1
|
Khan MA, Yumak S, Miyoshi H. Poly(A)-binding protein promotes VPg-dependent translation of potyvirus through enhanced binding of phosphorylated eIFiso4F and eIFiso4F∙eIF4B. PLoS One 2024; 19:e0300287. [PMID: 38696388 PMCID: PMC11065315 DOI: 10.1371/journal.pone.0300287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 02/24/2024] [Indexed: 05/04/2024] Open
Abstract
The phosphorylation of eukaryotic translational initiation factors has been shown to play a significant role in controlling the synthesis of protein. Viral infection, environmental stress, and growth circumstances cause phosphorylation or dephosphorylation of plant initiation factors. Our findings indicate that casein kinase 2 can phosphorylate recombinant wheat eIFiso4E and eIFiso4G generated from E. coli in vitro. For wheat eIFiso4E, Ser-207 was found to be the in vitro phosphorylation site. eIFiso4E lacks an amino acid that can be phosphorylated at the position corresponding to Ser-209, the phosphorylation site in mammalian eIF4E, yet phosphorylation of eIFiso4E has effects on VPg binding affinity that are similar to those of phosphorylation of mammalian eIF4E. The addition of VPg and phosphorylated eIFiso4F to depleted wheat germ extract (WGE) leads to enhancement of translation of both uncapped and capped viral mRNA. The addition of PABP together with eIFiso4Fp and eIF4B to depleted WGE increases both uncapped and capped mRNA translation. However, it exhibits a translational advantage specifically for uncapped mRNA, implying that the phosphorylation of eIFiso4F hinders cap binding while promoting VPg binding, thereby facilitating uncapped translation. These findings indicate TEV virus mediates VPg-dependent translation by engaging a mechanism entailing phosphorylated eIFiso4Fp and PABP. To elucidate the molecular mechanisms underlying these observed effects, we studied the impact of PABP and/or eIF4B on the binding of VPg with eIFiso4Fp. The inclusion of PABP and eIF4B with eIFiso4Fp resulted in about 2-fold increase in affinity for VPg (Kd = 24 ± 1.7 nM), as compared to the affinity of eIFiso4Fp alone (Kd = 41.0 ± 3.1 nM). The interactions between VPg and eIFiso4Fp were determined to be both enthalpically and entropically favorable, with the enthalpic contribution accounting for 76-97% of the ΔG at 25°C, indicating a substantial role of hydrogen bonding in enhancing the stability of the complex. The binding of PABP to eIFiso4Fp·4B resulted in a conformational alteration, leading to a significant enhancement in the binding affinity to VPg. These observations suggest PABP enhances the affinity between eIFiso4Fp and VPg, leading to an overall conformational change that provides a stable platform for efficient viral translation.
Collapse
Affiliation(s)
- Mateen A. Khan
- Department of Life Sciences, College of Science and General Studies, Alfaisal University Riyadh, Riyadh, Saudi Arabia
| | - Sumeyra Yumak
- Department of Science, Borough of Manhattan Community College, City University of New York, New York, NY, United States of America
| | - Hiroshi Miyoshi
- Department of Microbiology, St. Marianna University School of Medicine, Kawasaki, Japan
| |
Collapse
|
2
|
Attia RT, Ewida MA, Khaled E, Fahmy SA, Fawzy IM. Newly Synthesized Anticancer Purine Derivatives Inhibiting p-EIF4E Using Surface-Modified Lipid Nanovesicles. ACS OMEGA 2023; 8:37864-37881. [PMID: 37867723 PMCID: PMC10586017 DOI: 10.1021/acsomega.3c02991] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/15/2023] [Indexed: 10/24/2023]
Abstract
Translation of mRNA is one of the processes adopted by cancer cells to maintain survival via phosphorylated (p)-eIF4E overexpression. Once p-eIF4E binds to the cap structure of mRNA, it advocates a nonstop translation process. In this regard, 15 new-based GMP analogs were synthesized to target eIF4E and restrain its binding to cap mRNA. The compounds were tested against three types of cancer cell lines: Caco-2, HepG-2, MCF-7, and normal kidney cells (Vero cells). Most of the compounds showed high potency against breast cancer cells (MCF-7), characterized by the highest cancer type for overexpression of p-eIF4E. Compound 4b was found to be the most active against three cell lines, colon (Caco-2), hepatic (HepG-2), and breast (MCF-7), with positive IC50 values of 31.40, 27.15, and 21.71 μM, respectively. Then, chitosan-coated niosomes loaded with compound 4b (Cs/4b-NSs) were developed (as kinetically enhanced molecules) to improve the anticancer effects further. The prepared Cs/4b-NSs showed pronounced cytotoxicity compared to the free 4b against Caco2, Hepg2, and MCF-7 with IC50 values of 16.15, 26.66, and 6.90 μM, respectively. Then, the expression of both the phosphorylated and nonphosphorylated western blot techniques was conducted on MCF-7 cells treated with the most active compounds (based on the obtained IC50 values) to determine the total protein expression of both eIF4E and p-eIF4e. Interestingly, the selected most active compounds displayed 35.8-40.7% inhibition of p-eIF4E expression when evaluated on MCF-7 compared to Ribavirin (positive control). CS/4b-NSs showed the best inhibition (40.7%). The findings of the present joint in silico molecular docking, simulation dynamic studies, and experimental investigation suggest the potential use of niosomal nanovesicles as a promising nanocarrier for the targeted delivery of the newly synthesized compound 4b to eukaryotic initiation factor 4E. These outcomes support the possible use of Cs/4b-NSs in targeted cancer therapy.
Collapse
Affiliation(s)
- Reem T. Attia
- Department
of Pharmacology and Toxicology and Biochemistry, Faculty of Pharmacy, Future University in Egypt, Cairo 11835, Egypt
| | - Menna A. Ewida
- Department
of Pharmaceutical Chemistry, Faculty of Pharmacy, Future University in Egypt, Cairo 11835, Egypt
| | - Eman Khaled
- Faculty
of Pharmacy, Future University in Egypt, Cairo 11835, Egypt
| | - Sherif Ashraf Fahmy
- Chemistry
Department, School of Life and Medical Sciences, University of Hertfordshire Hosted by Global Academic Foundation, R5 New Garden City, New Administrative Capital, Cairo 11835, Egypt
| | - Iten M. Fawzy
- Department
of Pharmaceutical Chemistry, Faculty of Pharmacy, Future University in Egypt, Cairo 11835, Egypt
| |
Collapse
|
3
|
Lukaszewicz M, Mrozek AF, Bojarska E, Stelmach J, Stepinski J, Darzynkiewicz E. Contribution of Nudt12 enzyme to differentially methylated dinucleotides of 5'RNA cap structure. Biochim Biophys Acta Gen Subj 2023:130400. [PMID: 37301333 DOI: 10.1016/j.bbagen.2023.130400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/17/2023] [Accepted: 06/04/2023] [Indexed: 06/12/2023]
Abstract
Recent findings have substantially broadened our knowledge about the diversity of modifications of the 5'end of RNAs, an issue generally attributed to mRNA cap structure (m7GpppN). Nudt12 is one of the recently described new enzymatic activities involved in cap metabolism. However, in contrast to its roles in metabolite-cap turnover (e.g., NAD-cap) and NADH/NAD metabolite hydrolysis, little is known regarding its hydrolytic activity towards dinucleotide cap structures. In order to gain further insight into this Nudt12 activity, comprehensive analysis with a spectrum of cap-like dinucleotides was performed with respect to different nucleotide types adjacent to the (m7)G moiety and its methylation status. Among the tested compounds, GpppA, GpppAm, and Gpppm6Am were identified as novel potent Nudt12 substrates, with KM values in the same range as that of NADH. Interestingly, substrate inhibition of Nudt12 catalytic activity was detected in the case of the GpppG dinucleotide, a phenomenon not reported to date. Finally, comparison of Nudt12 with DcpS and Nud16, two other enzymes with known activity on dinucleotide cap structures, revealed their overlapping and more specific substrates. Altogether, these findings provide a basis for clarifying the role of Nudt12 in cap-like dinucleotide turnover.
Collapse
Affiliation(s)
- Maciej Lukaszewicz
- Department of Biophysics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland.
| | - Aleksandra-Ferenc Mrozek
- Department of Biophysics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Elzbieta Bojarska
- Department of Biophysics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Joanna Stelmach
- Department of Biophysics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Janusz Stepinski
- Department of Biophysics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Edward Darzynkiewicz
- Department of Biophysics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| |
Collapse
|
4
|
Bartish M, Abraham MJ, Gonçalves C, Larsson O, Rolny C, Del Rincón SV. The role of eIF4F-driven mRNA translation in regulating the tumour microenvironment. Nat Rev Cancer 2023; 23:408-425. [PMID: 37142795 DOI: 10.1038/s41568-023-00567-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/27/2023] [Indexed: 05/06/2023]
Abstract
Cells can rapidly adjust their proteomes in dynamic environments by regulating mRNA translation. There is mounting evidence that dysregulation of mRNA translation supports the survival and adaptation of cancer cells, which has stimulated clinical interest in targeting elements of the translation machinery and, in particular, components of the eukaryotic initiation factor 4F (eIF4F) complex such as eIF4E. However, the effect of targeting mRNA translation on infiltrating immune cells and stromal cells in the tumour microenvironment (TME) has, until recently, remained unexplored. In this Perspective article, we discuss how eIF4F-sensitive mRNA translation controls the phenotypes of key non-transformed cells in the TME, with an emphasis on the underlying therapeutic implications of targeting eIF4F in cancer. As eIF4F-targeting agents are in clinical trials, we propose that a broader understanding of their effect on gene expression in the TME will reveal unappreciated therapeutic vulnerabilities that could be used to improve the efficacy of existing cancer therapies.
Collapse
Affiliation(s)
- Margarita Bartish
- Department of Oncology, Faculty of Medicine, McGill University, Montreal, QC, Canada
- Segal Cancer Center, Lady Davis Institute and Jewish General Hospital, Montreal, QC, Canada
- Science for Life Laboratory, Stockholm, Sweden
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Madelyn J Abraham
- Department of Oncology, Faculty of Medicine, McGill University, Montreal, QC, Canada
- Segal Cancer Center, Lady Davis Institute and Jewish General Hospital, Montreal, QC, Canada
| | - Christophe Gonçalves
- Department of Oncology, Faculty of Medicine, McGill University, Montreal, QC, Canada
- Segal Cancer Center, Lady Davis Institute and Jewish General Hospital, Montreal, QC, Canada
| | - Ola Larsson
- Science for Life Laboratory, Stockholm, Sweden
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Charlotte Rolny
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden.
| | - Sonia V Del Rincón
- Department of Oncology, Faculty of Medicine, McGill University, Montreal, QC, Canada.
- Segal Cancer Center, Lady Davis Institute and Jewish General Hospital, Montreal, QC, Canada.
| |
Collapse
|
5
|
Loan Young T, Chang Wang K, James Varley A, Li B. Clinical Delivery of Circular RNA: Lessons Learned from RNA Drug Development. Adv Drug Deliv Rev 2023; 197:114826. [PMID: 37088404 DOI: 10.1016/j.addr.2023.114826] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/28/2023] [Accepted: 04/11/2023] [Indexed: 04/25/2023]
Abstract
Circular RNAs (circRNA) represent a distinct class of covalently closed-loop RNA molecules, which play diverse roles in regulating biological processes and disease states. The enhanced stability of synthetic circRNAs compared to their linear counterparts has recently garnered considerable research interest, paving the way for new therapeutic applications. While clinical circRNA technology is still in its early stages, significant advancements in mRNA technology offer valuable insights into its potential future applications. Two primary obstacles that must be addressed are the development of efficient production methods and the optimization of delivery systems. To expedite progress in this area, this review aims to provide an overview of the current state of knowledge on circRNA structure and function, outline recent techniques for synthesizing circRNAs, highlight key delivery strategies and applications, and discuss the current challenges and future prospects in the field of circRNA-based therapeutics.
