 and inflammatory pathways in chondrocytes.
Collapse
Affiliation(s)
- Ernesto Canalis
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, USA; Department of Medicine, UConn Health, Farmington, Connecticut, USA; UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA.
| | - Jungeun Yu
- Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut, USA; UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA
| | - Vijender Singh
- Computational Biology Core, Institute for System Genomics, UConn, Storrs, Connecticut, USA
| | - Magda Mocarska
- UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA
| | - Lauren Schilling
- UConn Musculoskeletal Institute, UConn Health, Farmington, Connecticut, USA
| |
Collapse
|
3
|
FBXL2 promotes E47 protein instability to inhibit breast cancer stemness and paclitaxel resistance. Oncogene 2023; 42:339-350. [PMID: 36460773 DOI: 10.1038/s41388-022-02559-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022]
Abstract
Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with a high risk of metastasis and recurrence. Although chemotherapy has greatly improved the clinical outcome of TNBC patients, acquired drug resistance remains a huge challenge for TNBC treatment. Breast cancer stem cells (BCSCs) play a critical role in breast cancer development, metastasis, recurrence, and chemotherapy resistance. Thus, it is of great importance to decipher the underlying molecular mechanism of BCSCs regulation for TNBC drug resistance. In this study, we demonstrate that the F-box protein FBXL2 is a critical negative regulator of BCSCs stemness and that downregulation of FBXL2 plays a causal role in TNBC drug resistance. We show that expression levels of FBXL2 significantly influence CD44high/CD24low subpopulation and the mammosphere formation ability of TNBC cells. Ectopic expression of FBXL2 inhibits initiation of TNBC and overcomes paclitaxel resistance in vivo. In addition, activation of FBXL2 by nebivolol, a clinically used small-molecule inhibitor of the beta-1 receptor, markedly overcomes BCSCs-induced paclitaxel resistance. Mechanistically, we show that FBXL2 targets transcriptional factor E47 for polyubiquitin- and proteasome-mediated degradation, resulting in inhibition of BCSC stemness. Clinical analyses indicate that low expression of FBXL2 correlates with high expression of E47 as well as with high stemness features, and is associated with poor clinical outcomes of breast cancer patients. Taken together, these results highlight that the FBXL2-E47 axis plays a critical role in the regulation of BCSC stemness and paclitaxel resistance. Thus, targeting FBXL2 might be a potential therapeutic strategy for drug-resistant TNBC.
Collapse
|
4
|
Kumar S, Basu M, Ghosh MK. Chaperone-assisted E3 ligase CHIP: A double agent in cancer. Genes Dis 2021; 9:1521-1555. [PMID: 36157498 PMCID: PMC9485218 DOI: 10.1016/j.gendis.2021.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/06/2021] [Indexed: 12/11/2022] Open
Abstract
The carboxy-terminus of Hsp70-interacting protein (CHIP) is a ubiquitin ligase and co-chaperone belonging to Ubox family that plays a crucial role in the maintenance of cellular homeostasis by switching the equilibrium of the folding-refolding mechanism towards the proteasomal or lysosomal degradation pathway. It links molecular chaperones viz. HSC70, HSP70 and HSP90 with ubiquitin proteasome system (UPS), acting as a quality control system. CHIP contains charged domain in between N-terminal tetratricopeptide repeat (TPR) and C-terminal Ubox domain. TPR domain interacts with the aberrant client proteins via chaperones while Ubox domain facilitates the ubiquitin transfer to the client proteins for ubiquitination. Thus, CHIP is a classic molecule that executes ubiquitination for degradation of client proteins. Further, CHIP has been found to be indulged in cellular differentiation, proliferation, metastasis and tumorigenesis. Additionally, CHIP can play its dual role as a tumor suppressor as well as an oncogene in numerous malignancies, thus acting as a double agent. Here, in this review, we have reported almost all substrates of CHIP established till date and classified them according to the hallmarks of cancer. In addition, we discussed about its architectural alignment, tissue specific expression, sub-cellular localization, folding-refolding mechanisms of client proteins, E4 ligase activity, normal physiological roles, as well as involvement in various diseases and tumor biology. Further, we aim to discuss its importance in HSP90 inhibitors mediated cancer therapy. Thus, this report concludes that CHIP may be a promising and worthy drug target towards pharmaceutical industry for drug development.
Collapse
|
5
|
Dengue virus infection impedes megakaryopoiesis in MEG-01 cells where the virus envelope protein interacts with the transcription factor TAL-1. Sci Rep 2020; 10:19587. [PMID: 33177556 PMCID: PMC7658202 DOI: 10.1038/s41598-020-76350-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 10/08/2020] [Indexed: 12/30/2022] Open
Abstract
Dengue virus (DENV) infection causes dengue fever in humans, which can lead to thrombocytopenia showing a marked reduction in platelet counts, and dengue hemorrhagic fever. The virus may cause thrombocytopenia either by destroying the platelets or by interfering with their generation via the process of megakaryopoiesis. MEG-01 is the human megakaryoblastic leukemia cell line that can be differentiated in vitro by phorbol-12-myristate-13-acetate (PMA) treatment to produce platelet-like-particles (PLPs). We have studied DENV infection of MEG-01 cells to understand its effect on megakaryopoiesis and the generation of PLPs. We observed that DENV could infect only naive MEG-01 cells, and differentiated cells were refractory to virus infection/replication. However, DENV-infected MEG-01 cells, when induced for differentiation with PMA, supported an enhanced viral replication. Following the virus infection, the MEG-01 cells showed a marked reduction in the surface expression of platelet markers (CD41, CD42a, and CD61), a decreased polyploidy, and significantly reduced PLP counts. DENV infection caused an enhanced Notch signaling in MEG-01 cells where the virus envelope protein was shown to interact with TAL-1, a host protein important for megakaryopoiesis. These observations provide new insight into the role of DENV in modulating the megakaryopoiesis and platelet production process.
