1
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Tariq D, Maurici N, Bartholomai BM, Chandrasekaran S, Dunlap JC, Bah A, Crane BR. Phosphorylation, disorder, and phase separation govern the behavior of Frequency in the fungal circadian clock. eLife 2024; 12:RP90259. [PMID: 38526948 PMCID: PMC10963029 DOI: 10.7554/elife.90259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024] Open
Abstract
Circadian clocks are composed of transcription-translation negative feedback loops that pace rhythms of gene expression to the diurnal cycle. In the filamentous fungus Neurospora crassa, the proteins Frequency (FRQ), the FRQ-interacting RNA helicase (FRH), and Casein-Kinase I (CK1) form the FFC complex that represses expression of genes activated by the white-collar complex (WCC). FRQ orchestrates key molecular interactions of the clock despite containing little predicted tertiary structure. Spin labeling and pulse-dipolar electron spin resonance spectroscopy provide domain-specific structural insights into the 989-residue intrinsically disordered FRQ and the FFC. FRQ contains a compact core that associates and organizes FRH and CK1 to coordinate their roles in WCC repression. FRQ phosphorylation increases conformational flexibility and alters oligomeric state, but the changes in structure and dynamics are non-uniform. Full-length FRQ undergoes liquid-liquid phase separation (LLPS) to sequester FRH and CK1 and influence CK1 enzymatic activity. Although FRQ phosphorylation favors LLPS, LLPS feeds back to reduce FRQ phosphorylation by CK1 at higher temperatures. Live imaging of Neurospora hyphae reveals FRQ foci characteristic of condensates near the nuclear periphery. Analogous clock repressor proteins in higher organisms share little position-specific sequence identity with FRQ; yet, they contain amino acid compositions that promote LLPS. Hence, condensate formation may be a conserved feature of eukaryotic clocks.
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Affiliation(s)
- Daniyal Tariq
- Department of Chemistry & Chemical Biology, Cornell UniversityIthacaUnited States
| | - Nicole Maurici
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Bradley M Bartholomai
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
| | | | - Jay C Dunlap
- Department of Molecular and Systems Biology, Geisel School of Medicine at DartmouthHanoverUnited States
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Brian R Crane
- Department of Chemistry & Chemical Biology, Cornell UniversityIthacaUnited States
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2
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Chakraborty A, Dutta A, Dettori LG, Daoud R, Li J, Gonzalez L, Xue X, Hehnly H, Sung P, Bah A, Feng W. Complex interplay between FMRP and DHX9 during DNA replication stress. J Biol Chem 2024; 300:105572. [PMID: 38110032 PMCID: PMC10825048 DOI: 10.1016/j.jbc.2023.105572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 11/28/2023] [Accepted: 12/06/2023] [Indexed: 12/20/2023] Open
Abstract
Mutations in, or deficiency of, fragile X messenger ribonucleoprotein (FMRP) is responsible for the Fragile X syndrome (FXS), the most common cause for inherited intellectual disability. FMRP is a nucleocytoplasmic protein, primarily characterized as a translation repressor with poorly understood nuclear function(s). We recently reported that FXS patient cells lacking FMRP sustain higher level of DNA double-strand breaks (DSBs) than normal cells, specifically at sequences prone to forming R-loops, a phenotype further exacerbated by DNA replication stress. Moreover, expression of FMRP, and not an FMRPI304N mutant known to cause FXS, reduced R-loop-associated DSBs. We subsequently reported that recombinant FMRP directly binds R-loops, primarily through the carboxyl terminal intrinsically disordered region. Here, we show that FMRP directly interacts with an RNA helicase, DHX9. This interaction, which is mediated by the amino terminal structured domain of FMRP, is reduced with FMRPI304N. We also show that FMRP inhibits DHX9 helicase activity on RNA:DNA hybrids and the inhibition is also dependent on the amino terminus. Furthermore, the FMRPI304N mutation causes both FMRP and DHX9 to persist on the chromatin in replication stress. These results suggest an antagonistic relationship between FMRP and DHX9 at the chromatin, where their proper interaction leads to dissociation of both proteins from the fully resolved R-loop. We propose that the absence or the loss of function of FMRP leads to persistent presence of DHX9 or both proteins, respectively, on the unresolved R-loop, ultimately leading to DSBs. Our study sheds new light on our understanding of the genome functions of FMRP.
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Affiliation(s)
- Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center San Antonio, San Antonio, Texas, USA
| | - Leonardo G Dettori
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Rosemarie Daoud
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jing Li
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Leticia Gonzalez
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA
| | - Xiaoyu Xue
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA
| | - Heidi Hehnly
- Department of Biology, Syracuse University, Syracuse, New York, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center San Antonio, San Antonio, Texas, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA.
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3
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Tsangaris TE, Smyth S, Gomes GNW, Liu ZH, Milchberg M, Bah A, Wasney GA, Forman-Kay JD, Gradinaru CC. Delineating Structural Propensities of the 4E-BP2 Protein via Integrative Modeling and Clustering. J Phys Chem B 2023; 127:7472-7486. [PMID: 37595014 PMCID: PMC10858721 DOI: 10.1021/acs.jpcb.3c04052] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
The intrinsically disordered 4E-BP2 protein regulates mRNA cap-dependent translation through interaction with the predominantly folded eukaryotic initiation factor 4E (eIF4E). Phosphorylation of 4E-BP2 dramatically reduces the level of eIF4E binding, in part by stabilizing a binding-incompatible folded domain. Here, we used a Rosetta-based sampling algorithm optimized for IDRs to generate initial ensembles for two phospho forms of 4E-BP2, non- and 5-fold phosphorylated (NP and 5P, respectively), with the 5P folded domain flanked by N- and C-terminal IDRs (N-IDR and C-IDR, respectively). We then applied an integrative Bayesian approach to obtain NP and 5P conformational ensembles that agree with experimental data from nuclear magnetic resonance, small-angle X-ray scattering, and single-molecule Förster resonance energy transfer (smFRET). For the NP state, inter-residue distance scaling and 2D maps revealed the role of charge segregation and pi interactions in driving contacts between distal regions of the chain (∼70 residues apart). The 5P ensemble shows prominent contacts of the N-IDR region with the two phosphosites in the folded domain, pT37 and pT46, and, to a lesser extent, delocalized interactions with the C-IDR region. Agglomerative hierarchical clustering led to partitioning of each of the two ensembles into four clusters with different global dimensions and contact maps. This helped delineate an NP cluster that, based on our smFRET data, is compatible with the eIF4E-bound state. 5P clusters were differentiated by interactions of C-IDR with the folded domain and of the N-IDR with the two phosphosites in the folded domain. Our study provides both a better visualization of fundamental structural poses of 4E-BP2 and a set of falsifiable insights on intrachain interactions that bias folding and binding of this protein.
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Affiliation(s)
- Thomas E Tsangaris
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Spencer Smyth
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Gregory-Neal W Gomes
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
| | - Zi Hao Liu
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Moses Milchberg
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Alaji Bah
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Gregory A Wasney
- Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Julie D Forman-Kay
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada
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Dettori LG, Torrejon D, Chakraborty A, Dutta A, Viennet T, Mohamed M, Li J, Guerrero AY, Papp C, Kuznetsov VA, Arthanari H, Sung P, Feng W, Bah A. Droplets, tails and loops: The role of intrinsic disorder in R-loop biology. Biophys J 2023; 122:200a. [PMID: 36782970 DOI: 10.1016/j.bpj.2022.11.1213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Leonardo Garcia Dettori
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | | | - Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Thibault Viennet
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | | | - Jing Li
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Alexander Y Guerrero
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Csaba Papp
- Department of Urology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Vladimir A Kuznetsov
- Department of Urology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY, USA
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5
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Li J, Garcia Dettori L, Landry S, Guerrero A, Chakraborty A, Feng W, Bah A. Investigating the mechanism of interaction of R-loops and the Fragile X protein, FMRP: An entanglement of disordered tails and multivalency. Biophys J 2023; 122:218a. [PMID: 36783064 DOI: 10.1016/j.bpj.2022.11.1301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Jing Li
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Leonardo Garcia Dettori
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Stephen Landry
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Alexander Guerrero
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
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Palumbo RJ, McKean N, Leatherman E, Namitz KEW, Connell L, Wolfe A, Moody K, Gostinčar C, Gunde-Cimerman N, Bah A, Hanes SD. Coevolution of the Ess1-CTD axis in polar fungi suggests a role for phase separation in cold tolerance. Sci Adv 2022; 8:eabq3235. [PMID: 36070379 PMCID: PMC9451162 DOI: 10.1126/sciadv.abq3235] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/21/2022] [Indexed: 06/14/2023]
Abstract
Most of the world's biodiversity lives in cold (-2° to 4°C) and hypersaline environments. To understand how cells adapt to such conditions, we isolated two key components of the transcription machinery from fungal species that live in extreme polar environments: the Ess1 prolyl isomerase and its target, the carboxy-terminal domain (CTD) of RNA polymerase II. Polar Ess1 enzymes are conserved and functional in the model yeast, Saccharomyces cerevisiae. By contrast, polar CTDs diverge from the consensus (YSPTSPS)26 and are not fully functional in S. cerevisiae. These CTDs retain the critical Ess1 Ser-Pro target motifs, but substitutions at Y1, T4, and S7 profoundly affected their ability to undergo phase separation in vitro and localize in vivo. We propose that environmentally tuned phase separation by the CTD and other intrinsically disordered regions plays an adaptive role in cold tolerance by concentrating enzymes and substrates to overcome energetic barriers to metabolic activity.
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Affiliation(s)
- Ryan J. Palumbo
- Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY 13210, USA
| | - Nathan McKean
- Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY 13210, USA
| | - Erinn Leatherman
- Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY 13210, USA
| | - Kevin E. W. Namitz
- Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY 13210, USA
| | - Laurie Connell
- School of Marine Sciences and Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469, USA
| | - Aaron Wolfe
- Ichor Life Sciences Inc., 2651 US Route 11, LaFayette, NY 13084, USA
- Lewis School of Health Sciences, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
- The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Kelsey Moody
- Ichor Life Sciences Inc., 2651 US Route 11, LaFayette, NY 13084, USA
- Lewis School of Health Sciences, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699, USA
- The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY 13210, USA
| | - Steven D. Hanes
- Department of Biochemistry and Molecular Biology, SUNY-Upstate Medical University, Syracuse, NY 13210, USA
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7
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Smyth S, Zhang Z, Bah A, Tsangaris TE, Dawson J, Forman-Kay JD, Gradinaru CC. Multisite phosphorylation and binding alter conformational dynamics of the 4E-BP2 protein. Biophys J 2022; 121:3049-3060. [PMID: 35841142 PMCID: PMC9463650 DOI: 10.1016/j.bpj.2022.07.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 05/19/2022] [Accepted: 07/11/2022] [Indexed: 11/02/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) play critical roles in regulatory protein interactions, but detailed structural/dynamic characterization of their ensembles remain challenging, both in isolation and when they form dynamic "fuzzy" complexes. Such is the case for mRNA cap-dependent translation initiation, which is regulated by the interaction of the predominantly folded eukaryotic initiation factor 4E (eIF4E) with the intrinsically disordered eIF4E binding proteins (4E-BPs) in a phosphorylation-dependent manner. Single-molecule Förster resonance energy transfer showed that the conformational changes of 4E-BP2 induced by binding to eIF4E are non-uniform along the sequence; while a central region containing both motifs that bind to eIF4E expands and becomes stiffer, the C-terminal region is less affected. Fluorescence anisotropy decay revealed a non-uniform segmental flexibility around six different labeling sites along the chain. Dynamic quenching of these fluorescent probes by intrinsic aromatic residues measured via fluorescence correlation spectroscopy report on transient intra- and inter-molecular contacts on nanosecond-to-microsecond timescales. Upon hyperphosphorylation, which induces folding of ∼40 residues in 4E-BP2, the quenching rates decreased at most labeling sites. The chain dynamics around sites in the C-terminal region far away from the two binding motifs significantly increased upon binding to eIF4E, suggesting that this region is also involved in the highly dynamic 4E-BP2:eIF4E complex. Our time-resolved fluorescence data paint a sequence-level rigidity map of three states of 4E-BP2 differing in phosphorylation or binding status and distinguish regions that form contacts with eIF4E. This study adds complementary structural and dynamics information to recent studies of 4E-BP2, and it constitutes an important step toward a mechanistic understanding of this important IDP via integrative modeling.
