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Baum B, Spang A. On the origin of the nucleus: a hypothesis. Microbiol Mol Biol Rev 2023; 87:e0018621. [PMID: 38018971 PMCID: PMC10732040 DOI: 10.1128/mmbr.00186-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023] Open
Abstract
SUMMARYIn this hypothesis article, we explore the origin of the eukaryotic nucleus. In doing so, we first look afresh at the nature of this defining feature of the eukaryotic cell and its core functions-emphasizing the utility of seeing the eukaryotic nucleoplasm and cytoplasm as distinct regions of a common compartment. We then discuss recent progress in understanding the evolution of the eukaryotic cell from archaeal and bacterial ancestors, focusing on phylogenetic and experimental data which have revealed that many eukaryotic machines with nuclear activities have archaeal counterparts. In addition, we review the literature describing the cell biology of representatives of the TACK and Asgardarchaeaota - the closest known living archaeal relatives of eukaryotes. Finally, bringing these strands together, we propose a model for the archaeal origin of the nucleus that explains much of the current data, including predictions that can be used to put the model to the test.
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Affiliation(s)
- Buzz Baum
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Anja Spang
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, the Netherlands
- Department of Evolutionary & Population Biology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, the Netherlands
- Department of Marine Microbiology and Biogeochemistry, NIOZ, Royal Netherlands Institute for Sea Research, Den Burg, the Netherlands
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2
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Kudzhaev AM, Andrianova AG, Gustchina AE, Smirnov IV, Rotanova TV. ATP-Dependent Lon Proteases in the Cellular Protein Quality Control System. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2022. [DOI: 10.1134/s1068162022040136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Bonn SM, Fushman D. Backbone NMR resonance assignment of the intrinsically disordered UBact protein from Nitrospira nitrosa. BIOMOLECULAR NMR ASSIGNMENTS 2022; 16:129-134. [PMID: 35107780 PMCID: PMC9081246 DOI: 10.1007/s12104-022-10070-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Ubiquitin signaling in eukaryotes is responsible for a variety of cellular outcomes, most notably proteasomal degradation. A recent bioinformatic study has revealed the existence of a new proteasomal operon in certain gram-negative bacteria phyla. This operon contains genes similar to those included in the prokaryotic ubiquitin-like protein (Pup) proteasomal operon, but do not themselves contain Pup. Instead, they encode for a protein termed UBact with 30% sequence similarity to Pup. Here, we report the near-complete NMR assignment of the backbone and partial assignment of the side chain chemical shifts of the UBact protein from Nitrospira nitrosa. The 1H-15N HSQC spectrum shows a narrow spread of proton NMR signals, characteristic of an intrinsically disordered protein. This chemical shift assignment will facilitate further NMR studies to explore the role of UBact in this new putative proteasomal operon.
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Affiliation(s)
- Steven M Bonn
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD, 20742, USA
| | - David Fushman
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD, 20742, USA.
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4
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Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020. [PMID: 31900730 DOI: 10.1007/s00709-019-01442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
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Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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5
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Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020; 257:621-753. [PMID: 31900730 PMCID: PMC7203096 DOI: 10.1007/s00709-019-01442-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/19/2019] [Indexed: 05/02/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
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Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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Molecular Factors of Hypochlorite Tolerance in the Hypersaline Archaeon Haloferax volcanii. Genes (Basel) 2018; 9:genes9110562. [PMID: 30463375 PMCID: PMC6267482 DOI: 10.3390/genes9110562] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 12/17/2022] Open
Abstract
Halophilic archaea thrive in hypersaline conditions associated with desiccation, ultraviolet (UV) irradiation and redox active compounds, and thus are naturally tolerant to a variety of stresses. Here, we identified mutations that promote enhanced tolerance of halophilic archaea to redox-active compounds using Haloferax volcanii as a model organism. The strains were isolated from a library of random transposon mutants for growth on high doses of sodium hypochlorite (NaOCl), an agent that forms hypochlorous acid (HOCl) and other redox acid compounds common to aqueous environments of high concentrations of chloride. The transposon insertion site in each of twenty isolated clones was mapped using the following: (i) inverse nested two-step PCR (INT-PCR) and (ii) semi-random two-step PCR (ST-PCR). Genes that were found to be disrupted in hypertolerant strains were associated with lysine deacetylation, proteasomes, transporters, polyamine biosynthesis, electron transfer, and other cellular processes. Further analysis revealed a ΔpsmA1 (α1) markerless deletion strain that produces only the α2 and β proteins of 20S proteasomes was hypertolerant to hypochlorite stress compared with wild type, which produces α1, α2, and β proteins. The results of this study provide new insights into archaeal tolerance of redox active compounds such as hypochlorite.