Collapse
|
6
|
Asmamaw MD, Liu Y, Zheng YC, Shi XJ, Liu HM. Skp2 in the ubiquitin-proteasome system: A comprehensive review. Med Res Rev 2020; 40:1920-1949. [PMID: 32391596 DOI: 10.1002/med.21675] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/26/2020] [Accepted: 04/27/2020] [Indexed: 12/19/2022]
Abstract
The ubiquitin-proteasome system (UPS) is a complex process that regulates protein stability and activity by the sequential actions of E1, E2 and E3 enzymes to influence diverse aspects of eukaryotic cells. However, due to the diversity of proteins in cells, substrate selection is a highly critical part of the process. As a key player in UPS, E3 ubiquitin ligases recruit substrates for ubiquitination specifically. Among them, RING E3 ubiquitin ligases which are the most abundant E3 ubiquitin ligases contribute to diverse cellular processes. The multisubunit cullin-RING ligases (CRLs) are the largest family of RING E3 ubiquitin ligases with tremendous plasticity in substrate specificity and regulate a vast array of cellular functions. The F-box protein Skp2 is a component of CRL1 (the prototype of CRLs) which is expressed in many tissues and participates in multiple cellular functions such as cell proliferation, metabolism, and tumorigenesis by contributing to the ubiquitination and subsequent degradation of several specific tumor suppressors. Most importantly, Skp2 plays a pivotal role in a plethora of cancer-associated signaling pathways. It enhances cell growth, accelerates cell cycle progression, promotes migration and invasion, and inhibits cell apoptosis among others. Hence, targeting Skp2 may represent a novel and attractive strategy for the treatment of different human cancers overexpressing this oncogene. In this review article, we summarized the known roles of Skp2 both in health and disease states in relation to the UPS.
Collapse
Affiliation(s)
- Moges Dessale Asmamaw
- State Key Laboratory of Esophageal Cancer Prevention & Treatment, Key Laboratory of Advanced Drug Preparation Technologies, Henan Key Laboratory of Drug Quality Control & Evaluation, School of Pharmaceutical Sciences, Zhengzhou University, Ministry of Education of China, Zhengzhou, Henan, China
| | - Ying Liu
- State Key Laboratory of Esophageal Cancer Prevention & Treatment, Key Laboratory of Advanced Drug Preparation Technologies, Henan Key Laboratory of Drug Quality Control & Evaluation, School of Pharmaceutical Sciences, Zhengzhou University, Ministry of Education of China, Zhengzhou, Henan, China
| | - Yi-Chao Zheng
- State Key Laboratory of Esophageal Cancer Prevention & Treatment, Key Laboratory of Advanced Drug Preparation Technologies, Henan Key Laboratory of Drug Quality Control & Evaluation, School of Pharmaceutical Sciences, Zhengzhou University, Ministry of Education of China, Zhengzhou, Henan, China
| | - Xiao-Jing Shi
- State Key Laboratory of Esophageal Cancer Prevention & Treatment, Key Laboratory of Advanced Drug Preparation Technologies, Henan Key Laboratory of Drug Quality Control & Evaluation, School of Pharmaceutical Sciences, Zhengzhou University, Ministry of Education of China, Zhengzhou, Henan, China
| | - Hong-Min Liu
- State Key Laboratory of Esophageal Cancer Prevention & Treatment, Key Laboratory of Advanced Drug Preparation Technologies, Henan Key Laboratory of Drug Quality Control & Evaluation, School of Pharmaceutical Sciences, Zhengzhou University, Ministry of Education of China, Zhengzhou, Henan, China
| |
Collapse
|
7
|
Liu J, Peng Y, Zhang J, Long J, Liu J, Wei W. Targeting SCF E3 Ligases for Cancer Therapies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1217:123-146. [PMID: 31898226 DOI: 10.1007/978-981-15-1025-0_9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
SKP1-cullin-1-F-box-protein (SCF) E3 ubiquitin ligase complex is responsible for the degradation of proteins in a strictly regulated manner, through which it exerts pivotal roles in regulating various key cellular processes including cell cycle and division, apoptosis, and differentiation. The substrate specificity of the SCF complex largely depends on the distinct F-box proteins, which function in either tumor promotion or suppression or in a context-dependent manner. Among the 69 F-box proteins identified in human genome, FBW7, SKP2, and β-TRCP have been extensively investigated among various types of cancer in respective of their roles in cancer development, progression, and metastasis. Moreover, several specific inhibitors have been developed to target those E3 ligases, and their efficiency in tumors has been determined. In this review, we provide a summary of the roles of SCF E3 ligases in cancer development, as well as the potential application of miRNA or specific inhibitors for cancer therapy.