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Affiliation(s)
- Spencer Smyth
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Zhenfu Zhang
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alaji Bah
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Thomas E Tsangaris
- Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Jennifer Dawson
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Julie D Forman-Kay
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Claudiu C Gradinaru
- Department of Physics, University of Toronto, Toronto, Ontario, Canada; Department of Chemical & Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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8
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Li X, Porter B, Kemraj A, Bah A, Kortylewski M, Kotula L. Abstract 2364: ABI1 regulates transcriptional activity of STAT3. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-2364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Prostate cancer (PCa) is characterized by the complexity of oncogenic signaling and heterogeneity of transcriptional landscapes. Adaptor protein ABI1 is a tumor suppressor in PCa as evidenced by its loss or downregulation in high grade and metastatic tumors. STAT3 activation is a hallmark of high-risk prostate tumors. ABI1 loss is associated with STAT3 activation leading to transcriptional reprogramming and epithelial-mesenchymal-transition (EMT) of prostate cancer cells (Nath, Li et al. 2019 Cell Commun Signal). EMT changes involve several homeobox transcription factors. The fact that ABI1 contains a homeobox homology region (HHR) suggested the possibility that it plays a role in EMT through directly regulating transcriptional activity by DNA binding.
Methods: To examine this hypothesis we set out to analyze ABI1-DNA binding. We purified ABI1 HHR and demonstrated its in vitro interactions with different homeobox DNA-binding consensus of double-stranded DNA sequences. We created DU145 ABI1 CRISPR KO cell line and rescue ABI1 expression using retroviral transfection with either ABI1 wild type or Abi1 HHR mutants. DU145 cell lines STAT3 cellular localization was studied by Immunofluorescence staining and the STAT3 transcription activities was studied by Firefly Luciferase Assays with STAT3 specific luciferase reporter plasmid.
Results: We found that the presence of alternatively spliced Exon 4-encoded sequence, located in the C-terminus of HHR, regulates binding of ABI1 to DNA. Structural NMR studies confirmed ABI1 binding to DNA. Subsequent functional studies using DU145 CRISPR KO cell lines expressing wild type or HHR mutants of ABI1 demonstrated that HHR regulates the nuclear localization and transcriptional activity of STAT3.
Conclusion: We propose that ABI1 is a critical regulator of STAT3 activity during prostate cancer progression by the ABI1 HHR mediated DNA binding mechanism.
Funding resources: NCI R01 CA161018; R21 CA260381
Conflicts of Interest Disclosure Statement: The authors declare no conflicts of interest.
Citation Format: Xiang Li, Baylee Porter, Allysa Kemraj, Alaji Bah, Marcin Kortylewski, Leszek Kotula. ABI1 regulates transcriptional activity of STAT3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2364.
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Affiliation(s)
- Xiang Li
- 1Upstate Medical University, Syracuse, NY
| | | | | | - Alaji Bah
- 1Upstate Medical University, Syracuse, NY
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Porter-Hansen BA, Bah A, Urbanucci A, Kukkonen K, Zhang F, Kung S, Fazli L, Gleave ME, Bratslavsky G, Kotula L. Abstract 2367: Characterizing the reciprocal regulation of an ABI1-dependent androgen receptor axis in prostate cancer. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-2367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Prostate cancer (PCa) affects nearly 50% of males over 60. Therapies for advanced PCa primarily target the androgen receptor (AR), a ligand-activated transcription factor, which is a key driver of PCa tumor growth. Our previous research demonstrated that ABI1 acts as a tumor suppressor in PCa. ABI1 is a scaffold protein for the WAVE Regulatory Complex, positively regulates cell adhesion, and inhibits integrin activation through sequestering key kinases. We have observed a physical interaction between AR and ABI1. In this study, we aim to characterize the ABI1-dependent AR regulation in PCa.
Method: We generated an ABI1 KO cell line model in LNCaP cells using CRISPR-Cas9. We then used mutagenesis to develop ABI1 binding mutants (W485N and ∆SH3) and generated ABI1 rescue cell lines in ABI1-KO. We performed qPCR, co-immunoprecipitation, subcellular fractionation, western blotting, in vitro assay, live-cell imaging, and PLA. We purified both AR and ABI1 proteins for in vitro analysis, performed turbidity and liquid-liquid droplet formation assays under DIC.
Results: In cellulo binding assays indicate interaction of AR-NTD with the ABI1-SH3 domain. Expression of ABI1-W485N in KO cell line showed decreased binding, while ABI1-∆SH3 showed no observable binding to AR in co-IP assays compared to wildtype control. We then performed subcellular fractionation assays and saw decreased AR nuclear localization compared to ABI1-WT control. Decreased nuclear localization in ABI1-W485N was associated with decreased mRNA expression of hallmark AR target genes, KLK3 and FKBP5. In vitro turbidity assays indicated the conditions in which AR and ABI1 have propensity to phase separate. We then performed a liquid-liquid droplet assay. AR and ABI1 formed liquid-liquid droplets individually. We labeled ABI1 with Alexaflour 488 and saw that ABI1 was recruited to AR droplets indicating that AR and ABI1 can co-phase separate. PLA assays in cellulo and in vivo patient tumor samples showed positive interactions of AR-ABI1 in the nucleus. We then used live-cell observation and saw co-localization of biomolecular condensates for AR and ABI1.
Conclusions: Our studies demonstrate that ABI1 plays a role in AR transcriptional pathway. Loss of ABI1 resulted in decreased nuclear AR and subsequent decrease in mRNA expression of AR target genes. Due to the intrinsically disordered structure of AR and ABI1, they were both able to phase separate individually as well as together. AR stimulation increased PLA interactions in nucleus of cells. The co-localization of AR and ABI1 in biomolecular condensates was changed upon androgen deprivation conditions. Future studies will investigate if anti-AR treatments could lead to the dysregulation of ABI1 and promote reactivation of AR pathway through ABI1-AR axis. Findings will allow for novel insights into the mechanisms underlying AR and ABI1 in prostate metastatic progression.
Citation Format: Baylee A. Porter-Hansen, Alaji Bah, Alfonso Urbanucci, Konsta Kukkonen, Fan Zhang, Sonia Kung, Ladan Fazli, Martin E. Gleave, Gennady Bratslavsky, Leszek Kotula. Characterizing the reciprocal regulation of an ABI1-dependent androgen receptor axis in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2367.
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Affiliation(s)
| | - Alaji Bah
- 1Upstate Medical University, Syracuse, NY
| | | | | | - Fan Zhang
- 4University of British Columbia, Vancouver, British Columbia, Canada
| | - Sonia Kung
- 4University of British Columbia, Vancouver, British Columbia, Canada
| | - Ladan Fazli
- 4University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin E. Gleave
- 4University of British Columbia, Vancouver, British Columbia, Canada
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Ahmadou I, Diakite I, Maiga A, Pamateck S, Darar I, Dorcas Y, Traore A, Konate M, Bah A, Saye Z, Doumbia A, Dembele BT, Traore A, Kante L, Togo A. [Covid-19 And Surgical Pathologies In General Surgery Of CHU Gabriel Toure Of Bamako]. Mali Med 2022; 38:7-11. [PMID: 38506202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
INTRODUCTION The pure digestive form of COVID-19 is possible and initially considered rare. Our objectives were to determine the frequency of COVID-19 in patients treated in general surgery, identify the circumstances of COVID-19 discoveries in surgery, describe the post-operative complications in patients operated on COVID-1919 and describe the reorganization of post-operative COVID-19 diagnosis management. MATERIALS AND METHODS We conducted a prospective descriptive study from March 2020 to August 2021 (18 months). All patients who have been operated on, hospitalized or consulted in the department, the Emergency Department (ERS) or other CHU-GT departments for surgical pathology with COVID-19 or infected with COVID-19 while hospitalized were included in the study. RESULTS 23 cases collected, representing 8.91% (23/258) of COVID-19 cases identified, a frequency of 1.27/month. The age group 66-75 was the most affected, the average age was 49.13 18.75 years, the predominance was male (sex ratio of 1.3). More than 34.78% were recruited at the SAU, 16 patients (69.56%) consulted in emergency, and digestive signs of COVID-19 were: Abdominal pain 20 cases (89.96%), anorexia 19 cases (82.61%), vomiting 8 cases (34.78%) and diarrhea 3 cases (13.04%). The pulmonary signs of COVID-19 were: Cough 18 cases (78.26%), chest pain 15 cases (65.22%), and dyspnea 9 cases (39.13%). Manifestations of COVID-19 were: pulmonary 9 cases, digestive 9 cases, associated 3 cases, incidental discovery 2 cases. The diagnostic mean was Thoracic CT (100%), Test-PCR 14 cases (60.86%) with a positive PCR test in 50% of cases. Surgical pathologies were surgical emergencies in 7 cases (30.43%), cancers in 6 cases (26.09%), COVID-19 digestive event (30.43%) and other 3 cases (13.04%). More than half of patients were operated on 12 cases (52.17%). The overall mortality was 60.87% and the mortality of surgical patients was 41.67%. CONCLUSION The infectious risk of COVID-19 during hospitalization, during or after digestive surgery is a real and potentially serious risk for the patient and caregivers.