Collapse
Affiliation(s)
- Tiana Loan Young
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Kevin Chang Wang
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Andrew James Varley
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Bowen Li
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3M2, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C1, Canada.
| |
Collapse
|
6
|
Sharma A, Nair R, Achreja A, Mittal A, Gupta P, Balakrishnan K, Edgar CL, Animasahun O, Dwivedi B, Barwick BG, Gupta VA, Matulis SM, Bhasin M, Lonial S, Nooka AK, Wiita AP, Boise LH, Nagrath D, Shanmugam M. Therapeutic implications of mitochondrial stress-induced proteasome inhibitor resistance in multiple myeloma. SCIENCE ADVANCES 2022; 8:eabq5575. [PMID: 36170375 PMCID: PMC9519052 DOI: 10.1126/sciadv.abq5575] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The connections between metabolic state and therapy resistance in multiple myeloma (MM) are poorly understood. We previously reported that electron transport chain (ETC) suppression promotes sensitivity to the BCL-2 antagonist venetoclax. Here, we show that ETC suppression promotes resistance to proteasome inhibitors (PIs). Interrogation of ETC-suppressed MM reveals integrated stress response-dependent suppression of protein translation and ubiquitination, leading to PI resistance. ETC and protein translation gene expression signatures from the CoMMpass trial are down-regulated in patients with poor outcome and relapse, corroborating our in vitro findings. ETC-suppressed MM exhibits up-regulation of the cystine-glutamate antiporter SLC7A11, and analysis of patient single-cell RNA-seq shows that clusters with low ETC gene expression correlate with higher SLC7A11 expression. Furthermore, erastin or venetoclax treatment diminishes mitochondrial stress-induced PI resistance. In sum, our work demonstrates that mitochondrial stress promotes PI resistance and underscores the need for implementing combinatorial regimens in MM cognizant of mitochondrial metabolic state.
Collapse
Affiliation(s)
- Aditi Sharma
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Remya Nair
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Abhinav Achreja
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Anjali Mittal
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Pulkit Gupta
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Kamakshi Balakrishnan
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Claudia L. Edgar
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Olamide Animasahun
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Bhakti Dwivedi
- Department of Biostatistics and Bioinformatics Shared Resource, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Benjamin G. Barwick
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Vikas A. Gupta
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Shannon M. Matulis
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Manoj Bhasin
- Department of Biostatistics and Bioinformatics Shared Resource, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | - Sagar Lonial
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Ajay K. Nooka
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Arun P. Wiita
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Lawrence H. Boise
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
| | - Deepak Nagrath
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Mala Shanmugam
- Department of Hematology and Medical Oncology, Winship Cancer Institute, School of Medicine, Emory University, Atlanta, GA, USA
- Corresponding author.
| |
Collapse
|
7
|
Kubacka D, Kozarski M, Baranowski MR, Wojcik R, Panecka-Hofman J, Strzelecka D, Basquin J, Jemielity J, Kowalska J. Substrate-Based Design of Cytosolic Nucleotidase IIIB Inhibitors and Structural Insights into Inhibition Mechanism. Pharmaceuticals (Basel) 2022; 15:ph15050554. [PMID: 35631380 PMCID: PMC9144445 DOI: 10.3390/ph15050554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/26/2022] Open
Abstract
Cytosolic nucleotidases (cNs) catalyze dephosphorylation of nucleoside 5’-monophosphates and thereby contribute to the regulation of nucleotide levels in cells. cNs have also been shown to dephosphorylate several therapeutically relevant nucleotide analogues. cN-IIIB has shown in vitro a distinctive activity towards 7-mehtylguanosine monophosphate (m7GMP), which is one key metabolites of mRNA cap. Consequently, it has been proposed that cN-IIIB participates in mRNA cap turnover and prevents undesired accumulation and salvage of m7GMP. Here, we sought to develop molecular tools enabling more advanced studies on the cellular role of cN-IIIB. To that end, we performed substrate and inhibitor property profiling using a library of 41 substrate analogs. The most potent hit compounds (identified among m7GMP analogs) were used as a starting point for structure–activity relationship studies. As a result, we identified several 7-benzylguanosine 5’-monophosphate (Bn7GMP) derivatives as potent, unhydrolyzable cN-IIIB inhibitors. The mechanism of inhibition was elucidated using X-ray crystallography and molecular docking. Finally, we showed that compounds that potently inhibit recombinant cN-IIIB have the ability to inhibit m7GMP decay in cell lysates.
Collapse
Affiliation(s)
- Dorota Kubacka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; (D.K.); (M.K.); (M.R.B.); (J.P.-H.); (D.S.)
| | - Mateusz Kozarski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; (D.K.); (M.K.); (M.R.B.); (J.P.-H.); (D.S.)
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
| | - Marek R. Baranowski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; (D.K.); (M.K.); (M.R.B.); (J.P.-H.); (D.S.)
| | - Radoslaw Wojcik
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
| | - Joanna Panecka-Hofman
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; (D.K.); (M.K.); (M.R.B.); (J.P.-H.); (D.S.)
| | - Dominika Strzelecka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; (D.K.); (M.K.); (M.R.B.); (J.P.-H.); (D.S.)
| | - Jerome Basquin
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany;
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Correspondence: (J.J.); (J.K.); Tel.: +4822-5543-774
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland; (D.K.); (M.K.); (M.R.B.); (J.P.-H.); (D.S.)
- Correspondence: (J.J.); (J.K.); Tel.: +4822-5543-774
| |
Collapse
|
8
|
Jensen KB, Dredge BK, Toubia J, Jin X, Iadevaia V, Goodall GJ, Proud CG. capCLIP: a new tool to probe translational control in human cells through capture and identification of the eIF4E-mRNA interactome. Nucleic Acids Res 2021; 49:e105. [PMID: 34255842 PMCID: PMC8501963 DOI: 10.1093/nar/gkab604] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/16/2021] [Accepted: 07/06/2021] [Indexed: 12/21/2022] Open
Abstract
Translation of eukaryotic mRNAs begins with binding of their m7G cap to eIF4E, followed by recruitment of other translation initiation factor proteins. We describe capCLIP, a novel method to comprehensively capture and quantify the eIF4E (eukaryotic initiation factor 4E) 'cap-ome' and apply it to examine the biological consequences of eIF4E-cap binding in distinct cellular contexts. First, we use capCLIP to identify the eIF4E cap-omes in human cells with/without the mTORC1 (mechanistic target of rapamycin, complex 1) inhibitor rapamycin, there being an emerging consensus that rapamycin inhibits translation of TOP (terminal oligopyrimidine) mRNAs by displacing eIF4E from their caps. capCLIP reveals that the representation of TOP mRNAs in the cap-ome is indeed systematically reduced by rapamycin, thus validating our new methodology. capCLIP also refines the requirements for a functional TOP sequence. Second, we apply capCLIP to probe the consequences of phosphorylation of eIF4E. We show eIF4E phosphorylation reduces overall eIF4E-mRNA association and, strikingly, causes preferential dissociation of mRNAs with short 5'-UTRs. capCLIP is a valuable new tool to probe the function of eIF4E and of other cap-binding proteins such as eIF4E2/eIF4E3.
Collapse
Affiliation(s)
- Kirk B Jensen
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - John Toubia
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia.,ACRF Cancer Genomics Facility, Centre for Cancer Biology, SA Pathology and University of South Australia, Frome Road, Adelaide, SA 5000, Australia
| | - Xin Jin
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Valentina Iadevaia
- School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Gregory J Goodall
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia.,Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia.,Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Christopher G Proud
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| |
Collapse
|
9
|
Knight JRP, Alexandrou C, Skalka GL, Vlahov N, Pennel K, Officer L, Teodosio A, Kanellos G, Gay DM, May-Wilson S, Smith EM, Najumudeen AK, Gilroy K, Ridgway RA, Flanagan DJ, Smith RCL, McDonald L, MacKay C, Cheasty A, McArthur K, Stanway E, Leach JD, Jackstadt R, Waldron JA, Campbell AD, Vlachogiannis G, Valeri N, Haigis KM, Sonenberg N, Proud CG, Jones NP, Swarbrick ME, McKinnon HJ, Faller WJ, Le Quesne J, Edwards J, Willis AE, Bushell M, Sansom OJ. MNK Inhibition Sensitizes KRAS-Mutant Colorectal Cancer to mTORC1 Inhibition by Reducing eIF4E Phosphorylation and c-MYC Expression. Cancer Discov 2021; 11:1228-1247. [PMID: 33328217 PMCID: PMC7611341 DOI: 10.1158/2159-8290.cd-20-0652] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 10/21/2020] [Accepted: 12/11/2020] [Indexed: 12/16/2022]
Abstract
KRAS-mutant colorectal cancers are resistant to therapeutics, presenting a significant problem for ∼40% of cases. Rapalogs, which inhibit mTORC1 and thus protein synthesis, are significantly less potent in KRAS-mutant colorectal cancer. Using Kras-mutant mouse models and mouse- and patient-derived organoids, we demonstrate that KRAS with G12D mutation fundamentally rewires translation to increase both bulk and mRNA-specific translation initiation. This occurs via the MNK/eIF4E pathway culminating in sustained expression of c-MYC. By genetic and small-molecule targeting of this pathway, we acutely sensitize KRASG12D models to rapamycin via suppression of c-MYC. We show that 45% of colorectal cancers have high signaling through mTORC1 and the MNKs, with this signature correlating with a 3.5-year shorter cancer-specific survival in a subset of patients. This work provides a c-MYC-dependent cotargeting strategy with remarkable potency in multiple Kras-mutant mouse models and metastatic human organoids and identifies a patient population that may benefit from its clinical application. SIGNIFICANCE: KRAS mutation and elevated c-MYC are widespread in many tumors but remain predominantly untargetable. We find that mutant KRAS modulates translation, culminating in increased expression of c-MYC. We describe an effective strategy targeting mTORC1 and MNK in KRAS-mutant mouse and human models, pathways that are also commonly co-upregulated in colorectal cancer.This article is highlighted in the In This Issue feature, p. 995.
Collapse
Affiliation(s)
| | | | - George L Skalka
- CRUK Beatson Institute, Glasgow, United Kingdom
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | | | - Kathryn Pennel
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Leah Officer
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Ana Teodosio
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | | | - David M Gay
- CRUK Beatson Institute, Glasgow, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | | | | | | | | | | | - Rachael C L Smith
- CRUK Beatson Institute, Glasgow, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Laura McDonald
- Drug Discovery Unit, CRUK Beatson Institute, Glasgow, United Kingdom
| | - Craig MacKay
- Drug Discovery Unit, CRUK Beatson Institute, Glasgow, United Kingdom
| | - Anne Cheasty
- CRUK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, United Kingdom
| | - Kerri McArthur
- CRUK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, United Kingdom
| | - Emma Stanway
- CRUK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, United Kingdom
| | - Joshua D Leach
- CRUK Beatson Institute, Glasgow, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | | | | | - Georgios Vlachogiannis
- Division of Molecular Pathology, The Institute of Cancer Research, London, United Kingdom
| | - Nicola Valeri
- Division of Molecular Pathology, The Institute of Cancer Research, London, United Kingdom
- Department of Medicine, The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Kevin M Haigis
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada
| | - Christopher G Proud
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, South Australia, Australia
- Department of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Neil P Jones
- CRUK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, United Kingdom
| | - Martin E Swarbrick
- CRUK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge, United Kingdom
| | | | | | - John Le Quesne
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
- Leicester Cancer Research Centre, University of Leicester, Leicester, United Kingdom
- Glenfield Hospital, Leicester University Hospitals NHS Trust, Leicester, United Kingdom
| | - Joanne Edwards
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anne E Willis
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Martin Bushell
- CRUK Beatson Institute, Glasgow, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Owen J Sansom
- CRUK Beatson Institute, Glasgow, United Kingdom.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
10
|
Warminski M, Kowalska J, Nowak E, Kubacka D, Tibble R, Kasprzyk R, Sikorski PJ, Gross JD, Nowotny M, Jemielity J. Structural Insights into the Interaction of Clinically Relevant Phosphorothioate mRNA Cap Analogs with Translation Initiation Factor 4E Reveal Stabilization via Electrostatic Thio-Effect. ACS Chem Biol 2021; 16:334-343. [PMID: 33439620 PMCID: PMC7901015 DOI: 10.1021/acschembio.0c00864] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
mRNA-based
therapies and vaccines constitute a disruptive technology
with the potential to revolutionize modern medicine. Chemically modified
5′ cap structures have provided access to mRNAs with superior
translational properties that could benefit the currently flourishing
mRNA field. Prime examples of compounds that enhance mRNA properties
are antireverse cap analog diastereomers that contain an O-to-S substitution
within the β-phosphate (β-S-ARCA D1 and D2), where D1
is used in clinically investigated mRNA vaccines. The compounds were
previously found to have high affinity for eukaryotic translation
initiation factor 4E (eIF4E) and augment translation in vitro and in vivo. However, the molecular basis for the
beneficial “thio-effect” remains unclear. Here, we employed
multiple biophysical techniques and captured 11 cap analog-eIF4E crystallographic
structures to investigate the consequences of the β-O-to-S or
-Se substitution on the interaction with eIF4E. We determined the SP/RP configurations
of β-S-ARCA and related compounds and obtained structural insights
into the binding. Unexpectedly, in both stereoisomers, the β-S/Se
atom occupies the same binding cavity between Lys162 and Arg157, indicating
that the key driving force for complex stabilization is the interaction
of negatively charged S/Se with positively charged amino acids. This
was observed for all structural variants of the cap and required significantly
different conformations of the triphosphate for each diastereomer.