Collapse
Affiliation(s)
- Jing Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yunhua Peng
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China.,Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jinfang Zhang
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jiangang Long
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiankang Liu
- Center for Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China.
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
8
|
Seo TW, Lee JS, Choi YN, Jeong DH, Lee SK, Yoo SJ. A novel function of cIAP1 as a mediator of CHIP-driven eIF4E regulation. Sci Rep 2017; 7:9816. [PMID: 28852129 PMCID: PMC5575267 DOI: 10.1038/s41598-017-10358-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/09/2017] [Indexed: 01/04/2023] Open
Abstract
eIF4E is an initiator protein in cap-dependent translation. Its overexpression is linked to tumorigenesis in various human cancers, suggesting that the levels of eIF4E must be under tight control in normal cells. Although several eIF4E regulatory mechanisms have been demonstrated, the intracellular mechanisms controlling eIF4E protein levels remain poorly understood. Here, we report that eIF4E is efficiently regulated by dual mechanisms, both involving human inhibitor of apoptosis family protein cIAP1. cIAP1 itself ubiquitinates eIF4E as an E3 ligase, and interestingly, cIAP1 also functions as a mediator to present eIF4E to another E3 ligase, CHIP. This collaborative activity of cIAP1 and CHIP directs eIF4E toward degradation, controlling its levels and suppressing tumorigenesis. Our results provide the first evidence for a mediator function of cIAP1 and collaborative activity of cIAP1 and CHIP, suggesting that maintaining balanced levels of these E3 ligases might be beneficial for normal cell growth.
Collapse
Affiliation(s)
- Tae Woong Seo
- Department of Biology, Kyung Hee University, Seoul, 02447, Korea
| | - Ji Sun Lee
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Korea.,Department of Biology, Kyung Hee University, Seoul, 02447, Korea
| | - Ye Na Choi
- Department of Biology, Kyung Hee University, Seoul, 02447, Korea
| | - Dar Heum Jeong
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Korea
| | - Sun Kyung Lee
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Korea
| | - Soon Ji Yoo
- Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Korea. .,Department of Biology, Kyung Hee University, Seoul, 02447, Korea.
| |
Collapse
|
9
|
Singh AK, Pati U. CHIP stabilizes amyloid precursor protein via proteasomal degradation and p53-mediated trans-repression of β-secretase. Aging Cell 2015; 14:595-604. [PMID: 25773675 PMCID: PMC4531073 DOI: 10.1111/acel.12335] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2015] [Indexed: 12/22/2022] Open
Abstract
In patient with Alzheimer’s disease (AD), deposition of amyloid-beta Aβ, a proteolytic cleavage of amyloid precursor protein (APP) by β-secretase/BACE1, forms senile plaque in the brain. BACE1 activation is caused due to oxidative stresses and dysfunction of ubiquitin–proteasome system (UPS), which is linked to p53 inactivation. As partial suppression of BACE1 attenuates Aβ generation and AD-related pathology, it might be an ideal target for AD treatment. We have shown that both in neurons and in HEK-APP cells, BACE1 is a new substrate of E3-ligase CHIP and an inverse relation exists between CHIP and BACE1 level. CHIP inhibits ectopic BACE1 level by promoting its ubiquitination and proteasomal degradation, thus reducing APP processing; it stabilizes APP in neurons, thus reducing Aβ. CHIPUbox domain physically interacts with BACE1; however, both U-box and TPR domain are essential for ubiquitination and degradation of BACE1. Further, BACE1 is a downstream target of p53 and overexpression of p53 decreases BACE1 level. In HEK-APP cells, CHIP is shown to negatively regulate BACE1 promoter through stabilization of p53’s DNA-binding conformation and its binding upon 5′ UTR element (+127 to +150). We have thus discovered that CHIP regulates p53-mediated trans-repression of BACE1 at both transcriptional and post-translational level. We propose that a CHIP–BACE1–p53 feedback loop might control APP stabilization, which could further be utilized for new therapeutic intervention in AD.
Collapse
Affiliation(s)
- Amir Kumar Singh
- School of Biotechnology Jawaharlal Nehru University New Delhi 110067 India
| | - Uttam Pati
- School of Biotechnology Jawaharlal Nehru University New Delhi 110067 India
| |
Collapse
|
10
|
Paul I, Ghosh MK. A CHIPotle in physiology and disease. Int J Biochem Cell Biol 2014; 58:37-52. [PMID: 25448416 DOI: 10.1016/j.biocel.2014.10.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 09/21/2014] [Accepted: 10/25/2014] [Indexed: 01/06/2023]
Abstract
The carboxy-terminus of Hsc70 interacting protein (CHIP) is known to function as a chaperone associated E3 ligase for several proteins and regulates a variety of physiological processes. Being a connecting link between molecular chaperones and 26S proteasomes, it is widely regarded as the central player in the cellular protein quality control system. Recent analyses have provided new insights on the biochemical and functional dynamics of CHIP. In this review article, we give a comprehensive account of our current knowledge on the biology of CHIP, which apart from shedding light on fundamental biological questions promises to provide a potential target for therapeutic intervention.
