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Medina-Suárez S, Ayra-Plasencia J, Pérez-Martínez L, Butter F, Machín F. Msc1 is a nuclear envelope protein that reinforces DNA repair in late mitosis. iScience 2024; 27:110250. [PMID: 39021806 PMCID: PMC11253511 DOI: 10.1016/j.isci.2024.110250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 04/15/2024] [Accepted: 06/08/2024] [Indexed: 07/20/2024] Open
Abstract
Precise double-strand break (DSB) repair is a paramount for genome stability. Homologous recombination (HR) repairs DSBs when cyclin-dependent kinase (CDK) activity is high, which correlates with the availability of the sister chromatid as a template. However, anaphase and telophase are paradoxical scenarios since high CDK favors HR despite sister chromatids being no longer aligned. To identify factors specifically involved in DSB repair in late mitosis, we have undertaken comparative proteomics in Saccharomyces cerevisiae and found that meiotic sister chromatid 1 (Msc1), a poorly characterized nuclear envelope protein, is significantly enriched upon both random and guided DSBs. We further show that Δmsc1 is more sensitive to DSBs in late mitosis, and has a delayed repair of DBSs, as indicated by increased Rad53 hyperphosphorylation, a higher presence of RPA foci, fewer Rad52 repair factories, and slower HR completion. We propose that Msc1 favors the later stages of HR and the timely completion of DSB repair before cytokinesis.
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Affiliation(s)
- Sara Medina-Suárez
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Jessel Ayra-Plasencia
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | | | - Falk Butter
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
- Institute of Molecular Virology and Cell Biology, Friedrich Loeffler Institute, 17493 Greifswald, Germany
| | - Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, 38010 Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Spain
- Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, 35450 Las Palmas de Gran Canaria, Spain
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2
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Fabijan A, Polis B, Zawadzka-Fabijan A, Korabiewska I, Zakrzewski K, Nowosławska E, Chojnacki M. Domains in Action: Understanding Ddi1's Diverse Functions in the Ubiquitin-Proteasome System. Int J Mol Sci 2024; 25:4080. [PMID: 38612889 PMCID: PMC11012796 DOI: 10.3390/ijms25074080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/01/2024] [Accepted: 04/03/2024] [Indexed: 04/14/2024] Open
Abstract
The ubiquitin-proteasome system (UPS) is a pivotal cellular mechanism responsible for the selective degradation of proteins, playing an essential role in proteostasis, protein quality control, and regulating various cellular processes, with ubiquitin marking proteins for degradation through a complex, multi-stage process. The shuttle proteins family is a very unique group of proteins that plays an important role in the ubiquitin-proteasome system. Ddi1, Dsk2, and Rad23 are shuttle factors that bind ubiquitinated substrates and deliver them to the 26S proteasome. Besides mediating the delivery of ubiquitinated proteins, they are also involved in many other biological processes. Ddi1, the least-studied shuttle protein, exhibits unique physicochemical properties that allow it to play non-canonical functions in the cells. It regulates cell cycle progression and response to proteasome inhibition and defines MAT type of yeast cells. The Ddi1 contains UBL and UBA domains, which are crucial for binding to proteasome receptors and ubiquitin respectively, but also an additional domain called RVP. Additionally, much evidence has been provided to question whether Ddi1 is a classical shuttle protein. For many years, the true nature of this protein remained unclear. Here, we highlight the recent discoveries, which shed new light on the structure and biological functions of the Ddi1 protein.
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Affiliation(s)
- Artur Fabijan
- Department of Neurosurgery, Polish-Mother’s Memorial Hospital Research Institute, 93-338 Lodz, Poland; (B.P.); (K.Z.); (E.N.)
| | - Bartosz Polis
- Department of Neurosurgery, Polish-Mother’s Memorial Hospital Research Institute, 93-338 Lodz, Poland; (B.P.); (K.Z.); (E.N.)
| | - Agnieszka Zawadzka-Fabijan
- Department of Rehabilitation Medicine, Faculty of Health Sciences, Medical University of Lodz, 90-419 Lodz, Poland;
| | - Izabela Korabiewska
- Department of Rehabilitation, Faculty of Dental Medicine, Medical University of Warsaw, 02-091 Warsaw, Poland;
| | - Krzysztof Zakrzewski
- Department of Neurosurgery, Polish-Mother’s Memorial Hospital Research Institute, 93-338 Lodz, Poland; (B.P.); (K.Z.); (E.N.)