This finding explains why both β-S-ARCA diastereomers have higher
affinity for eIF4E than unmodified caps. Binding affinities determined
for di-, tri-, and oligonucleotide cap analogs suggested that the
“thio-effect” was preserved in longer RNAs. Our observations
broaden the understanding of thiophosphate biochemistry and enable
the rational design of translationally active mRNAs and eIF4E-targeting
drugs.
Collapse
Affiliation(s)
- Marcin Warminski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Elzbieta Nowak
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Ksiecia Trojdena 4, 02-109 Warsaw, Poland
| | - Dorota Kubacka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Ryan Tibble
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, United States
| | - Renata Kasprzyk
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Pawel J. Sikorski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - John D. Gross
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, United States
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Ksiecia Trojdena 4, 02-109 Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| |
Collapse
|
11
|
Leroux LP, Chaparro V, Jaramillo M. Infection by the Protozoan Parasite Toxoplasma gondii Inhibits Host MNK1/2-eIF4E Axis to Promote Its Survival. Front Cell Infect Microbiol 2020; 10:488. [PMID: 33014898 PMCID: PMC7509071 DOI: 10.3389/fcimb.2020.00488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 08/06/2020] [Indexed: 11/13/2022] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii reprograms host gene expression through multiple mechanisms that promote infection, including the up-regulation of mTOR-dependent host mRNA translation. In addition to the mTOR-4E-BP1/2 axis, MAPK-interacting kinases 1 and 2 (MNK1/2) control the activity of the mRNA cap-binding protein eIF4E. Herein, we show that T. gondii inhibits the phosphorylation of MNK1/2 and their downstream target eIF4E in murine and human macrophages. Exposure to soluble T. gondii antigens (STAg) failed to fully recapitulate this phenotype indicating the requirement of live infection. Treatment with okadaic acid, a potent phosphatase inhibitor, restored phosphorylation of MNK1/2 and eIF4E regardless of infection. T. gondii replication was higher in macrophages isolated from mice mutated at the residue where eIF4E is phosphorylated (eIF4E S209A knock-in) than in wild-type (WT) control cells despite no differences in infection rates. Similarly, parasitemia in the mesenteric lymph nodes and spleen, as well as brain cyst burden were significantly augmented in infected eIF4E S209A knock-in mice compared to their WT counterparts. Of note, mutant mice were more susceptible to acute toxoplasmosis and displayed exacerbated levels of IFNγ. In all, these data suggest that the MNK1/2-eIF4E axis is required to control T. gondii infection and that its inactivation represents a strategy exploited by the parasite to promote its survival.
Collapse
Affiliation(s)
- Louis-Philippe Leroux
- Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC, Canada
| | - Visnu Chaparro
- Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC, Canada
| | - Maritza Jaramillo
- Institut National de la Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie (CAFSB), Laval, QC, Canada
| |
Collapse
|
12
|
Yang X, Zhong W, Cao R. Phosphorylation of the mRNA cap-binding protein eIF4E and cancer. Cell Signal 2020; 73:109689. [PMID: 32535199 PMCID: PMC8049097 DOI: 10.1016/j.cellsig.2020.109689] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 05/21/2020] [Accepted: 06/02/2020] [Indexed: 12/22/2022]
Abstract
Dysregulated protein synthesis is frequently involved in oncogenesis and cancer progression. Translation initiation is thought to be the rate-limiting step in protein synthesis, and the mRNA 5' cap-binding protein eukaryotic translation initiation factor 4E (eIF4E) is a pivotal factor that initiates translation. The activities of eIF4E are regulated at multiple levels, one of which is through its phosphorylation at Serine 209 by the mitogen-activated protein kinase-interacting kinases (MNKs, including MNK1 and MNK2). Benefiting from novel mouse genetic tools and pharmacological MNK inhibitors, our understanding of a role for eIF4E phosphorylation in tumor biology and cancer therapy has greatly evolved in recent years. Importantly, recent studies have found that the level of eIF4E phosphorylation is frequently upregulated in a wide variety of human cancer types, and phosphorylation of eIF4E drives a number of important processes in cancer biology, including cell transformation, proliferation, apoptosis, metastasis and angiogenesis. The MNK-eIF4E axis is being assessed as a therapeutic target either alone or in combination with other therapies in different cancer models. As novel MNK inhibitors are being developed, experimental studies bring new hope to cure human cancers that are not responsive to traditional therapies. Herein we review recent progress on our understanding of a mechanistic role for phosphorylation of eIF4E in cancer biology and therapy.
Collapse
Affiliation(s)
- Xiaotong Yang
- School of Medicine, Tsinghua University, Beijing 100084, China; National Engineering Research Center for the Emergency Drug, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China; Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA
| | - Wu Zhong
- National Engineering Research Center for the Emergency Drug, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
| | - Ruifeng Cao
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812, USA; Department of Neuroscience, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
| |
Collapse
|
13
|
Tabatabaei N, Hou S, Kim KW, Tahmasebi S. Signaling pathways that control mRNA translation initiation in macrophages. Cell Signal 2020; 73:109700. [PMID: 32593651 DOI: 10.1016/j.cellsig.2020.109700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/11/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022]
Abstract
Translational control in mammalian cells plays a critical role in regulating differentiation, cell growth, cell cycle and response to diverse stresses. Macrophages are one of the most versatile cell types in the body. They are professional phagocytic cells that can be found in almost all tissues and adapt tissue-specific functions. Recent studies highlight the importance of translational control in macrophages during invasion of pathogens, exposure to cytokines and in the context of tissue specific functions. In this review, we summarize the current knowledge regarding the role of mRNA translational control in regulation of macrophages.
Collapse
Affiliation(s)
- Negar Tabatabaei
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Shikun Hou
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA
| | - Ki-Wook Kim
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
| | - Soroush Tahmasebi
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, USA.
| |
Collapse
|
14
|
Abstract
Protein semisynthesis-defined herein as the assembly of a protein from a combination of synthetic and recombinant fragments-is a burgeoning field of chemical biology that has impacted many areas in the life sciences. In this review, we provide a comprehensive survey of this area. We begin by discussing the various chemical and enzymatic methods now available for the manufacture of custom proteins containing noncoded elements. This section begins with a discussion of methods that are more chemical in origin and ends with those that employ biocatalysts. We also illustrate the commonalities that exist between these seemingly disparate methods and show how this is allowing for the development of integrated chemoenzymatic methods. This methodology discussion provides the technical foundation for the second part of the review where we cover the great many biological problems that have now been addressed using these tools. Finally, we end the piece with a short discussion on the frontiers of the field and the opportunities available for the future.
Collapse
Affiliation(s)
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, United States
| |
Collapse
|
15
|
Sikorski PJ, Warminski M, Kubacka D, Ratajczak T, Nowis D, Kowalska J, Jemielity J. The identity and methylation status of the first transcribed nucleotide in eukaryotic mRNA 5' cap modulates protein expression in living cells. Nucleic Acids Res 2020; 48:1607-1626. [PMID: 31984425 PMCID: PMC7038993 DOI: 10.1093/nar/gkaa032] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/08/2020] [Accepted: 01/13/2020] [Indexed: 12/21/2022] Open
Abstract
7-Methylguanosine 5' cap on mRNA is necessary for efficient protein expression in vitro and in vivo. Recent studies revealed structural diversity of endogenous mRNA caps, which carry different 5'-terminal nucleotides and additional methylations (2'-O-methylation and m6A). Currently available 5'-capping methods do not address this diversity. We report trinucleotide 5' cap analogs (m7GpppN(m)pG), which are utilized by RNA polymerase T7 to initiate transcription from templates carrying Φ6.5 promoter and enable production of mRNAs differing in the identity of the first transcribed nucleotide (N = A, m6A, G, C, U) and its methylation status (±2'-O-methylation). HPLC-purified mRNAs carrying these 5' caps were used to study protein expression in three mammalian cell lines (3T3-L1, HeLa and JAWS II). The highest expression was observed for mRNAs carrying 5'-terminal A/Am and m6Am, whereas the lowest was observed for G and Gm. The mRNAs carrying 2'-O-methyl at the first transcribed nucleotide (cap 1) had significantly higher expression than unmethylated counterparts (cap 0) only in JAWS II dendritic cells. Further experiments indicated that the mRNA expression characteristic does not correlate with affinity for translation initiation factor 4E or in vitro susceptibility to decapping, but instead depends on mRNA purity and the immune state of the cells.
Collapse
Affiliation(s)
- Pawel J Sikorski
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Marcin Warminski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Dorota Kubacka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Tomasz Ratajczak
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Dominika Nowis
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
- Department of Genomic Medicine, Medical University of Warsaw, Nielubowicza 5, 02-097 Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| |
Collapse
|
16
|
Lama D, Verma CS. Deciphering the mechanistic effects of eIF4E phosphorylation on mRNA-cap recognition. Protein Sci 2019; 29:1373-1386. [PMID: 31811670 DOI: 10.1002/pro.3798] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 12/23/2022]
Abstract
The mRNA cap-binding oncoprotein "eIF4E" is phosphorylated at residue S209 by Mnk kinases, and is closely associated with tumor development and progression. Despite being well-established, mechanistic details at the molecular level of mRNA recognition by eIF4E due to phosphorylation have not been clearly elucidated. We investigated this through molecular modeling and simulations of the S209 phosphorylated derivative of eIF4E and explored the associated implication on the binding of the different variants of mRNA-cap analogs. A key feature that emerges as a result of eIF4E phosphorylation is a salt-bridge network between the phosphorylated S209 (pS209) and a specific pair of lysine residues (K159 and K162) within the cap-binding interface on eIF4E. This interaction linkage stabilizes the otherwise dynamic C-terminal region of the protein, resulting in the attenuation of the overall plasticity and accessibility of the binding pocket. The pS209-K159 salt-bridge also results in an energetically less favorable environment for the bound mRNA-cap primarily due to electrostatic repulsion between the negative potentials from the phosphates in the cap and those appearing as a result of phosphorylation of S209. These observations collectively imply that the binding of the mRNA-cap will be adversely affected in the phosphorylated derivative of eIF4E. We propose a mechanistic model highlighting the role of eIF4E phosphorylation as a regulatory tool in modulating eIF4E: mRNA-cap recognition and its potential impact on translation initiation.
Collapse
Affiliation(s)
- Dilraj Lama
- Biomolecular Modelling and Design Division, Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Chandra S Verma
- Biomolecular Modelling and Design Division, Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
17
|
Mishra RK, Datey A, Hussain T. mRNA Recruiting eIF4 Factors Involved in Protein Synthesis and Its Regulation. Biochemistry 2019; 59:34-46. [DOI: 10.1021/acs.biochem.9b00788] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Rishi Kumar Mishra
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Ayushi Datey
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| | - Tanweer Hussain
- Department of Molecular Reproduction, Development and Genetics, Division of Biological Sciences, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
18
|
Kats IR, Klann E. Translating from cancer to the brain: regulation of protein synthesis by eIF4F. ACTA ACUST UNITED AC 2019; 26:332-342. [PMID: 31416906 PMCID: PMC6699409 DOI: 10.1101/lm.050047.119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 07/03/2019] [Indexed: 12/27/2022]
Abstract
Formation of eukaryotic initiation factor 4F (eIF4F) is widely considered to be the rate-limiting step in cap-dependent translation initiation. Components of eIF4F are often up-regulated in various cancers, and much work has been done to elucidate the role of each of the translation initiation factors in cancer cell growth and survival. In fact, many of the basic mechanisms describing how eIF4F is assembled and how it functions to regulate translation initiation were first investigated in cancer cell lines. These same eIF4F translational control pathways also are relevant for neuronal signaling that underlies long-lasting synaptic plasticity and memory, and in neurological diseases where eIF4F and its upstream regulators are dysregulated. Although eIF4F is important in cancer and for brain function, there is not always a clear path to use the results of studies performed in cancer models to inform one of the roles that the same translation factors have in neuronal signaling. Issues arise when extrapolating from cell lines to tissue, and differences are likely to exist in how eIF4F and its upstream regulatory pathways are expressed in the diverse neuronal subtypes found in the brain. This review focuses on summarizing the role of eIF4F and its accessory proteins in cancer, and how this information has been utilized to investigate neuronal signaling, synaptic function, and animal behavior. Certain aspects of eIF4F regulation are consistent across cancer and neuroscience, whereas some results are more complicated to interpret, likely due to differences in the complexity of the brain, its billions of neurons and synapses, and its diverse cell types.