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Affiliation(s)
- I Ahmadou
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - I Diakite
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - A Maiga
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - S Pamateck
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - I Darar
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - Y Dorcas
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - A Traore
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - M Konate
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - A Bah
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - Z Saye
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - A Doumbia
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - B T Dembele
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - A Traore
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - L Kante
- Service de Chirurgie générale du CHU. Gabriel-Touré
| | - A Togo
- Service de Chirurgie générale du CHU. Gabriel-Touré
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11
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Mammadli M, Harris R, Suo L, May A, Gentile T, Waickman AT, Bah A, August A, Nurmemmedov E, Karimi M. Interleukin-2-inducible T-cell kinase (Itk) signaling regulates potent noncanonical regulatory T cells. Clin Transl Med 2021; 11:e625. [PMID: 34919342 PMCID: PMC8679839 DOI: 10.1002/ctm2.625] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/30/2021] [Accepted: 10/08/2021] [Indexed: 12/12/2022] Open
Abstract
Regulatory T cells (Tregs) play an important role in controlling autoimmunity and limiting tissue damage and inflammation. IL2-inducible T cell kinase (Itk) is part of the Tec family of tyrosine kinases and is a critical component of T cell receptor mediated signaling. Here, we showed that either genetic ablation of Itk signaling or inhibition of Itk signaling pathways resulted in increased frequency of "noncanonical" CD4+ CD25- FOXP3+ Tregs (ncTregs), as well as of "canonical" CD4+ CD25+ FOXP3+ Tregs (canTregs). Using in vivo models, we showed that ncTregs can avert the formation of acute graft-versus-host disease (GVHD), in part by reducing conventional T cell proliferation, proinflammatory cytokine production, and tissue damage. This reduction in GVHD occurred without disruption of graft-versus-leukaemia (GVL) effects. RNA sequencing revealed that a number of effector, cell adhesion, and migration molecules were upregulated in Itk-/- ncTregs. Furthermore, disrupting the SLP76: ITK interaction using a specific peptide inhibitor led to enhanced Treg development in both mouse and primary human cells. This peptide inhibitor also significantly reduced inflammatory cytokine production in primary GVHD patient samples and mouse T cells without causing cell death or apoptosis. We provide evidence that specifically targeting Itk signaling could be a therapeutic strategy to treat autoimmune disorders.
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Affiliation(s)
- Mahinbanu Mammadli
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Rebecca Harris
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Liye Suo
- Department of Pathology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Adriana May
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Teresa Gentile
- Department of Hematology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Adam T Waickman
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Avery August
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Elmar Nurmemmedov
- Department of Translational Neurosciences Saint John's Cancer Institute, Santa Monica, California, USA
| | - Mobin Karimi
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York, USA
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12
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Porter BA, Bah A, Urbanucci A, Zhang F, Kung S, Fazli L, Gleave M, Bratslavsky G, Kotula L. Abstract 2470: Defining the reciprocal regulation of Abi1 and the androgen receptor in prostate cancer. Cancer Res 2021. [DOI: 10.1158/1538-7445.am2021-2470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Prostate cancer (PCa) is a slowly progressing disease that affects nearly 50% of males over the age of 60. Current therapies for patients diagnosed with advanced PCa include Androgen Deprivation Therapy (ADT) and anti-androgen receptor (Anti-AR) treatment. PCa treatment primarily targets the androgen receptor (AR), a ligand-activated transcription factor, which is a key driver of PCa tumor growth. Our previous research has demonstrated that ABI1, acts as a tumor suppressor in PCa. ABI1 is a scaffold protein and an integral member of the WAVE Regulatory Complex (WRC), a nucleation promoting factor. UCSC database indicates there is an AR binding site within the ABI1 gene, suggesting AR plays a role in the transcriptional regulation of ABI1. In this study, we aim to characterize the ABI1-dependent AR regulation in PCa.
Method: We generated an ABI1 KO cell line model in LNCaP cells using CRISPR-Cas9. The efficiency of CRISPR-Cas9 was evaluated by Western Blotting and genomic alterations confirmed by DNA sequencing. In addition, we have generated ABI1 Isoform-specific rescue cell lines in our LNCaP ABI1 KO cell line with a binding mutation in the SH3 domain (ABI1-W485N) and an SH3 domain deleted (Abi1-ΔSH3) ABI1 protein. To understand AR and ABI1 dependent pathways we performed qPCR, co-immunoprecipitation, Western Blotting, ChIP, in vitro fluorescence spectra assay, immunofluorescence, proximity ligation assays. Results: In vitro binding assays indicate the interaction of AR, NTD poly-proline region, with the ABI1 SH3 domain. Expression of ABI1- W485N in our ABI1 CRISPR KO cell line showed decrease binding, while ABI1-ΔSH3 showed no binding to AR in co-IP assays compared to our control. Consequently, we saw decreased AR nuclear localization compared to our ABI1-WT control. Furthermore, decreased nuclear localization in our ABI1-W485N mutant was associated with decreased mRNA expression of hallmark AR target genes, Prostate-Specific-Antigen (KLK3), and TMPRSS2. ABI1 is an AR responsive gene and was confirmed with ChIP assays in an AR overexpression cell line. Further, the stimulation of AR transcriptional activity increased cell-cell adhesion in an ABI1 dependent system.
Conclusions: Our preliminary studies demonstrate that AR and ABI1 have a negative feedback pathway. The loss of ABI1 resulted in a decrease of nuclear AR and a subsequent decrease in mRNA expression of AR target genes. AR can also modulate ABI1 expression on a transcriptional level as needed for this pathway to function. Future studies will investigate if anti-AR treatments could lead to the dysregulation of ABI1 and promote EMT through STAT3 activation until AR transcriptional regulation on ABI1 is restored. These findings will allow for novel insights into the mechanisms underlying AR and ABI1 relationship in neoplastic progression.
Citation Format: Baylee A. Porter, Alaji Bah, Alfonso Urbanucci, Fan Zhang, Sonia Kung, Ladan Fazli, Martin Gleave, Gennady Bratslavsky, Leszek Kotula. Defining the reciprocal regulation of Abi1 and the androgen receptor in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2470.
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Affiliation(s)
| | - Alaji Bah
- 1SUNY Upstate Medical University, Syracuse, NY
| | | | - Fan Zhang
- 3Vancouver Prostate Centre, Vancouver, British Columbia, Canada
| | - Sonia Kung
- 3Vancouver Prostate Centre, Vancouver, British Columbia, Canada
| | - Ladan Fazli
- 3Vancouver Prostate Centre, Vancouver, British Columbia, Canada
| | - Martin Gleave
- 3Vancouver Prostate Centre, Vancouver, British Columbia, Canada
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13
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Ortiz MA, Mikhailova T, Li X, Porter BA, Bah A, Kotula L. Src family kinases, adaptor proteins and the actin cytoskeleton in epithelial-to-mesenchymal transition. Cell Commun Signal 2021; 19:67. [PMID: 34193161 PMCID: PMC8247114 DOI: 10.1186/s12964-021-00750-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Over a century of scientific inquiry since the discovery of v-SRC but still no final judgement on SRC function. However, a significant body of work has defined Src family kinases as key players in tumor progression, invasion and metastasis in human cancer. With the ever-growing evidence supporting the role of epithelial-mesenchymal transition (EMT) in invasion and metastasis, so does our understanding of the role SFKs play in mediating these processes. Here we describe some key mechanisms through which Src family kinases play critical role in epithelial homeostasis and how their function is essential for the propagation of invasive signals. Video abstract.
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Affiliation(s)
- Maria A Ortiz
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Tatiana Mikhailova
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA
| | - Xiang Li
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Baylee A Porter
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA
| | - Leszek Kotula
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA. .,Department of Urology, SUNY Upstate Medical University, Syracuse, USA.
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14
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Dettori LG, Torrejon D, Chakraborty A, Dutta A, Mohamed M, Papp C, Kuznetsov VA, Sung P, Feng W, Bah A. A Tale of Loops and Tails: The Role of Intrinsically Disordered Protein Regions in R-Loop Recognition and Phase Separation. Front Mol Biosci 2021; 8:691694. [PMID: 34179096 PMCID: PMC8222781 DOI: 10.3389/fmolb.2021.691694] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/14/2021] [Indexed: 11/13/2022] Open
Abstract
R-loops are non-canonical, three-stranded nucleic acid structures composed of a DNA:RNA hybrid, a displaced single-stranded (ss)DNA, and a trailing ssRNA overhang. R-loops perform critical biological functions under both normal and disease conditions. To elucidate their cellular functions, we need to understand the mechanisms underlying R-loop formation, recognition, signaling, and resolution. Previous high-throughput screens identified multiple proteins that bind R-loops, with many of these proteins containing folded nucleic acid processing and binding domains that prevent (e.g., topoisomerases), resolve (e.g., helicases, nucleases), or recognize (e.g., KH, RRMs) R-loops. However, a significant number of these R-loop interacting Enzyme and Reader proteins also contain long stretches of intrinsically disordered regions (IDRs). The precise molecular and structural mechanisms by which the folded domains and IDRs synergize to recognize and process R-loops or modulate R-loop-mediated signaling have not been fully explored. While studying one such modular R-loop Reader, the Fragile X Protein (FMRP), we unexpectedly discovered that the C-terminal IDR (C-IDR) of FMRP is the predominant R-loop binding site, with the three N-terminal KH domains recognizing the trailing ssRNA overhang. Interestingly, the C-IDR of FMRP has recently been shown to undergo spontaneous Liquid-Liquid Phase Separation (LLPS) assembly by itself or in complex with another non-canonical nucleic acid structure, RNA G-quadruplex. Furthermore, we have recently shown that FMRP can suppress persistent R-loops that form during transcription, a process that is also enhanced by LLPS via the assembly of membraneless transcription factories. These exciting findings prompted us to explore the role of IDRs in R-loop processing and signaling proteins through a comprehensive bioinformatics and computational biology study. Here, we evaluated IDR prevalence, sequence composition and LLPS propensity for the known R-loop interactome. We observed that, like FMRP, the majority of the R-loop interactome, especially Readers, contains long IDRs that are highly enriched in low complexity sequences with biased amino acid composition, suggesting that these IDRs could directly interact with R-loops, rather than being “mere flexible linkers” connecting the “functional folded enzyme or binding domains”. Furthermore, our analysis shows that several proteins in the R-loop interactome are either predicted to or have been experimentally demonstrated to undergo LLPS or are known to be associated with phase separated membraneless organelles. Thus, our overall results present a thought-provoking hypothesis that IDRs in the R-loop interactome can provide a functional link between R-loop recognition via direct binding and downstream signaling through the assembly of LLPS-mediated membrane-less R-loop foci. The absence or dysregulation of the function of IDR-enriched R-loop interactors can potentially lead to severe genomic defects, such as the widespread R-loop-mediated DNA double strand breaks that we recently observed in Fragile X patient-derived cells.
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Affiliation(s)
- Leonardo G Dettori
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Diego Torrejon
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Mohamed Mohamed
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Csaba Papp
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Urology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Vladimir A Kuznetsov
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, United States.,Bioinformatics Institute, ASTAR Biomedical Institutes, Singapore, Singapore
| | - Patrick Sung
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
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15
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Mammadli M, Huang W, Harris R, Xiong H, Weeks S, May A, Gentile T, Henty-Ridilla J, Waickman AT, August A, Bah A, Karimi M. Targeting SLP76:ITK interaction separates GVHD from GVL in allo-HSCT. iScience 2021; 24:102286. [PMID: 33851101 PMCID: PMC8024657 DOI: 10.1016/j.isci.2021.102286] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/27/2020] [Accepted: 03/04/2021] [Indexed: 12/14/2022] Open
Abstract
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapy for hematological malignancies, due to graft-versus-leukemia (GVL) activity mediated by alloreactive donor T cells. However, graft-versus-host disease (GVHD) is also mediated by these cells. Here, we assessed the effect of attenuating TCR-mediated SLP76:ITK interaction in GVL vs. GVHD effects after allo-HSCT. CD8+ and CD4+ donor T cells from mice expressing a Y145F mutation in SLP-76 did not cause GVHD but preserved GVL effects against B-ALL cells. SLP76Y145FKI CD8+ and CD4+ donor T cells also showed less inflammatory cytokine production and migration to GVHD target organs. We developed a novel peptide to specifically inhibit SLP76:ITK interactions, resulting in decreased phosphorylation of PLCγ1 and ERK, decreased cytokine production in human T cells, and separation of GVHD from GVL effects. Altogether, our data suggest that inhibiting SLP76:ITK interaction could be a therapeutic strategy to separate GVHD from GVL effects after allo-HSCT treatment.