Collapse
Affiliation(s)
- Indranil Paul
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research - Indian Institute of Chemical Biology (CSIR-IICB), 4, Raja S.C. Mullick Road, Kolkata 700032, India
| | - Mrinal K Ghosh
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research - Indian Institute of Chemical Biology (CSIR-IICB), 4, Raja S.C. Mullick Road, Kolkata 700032, India.
| |
Collapse
|
11
|
The E3 ligase CHIP: insights into its structure and regulation. BIOMED RESEARCH INTERNATIONAL 2014; 2014:918183. [PMID: 24868554 PMCID: PMC4017836 DOI: 10.1155/2014/918183] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 04/07/2014] [Indexed: 12/21/2022]
Abstract
The carboxy-terminus of Hsc70 interacting protein (CHIP) is a cochaperone E3 ligase containing three tandem repeats of tetratricopeptide (TPR) motifs and a C-terminal U-box domain separated by a charged coiled-coil region. CHIP is known to function as a central quality control E3 ligase and regulates several proteins involved in a myriad of physiological and pathological processes. Recent studies have highlighted varied regulatory mechanisms operating on the activity of CHIP which is crucial for cellular homeostasis. In this review article, we give a concise account of our current knowledge on the biochemistry and regulation of CHIP.
Collapse
|
12
|
Zhang P, Zhao Y, Sun XH. Notch-regulated periphery B cell differentiation involves suppression of E protein function. THE JOURNAL OF IMMUNOLOGY 2013; 191:726-36. [PMID: 23752615 DOI: 10.4049/jimmunol.1202134] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Notch signaling pathway plays important roles in promoting the generation of marginal zone (MZ) B cells at the expense of follicular (FO) B cells during periphery B cell maturation, but the underlying molecular mechanisms are not well understood. We hypothesize that Notch favors the generation of MZ B cells by downregulating E protein activity. In this study, we demonstrated that expression of Id2 and ankyrin-repeat SOCS box-containing protein 2 was elevated in MZ B cells and by Notch signaling. Id2 inhibits the DNA binding activity of E proteins, whereas ankyrin-repeat SOCS box-containing protein 2 facilitates E protein ubiquitination. Next, we examined the phenotypes of splenic B cells in mice expressing constitutively active Notch1 and/or two gain-of-function mutants of E proteins that counteract Id2-mediated inhibition or Notch-induced degradation. We found that upregulation of E proteins promoted the formation of FO B cells, whereas it suppressed the maturation of MZ B cells. In contrast, excessive amounts of Notch1 stimulated the differentiation of MZ B cells and inhibited the production of FO B cells. More interestingly, the effects of Notch1 were reversed by gain of E protein function. Furthermore, high levels of Bcl-6 expression in FO B cells was shown to be diminished by Notch signaling and restored by E proteins. In addition, E proteins facilitated and Notch hindered the differentiation of transitional B cells. Taken together, it appears that Notch regulates peripheral B cell differentiation, at least in part, through opposing E protein function.
Collapse
Affiliation(s)
- Ping Zhang
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | | | | |
Collapse
|
13
|
Smeets MFMA, Chan AC, Dagger S, Bradley CK, Wei A, Izon DJ. Fli-1 overexpression in hematopoietic progenitors deregulates T cell development and induces pre-T cell lymphoblastic leukaemia/lymphoma. PLoS One 2013; 8:e62346. [PMID: 23667468 PMCID: PMC3646842 DOI: 10.1371/journal.pone.0062346] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 03/20/2013] [Indexed: 12/28/2022] Open
Abstract
The Ets transcription factor Fli-1 is preferentially expressed in hematopoietic tissues and cells, including immature T cells, but the role of Fli-1 in T cell development has not been closely examined. To address this we retrovirally overexpressed Fli-1 in various in vitro and in vivo settings and analysed its effect on T cell development. We found that Fli-1 overexpression perturbed the DN to DP transition and inhibited CD4 development whilst enhancing CD8 development both in vitro and in vivo. Surprisingly, Fli-1 overexpression in vivo eventuated in development of pre-T cell lymphoblastic leukaemia/lymphoma (pre-T LBL). Known Fli-1 target genes such as the pro-survival Bcl-2 family members were not found to be upregulated. In contrast, we found increased NOTCH1 expression in all Fli-1 T cells and detected Notch1 mutations in all tumours. These data show a novel function for Fli-1 in T cell development and leukaemogenesis and provide a new mouse model of pre-T LBL to identify treatment options that target the Fli-1 and Notch1 signalling pathways.