Collapse
Affiliation(s)
- Ilona R Kats
- Sackler Graduate Program, New York University School of Medicine, New York, New York 10016, USA.,Center for Neural Science, New York University, New York, New York 10003, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York 10003, USA.,NYU Neuroscience Institute, New York University School of Medicine, New York, New York 10016, USA
| |
Collapse
|
19
|
Kopcial M, Wojtczak BA, Kasprzyk R, Kowalska J, Jemielity J. N1-Propargylguanosine Modified mRNA Cap Analogs: Synthesis, Reactivity, and Applications to the Study of Cap-Binding Proteins. Molecules 2019; 24:molecules24101899. [PMID: 31108861 PMCID: PMC6572376 DOI: 10.3390/molecules24101899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 01/07/2023] Open
Abstract
The mRNA 5′ cap consists of N7-methylguanosine bound by a 5′,5′-triphosphate bridge to the first nucleotide of the transcript. The cap interacts with various specific proteins and participates in all key mRNA-related processes, which may be of therapeutic relevance. There is a growing demand for new biophysical and biochemical methods to study cap–protein interactions and identify the factors which inhibit them. The development of such methods can be aided by the use of properly designed fluorescent molecular probes. Herein, we synthesized a new class of m7Gp3G cap derivatives modified with an alkyne handle at the N1-position of guanosine and, using alkyne-azide cycloaddition, we functionalized them with fluorescent tags to obtain potential probes. The cap derivatives and probes were evaluated in the context of two cap-binding proteins, eukaryotic translation initiation factor (eIF4E) and decapping scavenger (DcpS). Biochemical and biophysical studies revealed that N1-propargyl moiety did not significantly disturb cap–protein interaction. The fluorescent properties of the probes turned out to be in line with microscale thermophoresis (MST)-based binding assays.
Collapse
Affiliation(s)
- Michal Kopcial
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland.
- Centre of New Technologies, University of Warsaw; S. Banacha 2c, 02-097 Warsaw, Poland.
- Faculty of Physics, University of Warsaw; L. Pasteura 5, 02-093 Warsaw, Poland.
| | - Blazej A Wojtczak
- Centre of New Technologies, University of Warsaw; S. Banacha 2c, 02-097 Warsaw, Poland.
| | - Renata Kasprzyk
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland.
- Centre of New Technologies, University of Warsaw; S. Banacha 2c, 02-097 Warsaw, Poland.
- Faculty of Physics, University of Warsaw; L. Pasteura 5, 02-093 Warsaw, Poland.
| | - Joanna Kowalska
- Faculty of Physics, University of Warsaw; L. Pasteura 5, 02-093 Warsaw, Poland.
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw; S. Banacha 2c, 02-097 Warsaw, Poland.
| |
Collapse
|
20
|
Kasprzyk R, Starek BJ, Ciechanowicz S, Kubacka D, Kowalska J, Jemielity J. Fluorescent Turn-On Probes for the Development of Binding and Hydrolytic Activity Assays for mRNA Cap-Recognizing Proteins. Chemistry 2019; 25:6728-6740. [PMID: 30801798 DOI: 10.1002/chem.201900051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 02/21/2019] [Indexed: 12/16/2022]
Abstract
The m7 G cap is a unique nucleotide structure at the 5'-end of all eukaryotic mRNAs. The cap specifically interacts with numerous cellular proteins and participates in biological processes that are essential for cell growth and function. To provide small molecular probes to study important cap-recognizing proteins, we synthesized m7 G nucleotides labeled with fluorescent tags via the terminal phosph(on)ate group and studied how their emission properties changed upon protein binding or enzymatic cleavage. Only the pyrene-labeled compounds behaved as sensitive turn-on probes. A pyrene-labeled m7 GTP analogue showed up to eightfold enhanced fluorescence emission upon binding to eukaryotic translation initiation factor 4E (eIF4E) and over 30-fold enhancement upon cleavage by decapping scavenger (DcpS) enzyme. These observations served as the basis for developing binding- and hydrolytic-activity assays. The assay utility was validated with previously characterized libraries of eIF4E ligands and DcpS inhibitors. The DcpS assay was also applied to study hydrolytic activity and inhibition of endogenous enzyme in cytoplasmic extracts from HeLa and HEK cells.
Collapse
Affiliation(s)
- Renata Kasprzyk
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland.,College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Beata J Starek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Sylwia Ciechanowicz
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland.,College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Dorota Kubacka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| |
Collapse
|
21
|
Khan MA. Phosphorylation of translation initiation factor eIFiso4E promotes translation through enhanced binding to potyvirus VPg. J Biochem 2019; 165:167-176. [PMID: 30371907 DOI: 10.1093/jb/mvy091] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/28/2018] [Indexed: 12/13/2022] Open
Abstract
Interactions of phosphorylated eIFiso4E binding to VPg as a function of temperature and ionic strength were assessed employing fluorescence spectroscopic. Phosphorylation increased the binding affinity ∼3.5-fold between VPg and eIFiso4E under equilibrium conditions. Binding affinity of VPg for eIFiso4Ep correlates with the ability to enhance in vitro protein synthesis. Addition of VPg and eIFiso4Ep together to Dep WGE enhances the translation for both uncapped and capped mRNA. However, capped mRNA translation was inhibited with addition of eIFiso4Ep alone in dep WGE, suggesting that phosphorylation prevents the cap binding and favours the VPg binding to promotes translation. Temperature dependence showed that the phosphorylated form of the eIFiso4E is preferred for complex formation. A van't Hoff analysis reveals that eIFiso4Ep binding to VPg was enthalpy driven (ΔH = -43.9 ± 0.3 kJ.mol-1) and entropy-opposed (ΔS = -4.3 ± 0.1 J.mol-1K-1). Phosphorylation increased the enthalpic contributions ∼33% for eIFiso4Ep-VPg complex. The thermodynamic values and ionic strength dependence of binding data suggesting that phosphorylation increased hydrogen-bonding and decreased hydrophobic interactions, which leads to more stable complex formation and favour efficient viral translation. Overall these data correlate well with the observed translational data and provide more detailed information on the translational strategy of potyviruses.
Collapse
Affiliation(s)
- Mateen A Khan
- Department of Chemistry & Biochemistry, Hunter College of the City University of New York, 695 Park Ave, New York, USA.,Department of Life Sciences, College of Science and General Studies, Alfaisal University, Takhasusi Street, P.O. Box-50927, Riyadh, Saudi Arabia
| |
Collapse
|
22
|
Pazo A, Pérez-González A, Oliveros JC, Huarte M, Chavez JP, Nieto A. hCLE/RTRAF-HSPC117-DDX1-FAM98B: A New Cap-Binding Complex That Activates mRNA Translation. Front Physiol 2019; 10:92. [PMID: 30833903 PMCID: PMC6388641 DOI: 10.3389/fphys.2019.00092] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/25/2019] [Indexed: 11/29/2022] Open
Abstract
hCLE/C14orf166/RTRAF, DDX1, and HSPC117 are components of cytoplasmic mRNA-transporting granules kinesin-associated in dendrites. They have also been found in cytoplasmic ribosome-containing RNA granules that transport specific mRNAs halted for translation until specific neuronal signals renders them accessible to the translation machinery. hCLE associates to DDX1, HSPC117, and FAM98B in HEK293T cells and all four proteins bind to cap analog-containing resins. Competition and elution experiments indicate that binding of hCLE complex to cap resins is independent of eIF4E; the cap-binding factor needed for translation. Purified hCLE free of its associated proteins binds cap with low affinity suggesting that its interacting proteins modulate its cap association. hCLE silencing reduces hCLE accumulation and that of its interacting proteins and decreases mRNA translation. hCLE-associated RNAs have been isolated and sequenced; RNAs involved in mRNA translation are specifically associated. The data suggest that RNA granules may co-transport RNAs encoding proteins involved in specific functions together with RNAs that encode proteins needed for the translation of these specific RNAs and indicate an important role for hCLE modulating mRNA translation.
Collapse
Affiliation(s)
- Alejandra Pazo
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Alicia Pérez-González
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | | | - Maite Huarte
- Department of Gene Therapy and Regulation of Gene Expression, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain
| | - Juan Pablo Chavez
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Amelia Nieto
- Centro Nacional de Biotecnología (CSIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| |
Collapse
|
23
|
Sriram A, Bohlen J, Teleman AA. Translation acrobatics: how cancer cells exploit alternate modes of translational initiation. EMBO Rep 2018; 19:embr.201845947. [PMID: 30224410 DOI: 10.15252/embr.201845947] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 07/09/2018] [Accepted: 08/16/2018] [Indexed: 12/11/2022] Open
Abstract
Recent work has brought to light many different mechanisms of translation initiation that function in cells in parallel to canonical cap-dependent initiation. This has important implications for cancer. Canonical cap-dependent translation initiation is inhibited by many stresses such as hypoxia, nutrient limitation, proteotoxic stress, or genotoxic stress. Since cancer cells are often exposed to these stresses, they rely on alternate modes of translation initiation for protein synthesis and cell growth. Cancer mutations are now being identified in components of the translation machinery and in cis-regulatory elements of mRNAs, which both control translation of cancer-relevant genes. In this review, we provide an overview on the various modes of non-canonical translation initiation, such as leaky scanning, translation re-initiation, ribosome shunting, IRES-dependent translation, and m6A-dependent translation, and then discuss the influence of stress on these different modes of translation. Finally, we present examples of how these modes of translation are dysregulated in cancer cells, allowing them to grow, to proliferate, and to survive, thereby highlighting the importance of translational control in cancer.
Collapse
Affiliation(s)
- Ashwin Sriram
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Jonathan Bohlen
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Heidelberg University, Heidelberg, Germany
| | - Aurelio A Teleman
- German Cancer Research Center (DKFZ), Heidelberg, Germany .,Heidelberg University, Heidelberg, Germany
| |
Collapse
|
24
|
Muttach F, Muthmann N, Rentmeister A. Synthetic mRNA capping. Beilstein J Org Chem 2017; 13:2819-2832. [PMID: 30018667 PMCID: PMC5753152 DOI: 10.3762/bjoc.13.274] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 12/04/2017] [Indexed: 12/25/2022] Open
Abstract
Eukaryotic mRNA with its 5'-cap is of central importance for the cell. Many studies involving mRNA require reliable preparation and modification of 5'-capped RNAs. Depending on the length of the desired capped RNA, chemical or enzymatic preparation - or a combination of both - can be advantageous. We review state-of-the art methods and give directions for choosing the appropriate approach. We also discuss the preparation and properties of mRNAs with non-natural caps providing novel features such as improved stability or enhanced translational efficiency.