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Proteolytic systems of archaea: slicing, dicing, and mincing in the extreme. Emerg Top Life Sci 2018; 2:561-580. [PMID: 32953999 DOI: 10.1042/etls20180025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Archaea are phylogenetically distinct from bacteria, and some of their proteolytic systems reflect this distinction. Here, the current knowledge of archaeal proteolysis is reviewed as it relates to protein metabolism, protein homeostasis, and cellular regulation including targeted proteolysis by proteasomes associated with AAA-ATPase networks and ubiquitin-like modification. Proteases and peptidases that facilitate the recycling of peptides to amino acids as well as membrane-associated and integral membrane proteases are also reviewed.
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Seth-Pasricha M, Senn S, Sanman LE, Bogyo M, Nanda V, Bidle KA, Bidle KD. Catalytic linkage between caspase activity and proteostasis in Archaea. Environ Microbiol 2018; 21:286-298. [PMID: 30370585 DOI: 10.1111/1462-2920.14456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 11/29/2022]
Abstract
The model haloarchaeon, Haloferax volcanii possess an extremely high, and highly specific, basal caspase activity in exponentially growing cells that closely resembles caspase-4. This activity is specifically inhibited by the pan-caspase inhibitor, z-VAD-FMK, and has no cross-reactivity with other known protease families. Although it is one of the dominant cellular proteolytic activities in exponentially growing H. volcanii cells, the interactive cellular roles remain unknown and the protein(s) responsible for this activity remain elusive. Here, biochemical purification and in situ trapping with caspase targeted covalent inhibitors combined with genome-enabled proteomics, structural analysis, targeted gene knockouts and treatment with canavanine demonstrated a catalytic linkage between caspase activity and thermosomes, proteasomes and cdc48b, a cell division protein and proteasomal degradation facilitating ATPase, as part of an 'interactase' of stress-related protein complexes with an established link to the unfolded protein response (UPR). Our findings provide novel cellular and biochemical context for the observed caspase activity in Archaea and add new insight to understanding the role of this activity, implicating their possible role in the establishment of protein stress and ER associated degradation pathways in Eukarya.
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Affiliation(s)
- Mansha Seth-Pasricha
- Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Stefan Senn
- Abteilung für Chemie und Bioanalytik, Universität Salzburg, Salzburg, Austria
| | - Laura E Sanman
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Vikas Nanda
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
| | - Kelly A Bidle
- Department of Biology, Behavioral Neuroscience, and Health Sciences, Rider University, Lawrenceville, NJ, USA
| | - Kay D Bidle
- Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
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Esser D, Hoffmann L, Pham TK, Bräsen C, Qiu W, Wright PC, Albers SV, Siebers B. Protein phosphorylation and its role in archaeal signal transduction. FEMS Microbiol Rev 2016; 40:625-47. [PMID: 27476079 PMCID: PMC5007285 DOI: 10.1093/femsre/fuw020] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2016] [Indexed: 12/23/2022] Open
Abstract
Reversible protein phosphorylation is the main mechanism of signal transduction that enables cells to rapidly respond to environmental changes by controlling the functional properties of proteins in response to external stimuli. However, whereas signal transduction is well studied in Eukaryotes and Bacteria, the knowledge in Archaea is still rather scarce. Archaea are special with regard to protein phosphorylation, due to the fact that the two best studied phyla, the Euryarchaeota and Crenarchaeaota, seem to exhibit fundamental differences in regulatory systems. Euryarchaeota (e.g. halophiles, methanogens, thermophiles), like Bacteria and Eukaryotes, rely on bacterial-type two-component signal transduction systems (phosphorylation on His and Asp), as well as on the protein phosphorylation on Ser, Thr and Tyr by Hanks-type protein kinases. Instead, Crenarchaeota (e.g. acidophiles and (hyper)thermophiles) only depend on Hanks-type protein phosphorylation. In this review, the current knowledge of reversible protein phosphorylation in Archaea is presented. It combines results from identified phosphoproteins, biochemical characterization of protein kinases and protein phosphatases as well as target enzymes and first insights into archaeal signal transduction by biochemical, genetic and polyomic studies. The authors review the current knowledge about protein phosphorylation in Archaea and its impact on signaling in this organism group.
