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Araya LE, Soni IV, Hardy JA, Julien O. Deorphanizing Caspase-3 and Caspase-9 Substrates In and Out of Apoptosis with Deep Substrate Profiling. ACS Chem Biol 2021; 16:2280-2296. [PMID: 34553588 DOI: 10.1021/acschembio.1c00456] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Caspases are a family of enzymes that regulate biological processes such as inflammation and programmed cell death, through proteolysis. For example, in the intrinsic pathway of apoptosis, cell death signaling involves cytochrome c release from the mitochondria, which leads to the activation of caspase-9 and eventually the executioners caspase-3 and -7. One key step in our understanding of these proteases is to identify their respective protein substrates. Although hundreds of substrates have been linked to caspase-3, only a small handful of substrates have been reported for caspase-9. Employing deep profiling by subtiligase N-terminomics, we present here an unbiased analysis of caspase-3 and caspase-9 substrates in native cell lysates. We identified 906 putative protein substrates associated with caspase-3 and 124 protein substrates for caspase-9. This is the most comprehensive list of caspase substrates reported for each of these proteases, revealing a pool of new substrates that could not have been discovered using other approaches. Over half of the caspase-9 substrates were also cleaved by caspase-3, but often at unique sites, suggesting an evolved functional redundancy for these two proteases. Correspondingly, nearly half of the caspase-9 cleavage sites were not recognized by caspase-3. Our results suggest that in addition to its important role in activating the executioners, the role of caspase-9 is likely broader and more complex than previously appreciated, which includes proteolysis of key apoptotic substrates other than just caspase-3 and -7 and involvement in non-apoptotic pathways. Our results are well poised to aid the discovery of new biological functions for these two caspases.
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Affiliation(s)
- Luam E. Araya
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
| | - Ishankumar V. Soni
- Department of Chemistry, University of Massachusetts, Amherst 01003, Massachusetts, United States
| | - Jeanne A. Hardy
- Department of Chemistry, University of Massachusetts, Amherst 01003, Massachusetts, United States
| | - Olivier Julien
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
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Rambout X, Maquat LE. The nuclear cap-binding complex as choreographer of gene transcription and pre-mRNA processing. Genes Dev 2021; 34:1113-1127. [PMID: 32873578 PMCID: PMC7462061 DOI: 10.1101/gad.339986.120] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this review, Rambout and Maquat discuss known roles of the nuclear cap-binding complex (CBC) during the transcription of genes that encode proteins, stitching together past studies from diverse groups to describe the continuum of CBC-mediated checks and balances in eukaryotic cells. The largely nuclear cap-binding complex (CBC) binds to the 5′ caps of RNA polymerase II (RNAPII)-synthesized transcripts and serves as a dynamic interaction platform for a myriad of RNA processing factors that regulate gene expression. While influence of the CBC can extend into the cytoplasm, here we review the roles of the CBC in the nucleus, with a focus on protein-coding genes. We discuss differences between CBC function in yeast and mammals, covering the steps of transcription initiation, release of RNAPII from pausing, transcription elongation, cotranscriptional pre-mRNA splicing, transcription termination, and consequences of spurious transcription. We describe parameters known to control the binding of generic or gene-specific cofactors that regulate CBC activities depending on the process(es) targeted, illustrating how the CBC is an ever-changing choreographer of gene expression.