Collapse
Affiliation(s)
- Fabian Muttach
- University of Münster, Department of Chemistry, Institute of Biochemistry, Wilhelm-Klemm-Str. 2, 48149 Münster, Germany
| | - Nils Muthmann
- University of Münster, Department of Chemistry, Institute of Biochemistry, Wilhelm-Klemm-Str. 2, 48149 Münster, Germany
| | - Andrea Rentmeister
- University of Münster, Department of Chemistry, Institute of Biochemistry, Wilhelm-Klemm-Str. 2, 48149 Münster, Germany
- Cells-in-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, Germany
| |
Collapse
|
25
|
Rydzik AM, Warminski M, Sikorski PJ, Baranowski MR, Walczak S, Kowalska J, Zuberek J, Lukaszewicz M, Nowak E, W Claridge TD, Darzynkiewicz E, Nowotny M, Jemielity J. mRNA cap analogues substituted in the tetraphosphate chain with CX2: identification of O-to-CCl2 as the first bridging modification that confers resistance to decapping without impairing translation. Nucleic Acids Res 2017; 45:8661-8675. [PMID: 28666355 PMCID: PMC5587727 DOI: 10.1093/nar/gkx569] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/20/2017] [Indexed: 12/20/2022] Open
Abstract
Analogues of the mRNA 5'-cap are useful tools for studying mRNA translation and degradation, with emerging potential applications in novel therapeutic interventions including gene therapy. We report the synthesis of novel mono- and dinucleotide cap analogues containing dihalogenmethylenebisphosphonate moiety (i.e. one of the bridging O atom substituted with CCl2 or CF2) and their properties in the context of cellular translational and decapping machineries, compared to phosphate-unmodified and previously reported CH2-substituted caps. The analogues were bound tightly to eukaryotic translation initiation factor 4E (eIF4E), with CCl2-substituted analogues having the highest affinity. When incorporated into mRNA, the CCl2-substituted dinucleotide most efficiently promoted cap-dependent translation. Moreover, the CCl2-analogues were potent inhibitors of translation in rabbit reticulocyte lysate. The crystal structure of eIF4E in complex with the CCl2-analogue revealed a significantly different ligand conformation compared to that of the unmodified cap analogue, which likely contributes to the improved binding. Both CCl2- and CF2- analogues showed lower susceptibility to hydrolysis by the decapping scavenger enzyme (DcpS) and, when incorporated into RNA, conferred stability against major cellular decapping enzyme (Dcp2) to transcripts. Furthermore, the use of difluoromethylene cap analogues was exemplified by the development of 19F NMR assays for DcpS activity and eIF4E binding.
Collapse
Affiliation(s)
- Anna M Rydzik
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland.,Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Marcin Warminski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Pawel J Sikorski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Marek R Baranowski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Sylwia Walczak
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.,College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Joanna Zuberek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Maciej Lukaszewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Elzbieta Nowak
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Ksiecia Trojdena Street, 02-109 Warsaw, Poland
| | - Timothy D W Claridge
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland.,Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Marcin Nowotny
- Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Ksiecia Trojdena Street, 02-109 Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| |
Collapse
|
26
|
Khan MA, Goss DJ. Kinetic analyses of phosphorylated and non-phosphorylated eIFiso4E binding to mRNA cap analogues. Int J Biol Macromol 2017; 106:387-395. [PMID: 28797816 DOI: 10.1016/j.ijbiomac.2017.08.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/24/2017] [Accepted: 08/04/2017] [Indexed: 01/23/2023]
Abstract
Phosphorylation of eukaryotic initiation factors was previously shown to interact with m7G cap and play an important role in the regulation of translation initiation of protein synthesis. To gain further insight into the phosphorylation process of plant protein synthesis, the kinetics of phosphorylated wheat eIFiso4E binding to m7G cap analogues were examined. Phosphorylation of wheat eIFiso4E showed similar kinetic effects to human eIF4E binding to m7-G cap. Phosphorylation of eIFiso4E decreased the kinetic rate (2-fold) and increased the dissociation rate (2-fold) as compared to non-phosphorylated eIFiso4E binding to both mono- and di-nucleotide analogues at 22°C. Phosphorylated and non-phosphorylated eIFiso4E-m7G cap binding rates were found to be independent of concentration, suggesting conformational changes were rate limiting. Rate constant for phosphorylated and non-phosphorylated eIFiso4E binding to m7-G cap increased with temperature. Phosphorylation of eIFiso4E decreased (2-fold) the activation energy for both m7-G cap analogues binding as compared to non-phosphorylated eIFiso4E. The reduced energy barrier for the formation of eIFiso4E-m7-G cap complex suggests a more stable platform for further initiation complex formation and possible means of adapting variety of environmental conditions. Furthermore, the formation of phosphorylated eIFiso4E-cap complex may contribute to modulation of the initiation of protein synthesis in plants.
Collapse
Affiliation(s)
- Mateen A Khan
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, NY 10065, USA; Department of Life Sciences, College of Science and General Studies, Alfaisal University, Riyadh 11533, KSA, Saudi Arabia.
| | - Dixie J Goss
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, NY 10065, USA.
| |
Collapse
|
27
|
Vaklavas C, Blume SW, Grizzle WE. Translational Dysregulation in Cancer: Molecular Insights and Potential Clinical Applications in Biomarker Development. Front Oncol 2017; 7:158. [PMID: 28798901 PMCID: PMC5526920 DOI: 10.3389/fonc.2017.00158] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/06/2017] [Indexed: 01/04/2023] Open
Abstract
Although transcript levels have been traditionally used as a surrogate measure of gene expression, it is increasingly recognized that the latter is extensively and dynamically modulated at the level of translation (messenger RNA to protein). Over the recent years, significant progress has been made in dissecting the complex posttranscriptional mechanisms that regulate gene expression. This advancement in knowledge came hand in hand with the progress made in the methodologies to study translation both at gene-specific as well as global genomic level. The majority of translational control is exerted at the level of initiation; nonetheless, protein synthesis can be modulated at the level of translation elongation, termination, and recycling. Sequence and structural elements and epitranscriptomic modifications of individual transcripts allow for dynamic gene-specific modulation of translation. Cancer cells usurp the regulatory mechanisms that govern translation to carry out translational programs that lead to the phenotypic hallmarks of cancer. Translation is a critical nexus in neoplastic transformation. Multiple oncogenes and signaling pathways that are activated, upregulated, or mutated in cancer converge on translation and their transformative impact "bottlenecks" at the level of translation. Moreover, this translational dysregulation allows cancer cells to adapt to a diverse array of stresses associated with a hostile microenviroment and antitumor therapies. All elements involved in the process of translation, from the transcriptional template, the components of the translational machinery, to the proteins that interact with the transcriptome, have been found to be qualitatively and/or quantitatively perturbed in cancer. This review discusses the regulatory mechanisms that govern translation in normal cells and how translation becomes dysregulated in cancer leading to the phenotypic hallmarks of malignancy. We also discuss how dysregulated mediators or components of translation can be utilized as biomarkers with potential diagnostic, prognostic, or predictive significance. Such biomarkers have the potential advantage of uniform applicability in the face of inherent tumor heterogeneity and deoxyribonucleic acid instability. As translation becomes increasingly recognized as a process gone awry in cancer and agents are developed to target it, the utility and significance of these potential biomarkers is expected to increase.
Collapse
Affiliation(s)
- Christos Vaklavas
- Department of Medicine, Division of Hematology/Oncology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Scott W Blume
- Department of Medicine, Division of Hematology/Oncology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - William E Grizzle
- Department of Anatomic Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
28
|
Warminski M, Sikorski PJ, Warminska Z, Lukaszewicz M, Kropiwnicka A, Zuberek J, Darzynkiewicz E, Kowalska J, Jemielity J. Amino-Functionalized 5' Cap Analogs as Tools for Site-Specific Sequence-Independent Labeling of mRNA. Bioconjug Chem 2017; 28:1978-1992. [PMID: 28613834 DOI: 10.1021/acs.bioconjchem.7b00291] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
mRNA is a template for protein biosynthesis, and consequently mRNA transport, translation, and turnover are key elements in the overall regulation of gene expression. Along with growing interest in the mechanisms regulating mRNA decay and localization, there is an increasing need for tools enabling convenient fluorescent labeling or affinity tagging of mRNA. We report new mRNA 5' cap analog-based tools that enable site-specific labeling of RNA within the cap using N-hydroxysuccinimide (NHS) chemistry. We explored two complementary methods: a co-transcriptional labeling method, in which the label is first attached to a cap analog and then incorporated into RNA by in vitro transcription, and a post-transcriptional labeling method, in which an amino-functionalized cap analog is incorporated into RNA followed by chemical labeling of the resulting transcript. After testing the biochemical properties of RNAs carrying the novel modified cap structures, we demonstrated the utility of fluorescently labeled RNAs in decapping assays, RNA decay assays, and RNA visualization in cells. Finally, we also demonstrated that mRNAs labeled by the reported method are translationally active. We envisage that the novel analogs will provide an alternative to radiolabeling of mRNA caps for in vitro studies and open possibilities for new applications related to the study of mRNA fates in vivo.
Collapse
Affiliation(s)
- Marcin Warminski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw , 02-093, Warsaw, Poland
| | - Pawel J Sikorski
- Centre of New Technologies, University of Warsaw , 02-097, Warsaw, Poland
| | - Zofia Warminska
- Centre of New Technologies, University of Warsaw , 02-097, Warsaw, Poland.,College of Interfaculty Individual Studies of Mathematics and Natural Sciences, University of Warsaw , 02-093, Warsaw, Poland
| | - Maciej Lukaszewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw , 02-093, Warsaw, Poland
| | - Anna Kropiwnicka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw , 02-093, Warsaw, Poland
| | - Joanna Zuberek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw , 02-093, Warsaw, Poland
| | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw , 02-093, Warsaw, Poland.,Centre of New Technologies, University of Warsaw , 02-097, Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw , 02-093, Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw , 02-097, Warsaw, Poland
| |
Collapse
|
29
|
Warminski M, Sikorski PJ, Kowalska J, Jemielity J. Applications of Phosphate Modification and Labeling to Study (m)RNA Caps. Top Curr Chem (Cham) 2017; 375:16. [PMID: 28116583 PMCID: PMC5396385 DOI: 10.1007/s41061-017-0106-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/10/2017] [Indexed: 02/07/2023]
Abstract
The cap is a natural modification present at the 5' ends of eukaryotic messenger RNA (mRNA), which because of its unique structural features, mediates essential biological functions during the process of gene expression. The core structural feature of the mRNA cap is an N7-methylguanosine moiety linked by a 5'-5' triphosphate chain to the first transcribed nucleotide. Interestingly, other RNA 5' end modifications structurally and functionally resembling the m7G cap have been discovered in different RNA types and in different organisms. All these structures contain the 'inverted' 5'-5' oligophosphate bridge, which is necessary for interaction with specific proteins and also serves as a cleavage site for phosphohydrolases regulating RNA turnover. Therefore, cap analogs containing oligophosphate chain modifications or carrying spectroscopic labels attached to phosphate moieties serve as attractive molecular tools for studies on RNA metabolism and modification of natural RNA properties. Here, we review chemical, enzymatic, and chemoenzymatic approaches that enable preparation of modified cap structures and RNAs carrying such structures, with emphasis on phosphate-modified mRNA cap analogs and their potential applications.
Collapse
Affiliation(s)
- Marcin Warminski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089, Warsaw, Poland
| | - Pawel J Sikorski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089, Warsaw, Poland.
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland.
| |
Collapse
|
30
|
Role of Eukaryotic Initiation Factors during Cellular Stress and Cancer Progression. J Nucleic Acids 2016; 2016:8235121. [PMID: 28083147 PMCID: PMC5204094 DOI: 10.1155/2016/8235121] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 11/14/2016] [Indexed: 12/12/2022] Open
Abstract
Protein synthesis can be segmented into distinct phases comprising mRNA translation initiation, elongation, and termination. Translation initiation is a highly regulated and rate-limiting step of protein synthesis that requires more than 12 eukaryotic initiation factors (eIFs). Extensive evidence shows that the transcriptome and corresponding proteome do not invariably correlate with each other in a variety of contexts. In particular, translation of mRNAs specific to angiogenesis, tumor development, and apoptosis is altered during physiological and pathophysiological stress conditions. In cancer cells, the expression and functions of eIFs are hampered, resulting in the inhibition of global translation and enhancement of translation of subsets of mRNAs by alternative mechanisms. A precise understanding of mechanisms involving eukaryotic initiation factors leading to differential protein expression can help us to design better strategies to diagnose and treat cancer. The high spatial and temporal resolution of translation control can have an immediate effect on the microenvironment of the cell in comparison with changes in transcription. The dysregulation of mRNA translation mechanisms is increasingly being exploited as a target to treat cancer. In this review, we will focus on this context by describing both canonical and noncanonical roles of eIFs, which alter mRNA translation.