Collapse
Affiliation(s)
- Monique F. M. A. Smeets
- Haematology and Leukaemia Unit, St. Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
| | - Angela C. Chan
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Samantha Dagger
- School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia
| | | | - Andrew Wei
- Department of Clinical Haematology, The Alfred Hospital and The Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - David J. Izon
- Haematology and Leukaemia Unit, St. Vincent’s Institute, University of Melbourne, Fitzroy, Victoria, Australia
- * E-mail:
| |
Collapse
|
14
|
Qu X, Afelik S, Jensen JN, Bukys MA, Kobberup S, Schmerr M, Xiao F, Nyeng P, Veronica Albertoni M, Grapin-Botton A, Jensen J. Notch-mediated post-translational control of Ngn3 protein stability regulates pancreatic patterning and cell fate commitment. Dev Biol 2013; 376:1-12. [DOI: 10.1016/j.ydbio.2013.01.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 01/18/2013] [Accepted: 01/19/2013] [Indexed: 01/17/2023]
|
15
|
Wei S, Chu PC, Chuang HC, Hung WC, Kulp SK, Chen CS. Targeting the oncogenic E3 ligase Skp2 in prostate and breast cancer cells with a novel energy restriction-mimetic agent. PLoS One 2012; 7:e47298. [PMID: 23071779 PMCID: PMC3470570 DOI: 10.1371/journal.pone.0047298] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/12/2012] [Indexed: 11/18/2022] Open
Abstract
Substantial evidence supports the oncogenic role of the E3 ubiquitin ligase S-phase kinase-associated protein 2 (Skp2) in many types of cancers through its ability to target a broad range of signaling effectors for ubiquitination. Thus, this oncogenic E3 ligase represents an important target for cancer drug discovery. In this study, we report a novel mechanism by which CG-12, a novel energy restriction-mimetic agent (ERMA), down-regulates the expression of Skp2 in prostate cancer cells. Pursuant to our previous finding that upregulation of β-transducin repeat-containing protein (β-TrCP) expression represents a cellular response in cancer cells to ERMAs, including CG-12 and 2-deoxyglucose, we demonstrated that this β-TrCP accumulation resulted from decreased Skp2 expression. Evidence indicates that Skp2 targets β-TrCP for degradation via the cyclin-dependent kinase 2-facilitated recognition of the proline-directed phosphorylation motif 412SP. This Skp2 downregulation was attributable to Sirt1-dependent suppression of COP9 signalosome (Csn)5 expression in response to CG-12, leading to increased cullin 1 neddylation in the Skp1-cullin1-F-box protein complex and consequent Skp2 destabilization. Moreover, we determined that Skp2 and β-TrCP are mutually regulated, providing a feedback mechanism that amplifies the suppressive effect of ERMAs on Skp2. Specifically, cellular accumulation of β-TrCP reduced the expression of Sp1, a β-TrCP substrate, which, in turn, reduced Skp2 gene expression. This Skp2-β-TrCP-Sp1 feedback loop represents a novel crosstalk mechanism between these two important F-box proteins in cancer cells with aberrant Skp2 expression under energy restriction, which provides a proof-of-concept that the oncogenic Csn5/Skp2 signaling axis represents a “druggable” target for this novel ERMA.
Collapse
Affiliation(s)
- Shuo Wei
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Po-Chen Chu
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Hsiao-Ching Chuang
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Wen-Chun Hung
- National Institute of Cancer Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan
| | - Samuel K. Kulp
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
| | - Ching-Shih Chen
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America
- Institute of Basic Medical Sciences, National Cheng-Kung University, Tainan, Taiwan
- * E-mail:
| |
Collapse
|
16
|
The ubiquitin ligase CHIP regulates c-Myc stability and transcriptional activity. Oncogene 2012; 32:1284-95. [DOI: 10.1038/onc.2012.144] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
17
|
Slotman JA, da Silva Almeida AC, Hassink GC, van de Ven RHA, van Kerkhof P, Kuiken HJ, Strous GJ. Ubc13 and COOH terminus of Hsp70-interacting protein (CHIP) are required for growth hormone receptor endocytosis. J Biol Chem 2012; 287:15533-43. [PMID: 22433856 DOI: 10.1074/jbc.m111.302521] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Growth hormone receptor (GHR) endocytosis is a highly regulated process that depends on the binding and activity of the multimeric ubiquitin ligase, SCF(βTrCP) (Skp Cullin F-box). Despite a specific interaction between β-transducin repeat-containing protein (βTrCP) and the GHR, and a strict requirement for ubiquitination activity, the receptor is not an obligatory target for SCF(βTrCP)-directed Lys(48) polyubiquitination. We now show that also Lys(63)-linked ubiquitin chain formation is required for GHR endocytosis. We identified both the ubiquitin-conjugating enzyme Ubc13 and the ubiquitin ligase COOH terminus of Hsp70 interacting protein (CHIP) as being connected to this process. Ubc13 activity and its interaction with CHIP precede endocytosis of GHR. In addition to βTrCP, CHIP interacts specifically with the cytosolic tails of the dimeric GHR, identifying both Ubc13 and CHIP as novel factors in the regulation of cell surface availability of GHR.
Collapse
Affiliation(s)
- Johan A Slotman
- Department of Cell Biology, University Medical Center Utrecht and Institute of Biomembranes, 3584 CX Utrecht, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
18
|
Courtial N, Smink JJ, Kuvardina ON, Leutz A, Göthert JR, Lausen J. Tal1 regulates osteoclast differentiation through suppression of the master regulator of cell fusion DC-STAMP. FASEB J 2011; 26:523-32. [PMID: 21990371 DOI: 10.1096/fj.11-190850] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The balance between bone-forming osteoblasts and bone-resorbing osteoclasts is crucial to bone homeostasis, an equilibrium that is disturbed in many bone diseases. The transcription factor Tal1 is involved in the establishment of hematopoietic stem cells in the embryo and is a master regulator of hematopoietic gene expression in the adult. Here, we show that Tal1 is expressed in osteoclasts and that loss of Tal1 in osteoclast progenitors leads to altered expression of >1200 genes. We found that DC-STAMP, a key regulator of osteoclast cell fusion, is a direct target gene of Tal1 and show that Tal1 represses DC-STAMP expression by counteracting the activating function of the transcription factors PU.1 and MITF. The identification of Tal1 as a factor involved in cell fusion contributes to the understanding of osteoclast-associated diseases, including osteoporosis.