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Affiliation(s)
- Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642, USA.,Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
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Yan YB. Diverse functions of deadenylases in DNA damage response and genomic integrity. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1621. [PMID: 32790161 DOI: 10.1002/wrna.1621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/18/2022]
Abstract
DNA damage response (DDR) is a coordinated network of diverse cellular processes including the detection, signaling, and repair of DNA lesions, the adjustment of metabolic network and cell fate determination. To deal with the unavoidable DNA damage caused by either endogenous or exogenous stresses, the cells need to reshape the gene expression profile to allow efficient transcription and translation of DDR-responsive messenger RNAs (mRNAs) and to repress the nonessential mRNAs. A predominant method to adjust RNA fate is achieved by modulating the 3'-end oligo(A) or poly(A) length via the opposing actions of polyadenylation and deadenylation. Poly(A)-specific ribonuclease (PARN) and the carbon catabolite repressor 4 (CCR4)-Not complex, the major executors of deadenylation, are indispensable to DDR and genomic integrity in eukaryotic cells. PARN modulates cell cycle progression by regulating the stabilities of mRNAs and microRNA (miRNAs) involved in the p53 pathway and contributes to genomic stability by affecting the biogenesis of noncoding RNAs including miRNAs and telomeric RNA. The CCR4-Not complex is involved in diverse pathways of DDR including transcriptional regulation, signaling pathways, mRNA stabilities, translation regulation, and protein degradation. The RNA targets of deadenylases are tuned by the DDR signaling pathways, while in turn the deadenylases can regulate the levels of DNA damage-responsive proteins. The mutual feedback between deadenylases and the DDR signaling pathways allows the cells to precisely control DDR by dynamically adjusting the levels of sensors and effectors of the DDR signaling pathways. Here, the diverse functions of deadenylases in DDR are summarized and the underlying mechanisms are proposed according to recent findings. This article is categorized under: RNA Processing > 3' End Processing RNA in Disease and Development > RNA in Disease RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms.
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Affiliation(s)
- Yong-Bin Yan
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, China
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Dejene EA, Li Y, Showkatian Z, Ling H, Seto E. Regulation of poly(a)-specific ribonuclease activity by reversible lysine acetylation. J Biol Chem 2020; 295:10255-10270. [PMID: 32457045 DOI: 10.1074/jbc.ra120.012552] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 05/20/2020] [Indexed: 12/26/2022] Open
Abstract
Poly(A)-specific ribonuclease (PARN) is a 3'-exoribonuclease that plays an important role in regulating the stability and maturation of RNAs. Recently, PARN has been found to regulate the maturation of the human telomerase RNA component (hTR), a noncoding RNA required for telomere elongation. Specifically, PARN cleaves the 3'-end of immature, polyadenylated hTR to form the mature, nonpolyadenylated template. Despite PARN's critical role in mediating telomere maintenance, little is known about how PARN's function is regulated by post-translational modifications. In this study, using shRNA- and CRISPR/Cas9-mediated gene silencing and knockout approaches, along with 3'-exoribonuclease activity assays and additional biochemical methods, we examined whether PARN is post-translationally modified by acetylation and what effect acetylation has on PARN's activity. We found PARN is primarily acetylated by the acetyltransferase p300 at Lys-566 and deacetylated by sirtuin1 (SIRT1). We also revealed how acetylation of PARN can decrease its enzymatic activity both in vitro, using a synthetic RNA probe, and in vivo, by quantifying endogenous levels of adenylated hTR. Furthermore, we also found that SIRT1 can regulate levels of adenylated hTR through PARN. The findings of our study uncover a mechanism by which PARN acetylation and deacetylation regulate its enzymatic activity as well as levels of mature hTR. Thus, PARN's acetylation status may play a role in regulating telomere length.
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Affiliation(s)
- Eden A Dejene
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA.,George Washington University Cancer Center, Washington, D.C., USA
| | - Yixuan Li
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA.,George Washington University Cancer Center, Washington, D.C., USA
| | - Zahra Showkatian
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA.,George Washington University Cancer Center, Washington, D.C., USA
| | - Hongbo Ling
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA.,George Washington University Cancer Center, Washington, D.C., USA
| | - Edward Seto
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine and Health Sciences, Washington, D.C., USA .,George Washington University Cancer Center, Washington, D.C., USA
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Nucleolar Organization and Functions in Health and Disease. Cells 2020; 9:cells9030526. [PMID: 32106410 PMCID: PMC7140423 DOI: 10.3390/cells9030526] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 02/21/2020] [Indexed: 12/18/2022] Open
Abstract
The nucleolus is a prominent, membraneless compartment found within the nucleus of eukaryotic cells. It forms around ribosomal RNA (rRNA) genes, where it coordinates the transcription, processing, and packaging of rRNA to produce ribosomal subunits. Recent efforts to characterize the biophysical properties of the nucleolus have transformed our understanding of the assembly and organization of this dynamic compartment. Indeed, soluble macromolecules condense from the nucleoplasm to form nucleoli through a process called liquid–liquid phase separation. Individual nucleolar components rapidly exchange with the nucleoplasm and separate within the nucleolus itself to form distinct subcompartments. In addition to its essential role in ribosome biogenesis, the nucleolus regulates many aspects of cell physiology, including genome organization, stress responses, senescence and lifespan. Consequently, the nucleolus is implicated in several human diseases, such as Hutchinson–Gilford progeria syndrome, Diamond–Blackfan anemia, and various forms of cancer. This Special Issue highlights new insights into the physical and molecular mechanisms that control the architecture and diverse functions of the nucleolus, and how they break down in disease.