Collapse
|
31
|
Sciascia Q, Sales F, van der Linden D, Wards N, Oliver M, Blair H, McCoard S. Nutritional plane of twin-bearing ewes alters fetal mammary gland biochemical composition and mTOR/MAPK pathway signaling. J Anim Sci 2016; 93:699-708. [PMID: 26020751 DOI: 10.2527/jas.2014-8394] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Identifying the biochemical changes and molecular pathways that regulate fetal mammary development in response to maternal nutrition is important for understanding the link between fetal programming of mammary development and future lactation performance. Although there are published studies regarding biochemical changes in the developing mammary gland, there are currently no data on molecular pathway involvement in regulating ruminant fetal mammary development. This study investigated changes in fetal mammary biochemical indices and mechanistic target of rapamycin (mTOR)/mitogen activated protein kinase (MAPK) signaling at d 100 and 140 of gestation in an ovine model of restricted maternal nutrition. Ewes were randomly allocated to ad libitum (A) or maintenance (M) nutritional regimens, under New Zealand pastoral grazing conditions, from d 21 to 140 of pregnancy. At d 100 and 140 of pregnancy, a subgroup of twin-bearing dams was euthanized, and whole fetal mammary glands (fiber, skin, fat, and ducts) were collected. Mammary glands of fetuses carried by M-fed dams were heavier at d 100 than those of fetuses carried by A-fed dams ( = 0.03), with no difference in the abundance of mTOR/MAPK signaling proteins observed. At d 140, mammary glands of fetuses carried by M-fed dams were lighter ( = 0.07) than fetuses carried by A-fed dams because of decreased hyperplasia ( = 0.04) and hypertrophy ( = 0.09) but had increased protein synthetic capacity ( = 0.02). Increased protein synthetic capacity was associated with increased abundance of MAPK pathway signaling proteins eukaryotic intiation factor 4E (eIF4E)/eIF4E and mTOR pathway signaling proteins eukaryotic initiation factor 4E-binding protein 1 (4E-BP1)/4E-BP1 and ribosomal protein S6 (RPS6)/RPS6 ( ≤ 0.05). Increased abundance of MAPK/mTOR pathway proteins is proposed to mediate increased protein synthetic capacity via ribosome biogenesis and the availability of factors required to initiate protein translation. The primary regulator of 4E-BP1 phosphorylation at Ser65 and RPS6 at Ser235/236 is the activated form of mTOR: mTOR. To study potential tissue-specific mTOR, mTOR abundance mammary glands, separated into parenchyma and fat pad, were collected from d 140 fetuses carried by dams fed a lucerne-based pellet diet formulated to meet 100% of the NRC-recommended maintenance requirements. Results showed that the abundance of mTOR was primarily localized to the fat pad, indicating that the fat pad plays a potential role in regulating development of the fetal mammary gland.
Collapse
|
32
|
Ziemniak M, Kowalska J, Lukaszewicz M, Zuberek J, Wnek K, Darzynkiewicz E, Jemielity J. Phosphate-modified analogues of m(7)GTP and m(7)Gppppm(7)G-Synthesis and biochemical properties. Bioorg Med Chem 2015; 23:5369-81. [PMID: 26264844 DOI: 10.1016/j.bmc.2015.07.052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 07/24/2015] [Accepted: 07/25/2015] [Indexed: 01/05/2023]
Abstract
The synthesis and biochemical properties of 17 new mRNA cap analogues are reported. Six of these nucleotides are m(7)GTP derivatives, whereas 11 are 'two headed' tetraphosphate dinucleotides based on a m(7)Gppppm(7)G structure. The compounds contain either a boranophosphate or phosphorothioate moiety in the nucleoside neighbouring position(s) and some of them possess an additional methylene group between β and γ phosphorus atoms. The compounds were prepared by divalent metal chloride-mediated coupling of an appropriate m(7)GMP analogue with a given P(1),P(2)-di(1-imidazolyl) derivative. The analogues were evaluated as tools for studying cap-dependent processes in a number of biochemical assays, including determination of affinity to eukaryotic initiation factor eIF4E, susceptibility to enzymatic hydrolysis, and translational efficiency in vitro. The results indicate that modification in the phosphate chain can increase binding to cap-interacting proteins and provides higher resistance to degradation. Furthermore, modified derivatives of m(7)GTP were found to be potent inhibitors of cap-dependent translation in cell free systems.
Collapse
Affiliation(s)
- Marcin Ziemniak
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Maciej Lukaszewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Joanna Zuberek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Katarzyna Wnek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland; Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
| |
Collapse
|
33
|
Nowakowska M, Kowalska J, Martin F, d'Orchymont A, Zuberek J, Lukaszewicz M, Darzynkiewicz E, Jemielity J. Cap analogs containing 6-thioguanosine--reagents for the synthesis of mRNAs selectively photo-crosslinkable with cap-binding biomolecules. Org Biomol Chem 2015; 12:4841-7. [PMID: 24763507 DOI: 10.1039/c4ob00059e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Numerous biomolecules recognize the 7-methylguanosine cap structure present at the 5' ends of eukaryotic mRNAs. Photo-crosslinking is a valuable technique to study these interactions. We report three anti-reverse cap analogs containing a photo-activable nucleoside, 6-thioguanosine ((6S)G), that enable the synthesis of capped RNAs with (6S)G positioned exclusively as the first transcribed nucleotide. The effect of the 6-thioguanosine moiety on binding to the translation factor eIF4E and the efficiency of mRNA translation was determined. The utility of mRNAs with a (6S)G-modified cap in crosslinking experiments is shown by mapping the histone H4 cap-binding pocket.
Collapse
Affiliation(s)
- Monika Nowakowska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Baranowski MR, Nowicka A, Rydzik AM, Warminski M, Kasprzyk R, Wojtczak BA, Wojcik J, Claridge TDW, Kowalska J, Jemielity J. Synthesis of fluorophosphate nucleotide analogues and their characterization as tools for ¹⁹F NMR studies. J Org Chem 2015; 80:3982-97. [PMID: 25816092 DOI: 10.1021/acs.joc.5b00337] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
To broaden the scope of existing methods based on (19)F nucleotide labeling, we developed a new method for the synthesis of fluorophosphate (oligo)nucleotide analogues containing an O to F substitution at the terminal position of the (oligo)phosphate moiety and evaluated them as tools for (19)F NMR studies. Using three efficient and comprehensive synthetic approaches based on phosphorimidazolide chemistry and tetra-n-butylammonium fluoride, fluoromonophosphate, or fluorophosphate imidazolide as fluorine sources, we prepared over 30 fluorophosphate-containing nucleotides, varying in nucleobase type (A, G, C, U, m(7)G), phosphate chain length (from mono to tetra), and presence of additional phosphate modifications (thio, borano, imido, methylene). Using fluorophosphate imidazolide as fluorophosphorylating reagent for 5'-phosphorylated oligos we also synthesized oligonucleotide 5'-(2-fluorodiphosphates), which are potentially useful as (19)F NMR hybridization probes. The compounds were characterized by (19)F NMR and evaluated as (19)F NMR molecular probes. We found that fluorophosphate nucleotide analogues can be used to monitor activity of enzymes with various specificities and metal ion requirements, including human DcpS enzyme, a therapeutic target for spinal muscular atrophy. The compounds can also serve as reporter ligands for protein binding studies, as exemplified by studying interaction of fluorophosphate mRNA cap analogues with eukaryotic translation initiation factor (eIF4E).
Collapse
Affiliation(s)
- Marek R Baranowski
- †Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Anna Nowicka
- †Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland.,§Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Anna M Rydzik
- ‡Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Marcin Warminski
- †Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Renata Kasprzyk
- †Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Blazej A Wojtczak
- §Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Jacek Wojcik
- ∥Laboratory of Biological NMR, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Timothy D W Claridge
- ‡Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - Joanna Kowalska
- †Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
| | - Jacek Jemielity
- §Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| |
Collapse
|
35
|
Pelletier J, Graff J, Ruggero D, Sonenberg N. Targeting the eIF4F translation initiation complex: a critical nexus for cancer development. Cancer Res 2015; 75:250-63. [PMID: 25593033 DOI: 10.1158/0008-5472.can-14-2789] [Citation(s) in RCA: 261] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Elevated protein synthesis is an important feature of many cancer cells and often arises as a consequence of increased signaling flux channeled to eukaryotic initiation factor 4F (eIF4F), the key regulator of the mRNA-ribosome recruitment phase of translation initiation. In many cellular and preclinical models of cancer, eIF4F deregulation results in changes in translational efficiency of specific mRNA classes. Importantly, many of these mRNAs code for proteins that potently regulate critical cellular processes, such as cell growth and proliferation, enhanced cell survival and cell migration that ultimately impinge on several hallmarks of cancer, including increased angiogenesis, deregulated growth control, enhanced cellular survival, epithelial-to-mesenchymal transition, invasion, and metastasis. By being positioned as the molecular nexus downstream of key oncogenic signaling pathways (e.g., Ras, PI3K/AKT/TOR, and MYC), eIF4F serves as a direct link between important steps in cancer development and translation initiation. Identification of mRNAs particularly responsive to elevated eIF4F activity that typifies tumorigenesis underscores the critical role of eIF4F in cancer and raises the exciting possibility of developing new-in-class small molecules targeting translation initiation as antineoplastic agents.
Collapse
Affiliation(s)
- Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Québec, Canada. The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Québec, Canada. Department of Oncology, McGill University, Montreal, Québec, Canada.
| | - Jeremy Graff
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
| | - Davide Ruggero
- School of Medicine and Department of Urology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montreal, Québec, Canada. The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Québec, Canada
| |
Collapse
|
36
|
Five eIF4E isoforms from Arabidopsis thaliana are characterized by distinct features of cap analogs binding. Biochem Biophys Res Commun 2014; 456:47-52. [PMID: 25446076 DOI: 10.1016/j.bbrc.2014.11.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 11/11/2014] [Indexed: 01/08/2023]
Abstract
The assembly of the ribosome on majority of eukaryotic mRNAs is initiated by the recruitment of eIF4E protein to the mRNA 5' end cap structure. Flowering plants use two eIF4E isoforms, named eIF4E and eIF(iso)4E, as canonical translation initiation factors and possess a homolog of mammalian 4EHP (or eIF4E-2) termed nCBP. Plants from Brassicaceae family additionally conserve a close paralog of eIF4E which in Arabidopsis thaliana has two copies named eIF4E1b and eIF4E1c. In order to assess the efficiency of plant non-canonical (eIF4E1b/1c and nCBP) and canonical (eIF4E and eIF(iso)4E) eIF4E proteins to bind mRNAs we utilized fluorescence titrations to determine accurate binding affinities of five A.thaliana eIF4E isoforms for a series of cap analogs. We found that eIF4E binds cap analogs from 4-fold to 10-fold stronger than eIF(iso)4E, while binding affinities of nCBP and eIF(iso)4E are comparable. Furthermore, eIF4E1c interacts similarly strongly with the cap as eIF4E, but eIF4E1b binds cap analogs ca. 2-fold weaker than eIF4E1c, regardless of the 95% sequence identity between these two proteins. The use of differentially chemically modified cap analogs in binding studies and a detailed analysis of the obtained homology models gave us insight into the molecular characteristic of varying cap-binding abilities of Arabidopsis eIF4E isoforms.
Collapse
|
37
|
Veliath E, Gaffney BL, Jones RA. Synthesis of capped RNA using a DMT group as a purification handle. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2014; 33:40-52. [PMID: 24588755 DOI: 10.1080/15257770.2013.864417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We report a new method for synthesis of capped RNA or 2'-OMe RNA that uses a N(2-)4,4'-dimethoxytrityl (DMT) group as a lipophilic purification handle to allow convenient isolation and purification of the capped RNA. The DMT group is easily removed under mild conditions without degradation of the cap. We have used this approach to prepare capped 10- and 20-mers. This method is compatible with the many condensation reactions that have been reported for preparation of capped RNA or cap analogues.