| | - Emilia Nowosławska
- Department of Neurosurgery, Polish-Mother’s Memorial Hospital Research Institute, 93-338 Lodz, Poland; (B.P.); (K.Z.); (E.N.)
| | - Michał Chojnacki
- Department of Medical Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland;
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3
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Gnügge R, Symington LS. Efficient DNA double-strand break formation at single or multiple defined sites in the Saccharomyces cerevisiae genome. Nucleic Acids Res 2020; 48:e115. [PMID: 33053188 PMCID: PMC7672422 DOI: 10.1093/nar/gkaa833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 08/18/2020] [Accepted: 09/28/2020] [Indexed: 01/08/2023] Open
Abstract
DNA double-strand breaks (DSBs) are common genome lesions that threaten genome stability and cell survival. Cells use sophisticated repair machineries to detect and heal DSBs. To study DSB repair pathways and associated factors, inducible site-specific endonucleases have proven to be fundamental tools. In Saccharomyces cerevisiae, galactose-inducible rare-cutting endonucleases are commonly used to create a single DSB at a unique cleavage site. Galactose induction requires cell cultivation in suboptimal growth media, which is tedious especially when working with slow growing DSB repair mutants. Moreover, endonucleases that simultaneously create DSBs in multiple defined and unique loci of the yeast genome are not available, hindering studies of DSB repair in different genomic regions and chromatin contexts. Here, we present new tools to overcome these limitations. We employ a heterologous media-independent induction system to express the yeast HO endonuclease or bacterial restriction enzymes for single or multiple DSB formation, respectively. The systems facilitate tightly controlled and efficient DSB formation at defined genomic sites and will be valuable tools to study DSB repair at a local and genome-wide scale.
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Affiliation(s)
- Robert Gnügge
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA.,Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
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4
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Okeke E, Chen L, Madura K. The Cellular Location of Rad23, a Polyubiquitin Chain-Binding Protein, Plays a Key Role in Its Interaction with Substrates of the Proteasome. J Mol Biol 2020; 432:2388-2404. [PMID: 32147457 DOI: 10.1016/j.jmb.2020.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 11/30/2022]
Abstract
Well-studied structural motifs in Rad23 have been shown to bind polyubiquitin chains and the proteasome. These domains are predicted to enable Rad23 to transport polyubiquitylated (polyUb) substrates to the proteasome (Chen and Madura, 2002 [1]). The validation of this model, however, has been hindered by the lack of specific physiological substrates of Rad23. We report here that Rad23 can bind Ho-endonuclease (Ho-endo), a nuclear protein that initiates mating-type switching in Saccharomyces cerevisiae. We observed that the degradation of Ho-endo required export from the nucleus, in agreement with a previous report (Kaplun et al., 2003 [2]), and suggests that Rad23 can traffic proteins out of the nucleus. In agreement, the subcellular distribution of Rad23 is noticeably altered in genetic mutants that disrupt nucleocytoplasmic trafficking. Significantly, the location of Rad23 affected its binding to polyUb substrates. Mutations in nuclear export stabilized substrates, and caused accumulation in the nucleus. Importantly, Rad23 also accumulated in the nucleus in an export mutant, and bound to higher levels of polyUb proteins. In contrast, Rad23 is localized in the cytosol in rna1-1, a nucleocytoplasmic transport mutant, and it forms reduced binding to polyUb substrates. These and other studies indicate that substrates that are conjugated to polyubiquitin chains in the nucleus may rely on an export-dependent mechanism to be degraded by the proteasome. The evolutionary conservation of Rad23 and similar substrate-trafficking proteins predicts an important role for export in the turnover of nuclear proteins.
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Affiliation(s)
- Evelyn Okeke
- Department of Pharmacology - SPH 383, Robert Wood Johnson Medical School, Rutgers University, 683 Hoes Lane, Piscataway, NJ 08854, USA
| | - Li Chen
- Department of Pharmacology - SPH 383, Robert Wood Johnson Medical School, Rutgers University, 683 Hoes Lane, Piscataway, NJ 08854, USA
| | - Kiran Madura
- Department of Pharmacology - SPH 383, Robert Wood Johnson Medical School, Rutgers University, 683 Hoes Lane, Piscataway, NJ 08854, USA.