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Translation Efficiency and Degradation of ER-Associated mRNAs Modulated by ER-Anchored poly(A)-Specific Ribonuclease (PARN). Cells 2020; 9:cells9010162. [PMID: 31936572 PMCID: PMC7017053 DOI: 10.3390/cells9010162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/05/2020] [Accepted: 01/07/2020] [Indexed: 12/21/2022] Open
Abstract
Translation is spatiotemporally regulated and endoplasmic reticulum (ER)-associated mRNAs are generally in efficient translation. It is unclear whether the ER-associated mRNAs are deadenylated or degraded on the ER surface in situ or in the cytosol. Here, we showed that ER possessed active deadenylases, particularly the poly(A)-specific ribonuclease (PARN), in common cell lines and mouse tissues. Consistently, purified recombinant PARN exhibited a strong ability to insert into the Langmuir monolayer and liposome. ER-anchored PARN was found to be able to reshape the poly(A) length profile of the ER-associated RNAs by suppressing long poly(A) tails without significantly influencing the cytosolic RNAs. The shortening of long poly(A) tails did not affect global translation efficiency, which suggests that the non-specific action of PARN towards long poly(A) tails was beyond the scope of translation regulation on the ER surface. Transcriptome sequencing analysis indicated that the ER-anchored PARN trigged the degradation of a small subset of ER-enriched transcripts. The ER-anchored PARN modulated the translation of its targets by redistributing ribosomes to heavy polysomes, which suggests that PARN might play a role in dynamic ribosome reallocation. During DNA damage response, MK2 phosphorylated PARN-Ser557 to modulate PARN translocation from the ER to cytosol. The ER-anchored PARN modulated DNA damage response and thereby cell viability by promoting the decay of ER-associated MDM2 transcripts with low ribosome occupancy. These findings revealed that highly regulated communication between mRNA degradation rate and translation efficiency is present on the ER surface in situ and PARN might contribute to this communication by modulating the dynamic ribosome reallocation between transcripts with low and high ribosome occupancies.
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MacGowan SA, Madeira F, Britto‐Borges T, Warowny M, Drozdetskiy A, Procter JB, Barton GJ. The Dundee Resource for Sequence Analysis and Structure Prediction. Protein Sci 2020; 29:277-297. [PMID: 31710725 PMCID: PMC6933851 DOI: 10.1002/pro.3783] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/07/2019] [Accepted: 11/07/2019] [Indexed: 11/06/2022]
Abstract
The Dundee Resource for Sequence Analysis and Structure Prediction (DRSASP; http://www.compbio.dundee.ac.uk/drsasp.html) is a collection of web services provided by the Barton Group at the University of Dundee. DRSASP's flagship services are the JPred4 webserver for secondary structure and solvent accessibility prediction and the JABAWS 2.2 webserver for multiple sequence alignment, disorder prediction, amino acid conservation calculations, and specificity-determining site prediction. DRSASP resources are available through conventional web interfaces and APIs but are also integrated into the Jalview sequence analysis workbench, which enables the composition of multitool interactive workflows. Other existing Barton Group tools are being brought under the banner of DRSASP, including NoD (Nucleolar localization sequence detector) and 14-3-3-Pred. New resources are being developed that enable the analysis of population genetic data in evolutionary and 3D structural contexts. Existing resources are actively developed to exploit new technologies and maintain parity with evolving web standards. DRSASP provides substantial computational resources for public use, and since 2016 DRSASP services have completed over 1.5 million jobs.
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Affiliation(s)
- Stuart A. MacGowan
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
| | - Fábio Madeira
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
| | - Thiago Britto‐Borges
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
| | - Mateusz Warowny
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
| | - Alexey Drozdetskiy
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
| | - James B. Procter
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
| | - Geoffrey J. Barton
- Division of Computational BiologyCollege of Life Sciences, University of DundeeUK
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