Collapse
Affiliation(s)
- Elizabeth Veliath
- a Department of Chemistry and Chemical Biology, Rutgers , The State University of New Jersey , Piscataway , New Jersey , USA
| | | | | |
Collapse
|
38
|
Proud CG. Mnks, eIF4E phosphorylation and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:766-73. [PMID: 25450520 DOI: 10.1016/j.bbagrm.2014.10.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 10/06/2014] [Accepted: 10/18/2014] [Indexed: 01/18/2023]
Abstract
The MAP kinase signal-integrating kinases or MAP kinase-interacting protein kinases (Mnks) are activated by signaling through the oncogenic MAP kinase (ERK) pathway. The best-known Mnk substrate is eukaryotic initiation factor eIF4E, the protein which binds the 5'-cap structure of eukaryotic mRNAs and helps to recruit ribosomes to them. eIF4E is a well-established proto-oncogene, whose expression or activation is associated with transformation and tumorigenesis. Mnks phosphorylate eIF4E at a single site. Increasing evidence implicates the Mnks and/or phosphorylation of eIF4E in cell transformation, tumorigenesis or tumor progression, in a growing range of settings. Mnks and/or the phosphorylation of eIF4E have been suggested to regulate the expression of proteins involved in cell cycle progression, cell survival and cell motility. Further work is needed to extend our understanding of the impact of the Mnks on gene expression, explore the biochemical mechanisms involved and evaluate the utility of targeting the Mnks in cancer therapy. This article is part of a Special Issue entitled: Translation and Cancer.
Collapse
Affiliation(s)
- Christopher G Proud
- South Australian Health & Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.
| |
Collapse
|
39
|
Multiplicity of 5' cap structures present on short RNAs. PLoS One 2014; 9:e102895. [PMID: 25079783 PMCID: PMC4117478 DOI: 10.1371/journal.pone.0102895] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 06/24/2014] [Indexed: 12/18/2022] Open
Abstract
Most RNA molecules are co- or post-transcriptionally modified to alter their chemical and functional properties to assist in their ultimate biological function. Among these modifications, the addition of 5′ cap structure has been found to regulate turnover and localization. Here we report a study of the cap structure of human short (<200 nt) RNAs (sRNAs), using sequencing of cDNA libraries prepared by enzymatic pretreatment of the sRNAs with cap sensitive-specificity, thin layer chromatographic (TLC) analyses of isolated cap structures and mass spectrometric analyses for validation of TLC analyses. Processed versions of snoRNAs and tRNAs sequences of less than 50 nt were observed in capped sRNA libraries, indicating additional processing and recapping of these annotated sRNAs biotypes. We report for the first time 2,7 dimethylguanosine in human sRNAs cap structures and surprisingly we find multiple type 0 cap structures (mGpppC, 7mGpppG, GpppG, GpppA, and 7mGpppA) in RNA length fractions shorter than 50 nt. Finally, we find the presence of additional uncharacterized cap structures that wait determination by the creation of needed reference compounds to be used in TLC analyses. These studies suggest the existence of novel biochemical pathways leading to the processing of primary and sRNAs and the modifications of their RNA 5′ ends with a spectrum of chemical modifications.
Collapse
|
40
|
Pettersson F, del Rincon SV, Miller WH. Eukaryotic translation initiation factor 4E as a novel therapeutic target in hematological malignancies and beyond. Expert Opin Ther Targets 2014; 18:1035-48. [DOI: 10.1517/14728222.2014.937426] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
41
|
Sciascia Q, Pacheco D, McCoard SA. Increased milk protein synthesis in response to exogenous growth hormone is associated with changes in mechanistic (mammalian) target of rapamycin (mTOR)C1-dependent and independent cell signaling. J Dairy Sci 2013; 96:2327-2338. [PMID: 23462168 DOI: 10.3168/jds.2012-6267] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 01/02/2013] [Indexed: 01/17/2023]
Abstract
The objective of this study was to determine if increased milk protein synthesis observed in lactating dairy cows treated with growth hormone (GH) was associated with mechanistic (or mammalian) target of rapamycin complex 1 (mTORC1) regulation of downstream factors controlling nucleocytoplasmic export and translation of mRNA. To address this objective, biochemical indices of mammary growth and secretory activity and the abundance and phosphorylation status of mTORC1 pathway factors were measured in mammary tissues harvested from nonpregnant lactating dairy cows 6 d after treatment with a slow-release formulation of GH or saline (n=4/group). Treatment with GH increased mammary parenchymal weight and total protein content and tended to increase ribosome number and cell size, whereas protein synthetic efficiency, capacity, and cell number were unchanged. Cellular abundance of the mTORC1 components mTOR and (phosphorylated) mTOR(Ser2448) increased, as did complex eukaryotic initiation factor 4E:eukaryotic initiation factor 4E binding protein 1 (eIF4E:4EBP1), whereas no change was observed for mTORC1-downstream targets 4EBP1, 4EBP1(Ser65), p70/p85(S6K) and p70(S6K)Thre389/p85(S6K)Thre412. Changes in activation were not observed for any of the targets measured. These results indicate that GH treatment influences signaling to mTORC1 but not downstream targets involved in the nucleocytoplasmic export and translation of mRNA. Increased eIF4E:4EBP1 complex formation indicates involvement of the mitogen-activated protein kinase (MAPK) pathway. Abundance of MAPK pathway components eIF4E, eIF4E(Ser209), eIF4E:eIF4G complex, MAP kinase-interacting serine/threonine-protein kinase 1 (MKNK1), MKNK1(Thr197202), and ribosomal protein S6 kinase, 90kDa, polypeptide 1 (RPS6KA1) increased significantly in response to GH, whereas relative activation of the proteins was unchanged. Expression of IGFBP3 and IGFBP5 increased, that of IGF1R decreased, and that of IGF1 remained unchanged in response to GH. PatSearch analysis of the milk caseins αS1-casein, αS2-casein, and β-casein, MAPK signaling target RPS6KA1, and proliferation gene IGFBP3 mRNA indicated that all contained putative eIF4E-sensitivity elements. In response to GH, these genes were all upregulated, suggesting that increased abundance of eIF4E and eIF4E(Ser209) plays a role in mediating their nucleocytoplasmic export. We propose that, in response to GH, the IGF1-IGF1R-MAPK signaling cascade regulates eIF4E-mediated nucleocytoplasmic export and translation of mRNA, whereas mTOR controls cell renewal, cell turnover, and rRNA transcription through an alternative signaling cascade.
Collapse
Affiliation(s)
- Q Sciascia
- Animal Nutrition Team, Animal Nutrition and Health Group, AgResearch Grasslands, Private Bag 11008, Palmerston North 4442, New Zealand
| | - D Pacheco
- Animal Nutrition Team, Animal Nutrition and Health Group, AgResearch Grasslands, Private Bag 11008, Palmerston North 4442, New Zealand
| | - S A McCoard
- Animal Nutrition Team, Animal Nutrition and Health Group, AgResearch Grasslands, Private Bag 11008, Palmerston North 4442, New Zealand.
| |
Collapse
|
42
|
Szczepaniak SA, Zuberek J, Darzynkiewicz E, Kufel J, Jemielity J. Affinity resins containing enzymatically resistant mRNA cap analogs--a new tool for the analysis of cap-binding proteins. RNA (NEW YORK, N.Y.) 2012; 18:1421-32. [PMID: 22589334 PMCID: PMC3383972 DOI: 10.1261/rna.032078.111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/12/2012] [Indexed: 05/21/2023]
Abstract
Cap-binding proteins have been routinely isolated using m⁷GTP-Sepharose; however, this resin is inefficient for proteins such as DcpS (scavenger decapping enzyme), which interacts not only with the 7-methylguanosine, but also with the second cap base. In addition, DcpS purification may be hindered by the reduced resin capacity due to the ability of DcpS to hydrolyze m⁷GTP. Here, we report the synthesis of new affinity resins, m⁷GpCH₂pp- and m⁷GpCH₂ppA-Sepharoses, with attached cap analogs resistant to hydrolysis by DcpS. Biochemical tests showed that these matrices, as well as a hydrolyzable m⁷GpppA-Sepharose, bind recombinant mouse eIF4E²⁸⁻²¹⁷ specifically and at high capacity. In addition, purification of cap-binding proteins from yeast extracts confirmed the presence of all expected cap-binding proteins, including DcpS in the case of m⁷GpCH₂pp- and m⁷GpCH₂ppA-Sepharoses. In contrast, binding studies in vitro demonstrated that recombinant human DcpS efficiently bound only m⁷GpCH₂ppA-Sepharose. Our data prove the applicability of these novel resins, especially m⁷GpCH₂ppA-Sepharose, in biochemical studies such as the isolation and identification of cap-binding proteins from different organisms.
Collapse
Affiliation(s)
- Sylwia Anna Szczepaniak
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 02-089 Warsaw, Poland
| | - Joanna Zuberek
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, 02-106 Warsaw, Poland
| | - Jacek Jemielity
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| |
Collapse
|
43
|
Thillier Y, Decroly E, Morvan F, Canard B, Vasseur JJ, Debart F. Synthesis of 5' cap-0 and cap-1 RNAs using solid-phase chemistry coupled with enzymatic methylation by human (guanine-N⁷)-methyl transferase. RNA (NEW YORK, N.Y.) 2012; 18:856-68. [PMID: 22334760 PMCID: PMC3312571 DOI: 10.1261/rna.030932.111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 11/19/2011] [Indexed: 05/19/2023]
Abstract
The 5' end of eukaryotic mRNA carries a N(7)-methylguanosine residue linked by a 5'-5' triphosphate bond. This cap moiety ((7m)GpppN) is an essential RNA structural modification allowing its efficient translation, limiting its degradation by cellular 5' exonucleases and avoiding its recognition as "nonself" by the innate immunity machinery. In vitro synthesis of capped RNA is an important bottleneck for many biological studies. Moreover, the lack of methods allowing the synthesis of large amounts of RNA starting with a specific 5'-end sequence have hampered biological and structural studies of proteins recognizing the cap structure or involved in the capping pathway. Due to the chemical nature of N(7)-methylguanosine, the synthesis of RNAs possessing a cap structure at the 5' end is still a significant challenge. In the present work, we combined a chemical synthesis method and an enzymatic methylation assay in order to produce large amounts of RNA oligonucleotides carrying a cap-0 or cap-1. Short RNAs were synthesized on solid support by the phosphoramidite 2'-O-pivaloyloxymethyl chemistry. The cap structure was then coupled by the addition of GDP after phosphorylation of the terminal 5'-OH and activation by imidazole. After deprotection and release from the support, GpppN-RNAs or GpppN(2'-Om)-RNAs were purified before the N(7)-methyl group was added by enzymatic means using the human (guanine-N(7))-methyl transferase to yield (7m)GpppN-RNAs (cap-0) or (7m)GpppN(2'-Om)-RNAs (cap-1). The RNAs carrying different cap structures (cap, cap-0 or, cap-1) act as bona fide substrates mimicking cellular capped RNAs and can be used for biochemical and structural studies.
Collapse
Affiliation(s)
- Yann Thillier
- IBMM, UMR 5247 CNRS-UM1-UM2, Université Montpellier 2, 34095 Montpellier cedex 05, France
| | - Etienne Decroly
- AFMB, UMR 6098 CNRS-Universités d'Aix-Marseille I et II, 13288 Marseille cedex 9, France
| | - François Morvan
- IBMM, UMR 5247 CNRS-UM1-UM2, Université Montpellier 2, 34095 Montpellier cedex 05, France
| | - Bruno Canard
- AFMB, UMR 6098 CNRS-Universités d'Aix-Marseille I et II, 13288 Marseille cedex 9, France
| | - Jean-Jacques Vasseur
- IBMM, UMR 5247 CNRS-UM1-UM2, Université Montpellier 2, 34095 Montpellier cedex 05, France
| | - Françoise Debart
- IBMM, UMR 5247 CNRS-UM1-UM2, Université Montpellier 2, 34095 Montpellier cedex 05, France
| |
Collapse
|
44
|
Ziaei S, Shimada N, Kucharavy H, Hubbard K. MNK1 expression increases during cellular senescence and modulates the subcellular localization of hnRNP A1. Exp Cell Res 2011; 318:500-8. [PMID: 22227431 DOI: 10.1016/j.yexcr.2011.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 12/14/2011] [Accepted: 12/16/2011] [Indexed: 12/15/2022]
Abstract
Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is an RNA-binding protein that modulates splice site usage, polyadenylation, and cleavage efficiency. This protein has also been implicated in mRNA stability and transport from the nucleus. We have previously demonstrated that hnRNP A1 had diminished protein levels and showed cytoplasmic accumulation in senescent human diploid fibroblasts. Furthermore, we have shown that inhibition of p38 MAPK, a key regulator of cellular senescence, elevated hnRNP A1 protein levels and inhibited hnRNP A1 cytoplasmic localization. In this study, we have explored the possible involvement of MNK1, one of the downstream effector of p38 MAPK, in the regulation of hnRNP A1. We have demonstrated that pharmacological inhibition of MNK1 by CGP 57380 decreased the phosphorylation levels of hnRNP A1 in young and senescent fibroblast cells and blocked the cytoplasmic accumulation of hnRNP A1 in senescent cells. In addition, MNK1 formed a complex with hnRNP A1 in vivo. The expression levels of MNK1, phospho-MNK1, and phospho-eIF4E proteins were found to be elevated in senescent cells. These data suggest that MNK1 regulates the phosphorylation and the subcellular distribution of hnRNP A1 and that MNK1 may play a role in the induction of senescence.