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Affiliation(s)
- Mahinbanu Mammadli
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 766 Irving Avenue, Weiskotten Hall Suite 2281, Syracuse, NY 13210, USA
| | - Weishan Huang
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Rebecca Harris
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 766 Irving Avenue, Weiskotten Hall Suite 2281, Syracuse, NY 13210, USA
| | - Hui Xiong
- Department of Radiology, Jiangxi Health Vocational College, Nanchang, 330052, China
| | - Samuel Weeks
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 766 Irving Avenue, Weiskotten Hall Suite 2281, Syracuse, NY 13210, USA
| | - Adriana May
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 766 Irving Avenue, Weiskotten Hall Suite 2281, Syracuse, NY 13210, USA
| | - Teresa Gentile
- Division of Hematology, translational research, SUNY Upstate Medical University, Syracuse NY 13210, USA
| | - Jessica Henty-Ridilla
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Adam T. Waickman
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 766 Irving Avenue, Weiskotten Hall Suite 2281, Syracuse, NY 13210, USA
| | - Avery August
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Mobin Karimi
- Department of Microbiology and Immunology, SUNY Upstate Medical University, 766 Irving Avenue, Weiskotten Hall Suite 2281, Syracuse, NY 13210, USA
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16
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Szczesniak LM, Bonzerato CG, Schulman JJ, Bah A, Wojcikiewicz RJH. Bok binds to a largely disordered loop in the coupling domain of type 1 inositol 1,4,5-trisphosphate receptor. Biochem Biophys Res Commun 2021; 553:180-186. [PMID: 33773141 DOI: 10.1016/j.bbrc.2021.03.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 03/09/2021] [Indexed: 12/28/2022]
Abstract
Bcl-2-related ovarian killer (Bok) binds tightly to inositol 1,4,5-trisphosphate receptors (IP3Rs). To better understand this interaction, we sought to elucidate the Bok binding determinants in IP3R1, focusing on the ∼75 amino acid loop (residues 1882-1957) between α helices 72 and 73. Bioinformatic analysis revealed that the majority of this loop is intrinsically disordered, with two flanking regions of high disorder next to a low disorder central region (∼residues 1914-1926) that is predicted to contain two fused, disjointed transient helical elements. Experiments with IP3R1 mutants, combined with computational analysis, indicated that small deletions in this central region block Bok binding due to perturbation of the helical elements. Studies in vitro with purified Bok and IP3R1-derived peptides revealed high affinity binding to amino acids 1898-1940 of IP3R1 (Kd ∼65 nM) and that binding affinity is also dependent upon both of the high disorder flanking regions. The strength of the Bok-IP3R1 interaction was demonstrated by the ability of IP3R1 or Bok to recruit transmembrane domain-free Bok or IP3R1 mutants, respectively, to membranes in intact cells, and that these two mutants can bind in the cytosol independently of membrane association. Overall, we show that Bok binding to IP3R1 occurs within a largely disordered loop between α helices 72 and 73 and that high affinity binding is mediated by multivalent interactions.
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Affiliation(s)
- Laura M Szczesniak
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Caden G Bonzerato
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
| | | | - Alaji Bah
- Department of Biochemistry, Department of Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
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Sarr JMA, Brochier T, Brehmer P, Perrot Y, Bah A, Sarré A, Jeyid MA, Sidibeh M, El Ayoubi S. Complex data labeling with deep learning methods: Lessons from fisheries acoustics. ISA Trans 2021; 109:113-125. [PMID: 33097221 DOI: 10.1016/j.isatra.2020.09.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 05/12/2020] [Accepted: 09/30/2020] [Indexed: 06/11/2023]
Abstract
Quantitative and qualitative analysis of acoustic backscattered signals from the seabed bottom to the sea surface is used worldwide for fish stocks assessment and marine ecosystem monitoring. Huge amounts of raw data are collected yet require tedious expert labeling. This paper focuses on a case study where the ground truth labels are non-obvious: echograms labeling, which is time-consuming and critical for the quality of fisheries and ecological analysis. We investigate how these tasks can benefit from supervised learning algorithms and demonstrate that convolutional neural networks trained with non-stationary datasets can be used to stress parts of a new dataset needing human expert correction. Further development of this approach paves the way toward a standardization of the labeling process in fisheries acoustics and is a good case study for non-obvious data labeling processes.
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Affiliation(s)
- Jean-Michel A Sarr
- Université Cheikh Anta Diop de Dakar UCAD, Ecole Supérieure Polytechnique, BP 15915, Dakar Fann, Senegal; IRD, Sorbonne Université, UMMISCO, F-93143, Bondy, France.
| | - Timothée Brochier
- Université Cheikh Anta Diop de Dakar UCAD, Ecole Supérieure Polytechnique, BP 15915, Dakar Fann, Senegal; IRD, Sorbonne Université, UMMISCO, F-93143, Bondy, France.
| | - P Brehmer
- IRD, Univ Brest, CNRS, Ifremer, LEMAR, Plouzané, France; ISRA, CRODT, Pole de recherche de Hann, BP2241, Dakar, Senegal
| | - Y Perrot
- IRD, Univ Brest, CNRS, Ifremer, LEMAR, Plouzané, France
| | - A Bah
- Université Cheikh Anta Diop de Dakar UCAD, Ecole Supérieure Polytechnique, BP 15915, Dakar Fann, Senegal; IRD, Sorbonne Université, UMMISCO, F-93143, Bondy, France
| | - A Sarré
- ISRA, CRODT, Pole de recherche de Hann, BP2241, Dakar, Senegal
| | | | - M Sidibeh
- Fisheries Department (FD), Marina Bay, Banjul, The Gambia
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Smyth S, Tsangaris T, Bah A, Forman-Kay JD, Gradinaru CC. Modelling the Multifarious Conformations of the Intrinsically Disordered Protein 4E-BP2 with sm-FRET, SAXS & PRE Restraints. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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19
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Madhav N, Bosa HK, Agyarko RD, Stephenson N, Miller K, Gallivan M, Lam C, Meadows A, Sridharan V, Bah A, Béavogui M. Development of a risk modeling approach to enhance the effectiveness of epidemic preparedness, response, and financing strategies in African countries. Int J Infect Dis 2020. [DOI: 10.1016/j.ijid.2020.09.565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Mammadli M, Huang W, Harris R, Sultana A, Cheng Y, Tong W, Pu J, Gentile T, Dsouza S, Yang Q, Bah A, August A, Karimi M. Targeting Interleukin-2-Inducible T-Cell Kinase (ITK) Differentiates GVL and GVHD in Allo-HSCT. Front Immunol 2020; 11:593863. [PMID: 33324410 PMCID: PMC7726260 DOI: 10.3389/fimmu.2020.593863] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/29/2020] [Indexed: 01/04/2023] Open
Abstract
Allogeneic hematopoietic stem cell transplantation is a potentially curative procedure for many malignant diseases. Donor T cells prevent disease recurrence via graft-versus-leukemia (GVL) effect. Donor T cells also contribute to graft-versus-host disease (GVHD), a debilitating and potentially fatal complication. Novel treatment strategies are needed which allow preservation of GVL effects without causing GVHD. Using murine models, we show that targeting IL-2-inducible T cell kinase (ITK) in donor T cells reduces GVHD while preserving GVL effects. Both CD8+ and CD4+ donor T cells from Itk-/- mice produce less inflammatory cytokines and show decrease migration to GVHD target organs such as the liver and small intestine, while maintaining GVL efficacy against primary B-cell acute lymphoblastic leukemia (B-ALL). Itk-/- T cells exhibit reduced expression of IRF4 and decreased JAK/STAT signaling activity but upregulating expression of Eomesodermin (Eomes) and preserve cytotoxicity, necessary for GVL effect. Transcriptome analysis indicates that ITK signaling controls chemokine receptor expression during alloactivation, which in turn affects the ability of donor T cells to migrate to GVHD target organs. Our data suggest that inhibiting ITK could be a therapeutic strategy to reduce GVHD while preserving the beneficial GVL effects following allo-HSCT treatment.
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Affiliation(s)
- Mahinbanu Mammadli
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Weishan Huang
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States.,Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Rebecca Harris
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Aisha Sultana
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Ying Cheng
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Wei Tong
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Jeffery Pu
- Department of Hematology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Teresa Gentile
- Department of Hematology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Shanti Dsouza
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Qi Yang
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Avery August
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Mobin Karimi
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, United States
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Baker-Williams AJ, Hashmi F, Budzyński MA, Woodford MR, Gleicher S, Himanen SV, Makedon AM, Friedman D, Cortes S, Namek S, Stetler-Stevenson WG, Bratslavsky G, Bah A, Mollapour M, Sistonen L, Bourboulia D. Co-chaperones TIMP2 and AHA1 Competitively Regulate Extracellular HSP90:Client MMP2 Activity and Matrix Proteolysis. Cell Rep 2020; 28:1894-1906.e6. [PMID: 31412254 DOI: 10.1016/j.celrep.2019.07.045] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/01/2019] [Accepted: 07/15/2019] [Indexed: 11/26/2022] Open
Abstract
The extracellular molecular chaperone heat shock protein 90 (eHSP90) stabilizes protease client the matrix metalloproteinase 2 (MMP2), leading to tumor cell invasion. Although co-chaperones are critical modulators of intracellular HSP90:client function, how the eHSP90:MMP2 complex is regulated remains speculative. Here, we report that the tissue inhibitor of metalloproteinases-2 (TIMP2) is a stress-inducible extracellular co-chaperone that binds to eHSP90, increases eHSP90 binding to ATP, and inhibits its ATPase activity. In addition to disrupting the eHSP90:MMP2 complex and terminally inactivating MMP2, TIMP2 loads the client to eHSP90, keeping the protease in a transient inhibitory state. Secreted activating co-chaperone AHA1 displaces TIMP2 from the complex, providing a "reactivating" mechanism for MMP2. Gene knockout or blocking antibodies targeting TIMP2 and AHA1 released by HT1080 cancer cells modify their gelatinolytic activity. Our data suggest that TIMP2 and AHA1 co-chaperones function as a molecular switch that determines the inhibition and reactivation of the eHSP90 client protein MMP2.