Collapse
Affiliation(s)
- Nadine Courtial
- Georg-Speyer-Haus, Institute for Biomedical Research, Frankfurt, Germany
| | | | | | | | | | | |
Collapse
|
19
|
Role of helix-loop-helix proteins during differentiation of erythroid cells. Mol Cell Biol 2011; 31:1332-43. [PMID: 21282467 DOI: 10.1128/mcb.01186-10] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Helix-loop-helix (HLH) proteins play a profound role in the process of development and cellular differentiation. Among the HLH proteins expressed in differentiating erythroid cells are the ubiquitous proteins Myc, USF1, USF2, and TFII-I, as well as the hematopoiesis-specific transcription factor Tal1/SCL. All of these HLH proteins exhibit distinct functions during the differentiation of erythroid cells. For example, Myc stimulates the proliferation of erythroid progenitor cells, while the USF proteins and Tal1 regulate genes that specify the differentiated phenotype. This minireview summarizes the known activities of Myc, USF, TFII-I, and Tal11/SCL and discusses how they may function sequentially, cooperatively, or antagonistically in regulating expression programs during the differentiation of erythroid cells.
Collapse
|
20
|
Nie L, Zhao Y, Wu W, Yang YZ, Wang HC, Sun XH. Notch-induced Asb2 expression promotes protein ubiquitination by forming non-canonical E3 ligase complexes. Cell Res 2010; 21:754-69. [PMID: 21119685 DOI: 10.1038/cr.2010.165] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Notch signaling controls multiple developmental processes, thus demanding versatile functions. We have previously shown that this may be partly achieved by accelerating ubiquitin-mediated degradation of important regulators of differentiation. However, the underlying mechanism was unknown. We now find that Notch signaling transcriptionally activates the gene encoding ankyrin-repeat SOCS box-containing protein 2 (Asb2). Asb2 promotes the ubiquitination of Notch targets such as E2A and Janus kinase (Jak) 2, and a dominant-negative (DN) mutant of Asb2 blocks Notch-induced degradation of these proteins. Asb2 likely binds Jak2 directly but associates with E2A through Skp2. We next provide evidence to suggest that Asb2 bridges the formation of non-canonical cullin-based complexes through interaction with not only ElonginB/C and Cullin (Cul) 5, but also the F-box-containing protein, Skp2, which is known to associate with Skp1 and Cul1. Consistently, ablating the function of Cul1 or Cul5 using DN mutants or siRNAs protected both E2A and Jak2 from Asb2-mediated or Notch-induced degradation. By shifting monomeric E3 ligase complexes to dimeric forms through activation of Asb2 transcription, Notch could effectively control the turnover of a variety of substrates and it exerts diverse effects on cell proliferation and differentiation.
Collapse
Affiliation(s)
- Lei Nie
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
| | | | | | | | | | | |
Collapse
|
21
|
Panepucci RA, Oliveira LHB, Zanette DL, Viu Carrara RDC, Araujo AG, Orellana MD, Bonini de Palma PV, Menezes CCBO, Covas DT, Zago MA. Increased levels of NOTCH1, NF-kappaB, and other interconnected transcription factors characterize primitive sets of hematopoietic stem cells. Stem Cells Dev 2010; 19:321-32. [PMID: 19686049 DOI: 10.1089/scd.2008.0397] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
As previously shown, higher levels of NOTCH1 and increased NF-kappaB signaling is a distinctive feature of the more primitive umbilical cord blood (UCB) CD34+ hematopoietic stem cells (HSCs), as compared to bone marrow (BM). Differences between BM and UCB cell composition also account for this finding. The CD133 marker defines a more primitive cell subset among CD34+ HSC with a proposed hemangioblast potential. To further evaluate the molecular basis related to the more primitive characteristics of UCB and CD133+ HSC, immunomagnetically purified human CD34+ and CD133+ cells from BM and UCB were used on gene expression microarrays studies. UCB CD34+ cells contained a significantly higher proportion of CD133+ cells than BM (70% and 40%, respectively). Cluster analysis showed that BM CD133+ cells grouped with the UCB cells (CD133+ and CD34+) rather than to BM CD34+ cells. Compared with CD34+ cells, CD133+ had a higher expression of many transcription factors (TFs). Promoter analysis on all these TF genes revealed a significantly higher frequency (than expected by chance) of NF-kappaB-binding sites (BS), including potentially novel NF-kappaB targets such as RUNX1, GATA3, and USF1. Selected transcripts of TF related to primitive hematopoiesis and self-renewal, such as RUNX1, GATA3, USF1, TAL1, HOXA9, HOXB4, NOTCH1, RELB, and NFKB2 were evaluated by real-time PCR and were all significantly positively correlated. Taken together, our data indicate the existence of an interconnected transcriptional network characterized by higher levels of NOTCH1, NF-kappaB, and other important TFs on more primitive HSC sets.