Collapse
Affiliation(s)
- Samira Ziaei
- City College of New York, City University of New York, New York, NY, USA.
| | | | | | | |
Collapse
|
45
|
Adeli K. Translational control mechanisms in metabolic regulation: critical role of RNA binding proteins, microRNAs, and cytoplasmic RNA granules. Am J Physiol Endocrinol Metab 2011; 301:E1051-64. [PMID: 21971522 DOI: 10.1152/ajpendo.00399.2011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Regulated cell metabolism involves acute and chronic regulation of gene expression by various nutritional and endocrine stimuli. To respond effectively to endogenous and exogenous signals, cells require rapid response mechanisms to modulate transcript expression and protein synthesis and cannot, in most cases, rely on control of transcriptional initiation that requires hours to take effect. Thus, co- and posttranslational mechanisms have been increasingly recognized as key modulators of metabolic function. This review highlights the critical role of mRNA translational control in modulation of global protein synthesis as well as specific protein factors that regulate metabolic function. First, the complex lifecycle of eukaryotic mRNAs will be reviewed, including our current understanding of translational control mechanisms, regulation by RNA binding proteins and microRNAs, and the role of RNA granules, including processing bodies and stress granules. Second, the current evidence linking regulation of mRNA translation with normal physiological and metabolic pathways and the associated disease states are reviewed. A growing body of evidence supports a key role of translational control in metabolic regulation and implicates translational mechanisms in the pathogenesis of metabolic disorders such as type 2 diabetes. The review also highlights translational control of apolipoprotein B (apoB) mRNA by insulin as a clear example of endocrine modulation of mRNA translation to bring about changes in specific metabolic pathways. Recent findings made on the role of 5'-untranslated regions (5'-UTR), 3'-UTR, RNA binding proteins, and RNA granules in mediating insulin regulation of apoB mRNA translation, apoB protein synthesis, and hepatic lipoprotein production are discussed.
Collapse
Affiliation(s)
- Khosrow Adeli
- Program in Molecular Structure & Function, Research Institute, The Hospital for Sick Children, Atrium 3653, 555 University Ave., Toronto, ON, M5G 1X8 Canada.
| |
Collapse
|
46
|
Kiraga-Motoszko K, Niedzwiecka A, Modrak-Wojcik A, Stepinski J, Darzynkiewicz E, Stolarski R. Thermodynamics of molecular recognition of mRNA 5' cap by yeast eukaryotic initiation factor 4E. J Phys Chem B 2011; 115:8746-54. [PMID: 21650456 DOI: 10.1021/jp2012039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular mechanisms underlying the recognition of the mRNA 5' terminal structure called "cap" by the eukaryotic initiation factor 4E (eIF4E) are crucial for cap-dependent translation. To gain a deeper insight into how the yeast eIF4E interacts with the cap structure, isothermal titration calorimetry and the van't Hoff analysis based on intrinsic protein fluorescence quenching upon titration with a series of chemical cap analogs were performed, providing a consistent thermodynamic description of the binding process in solution. Equilibrium association constants together with thermodynamic parameters revealed similarities and differences between yeast and mammalian eIF4Es. The yeast eIF4E complex formation was enthalpy-driven and entropy-opposed for each cap analog at 293 K. A nontrivial isothermal enthalpy–entropy compensation was found, described by a compensation temperature, T(c) = 411 ± 18 K. For a low affinity analog, 7-methylguanosine monophosphate, a heat capacity change was detected, ΔC(p)° = +5.2 ± 1.3 kJ·mol(-1)·K(-1). The charge-related interactions involving the 5′-5′ triphosphate bridge of the cap and basic amino acid side chains at the yeast eIF4E cap-binding site were significantly weaker (by ΔΔH°(vH) of about +10 kJ·mol(-1)) than those for the mammalian homologues, suggesting their optimization during the evolution.
Collapse
Affiliation(s)
- Katarzyna Kiraga-Motoszko
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | | | | | | | | | | |
Collapse
|
47
|
Su W, Slepenkov S, Grudzien-Nogalska E, Kowalska J, Kulis M, Zuberek J, Lukaszewicz M, Darzynkiewicz E, Jemielity J, Rhoads RE. Translation, stability, and resistance to decapping of mRNAs containing caps substituted in the triphosphate chain with BH3, Se, and NH. RNA (NEW YORK, N.Y.) 2011; 17:978-88. [PMID: 21447710 PMCID: PMC3078746 DOI: 10.1261/rna.2430711] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Accepted: 02/15/2011] [Indexed: 05/23/2023]
Abstract
Decapping is an essential step in multiple pathways of mRNA degradation. Previously, we synthesized mRNAs containing caps that were resistant to decapping, both to dissect the various pathways for mRNA degradation and to stabilize mRNA for more sustained protein expression. mRNAs containing an α-β CH(2) group are resistant to in vitro cleavage by the decapping enzyme hDcp2 but poorly translated. mRNAs containing an S substitution at the β-phosphate are well translated but only partially resistant to hDcp2. We now describe seven new cap analogs substituted at the β-phosphate with BH(3) or Se, or substituted at either the α-β or β-γ O with NH. The analogs differ in affinity for eIF4E and efficiency of in vitro incorporation into mRNA by T7 RNA polymerase. Luciferase mRNAs capped with these analogs differ in resistance to hDcp2 hydrolysis in vitro, translational efficiency in rabbit reticulocyte lysate and in HeLa cells, and stability in HeLa cells. Whereas mRNAs capped with m(2)(7,2'-O)Gpp(S)pG were previously found to have the most favorable properties of translational efficiency and stability in mammalian cells, mRNAs capped with m(7)Gpp(BH3)pm(7)G are translated with the same efficiency but are more stable. Interestingly, some mRNAs exhibit a lag of up to 60 min before undergoing first-order decay (t(1/2) ≅ 25 min). Only mRNAs that are efficiently capped, resistant to decapping in vitro, and actively translated have long lag phases.
Collapse
Affiliation(s)
- Wei Su
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-3932, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
eIF4E phosphorylation promotes tumorigenesis and is associated with prostate cancer progression. Proc Natl Acad Sci U S A 2010; 107:14134-9. [PMID: 20679199 DOI: 10.1073/pnas.1005320107] [Citation(s) in RCA: 397] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Translational regulation plays a critical role in the control of cell growth and proliferation. A key player in translational control is eIF4E, the mRNA 5' cap-binding protein. Aberrant expression of eIF4E promotes tumorigenesis and has been implicated in cancer development and progression. The activity of eIF4E is dysregulated in cancer. Regulation of eIF4E is partly achieved through phosphorylation. However, the physiological significance of eIF4E phosphorylation in mammals is not clear. Here, we show that knock-in mice expressing a nonphosphorylatable form of eIF4E are resistant to tumorigenesis in a prostate cancer model. By using a genome-wide analysis of translated mRNAs, we show that the phosphorylation of eIF4E is required for translational up-regulation of several proteins implicated in tumorigenesis. Accordingly, increased phospho-eIF4E levels correlate with disease progression in patients with prostate cancer. Our findings establish eIF4E phosphorylation as a critical event in tumorigenesis. These findings raise the possibility that chemical compounds that prevent the phosphorylation of eIF4E could act as anticancer drugs.
Collapse
|
49
|
Jia Y, Chiu TL, Amin EA, Polunovsky V, Bitterman PB, Wagner CR. Design, synthesis and evaluation of analogs of initiation factor 4E (eIF4E) cap-binding antagonist Bn7-GMP. Eur J Med Chem 2009; 45:1304-13. [PMID: 20060622 DOI: 10.1016/j.ejmech.2009.11.054] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 11/17/2009] [Accepted: 11/27/2009] [Indexed: 01/19/2023]
Abstract
Aberrant regulation of cap-dependent translation has been frequently observed in the development of cancer. Association of the cap-binding protein eIF4E with N(7)-methylated guanosine capped mRNA is the rate limiting step governing translation initiation; and therefore represents an attractive process for cancer drug discovery. Previously, replacement of the 7-Me group of the Me(7)-guanosine monophosphate with a benzyl group has been found to increase binding affinity to eIF4E. Recent X-ray crystallographic studies have revealed that the cap-binding pocket undergoes a unique structural change in order to accommodate the benzyl group. To explore the structure-activity relationships governing the affinity of N(7)-benzylated guanosine monophosphate (Bn(7)-GMP) for eIF4E, we virtually screened a library of 80 Bn(7)-GMP analogs utilizing CombiGlide as implemented in Schrodinger. A subset library of substituted Bn(7)-GMP analogs was synthesized and their dissociation constants (K(d)) were determined. Due to the poor correlation between docking/scoring results and experimental binding affinities, three-dimensional quantitative structure-activity relationship (3D-QSAR) calculations were performed. Two highly predictive and self-consistent CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) models were derived and optimized. These models may be useful for the future design of eIF4E cap-binding antagonists.
Collapse
Affiliation(s)
- Yan Jia
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | | | | | | |
Collapse
|
50
|
Liu W, Zhao R, McFarland C, Kieft J, Niedzwiecka A, Jankowska-Anyszka M, Stepinski J, Darzynkiewicz E, Jones DNM, Davis RE. Structural insights into parasite eIF4E binding specificity for m7G and m2,2,7G mRNA caps. J Biol Chem 2009; 284:31336-49. [PMID: 19710013 PMCID: PMC2781531 DOI: 10.1074/jbc.m109.049858] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 08/19/2009] [Indexed: 01/02/2023] Open
Abstract
The eukaryotic translation initiation factor eIF4E recognizes the mRNA cap, a key step in translation initiation. Here we have characterized eIF4E from the human parasite Schistosoma mansoni. Schistosome mRNAs have either the typical monomethylguanosine (m(7)G) or a trimethylguanosine (m(2,2,7)G) cap derived from spliced leader trans-splicing. Quantitative fluorescence titration analyses demonstrated that schistosome eIF4E has similar binding specificity for both caps. We present the first crystal structure of an eIF4E with similar binding specificity for m(7)G and m(2,2,7)G caps. The eIF4E.m(7)GpppG structure demonstrates that the schistosome protein binds monomethyl cap in a manner similar to that of single specificity eIF4Es and exhibits a structure similar to other known eIF4Es. The structure suggests an alternate orientation of a conserved, key Glu-90 in the cap-binding pocket that may contribute to dual binding specificity and a position for mRNA bound to eIF4E consistent with biochemical data. Comparison of NMR chemical shift perturbations in schistosome eIF4E on binding m(7)GpppG and m(2,2,7)GpppG identified key differences between the two complexes. Isothermal titration calorimetry demonstrated significant thermodynamics differences for the binding process with the two caps (m(7)G versus m(2,2,7)G). Overall the NMR and isothermal titration calorimetry data suggest the importance of intrinsic conformational flexibility in the schistosome eIF4E that enables binding to m(2,2,7)G cap.
Collapse
Affiliation(s)
- Weizhi Liu
- From the Departments of Biochemistry and Molecular Genetics and
| | - Rui Zhao
- From the Departments of Biochemistry and Molecular Genetics and
| | - Craig McFarland
- From the Departments of Biochemistry and Molecular Genetics and
| | - Jeffrey Kieft
- From the Departments of Biochemistry and Molecular Genetics and
| | - Anna Niedzwiecka
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
- Biological Physics Group, Institute of Physics, Polish Academy of Sciences, 32/46 Lotnikow Avenue, 02-668 Warsaw, Poland
| | | | - Janusz Stepinski
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - Edward Darzynkiewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-089 Warsaw, Poland
| | - David N. M. Jones
- **Pharmacology, University of Colorado School of Medicine, Aurora, Colorado 80045
| | | |
Collapse
|