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5
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Marshall RS, Hua Z, Mali S, McLoughlin F, Vierstra RD. ATG8-Binding UIM Proteins Define a New Class of Autophagy Adaptors and Receptors. Cell 2019; 177:766-781.e24. [PMID: 30955882 DOI: 10.1016/j.cell.2019.02.009] [Citation(s) in RCA: 197] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/14/2019] [Accepted: 02/08/2019] [Indexed: 01/02/2023]
Abstract
During autophagy, vesicle dynamics and cargo recruitment are driven by numerous adaptors and receptors that become tethered to the phagophore through interactions with lipidated ATG8/LC3 decorating the expanding membrane. Most currently described ATG8-binding proteins exploit a well-defined ATG8-interacting motif (AIM, or LC3-interacting region [LIR]) that contacts a hydrophobic patch on ATG8 known as the LIR/AIM docking site (LDS). Here we describe a new class of ATG8 interactors that exploit ubiquitin-interacting motif (UIM)-like sequences for high-affinity binding to an alternative ATG8 interaction site. Assays with candidate UIM-containing proteins together with unbiased screens identified a large collection of UIM-based ATG8 interactors in plants, yeast, and humans. Analysis of a subset also harboring ubiquitin regulatory X (UBX) domains revealed a role for UIM-directed autophagy in clearing non-functional CDC48/p97 complexes, including some impaired in human disease. With this new class of adaptors and receptors, we greatly extend the reach of selective autophagy and identify new factors regulating autophagic vesicle dynamics.
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Affiliation(s)
- Richard S Marshall
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Zhihua Hua
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
| | - Sujina Mali
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Fionn McLoughlin
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA.
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6
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Chen D, Lv B, Kobayashi S, Xiong Y, Sun P, Lin Y, Genovese S, Epifano F, Hou S, Tang F, Ji Y, Yu D. Madagascine Induces Vasodilatation via Activation of AMPK. Front Pharmacol 2016; 7:435. [PMID: 27932979 PMCID: PMC5122745 DOI: 10.3389/fphar.2016.00435] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/01/2016] [Indexed: 11/13/2022] Open
Abstract
Madagascine (3-isopentenyloxyemodin) can be chemically synthesized or purified from several Rhamnus species, and it is found to have more potent biological activities than the parent compound emodin. The aim of this study is to characterize the vasodilatory effect of madagascine on vasoconstriction and sphingosylphosphorylcholine induced vasospasm in ex vivo and reveal the potential mechanisms in vitro. The effects of madagascine on vasoconstriction of rat mesenteric resistance arteries (MRAs) induced by K+, methoxamine, and endothelin-1 were, respectively, studied. The cholesterol-enriched porcine coronary vascular smooth muscle (VSM) strips were used to investigate the effects of madagascine on abnormal constriction induced by sphingosylphosphorylcholine (SPC) which has a pivotal role in vasospasm. The vasodilatory effect was induced by madagascine (0.3-100 μM) in isolated rat MRAs and the vasodilatory effect was blocked by NO synthase inhibitor L-NAME and AMPK inhibitor compound C. Madagascine (10 μM) also significantly relaxed the abnormal constriction in porcine VSM induced by SPC and the effect was abolished by compound C. Madagascine significantly increased the phosphorylation of endothelial nitric oxide synthase (eNOS) in endothelial cells while decreasing the phosphorylation of myosin phosphatase target subunit 1 (MYPT1) in VSM cells. Madagascine-induced vasodilatation was abrogated using small interfering RNA knockdown of AMPK. In summary, madagascine exerted vasodilatation through activating AMPK, leading to the activation of eNOS in endothelium and inhibition of ROCK/MYPT1 in VSM. This study suggests the potential value of madagascine in amelioration of vasospasm related cardiovascular diseases.