Collapse
Affiliation(s)
- Rodrigo Alexandre Panepucci
- Department of Clinical Medicine of the Faculty of Medicine of Ribeirao Preto-USP, Center for Cell Therapy and Regional Blood Center, Araraquara, São Paulo, Brazil.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Tang Y, Urs S, Boucher J, Bernaiche T, Venkatesh D, Spicer DB, Vary CPH, Liaw L. Notch and transforming growth factor-beta (TGFbeta) signaling pathways cooperatively regulate vascular smooth muscle cell differentiation. J Biol Chem 2010; 285:17556-63. [PMID: 20368328 PMCID: PMC2878520 DOI: 10.1074/jbc.m109.076414] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 03/05/2010] [Indexed: 12/29/2022] Open
Abstract
Notch and transforming growth factor-beta (TGFbeta) play pivotal roles during vascular development and the pathogenesis of vascular disease. The interaction of these two pathways is not fully understood. The present study utilized primary human smooth muscle cells (SMC) to examine molecular cross-talk between TGFbeta1 and Notch signaling on contractile gene expression. Activation of Notch signaling using Notch intracellular domain or Jagged1 ligand induced smooth muscle alpha-actin (SM actin), smooth muscle myosin heavy chain, and calponin1, and the expression of Notch downstream effectors hairy-related transcription factors. Similarly, TGFbeta1 treatment of human aortic smooth muscle cells induced SM actin, calponin1, and smooth muscle protein 22-alpha (SM22alpha) in a dose- and time-dependent manner. Hairy-related transcription factor proteins, which antagonize Notch activity, also suppressed the TGFbeta1-induced increase in SMC markers, suggesting a general mechanism of inhibition. We found that Notch and TGFbeta1 cooperatively activate SMC marker transcripts and protein through parallel signaling axes. Although the intracellular domain of Notch4 interacted with phosphoSmad2/3 in SMC, this interaction was not observed with Notch1 or Notch2. However, we found that CBF1 co-immunoprecipitated with phosphoSmad2/3, suggesting a mechanism to link canonical Notch signaling to phosphoSmad activity. Indeed, the combination of Notch activation and TGFbeta1 treatment led to synergistic activation of a TGFbeta-responsive promoter. This increase corresponded to increased levels of phosphoSmad2/3 interaction at Smad consensus binding sites within the SM actin, calponin1, and SM22alpha promoters. Thus, Notch and TGFbeta coordinately induce a molecular and functional contractile phenotype by co-regulation of Smad activity at SMC promoters.
Collapse
Affiliation(s)
- Yuefeng Tang
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Sumithra Urs
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Joshua Boucher
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Tyler Bernaiche
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Deepak Venkatesh
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Douglas B. Spicer
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Calvin P. H. Vary
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Lucy Liaw
- From the Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| |
Collapse
|
23
|
Askew EB, Bai S, Hnat AT, Minges JT, Wilson EM. Melanoma antigen gene protein-A11 (MAGE-11) F-box links the androgen receptor NH2-terminal transactivation domain to p160 coactivators. J Biol Chem 2009; 284:34793-808. [PMID: 19828458 DOI: 10.1074/jbc.m109.065979] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Androgen-dependent transcriptional activity by the androgen receptor (AR) and its coregulators is required for male reproductive development and function. In humans and other primates, melanoma antigen gene protein-A11 (MAGE-11) is an AR selective coregulator that increases AR transcriptional activity. Here we show that the interaction between AR and MAGE-11 is mediated by AR NH(2)-terminal FXXLF motif binding to a highly conserved MAGE-11 F-box in the MAGE homology domain, and is modulated by serum stimulation of mitogen-activated protein kinase phosphorylation of MAGE-11 Ser-174. The MAGE-11-dependent increase in AR transcriptional activity is mediated by a direct interaction between MAGE-11 and transcriptional intermediary factor 2 (TIF2) through the NH(2)-terminal region of TIF2, and by a MAGE-11 FXXIF motif interaction with an F-box-like region in activation domain 1 of TIF2. The results suggest that MAGE-11 functions as a bridging factor to recruit AR coactivators through a novel FXX(L/I)F motif-F-box interaction paradigm.
Collapse
Affiliation(s)
- Emily B Askew
- Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599-7500, USA
| | | | | | | | | |
Collapse
|
24
|
|
25
|
TGF-β induces degradation of TAL1/SCL by the ubiquitin-proteasome pathway through AKT-mediated phosphorylation. Blood 2009; 113:6695-8. [DOI: 10.1182/blood-2008-07-166835] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Abstract
T-cell acute lymphoblastic leukemia 1 (TAL1), also known as stem cell leukemia (SCL), plays important roles in differentiation of hematopoietic and endothelial cells and is deregulated in a high percentage of T-cell acute lymphoblastic leukemia (T-ALL). In this report we show that the intracellular concentration of TAL1 is regulated by transforming growth factor β (TGF-β), which triggers its polyubiquitylation and degradation by the proteasome. This effect is mediated by AKT1, which phosphorylates TAL1 at threonine 90. Immunoprecipitation experiments showed that this event increases association of TAL1 with the E3 ubiquitin ligase CHIP. The E47 heterodimerization partner of TAL1 hinders this association. Our observations indicate that activation of the TGF-β and phosphatidylinositol 3-kinase/AKT pathways might reverse overexpression of TAL1 in leukemic cells by inducing proteolysis of this important oncogene.