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Affiliation(s)
- Dominik Esser
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
| | - Lena Hoffmann
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Trong Khoa Pham
- ChELSI Institute, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - Christopher Bräsen
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
| | - Wen Qiu
- ChELSI Institute, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
| | - Phillip C Wright
- ChELSI Institute, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK School of Chemical Engineering and Advanced Materials, Faculty of Science, Agriculture and Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Bettina Siebers
- Molecular Enzyme Technology and Biochemistry, Biofilm Centre, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
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Hwang S, Cordova B, Chavarria N, Elbanna D, McHugh S, Rojas J, Pfeiffer F, Maupin-Furlow JA. Conserved active site cysteine residue of archaeal THI4 homolog is essential for thiamine biosynthesis in Haloferax volcanii. BMC Microbiol 2014; 14:260. [PMID: 25348237 PMCID: PMC4215014 DOI: 10.1186/s12866-014-0260-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 09/29/2014] [Indexed: 01/12/2023] Open
Abstract
Background Thiamine (vitamin B1) is synthesized de novo by certain yeast, fungi, plants, protozoans, bacteria and archaea. The pathway of thiamine biosynthesis by archaea is poorly understood, particularly the route of sulfur relay to form the thiazole ring. Archaea harbor structural homologs of both the bacterial (ThiS-ThiF) and eukaryotic (THI4) proteins that mobilize sulfur to thiazole ring precursors by distinct mechanisms. Results Based on comparative genome analysis, halophilic archaea are predicted to synthesize the pyrimidine moiety of thiamine by the bacterial pathway, initially suggesting that also a bacterial ThiS-ThiF type mechanism for synthesis of the thiazole ring is used in which the sulfur carrier ThiS is first activated by ThiF-catalyzed adenylation. The only ThiF homolog of Haloferax volcanii (UbaA) was deleted but this had no effect on growth in the absence of thiamine. Usage of the eukaryotic THI4-type sulfur relay was initially considered less likely for thiamine biosynthesis in archaea, since the active-site cysteine residue of yeast THI4p that donates the sulfur to the thiazole ring by a suicide mechanism is replaced by a histidine residue in many archaeal THI4 homologs and these are described as D-ribose-1,5-bisphosphate isomerases. The THI4 homolog of the halophilic archaea, including Hfx. volcanii (HVO_0665, HvThi4) was found to differ from that of methanogens and thermococci by having a cysteine residue (Cys165) corresponding to the conserved active site cysteine of yeast THI4p (Cys205). Deletion of HVO_0665 generated a thiamine auxotroph that was trans-complemented by a wild-type copy of HVO_0665, but not the modified gene encoding an HvThi4 C165A variant. Conclusions Based on our results, we conclude that the archaeon Hfx. volcanii uses a yeast THI4-type mechanism for sulfur relay to form the thiazole ring of thiamine. We extend this finding to a relatively large group of archaea, including haloarchaea, ammonium oxidizing archaea, and some methanogen and Pyrococcus species, by observing that these organisms code for THI4 homologs that have a conserved active site cysteine residue which is likely used in thiamine biosynthesis. Thus, archaeal members of IPR002922 THI4 family that have a conserved cysteine active site should be reexamined for a function in thiamine biosynthesis. Electronic supplementary material The online version of this article (doi:10.1186/s12866-014-0260-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sungmin Hwang
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA.
| | - Bryan Cordova
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA.
| | - Nikita Chavarria
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA.
| | - Dina Elbanna
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA.
| | - Stephen McHugh
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA.
| | - Jenny Rojas
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA.
| | - Friedhelm Pfeiffer
- Department of Membrane Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany.
| | - Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA. .,Genetics Institute, University of Florida, Gainesville, FL, 32611-0700, USA.
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Abstract
Prokaryotes form ubiquitin (Ub)-like isopeptide bonds on the lysine residues of proteins by at least two distinct pathways that are reversible and regulated. In mycobacteria, the C-terminal Gln of Pup (prokaryotic ubiquitin-like protein) is deamidated and isopeptide linked to proteins by a mechanism distinct from ubiquitylation in enzymology yet analogous to ubiquitylation in targeting proteins for destruction by proteasomes. Ub-fold proteins of archaea (SAMPs, small archaeal modifier proteins) and Thermus (TtuB, tRNA-two-thiouridine B) that differ from Ub in amino acid sequence, yet share a common β-grasp fold, also form isopeptide bonds by a mechanism that appears streamlined compared with ubiquitylation. SAMPs and TtuB are found to be members of a small group of Ub-fold proteins that function not only in protein modification but also in sulfur-transfer pathways associated with tRNA thiolation and molybdopterin biosynthesis. These multifunctional Ub-fold proteins are thought to be some of the most ancient of Ub-like protein modifiers.
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Affiliation(s)
- Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611;
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12
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Abstract
Proteasomes are ATP-dependent protein degradation machines present in all archaea and eukaryotes, and found in several bacterial species of the order Actinomycetales. Mycobacterium tuberculosis (Mtb), an Actinomycete pathogenic to humans, requires proteasome function to cause disease. In this chapter, we describe what is currently understood about the biochemistry of the Mtb proteasome and its role in virulence. The characterization of the Mtb proteasome has led to the discovery that proteins can be targeted for degradation by a small protein modifier in bacteria as they are in eukaryotes. Furthermore, the understanding of proteasome function in Mtb has helped reveal new insight into how the host battles infections.
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Affiliation(s)
- Marie I Samanovic
- Department of Microbiology, New York University School of Medicine, 550 First Avenue, MSB 236, New York, NY, 10016, USA
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