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Affiliation(s)
- Alexander J Baker-Williams
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Fiza Hashmi
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Marek A Budzyński
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, 20520 Turku, Finland; Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Mark R Woodford
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Stephanie Gleicher
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Samu V Himanen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, 20520 Turku, Finland; Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Alan M Makedon
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Derek Friedman
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; College of Medicine, MD Program, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Stephanie Cortes
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; College of Medicine, MD Program, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Sara Namek
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | | | - Gennady Bratslavsky
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Alaji Bah
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Mehdi Mollapour
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Lea Sistonen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, 20520 Turku, Finland; Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Dimitra Bourboulia
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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El Saadi N, Bah A, Mahdjoub T, Kribs C. On the sylvatic transmission of T. cruzi, the parasite causing Chagas disease: a view from an agent-based model. Ecol Modell 2020. [DOI: 10.1016/j.ecolmodel.2020.109001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Konaté M, Traoré A, Bah A, Diop T, Karembé B, Amadou I, Mangané MI, Samaké M, Dembelé SB, Dicko FB, Diakité I, Koné T, Maïga A, Sidibé B, Saye Z, Konaté S, Dembelé BT, Kanté L, Togo A. [Health care-associated infections in teaching hospital Gabriel TOURE]. Mali Med 2020; 35:39-42. [PMID: 37978754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
OBJECTIVES To study health care-associated infections (HCAI) in teaching hospital Gabriel TOURE. METHODOLOGY This was a prospective study of 6 months (from April to September 2016) which included patients admitted to the General Surgery Department, operated or not, except those who had undergone a necrosectomy. The criteria used for the diagnosis of the infection were those of the CDC of Atlanta. RESULTS A total of 200 patients were included in the study. Twenty one patients developed IAS that is a frequency of 10.5%. There were 11 men and 10 women with a mean age of 37.7 years with a standard deviation of 17.6 years. Surgical site infection was the most common HCAI (77.3%) followed by urinary tract infection (13.6%) and burn infection (9.1%). The influencing factors were those related to the patients (nutritional status p = 0.004, anemia RR = 3.1 IC p = 0.003 and diabetes), those related to the surgical intervention (the duration of the intervention ≥ 2H, p = 0,0001, the Altemeier class 3 and 4, RR = 4.24, IC p = 0.005, the number of interveners in the blocks ≥7, p = 0.000, the NNISS score 1 and 2 p = 0.0009), invasive procedures (bladder catheter ≥ 4 days p = 0.0000). Escherichia coli was the most isolated microorganism (31.2%) followed by Klebsiella pneumonia and A baumannii (18.7%). The treatment was local (twice-daily dressing with antiseptics), surgical (necrosectomy 16% and re-intervention 10%) and general (adapted to the antibiogram). The consequences of HCAI were an extension of total hospital stay (greater than 7 days) with p = 0.0000, morbidity 3% and mortality 5%. CONCLUSION HCAI remains a concern in our country and globally. They prolong the hospital stay. The implementation of a prevention, control and surveillance program will improve the quality of care by significantly reducing HCAI.
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Bah A, El Abasse Z. Quantification of rheumatic mitral stenosis severity with three dimensional vena contracta area. Archives of Cardiovascular Diseases Supplements 2020. [DOI: 10.1016/j.acvdsp.2019.09.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Diallo A, Traoré B, Diassana M, Maiga A, Bah A, Traore A, Konaté M, Karambé A, Koné A, Touré L, Traoré T, Traoré S, Dembélé O, Kanté M, Dembélé M, Diakité ML. [Foreskin Cyst After Circumcision At The Hospital Of Sikasso (MALI)]. Mali Med 2020; 35:51-53. [PMID: 37978743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Cyst scar post circumcision of the stump of the prepuce is pathology of which we have not found any cases in the literature. The circumcision traditional is still practiced in our regions with its attendant complications, in particular, the high section, the whole or part of the gland, infections. The case we report concerns a patient 24 years of age, having a large cyst of 8cm diameter, evolving for the past 17 years. The patient has not informed his parents that when the desire to marry has become very pressing. The consultation was motivated by the psychological trauma, the discomfort and the pain caused by the infection, and the fistulisation. The treatment was surgical with bedroom suites. This observation underscores the importance of the knowledge of good surgical technique in order to minimize complications; it also sheds light on the taboo side of the pathologies the sphere uro-genitale.
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Affiliation(s)
- A Diallo
- Service de chirurgie général de l'hôpital de Sikasso
| | - B Traoré
- Service de chirurgie général de l'hôpital de Sikasso
| | | | - A Maiga
- Service de chirurgie général de l'hôpital de Sikasso
| | - A Bah
- Service de chirurgie générale CHU Gabriel Touré
| | - A Traore
- Service de chirurgie générale CHU Gabriel Touré
| | - M Konaté
- Service de chirurgie générale CHU Gabriel Touré
| | - A Karambé
- Service de chirurgie générale CHU Gabriel Touré
| | - A Koné
- Service de chirurgie générale CHU de Kati
| | - L Touré
- Service de chirurgie générale CHU Gabriel Touré
- Service de traumatologie de l'hôpital de Sikasso
| | - T Traoré
- Service de traumatologie de l'hôpital de Sikasso
| | - S Traoré
- Service d'urologie de l'hôpital de Sikasso
| | - O Dembélé
- Service d'urologie de l'hôpital de Sikasso
| | - M Kanté
- Service d'anesthésie réanimation de l'hôpital de Sikasso
| | - M Dembélé
- Service d'anesthésie réanimation de l'hôpital de Sikasso
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Bah A, El Abasse Z, Drighil A, Habbal R. Congenital mitral stenosis: About 26 cases. Archives of Cardiovascular Diseases Supplements 2020. [DOI: 10.1016/j.acvdsp.2019.09.370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Oumar Bah A, Lam M, Bah A, Bowong S. Theoretical assessment of the impact of desert aerosols on the dynamical transmission of meningitidis serogroup A. INT J BIOMATH 2019. [DOI: 10.1142/s1793524519500608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This paper has been motivated by the following biological question: how influential are desert aerosols in the transmission of meningitidis serogroup A (MenA)? A mathematical model for the dynamical transmission of MenA is considered, with the aim of investigating the impact of desert aerosols. Sensitivity analysis of the model has been performed in order to determine the impact of related parameters on meningitis outbreak. We derive the basic reproduction number [Formula: see text]. We prove that there exists a threshold parameter [Formula: see text] such that when [Formula: see text], the disease-free equilibrium is globally asymptotically stable (GAS). However, when [Formula: see text], the model exhibits the phenomenon of backward bifurcation. At the endemic level, we show that the number of infectious individuals in the presence of desert aerosols is larger than the corresponding number without the presence of desert aerosols. In conjunction with the inequality [Formula: see text] where [Formula: see text] is the basic reproduction number without desert aerosols, we found that the ingestion of aerosols by carriers will increase the endemic level, and the severity of the outbreak. This suggests that the control of MenA passes through a combination of a large coverage vaccination of young susceptible individuals and the production of a vaccine with a high level of efficacy as well as respecting the hygienic rules to avoid the inhalation of desert aerosols. Theoretical results are supported by numerical simulations.
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Affiliation(s)
- A. Oumar Bah
- Department of Mathematics, Faculty of Science and Technic, Université Cheikh Anta Diopde Dakar, Dakar-Fann, Senegal
| | - M. Lam
- Department of Mathematics, Faculty of Science and Technic, Université Cheikh Anta Diopde Dakar, Dakar-Fann, Senegal
| | - A. Bah
- Department of Computer Engineering, National Advanced School of Engineering, Université Cheikh Anta Diopde Dakar, Dakar-Fann, Senegal
| | - S. Bowong
- Laboratory of Mathematics, Department of Mathematics, and Computer Science, Faculty of Science, University of Douala, P. O. Box 24157, Douala, Cameroon
- UMI 209 IRD and UPMC UMMISCO, 32 Avenue Henri Varagnat, 93143 Bondy Cedex, France
- Project Team GRIMCAPE, University of Yaoundé, Yaoundé, Cameroon
- The African Center of Excellence in Information, and Communication Technologies (CETIC), National Advanced School of Engineering, University of Yaoundé 1, Yaoundé, Cameroon
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Balde C, Lam M, Bah A, Bowong S, Tewa JJ. Theoretical assessment of the impact of environmental contamination on the dynamical transmission of polio. INT J BIOMATH 2019. [DOI: 10.1142/s1793524519500128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A mathematical model for the dynamical transmission of polio is considered, with the aim of investigating the impact of environment contamination. The model captures two infection pathways through both direct human-to-human transmission and indirect human-to-environment-to-human transmission by incorporating the environment as a transition and/or reservoir of viruses. We derive the basic reproduction number [Formula: see text]. We show that the disease free equilibrium is globally asymptotically stable (GAS) if [Formula: see text], while if [Formula: see text], there exists a unique endemic equilibrium which is locally asymptotically stable (LAS). Similar results hold for environmental contamination free sub-model (without the incorporation of the indirect transmission). At the endemic level, we show that the number of infected individuals for the model with the environmental-related contagion is greater than the corresponding number for the environmental contamination free sub-model. In conjunction with the inequality [Formula: see text], where [Formula: see text] is the basic reproduction number for the environmental contamination free sub-model, our finding suggests that the contaminated environment plays a detrimental role on the transmission dynamics of polio disease by increasing the endemic level and the severity of the outbreak. Therefore, it is natural to implement control strategies to reduce the severity of the disease by providing adequate hygienic living conditions, educate populations at risk to follow rigorously those basic hygienic rules in order to avoid adequate contacts with suspected contaminated objects. Further, we perform numerical simulations to support the theory.
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Affiliation(s)
- C. Balde
- Department of Mathematics, Faculty of Science and Technic, University Cheikh Anta Diop, Dakar, Senegal
| | - M. Lam
- Department of Mathematics, Faculty of Science and Technic, University Cheikh Anta Diop, Dakar, Senegal
| | - A. Bah
- Department of Computer Engineering, National Advanced School of Engineering, University Cheikh Anta Diop, Dakar, Senegal
| | - S. Bowong
- Laboratory of Mathematics, Department of Mathematics and Computer Science, Faculty of Science, University of Douala, P. O. Box 24157 Douala, Cameroon
- IRD, Sorbonne University, UHHISCO, F-93143, Bondy, France
- Team GRIMCAPE, Yaounde, Cameroon
- The African Center of Excellence in Information, and Communication Technologies (CETIC), University of Yaounde 1, Cameroon
| | - J. J. Tewa
- National Advanced School of Engineering, University of Yaounde I, P. O. Box 8390 Yaounde, Cameroon
- IRD, Sorbonne University, UHHISCO, F-93143, Bondy, France
- Team GRIMCAPE, Yaounde, Cameroon
- The African Center of Excellence in Information, and Communication Technologies (CETIC), University of Yaounde 1, Cameroon
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Dembélé SB, Diakité I, Samaké M, Coulibaly B, Saye Z, Bah A, Konaté S, Togo E, Sidibé BY, Coulibaly Z, Kanté L, Togo A. [Breast Cancer: Immunohistochemistry And Prognosis At Gabriel Touré Teaching Hospital In Bamako-Mali]. Mali Med 2019; 34:36-39. [PMID: 35897225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
UNLABELLED Breast cancer is the second cancer of women in Mali. Immunohistochemistry is poorly performed in our African countries. OBJECTIVES To describe the immunohistochemical aspect and determine the prognosis of breast cancer. METHODOLOGY This is a retrospective descriptive study (March 2006-July 2016) in the General Surgery Department of Gabriel Toure University Hospital in Bamako, Mali. Immunohistochemistry was performed in all patients through a collaboration of our German partners. RESULTS We collected 98 patients (95 women and 3 men) with an average age of 40.04 ± 13.07 years. Twenty-two patients (22.44%) had a personal history of benign breast disease. In 16 patients (16.33%), we found a family breast cancer. The most common histological types were intra ductal carcinoma with 84 (85.72%) and invasive lobular carcinoma in 9 cases (9.18%). Immunohistochemistry found a predominance of triple negative with forty nine patients (50%) followed by Luminal A subtype with 26 cases (26.23%). According to the TNM classification, 44 patients (44.90%) were received at stage III. The median survival was 60 months in the group of patients who received hormone therapy versus 28 months for the group without hormone therapy (p = 0.007). CONCLUSION Immunohistochemistry is essential for the adequate management of breast cancer. Its realization has allowed us to improve the prognosis of hormone-dependent cancers.