Collapse
|
26
|
Mathieu D. [The bHLH TAL1 protein: a key molecule in the hematopoietic and endothelial systems]. JOURNAL DE LA SOCIETE DE BIOLOGIE 2009; 203:143-53. [PMID: 19527627 DOI: 10.1051/jbio/2009017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The formation of blood cells and vascular networks occurs simultaneously during development, and both lineages remain in close association in all adult tissues. The functional setting of both systems within the embryo and their renewal during adult life are highly complex processes, and require the involvement of numerous molecular actors, the activities of which are often overlapping. Here, I review the activity of TAL-1, a basic-helix-loop-helix transcription factor, which plays a key role in the formation and functioning of both blood and endothelial systems, with a particular emphasis on recent data that associate TAL-1 with angiogenesis.
Collapse
Affiliation(s)
- Danièle Mathieu
- Institut de Génétique Moléculaire, CNRS-UMR 5535, Universités de Montpellier 1 et Montpellier 2, 1919 route de Mende, 34293 Montpellier Cedex 1, France.
| |
Collapse
|
27
|
The transcriptional program controlled by the stem cell leukemia gene Scl/Tal1 during early embryonic hematopoietic development. Blood 2009; 113:5456-65. [PMID: 19346495 DOI: 10.1182/blood-2009-01-200048] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The basic helix-loop-helix transcription factor Scl/Tal1 controls the development and subsequent differentiation of hematopoietic stem cells (HSCs). However, because few Scl target genes have been validated to date, the underlying mechanisms have remained largely unknown. In this study, we have used ChIP-Seq technology (coupling chromatin immunoprecipitation with deep sequencing) to generate a genome-wide catalog of Scl-binding events in a stem/progenitor cell line, followed by validation using primary fetal liver cells and comprehensive transgenic mouse assays. Transgenic analysis provided in vivo validation of multiple new direct Scl target genes and allowed us to reconstruct an in vivo validated network consisting of 17 factors and their respective regulatory elements. By coupling ChIP-Seq in model cell lines with in vivo transgenic validation and sophisticated bioinformatic analysis, we have identified a widely applicable strategy for the reconstruction of stem cell regulatory networks in which biologic material is otherwise limiting. Moreover, in addition to revealing multiple previously unrecognized links to known HSC regulators, as well as novel links to genes not previously implicated in HSC function, comprehensive transgenic analysis of regulatory elements provided substantial new insights into the transcriptional control of several important hematopoietic regulators, including Cbfa2t3h/Eto2, Cebpe, Nfe2, Zfpm1/Fog1, Erg, Mafk, Gfi1b, and Myb.
Collapse
|
28
|
Shin M, Nagai H, Sheng G. Notch mediates Wnt and BMP signals in the early separation of smooth muscle progenitors and blood/endothelial common progenitors. Development 2009; 136:595-603. [DOI: 10.1242/dev.026906] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During embryonic development in amniotes, the extraembryonic mesoderm,where the earliest hematopoiesis and vasculogenesis take place, also generates smooth muscle cells (SMCs). It is not well understood how the differentiation of SMCs is linked to that of blood (BCs) and endothelial (ECs) cells. Here we show that, in the chick embryo, the SMC lineage is marked by the expression of a bHLH transcription factor, dHand. Notch activity in nascent ventral mesoderm cells promotes SMC progenitor formation and mediates the separation of SMC and BC/EC common progenitors marked by another bHLH factor, Scl. This is achieved by crosstalk with the BMP and Wnt pathways,which are involved in mesoderm ventralization and SMC lineage induction,respectively. Our findings reveal a novel role of the Notch pathway in early ventral mesoderm differentiation, and suggest a stepwise separation among its three main lineages, first between SMC progenitors and BC/EC common progenitors, and then between BCs and ECs.
Collapse
Affiliation(s)
- Masahiro Shin
- RIKEN Center for Developmental Biology, Laboratory for Early Embryogenesis, Kobe, Hyogo 650-0047, Japan
| | - Hiroki Nagai
- RIKEN Center for Developmental Biology, Laboratory for Early Embryogenesis, Kobe, Hyogo 650-0047, Japan
| | - Guojun Sheng
- RIKEN Center for Developmental Biology, Laboratory for Early Embryogenesis, Kobe, Hyogo 650-0047, Japan
| |
Collapse
|
29
|
Frescas D, Pagano M. Deregulated proteolysis by the F-box proteins SKP2 and beta-TrCP: tipping the scales of cancer. Nat Rev Cancer 2008; 8:438-49. [PMID: 18500245 PMCID: PMC2711846 DOI: 10.1038/nrc2396] [Citation(s) in RCA: 721] [Impact Index Per Article: 45.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The maintenance and preservation of distinct phases during the cell cycle is a highly complex and coordinated process. It is regulated by phosphorylation--through the activity of cyclin-dependent kinases (CDKs)--and protein degradation, which occurs through ubiquitin ligases such as SCF (SKP1-CUL1-F-box protein) complexes and APC/C (anaphase-promoting complex/cyclosome). Here, we explore the functionality and biology of the F-box proteins, SKP2 (S-phase kinase-associated protein 2) and beta-TrCP (beta-transducin repeat-containing protein), which are emerging as important players in cancer biogenesis owing to the deregulated proteolysis of their substrates.
Collapse
Affiliation(s)
- David Frescas
- Department of Pathology, NYU Cancer Institute, New York University School of Medicine, 550 First Avenue, New York, New York 10016, USA
| | | |
Collapse
|