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Affiliation(s)
| | - Bochao Lv
- Yamaguchi University School of Medicine, Yamaguchi Japan
| | - Sei Kobayashi
- Yamaguchi University School of Medicine, Yamaguchi Japan
| | - Yongjian Xiong
- Central Laboratory, the First Affiliated Hospital, Dalian Medical University Dalian, China
| | | | - Yuan Lin
- Dalian Medical University, Dalian China
| | - Salvatore Genovese
- Dipartimento di Farmacia, Università degli Studi "G. D'Annunzio" Chieti-Pescara, Chieti Italy
| | - Francesco Epifano
- Dipartimento di Farmacia, Università degli Studi "G. D'Annunzio" Chieti-Pescara, Chieti Italy
| | | | | | - Yunyan Ji
- Dalian Medical University, Dalian China
| | - Dandan Yu
- Dalian Medical University, Dalian China
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7
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Trempe JF, Šašková KG, Sivá M, Ratcliffe CDH, Veverka V, Hoegl A, Ménade M, Feng X, Shenker S, Svoboda M, Kožíšek M, Konvalinka J, Gehring K. Structural studies of the yeast DNA damage-inducible protein Ddi1 reveal domain architecture of this eukaryotic protein family. Sci Rep 2016; 6:33671. [PMID: 27646017 PMCID: PMC5028754 DOI: 10.1038/srep33671] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 09/01/2016] [Indexed: 12/16/2022] Open
Abstract
The eukaryotic Ddi1 family is defined by a conserved retroviral aspartyl protease-like (RVP) domain found in association with a ubiquitin-like (UBL) domain. Ddi1 from Saccharomyces cerevisiae additionally contains a ubiquitin-associated (UBA) domain. The substrate specificity and role of the protease domain in the biological functions of the Ddi family remain unclear. Yeast Ddi1 has been implicated in the regulation of cell cycle progression, DNA-damage repair, and exocytosis. Here, we investigated the multi-domain structure of yeast Ddi1 using X-ray crystallography, nuclear magnetic resonance, and small-angle X-ray scattering. The crystal structure of the RVP domain sheds light on a putative substrate recognition site involving a conserved loop. Isothermal titration calorimetry confirms that both UBL and UBA domains bind ubiquitin, and that Ddi1 binds K48-linked diubiquitin with enhanced affinity. The solution NMR structure of a helical domain that precedes the protease displays tertiary structure similarity to DNA-binding domains from transcription regulators. Our structural studies suggest that the helical domain could serve as a landing platform for substrates in conjunction with attached ubiquitin chains binding to the UBL and UBA domains.
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Affiliation(s)
- Jean-François Trempe
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Klára Grantz Šašková
- Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 10 Prague 6, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, 120 00 Prague 2, Czech Republic
| | - Monika Sivá
- Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 10 Prague 6, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, 120 00 Prague 2, Czech Republic.,First Faculty of Medicine, Charles University in Prague, Katerinska 32, 121 08, Prague 2, Czech Republic
| | - Colin D H Ratcliffe
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Václav Veverka
- Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 10 Prague 6, Czech Republic
| | - Annabelle Hoegl
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Marie Ménade
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Xin Feng
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Solomon Shenker
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
| | - Michal Svoboda
- Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 10 Prague 6, Czech Republic.,Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, 120 00 Prague 2, Czech Republic
| | - Milan Kožíšek
- Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 10 Prague 6, Czech Republic
| | - Jan Konvalinka
- Gilead Sciences and IOCB Research Center, Institute of Organic Chemistry and Biochemistry of the Academy of Sciences of the Czech Republic, Flemingovo n. 2, 166 10 Prague 6, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Hlavova 8, 120 00 Prague 2, Czech Republic
| | - Kalle Gehring
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Montreal, QC, H3G 0B1, Canada
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8
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Abstract
The budding yeast Saccharomyces cerevisiae has two alternative mating types designated MATa and MATα. These are distinguished by about 700 bp of unique sequences, Ya or Yα, including divergent promoter sequences and part of the open reading frames of genes that regulate mating phenotype. Homothallic budding yeast, carrying an active HO endonuclease gene, HO, can switch mating type through a recombination process known as gene conversion, in which a site-specific double-strand break (DSB) created immediately adjacent to the Y region results in replacement of the Y sequences with a copy of the opposite mating type information, which is harbored in one of two heterochromatic donor loci, HMLα or HMRa. HO gene expression is tightly regulated to ensure that only half of the cells in a lineage switch to the opposite MAT allele, thus promoting conjugation and diploid formation. Study of the silencing of these loci has provided a great deal of information about the role of the Sir2 histone deacetylase and its associated Sir3 and Sir4 proteins in creating heterochromatic regions. MAT switching has been examined in great detail to learn about the steps in homologous recombination. MAT switching is remarkably directional, with MATa recombining preferentially with HMLα and MATα using HMRa. Donor preference is controlled by a cis-acting recombination enhancer located near HML. RE is turned off in MATα cells but in MATa binds multiple copies of the Fkh1 transcription factor whose forkhead-associated phosphothreonine binding domain localizes at the DSB, bringing HML into conjunction with MATa.