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Affiliation(s)
- S B Dembélé
- Service de chirurgie générale CHU Gabriel Touré
| | - I Diakité
- Service de chirurgie générale CHU Gabriel Touré
| | - M Samaké
- Service de chirurgie générale CHU Gabriel Touré
| | | | - Z Saye
- Service de chirurgie générale CHU Gabriel Touré
| | - A Bah
- Service de chirurgie générale CHU Gabriel Touré
| | - S Konaté
- Service de chirurgie générale CHU Gabriel Touré
| | - E Togo
- Service de Gynécologie Obstétrique CHU Point G
| | - B Y Sidibé
- Service de chirurgie générale CHU Gabriel Touré
| | - Z Coulibaly
- Service de chirurgie générale CHU Gabriel Touré
| | - L Kanté
- Service de chirurgie générale CHU Gabriel Touré
| | - A Togo
- Service de chirurgie générale CHU Gabriel Touré
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Yuwen T, Bah A, Brady JP, Ferrage F, Bouvignies G, Kay LE. Measuring Solvent Hydrogen Exchange Rates by Multifrequency Excitation 15N CEST: Application to Protein Phase Separation. J Phys Chem B 2018; 122:11206-11217. [DOI: 10.1021/acs.jpcb.8b06820] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Alaji Bah
- Hospital for Sick Children, Program in Molecular Medicine, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
| | | | - Fabien Ferrage
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Guillaume Bouvignies
- Laboratoire des Biomolécules, LBM, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Lewis E. Kay
- Hospital for Sick Children, Program in Molecular Medicine, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
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Jalal Y, Bah A, Zaddoug O, Zine A, Jaafar A. Lipomatosis of interdigital nerves: Unusual localization. Foot (Edinb) 2018; 36:21-24. [PMID: 30326348 DOI: 10.1016/j.foot.2018.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 03/16/2018] [Accepted: 04/23/2018] [Indexed: 02/04/2023]
Abstract
Lipomatosis of the nerve (LN) is a rare benign tumor that is characterized by proliferating fibrous fatty tissue surrounding and infiltrating the peripheral nerves. While there are numerous case reports of LN affecting the median nerve and its branches, there are few reports, to the authors' knowledge, of their occurrence in the foot and ankle. A rare case of LN involving the second and third interdigital nerve in a 41-year-old man, which was successfully treated with surgical excision, is reported.
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Affiliation(s)
- Y Jalal
- Orthopedic Surgery and Traumatology Department, Military Hospital Mohamed V (HMIMV), Faculty of Medicine and Pharmacy of Rabat, BP 10100 Rabat, Morocco.
| | - A Bah
- Orthopedic Surgery and Traumatology Department, Military Hospital Mohamed V (HMIMV), Faculty of Medicine and Pharmacy of Rabat, BP 10100 Rabat, Morocco.
| | - O Zaddoug
- Orthopedic Surgery and Traumatology Department, Military Hospital Mohamed V (HMIMV), Faculty of Medicine and Pharmacy of Rabat, BP 10100 Rabat, Morocco.
| | - A Zine
- Orthopedic Surgery and Traumatology Department, Military Hospital Mohamed V (HMIMV), Faculty of Medicine and Pharmacy of Rabat, BP 10100 Rabat, Morocco.
| | - A Jaafar
- Orthopedic Surgery and Traumatology Department, Military Hospital Mohamed V (HMIMV), Faculty of Medicine and Pharmacy of Rabat, BP 10100 Rabat, Morocco.
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Vernon RM, Chong PA, Tsang B, Kim TH, Bah A, Farber P, Lin H, Forman-Kay JD. Pi-Pi contacts are an overlooked protein feature relevant to phase separation. eLife 2018; 7:31486. [PMID: 29424691 PMCID: PMC5847340 DOI: 10.7554/elife.31486] [Citation(s) in RCA: 450] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 02/08/2018] [Indexed: 12/12/2022] Open
Abstract
Protein phase separation is implicated in formation of membraneless organelles, signaling puncta and the nuclear pore. Multivalent interactions of modular binding domains and their target motifs can drive phase separation. However, forces promoting the more common phase separation of intrinsically disordered regions are less understood, with suggested roles for multivalent cation-pi, pi-pi, and charge interactions and the hydrophobic effect. Known phase-separating proteins are enriched in pi-orbital containing residues and thus we analyzed pi-interactions in folded proteins. We found that pi-pi interactions involving non-aromatic groups are widespread, underestimated by force-fields used in structure calculations and correlated with solvation and lack of regular secondary structure, properties associated with disordered regions. We present a phase separation predictive algorithm based on pi interaction frequency, highlighting proteins involved in biomaterials and RNA processing.
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Affiliation(s)
| | - Paul Andrew Chong
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Brian Tsang
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Tae Hun Kim
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Alaji Bah
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Patrick Farber
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Hong Lin
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada
| | - Julie Deborah Forman-Kay
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
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Smyth S, Zhang Z, Bah A, Forman-Kay JD, Gradinaru CC. Probing the Conformational Dynamics of the Disordered 4E-BP2 Protein in Different Phosphorylation States using Single-Molecule Fluorescence. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Bah A, Lateur GM, Kouevidjin BT, Bassinga JYS, Issa M, Jaafar A, Beaudouin E. Chronic anterior shoulder instability with significant Hill-Sachs lesion: Arthroscopic Bankart with remplissage versus open Latarjet procedure. Orthop Traumatol Surg Res 2018; 104:17-22. [PMID: 29248765 DOI: 10.1016/j.otsr.2017.11.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 11/10/2017] [Accepted: 11/16/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND The objective of this study was to compare short-term shoulder stability after arthroscopic Bankart repair with remplissage versus the open Latarjet procedure in patients who had chronic anterior shoulder instability with a significant Hill-Sachs lesion. HYPOTHESIS The dislocation recurrence rate is higher after Bankart repair with remplissage than after open Latarjet. PATIENTS AND METHODS An observational non-randomised retrospective cohort study was conducted at two surgical centres in patients treated for chronic anterior shoulder instability with a significant Hill-Sachs defect between January 2009 and July 2014. The study compared 43 patients managed by arthroscopic Bankart repair and remplissage and 43 patients managed with open Latarjet. The two groups were matched on age at surgery and on follow-up duration. All patients were evaluated by independent observers based on a questionnaire including recurrences, range of motion, and functional outcomes (Shoulder Subjective Value [SSV], Walch-Duplay score, and Rowe score). RESULTS Mean follow-up was 47.3 months (range, 24-67 months). The recurrence rate at last follow-up was not significantly different between the two groups (9.3% versus 11.2%; P=0.67). The Bankart group had significantly greater loss of external rotation and a significantly higher proportion of patients with residual pain (21% versus 9%, P=0.023). The SSV, Walch-Duplay score, and Rowe score values were similar between groups. DISCUSSION In patients who had chronic anterior shoulder instability with a significant Hill-Sachs lesion, arthroscopic Bankart repair with remplissage and open Latarjet were reliable and safe procedures associated with low and similar recurrence rates. However, loss of external rotation and residual pain were significantly more common with the combined Bankart-remplissage procedure. LEVEL OF EVIDENCE III; comparative retrospective study.
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Affiliation(s)
- A Bah
- Secrétariat d'orthopédie, centre hospitalier métropole Savoie-de-Chambéry, 7, square Massalez, 73000 Chambéry, France.
| | - G M Lateur
- Sports orthopaedic surgery and traumatology, Grenoble university hospital, hôpital Sud, Grenoble, France
| | - B T Kouevidjin
- Secrétariat d'orthopédie, centre hospitalier métropole Savoie-de-Chambéry, 7, square Massalez, 73000 Chambéry, France
| | - J Y S Bassinga
- Orthopaedic and trauma surgery 1, Mohammed V de Rabat military training hospital, avenue des Forces-Armées-Royales, Hay Riad, 10100 Rabat, Morocco
| | - M Issa
- Secrétariat d'orthopédie, centre hospitalier métropole Savoie-de-Chambéry, 7, square Massalez, 73000 Chambéry, France
| | - A Jaafar
- Orthopaedic and trauma surgery 1, Mohammed V de Rabat military training hospital, avenue des Forces-Armées-Royales, Hay Riad, 10100 Rabat, Morocco
| | - E Beaudouin
- Secrétariat d'orthopédie, centre hospitalier métropole Savoie-de-Chambéry, 7, square Massalez, 73000 Chambéry, France
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Sidibé BY, Dembélé BT, Bah A, Maiga A, Coulibaly A, Traoré A, Konaté M, Kelly B, Traoré AA, Koné T, Karembé B, Kanté L, Diakité I, Almeimoune AH, Togo A. [Bilio-Digestives Derivative In The Palliative Surgery Of Pancreatic Head Cancer At The CHU Gabriel TOURE]. Mali Med 2018; 33:29-32. [PMID: 35897198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
OBJECTIVES Our objective was to determine the frequency of bilio-digestive bypass in palliative surgery in pancreatic head cancers, to determine the clinical and para-clinical aspects and to analyze the results of the treatment. METHODS This was a-15 year retrospective study from 1999 to 2014 including any patient with confirmed pancreatic cancer in the anatomo-pathology treated by palliative surgery in the department. RESULTS In 15 years, we operated152 cases of cancer of the head of the pancreas. The bilio-digestive derivation was performed in 78 patients, or 51.32%. The average age was 58.61 years ± 11.22 years with the extremes of 34 and 79 years old, the sex ratio was 1.44. The disease duration was 4.88 months on average with a standard deviation of 4.28 months and extremes of 1 and 24 months. Courvoisier-Terrier's disease was observed in 76 cases with lesions of the cases. The average pancreatic tumor size was 62.98 mm, and standard deviation = 8.68 with the extremes of45 and 121 mm. We performed a choledoco-duodenal anastomosis and a gastro-entero-anastomosis (GEA) in 85.90% of cases (n = 67), a choledocojejunal anastomosis and a GEA in 7 cases and a choledoco-duodenal anastomosis without GEA in 4 cases. The morbidity and the mortality rates were15.4% and 6.41%, respectively. At six (6) months postsurgery, a complete disappearance the majority of the functional signs was observed. CONCLUSION Pancreatic cancer is a slowly developing tumor. Therefore its diagnosis is late; the derivation makes it possible to improve the quality of life of the patients.
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Affiliation(s)
- B Y Sidibé
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - B T Dembélé
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - A Bah
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - A Maiga
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - A Coulibaly
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - A Traoré
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - M Konaté
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - B Kelly
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - A A Traoré
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - T Koné
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - B Karembé
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - L Kanté
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - I Diakité
- Département de chirurgie CHU Gabriel Touré de Bamako, Mali
| | - A H Almeimoune
- Département d'anesthésie, de réanimation et de médecine d'urgence CHU Gabriel Touré
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Brady JP, Farber PJ, Sekhar A, Lin YH, Huang R, Bah A, Nott TJ, Chan HS, Baldwin AJ, Forman-Kay JD, Kay LE. Structural and hydrodynamic properties of an intrinsically disordered region of a germ cell-specific protein on phase separation. Proc Natl Acad Sci U S A 2017; 114:E8194-E8203. [PMID: 28894006 PMCID: PMC5625912 DOI: 10.1073/pnas.1706197114] [Citation(s) in RCA: 300] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Membrane encapsulation is frequently used by the cell to sequester biomolecules and compartmentalize their function. Cells also concentrate molecules into phase-separated protein or protein/nucleic acid "membraneless organelles" that regulate a host of biochemical processes. Here, we use solution NMR spectroscopy to study phase-separated droplets formed from the intrinsically disordered N-terminal 236 residues of the germ-granule protein Ddx4. We show that the protein within the concentrated phase of phase-separated Ddx4, [Formula: see text], diffuses as a particle of 600-nm hydrodynamic radius dissolved in water. However, NMR spectra reveal sharp resonances with chemical shifts showing [Formula: see text] to be intrinsically disordered. Spin relaxation measurements indicate that the backbone amides of [Formula: see text] have significant mobility, explaining why high-resolution spectra are observed, but motion is reduced compared with an equivalently concentrated nonphase-separating control. Observation of a network of interchain interactions, as established by NOE spectroscopy, shows the importance of Phe and Arg interactions in driving the phase separation of Ddx4, while the salt dependence of both low- and high-concentration regions of phase diagrams establishes an important role for electrostatic interactions. The diffusion of a series of small probes and the compact but disordered 4E binding protein 2 (4E-BP2) protein in [Formula: see text] are explained by an excluded volume effect, similar to that found for globular protein solvents. No changes in structural propensities of 4E-BP2 dissolved in [Formula: see text] are observed, while changes to DNA and RNA molecules have been reported, highlighting the diverse roles that proteinaceous solvents play in dictating the properties of dissolved solutes.
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Affiliation(s)
- Jacob P Brady
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Patrick J Farber
- Division of Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 0A4
| | - Ashok Sekhar
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Yi-Hsuan Lin
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
- Division of Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 0A4
| | - Rui Huang
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Alaji Bah
- Division of Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 0A4
| | - Timothy J Nott
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Hue Sun Chan
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Andrew J Baldwin
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Julie D Forman-Kay
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8;
- Division of Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 0A4
| | - Lewis E Kay
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8;
- Department of Chemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8
- Division of Molecular Medicine, The Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 0A4
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Scanlon DP, Bah A, Krzeminski M, Zhang W, Leduc-Pessah HL, Dong YN, Forman-Kay JD, Salter MW. An evolutionary switch in ND2 enables Src kinase regulation of NMDA receptors. Nat Commun 2017; 8:15220. [PMID: 28508887 PMCID: PMC5440837 DOI: 10.1038/ncomms15220] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/10/2017] [Indexed: 12/22/2022] Open
Abstract
The non-receptor tyrosine kinase Src is a key signalling hub for upregulating the function of N-methyl D-aspartate receptors (NMDARs). Src is anchored within the NMDAR complex via NADH dehydrogenase subunit 2 (ND2), a mitochondrially encoded adaptor protein. The interacting regions between Src and ND2 have been broadly identified, but the interaction between ND2 and the NMDAR has remained elusive. Here we generate a homology model of ND2 and dock it onto the NMDAR via the transmembrane domain of GluN1. This interaction is enabled by the evolutionary loss of three helices in bilaterian ND2 proteins compared to their ancestral homologues. We experimentally validate our model and demonstrate that blocking this interaction with an ND2 fragment identified in our experimental studies prevents Src-mediated upregulation of NMDAR currents in neurons. Our findings establish the mode of interaction between an NMDAR accessory protein with one of the core subunits of the receptor. N-methyl D-aspartate receptor (NMDAR) activity is modulated by Src tyrosine kinase via the mitochondrial protein NADH dehydrogenase subunit 2 (ND2). Here the authors show that ND2 interacts with the transmembrane region of NMDAR GluN1 subunit, a process that is crucial for Src regulation of NMDAR activity.
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Affiliation(s)
- David P Scanlon
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Alaji Bah
- Program in Molecular Medicine, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Mickaël Krzeminski
- Program in Molecular Medicine, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Wenbo Zhang
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Heather L Leduc-Pessah
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Yi Na Dong
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Julie D Forman-Kay
- Program in Molecular Medicine, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Michael W Salter
- Program in Neurosciences &Mental Health, The Hospital for Sick Children, 686 Bay St, Toronto, Ontario, Canada M5G 0A4.,Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
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Bowong S, Mountaga L, Bah A, Tewa JJ, Kurths J. Parameter and state estimation in a Neisseria meningitidis model: A study case of Niger. Chaos 2016; 26:123115. [PMID: 28039983 DOI: 10.1063/1.4971783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Neisseria meningitidis (Nm) is a major cause of bacterial meningitidis outbreaks in Africa and the Middle East. The availability of yearly reported meningitis cases in the African meningitis belt offers the opportunity to analyze the transmission dynamics and the impact of control strategies. In this paper, we propose a method for the estimation of state variables that are not accessible to measurements and an unknown parameter in a Nm model. We suppose that the yearly number of Nm induced mortality and the total population are known inputs, which can be obtained from data, and the yearly number of new Nm cases is the model output. We also suppose that the Nm transmission rate is an unknown parameter. We first show how the recruitment rate into the population can be estimated using real data of the total population and Nm induced mortality. Then, we use an auxiliary system called observer whose solutions converge exponentially to those of the original model. This observer does not use the unknown infection transmission rate but only uses the known inputs and the model output. This allows us to estimate unmeasured state variables such as the number of carriers that play an important role in the transmission of the infection and the total number of infected individuals within a human community. Finally, we also provide a simple method to estimate the unknown Nm transmission rate. In order to validate the estimation results, numerical simulations are conducted using real data of Niger.
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Affiliation(s)
- S Bowong
- Laboratory of Mathematics, Department of Mathematics and Computer Science, Faculty of Science, University of Douala, P.O. Box 24157 Douala, Cameroon
| | - L Mountaga
- Department of Mathematics, Faculty of Science and Technic, University Cheikh Anta Diop, Dakar, Senegal
| | - A Bah
- UMI 209 IRD and UPMC UMMISCO, Bondy, France
| | - J J Tewa
- UMI 209 IRD and UPMC UMMISCO, Bondy, France
| | - J Kurths
- Postdam Institute for Climate Impact Research (PIK), Telegraphenberg A 31, 14412 Potsdam, Germany
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Goheen MM, Wegmüller R, Bah A, Darboe B, Danso E, Affara M, Gardner D, Patel JC, Prentice AM, Cerami C. Anemia Offers Stronger Protection Than Sickle Cell Trait Against the Erythrocytic Stage of Falciparum Malaria and This Protection Is Reversed by Iron Supplementation. EBioMedicine 2016; 14:123-130. [PMID: 27852523 PMCID: PMC5161422 DOI: 10.1016/j.ebiom.2016.11.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/05/2016] [Accepted: 11/07/2016] [Indexed: 11/28/2022] Open
Abstract
Background Iron deficiency causes long-term adverse consequences for children and is the most common nutritional deficiency worldwide. Observational studies suggest that iron deficiency anemia protects against Plasmodium falciparum malaria and several intervention trials have indicated that iron supplementation increases malaria risk through unknown mechanism(s). This poses a major challenge for health policy. We investigated how anemia inhibits blood stage malaria infection and how iron supplementation abrogates this protection. Methods This observational cohort study occurred in a malaria-endemic region where sickle-cell trait is also common. We studied fresh RBCs from anemic children (135 children; age 6–24 months; hemoglobin < 11 g/dl) participating in an iron supplementation trial (ISRCTN registry, number ISRCTN07210906) in which they received iron (12 mg/day) as part of a micronutrient powder for 84 days. Children donated RBCs at baseline, Day 49, and Day 84 for use in flow cytometry-based in vitro growth and invasion assays with P. falciparum laboratory and field strains. In vitro parasite growth in subject RBCs was the primary endpoint. Findings Anemia substantially reduced the invasion and growth of both laboratory and field strains of P. falciparum in vitro (~ 10% growth reduction per standard deviation shift in hemoglobin). The population level impact against erythrocytic stage malaria was 15.9% from anemia compared to 3.5% for sickle-cell trait. Parasite growth was 2.4 fold higher after 49 days of iron supplementation relative to baseline (p < 0.001), paralleling increases in erythropoiesis. Interpretation These results confirm and quantify a plausible mechanism by which anemia protects African children against falciparum malaria, an effect that is substantially greater than the protection offered by sickle-cell trait. Iron supplementation completely reversed the observed protection and hence should be accompanied by malaria prophylaxis. Lower hemoglobin levels typically seen in populations of African descent may reflect past genetic selection by malaria. Funding National Institute of Child Health and Development, Bill and Melinda Gates Foundation, UK Medical Research Council (MRC) and Department for International Development (DFID) under the MRC/DFID Concordat. P. falciparum laboratory and field strains invade and grow less efficiently in RBCs from anemic children. Deficits in invasion and growth for erythrocytic stage P. falciparum are reversed when RBCs are used from anemic children receiving iron supplementation for 49 and 84 days. The population level impact of protection against malaria from anemia was greater than that for sickle-cell trait.
The long-term consequences of anemia are severe, and it is easily treatable. However, concerns remain about the safety of iron supplements, particularly for children in malaria-endemic countries lacking adequate access to health services. We used RBCs from Gambian children before, during, and after 12 weeks of daily iron supplementation for in vitro P. falciparum assays. P. falciparum invasion and growth was decreased in anemic RBCs and increased after 49 days of iron supplementation relative to baseline (p < 0.001), paralleling increases in young RBCs, which the parasite prefers. The parasite growth protection from anemia was substantial, providing greater population level impact than sickle-cell trait.
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Affiliation(s)
- M M Goheen
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, CB# 7435, Chapel Hill, NC 27599-7435, USA.
| | - R Wegmüller
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - A Bah
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - B Darboe
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - E Danso
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - M Affara
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - D Gardner
- University of North Carolina School of Medicine, CB# 9535, Chapel Hill, NC 27599-9535, USA
| | - J C Patel
- Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, CB# 7435, Chapel Hill, NC 27599-7435, USA
| | - A M Prentice
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia; London School of Hygiene & Tropical Medicine, Keppel Street, WC1E 7HT London, UK
| | - C Cerami
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
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Kaba M, Sinayoko M, Touré A, Bah A, Sylla D, Diakité F, Chérif I, Bah A, Bah A, Touré Y. Profil épidémiologique et clinique des patients atteints de syndrome métabolique dans un service de médecine interne à Conakry. Nephrol Ther 2016. [DOI: 10.1016/j.nephro.2016.07.133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Post-translational modifications (PTMs) produce significant changes in the structural properties of intrinsically disordered proteins (IDPs) by affecting their energy landscapes. PTMs can induce a range of effects, from local stabilization or destabilization of transient secondary structure to global disorder-to-order transitions, potentially driving complete state changes between intrinsically disordered and folded states or dispersed monomeric and phase-separated states. Here, we discuss diverse biological processes that are dependent on PTM regulation of IDPs. We also present recent tools for generating homogenously modified IDPs for studies of PTM-mediated IDP regulatory mechanisms.
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Affiliation(s)
- Alaji Bah
- From the Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, Ontario M5G 0A4 and the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Julie D Forman-Kay
- From the Program in Molecular Structure & Function, The Hospital for Sick Children, Toronto, Ontario M5G 0A4 and the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Zhang Z, Bah A, Sajjad H, Forman-Kay JD, Gradinaru CC. Single-Molecule Dissection of the Conformations, Dynamics and Binding of the Disordered 4E-BP2 Protein. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.2976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Bah A, Vernon RM, Siddiqui Z, Krzeminski M, Muhandiram R, Zhao C, Sonenberg N, Kay LE, Forman-Kay JD. Folding of an intrinsically disordered protein by phosphorylation as a regulatory switch. Nature 2014; 519:106-9. [PMID: 25533957 DOI: 10.1038/nature13999] [Citation(s) in RCA: 392] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 10/24/2014] [Indexed: 11/09/2022]
Abstract
Intrinsically disordered proteins play important roles in cell signalling, transcription, translation and cell cycle regulation. Although they lack stable tertiary structure, many intrinsically disordered proteins undergo disorder-to-order transitions upon binding to partners. Similarly, several folded proteins use regulated order-to-disorder transitions to mediate biological function. In principle, the function of intrinsically disordered proteins may be controlled by post-translational modifications that lead to structural changes such as folding, although this has not been observed. Here we show that multisite phosphorylation induces folding of the intrinsically disordered 4E-BP2, the major neural isoform of the family of three mammalian proteins that bind eIF4E and suppress cap-dependent translation initiation. In its non-phosphorylated state, 4E-BP2 interacts tightly with eIF4E using both a canonical YXXXXLΦ motif (starting at Y54) that undergoes a disorder-to-helix transition upon binding and a dynamic secondary binding site. We demonstrate that phosphorylation at T37 and T46 induces folding of residues P18-R62 of 4E-BP2 into a four-stranded β-domain that sequesters the helical YXXXXLΦ motif into a partly buried β-strand, blocking its accessibility to eIF4E. The folded state of pT37pT46 4E-BP2 is weakly stable, decreasing affinity by 100-fold and leading to an order-to-disorder transition upon binding to eIF4E, whereas fully phosphorylated 4E-BP2 is more stable, decreasing affinity by a factor of approximately 4,000. These results highlight stabilization of a phosphorylation-induced fold as the essential mechanism for phospho-regulation of the 4E-BP:eIF4E interaction and exemplify a new mode of biological regulation mediated by intrinsically disordered proteins.
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Affiliation(s)
- Alaji Bah
- 1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Robert M Vernon
- 1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Zeba Siddiqui
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Mickaël Krzeminski
- 1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Ranjith Muhandiram
- 1] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada [2] Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Charlie Zhao
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montréal, Quebec H3G 1Y6, Canada
| | - Lewis E Kay
- 1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada [3] Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada [4] Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Julie D Forman-Kay
- 1] Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada [2] Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Kaba M, Camara M, Cissé M, Tounkara T, Traoré M, Bah A, Kourouma M. Suivi du taux de la créatinine sérique au cours du traitement antirétroviral à Conakry. Nephrol Ther 2014. [DOI: 10.1016/j.nephro.2014.07.257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kouamo J, No author NA, Dawaye S, Bah A. Evaluation of bovine (Bos indicus) ovarian potential for in vitro embryo production in the Adamawa plateau (Cameroon). Open Vet J 2014. [DOI: 10.5455/ovj.2014.v4.i2.p128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An abattoir study was conducted to evaluate the ovarian potential of 201 local zebu cattle from Ngaoundere, Adamawa region (Cameroon) for in vitro embryo production (IVEP). The ovaries were excised, submerged in normal saline solution (0.9%) and transported to the laboratory for a detailed evaluation. Follicles on each ovary were counted, their diameters (F) measured and were grouped into 3 categories: small (F < 3 mm), medium (3 = F = 8 mm) and large (F > 8 mm). Each ovary was then sliced into a petri dish; the oocytes were recovered in Dulbecco’s phosphate buffered saline, examined under a stereoscope (x10) and graded into four groups based on the morphology of cumulus oophorus cells and cytoplasmic changes of the oocytes. Grade I (GI): oocytes with more than 4 layers of bunch of compact cumulus cells mass with evenly granulated cytoplasm; grade II (GII): oocyte with at least 2–4 layers of compact cumulus cell mass with evenly granulated cytoplasm; grade III (GIII): oocyte with at least one layer of compact cumulus cell mass with evenly granulated cytoplasm; grade IV (GIV): denuded oocyte with no cumulus cells or incomplete layer of cumulus cell or expanded cells and having dark or unevenly granulated cytoplasm. The effects of both ovarian (ovarian localization, corpus luteum, size and weight of ovary) and non-ovarian factors (breed, age, body condition score (BCS) and pregnancy status of cow) on the follicular population and oocyte recovery rate were determined. There were an average of 16.75±0.83 follicles per ovary. The small, medium and large follicles were 8.39±0.60, 8.14±0.43 and 0.21±0.02 respectively. Oocyte recovery was 10.97±0.43 per ovary (65%). Oocytes graded I, II, III and IV were 3.53±0.19 (32.21%), 2.72±0.15 (24.82%), 2.24±0.15 (20.43%) and 2.47±0.20 (22.54%) respectively. The oocyte quality index was 2.26. Younger non pregnant cows having BCS of 3 and large ovaries presented higher number of follicles and oocyte quality (P < 0.05) compared with other animals. Oocytes with quality (grade I and II) acceptable for IVEP constituted 57.15% of the harvest. This study indicated that factors such as age, pregnancy status, BCS and ovarian size must be taken into account to increase the potential of the ovary for IVEP.
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Lukhele S, Bah A, Lin H, Sonenberg N, Forman-Kay JD. Interaction of the eukaryotic initiation factor 4E with 4E-BP2 at a dynamic bipartite interface. Structure 2013; 21:2186-96. [PMID: 24207126 DOI: 10.1016/j.str.2013.08.030] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/29/2013] [Accepted: 08/13/2013] [Indexed: 10/26/2022]
Abstract
Cap-dependent translation initiation is regulated by the interaction of eukaryotic initiation factor 4E (eIF4E) with eIF4E binding proteins (4E-BPs). Whereas the binding of 4E-BP peptides containing the eIF4E-binding ⁵⁴YXXXXLΦ⁶⁰ motif has been studied, atomic-level characterization of the interaction of eIF4E with full-length 4E-BPs has been lacking. Here, we use isothermal titration calorimetry and nuclear magnetic resonance spectroscopy to characterize the dynamic, structural and binding properties of 4E-BP2. Although disordered, 4E-BP2 contains significant fluctuating secondary structure and binds eIF4E at an extensive bipartite interface including the canonical ⁵⁴YXXXXLΦ⁶⁰ and ⁷⁸IPGVT⁸² sites. Each of the two binding elements individually has submicromolar affinity and exchange on and off of the eIF4E surface within the context of the overall nanomolar complex. This dynamic interaction facilitates exposure of regulatory phosphorylation sites within the complex. The 4E-BP2 interface on eIF4E overlaps yet is more extensive than the eIF4G:eIF4E interface, suggesting that these key interactions may be differentially targeted for therapeutics.
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Affiliation(s)
- Sabelo Lukhele
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
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Kaba M, Bakala M, Sow T, Bah A, Kourouma M, Soumah A, Diakité F. Événements cardiovasculaires chez l’insuffisant rénal chronique hypertendu à Conakry. Nephrol Ther 2012. [DOI: 10.1016/j.nephro.2012.07.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bouvignies G, Vallurupalli P, Hansen DF, Correia BE, Lange O, Bah A, Vernon RM, Dahlquist FW, Baker D, Kay LE. Solution structure of a minor and transiently formed state of a T4 lysozyme mutant. Nature 2011; 477:111-4. [PMID: 21857680 DOI: 10.1038/nature10349] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 06/30/2011] [Indexed: 11/09/2022]
Abstract
Proteins are inherently plastic molecules, whose function often critically depends on excursions between different molecular conformations (conformers). However, a rigorous understanding of the relation between a protein's structure, dynamics and function remains elusive. This is because many of the conformers on its energy landscape are only transiently formed and marginally populated (less than a few per cent of the total number of molecules), so that they cannot be individually characterized by most biophysical tools. Here we study a lysozyme mutant from phage T4 that binds hydrophobic molecules and populates an excited state transiently (about 1 ms) to about 3% at 25 °C (ref. 5). We show that such binding occurs only via the ground state, and present the atomic-level model of the 'invisible', excited state obtained using a combined strategy of relaxation-dispersion NMR (ref. 6) and CS-Rosetta model building that rationalizes this observation. The model was tested using structure-based design calculations identifying point mutants predicted to stabilize the excited state relative to the ground state. In this way a pair of mutations were introduced, inverting the relative populations of the ground and excited states and altering function. Our results suggest a mechanism for the evolution of a protein's function by changing the delicate balance between the states on its energy landscape. More generally, they show that our approach can generate and validate models of excited protein states.
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Affiliation(s)
- Guillaume Bouvignies
- Department of Molecular Genetics, The University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Pozzi N, Chen R, Chen Z, Bah A, Di Cera E. Rigidification of the autolysis loop enhances Na(+) binding to thrombin. Biophys Chem 2011; 159:6-13. [PMID: 21536369 DOI: 10.1016/j.bpc.2011.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 04/04/2011] [Accepted: 04/04/2011] [Indexed: 01/09/2023]
Abstract
Binding of Na(+) to thrombin ensures high activity toward physiological substrates and optimizes the procoagulant and prothrombotic roles of the enzyme in vivo. Under physiological conditions of pH and temperature, the binding affinity of Na(+) is weak due to large heat capacity and enthalpy changes associated with binding, and the K(d)=80 mM ensures only 64% saturation of the site at the concentration of Na(+) in the blood (140 mM). Residues controlling Na(+) binding and activation have been identified. Yet, attempts to improve the interaction of Na(+) with thrombin and possibly increase catalytic activity under physiological conditions have so far been unsuccessful. Here we report how replacement of the flexible autolysis loop of human thrombin with the homologous rigid domain of the murine enzyme results in a drastic (up to 10-fold) increase in Na(+) affinity and a significant improvement in the catalytic activity of the enzyme. Rigidification of the autolysis loop abolishes the heat capacity change associated with Na(+) binding observed in the wild-type and also increases the stability of thrombin. These findings have general relevance to protein engineering studies of clotting proteases and trypsin-like enzymes.
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Affiliation(s)
- Nicola Pozzi
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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