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9
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Nowicka U, Zhang D, Walker O, Krutauz D, Castañeda CA, Chaturvedi A, Chen TY, Reis N, Glickman MH, Fushman D. DNA-damage-inducible 1 protein (Ddi1) contains an uncharacteristic ubiquitin-like domain that binds ubiquitin. Structure 2015; 23:542-557. [PMID: 25703377 DOI: 10.1016/j.str.2015.01.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/19/2014] [Accepted: 01/12/2015] [Indexed: 11/28/2022]
Abstract
Ddi1 belongs to a family of shuttle proteins targeting polyubiquitinated substrates for proteasomal degradation. Unlike the other proteasomal shuttles, Rad23 and Dsk2, Ddi1 remains an enigma: its function is not fully understood and structural properties are poorly characterized. We determined the structure and binding properties of the ubiquitin-like (UBL) and ubiquitin-associated (UBA) domains of Ddi1 from Saccharomyces cerevisiae. We found that while Ddi1UBA forms a characteristic UBA:ubiquitin complex, Ddi1UBL has entirely uncharacteristic binding preferences. Despite having a ubiquitin-like fold, Ddi1UBL does not interact with typical UBL receptors but unexpectedly binds ubiquitin, forming a unique interface mediated by hydrophobic contacts and by salt bridges between oppositely charged residues of Ddi1UBL and ubiquitin. In stark contrast to ubiquitin and other UBLs, the β-sheet surface of Ddi1UBL is negatively charged and therefore is recognized in a completely different way. The dual functionality of Ddi1UBL, capable of binding both ubiquitin and proteasome, suggests an intriguing mechanism for Ddi1 as a proteasomal shuttle.
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Affiliation(s)
- Urszula Nowicka
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Daoning Zhang
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Olivier Walker
- Institut des Sciences Analytiques, UMR5280-Université de Lyon, 69100 Villeurbanne, France
| | - Daria Krutauz
- Department of Biology, Technion - Israel Institute of Technology, 32000 Haifa, Israel
| | - Carlos A Castañeda
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Apurva Chaturvedi
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Tony Y Chen
- Department of Chemistry and Biochemistry, Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - Noa Reis
- Department of Biology, Technion - Israel Institute of Technology, 32000 Haifa, Israel
| | - Michael H Glickman
- Department of Biology, Technion - Israel Institute of Technology, 32000 Haifa, Israel
| | - 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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10
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Swaney DL, Beltrao P, Starita L, Guo A, Rush J, Fields S, Krogan NJ, Villén J. Global analysis of phosphorylation and ubiquitylation cross-talk in protein degradation. Nat Methods 2013; 10:676-82. [PMID: 23749301 DOI: 10.1038/nmeth.2519] [Citation(s) in RCA: 459] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 05/02/2013] [Indexed: 12/17/2022]
Abstract
Cross-talk between different types of post-translational modifications on the same protein molecule adds specificity and combinatorial logic to signal processing, but it has not been characterized on a large-scale basis. We developed two methods to identify protein isoforms that are both phosphorylated and ubiquitylated in the yeast Saccharomyces cerevisiae, identifying 466 proteins with 2,100 phosphorylation sites co-occurring with 2,189 ubiquitylation sites. We applied these methods quantitatively to identify phosphorylation sites that regulate protein degradation via the ubiquitin-proteasome system. Our results demonstrate that distinct phosphorylation sites are often used in conjunction with ubiquitylation and that these sites are more highly conserved than the entire set of phosphorylation sites. Finally, we investigated how the phosphorylation machinery can be regulated by ubiquitylation. We found evidence for novel regulatory mechanisms of kinases and 14-3-3 scaffold proteins via proteasome-independent ubiquitylation.
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Affiliation(s)
- Danielle L Swaney
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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11
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Eremenko E, Ben-Zvi A, Morozova-Roche LA, Raveh D. Aggregation of human S100A8 and S100A9 amyloidogenic proteins perturbs proteostasis in a yeast model. PLoS One 2013; 8:e58218. [PMID: 23483999 PMCID: PMC3590125 DOI: 10.1371/journal.pone.0058218] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 02/01/2013] [Indexed: 12/31/2022] Open
Abstract
Amyloid aggregates of the calcium-binding EF-hand proteins, S100A8 and S100A9, have been found in the corpora amylacea of patients with prostate cancer and may play a role in carcinogenesis. Here we present a novel model system using the yeast Saccharomyces cerevisiae to study human S100A8 and S100A9 aggregation and toxicity. We found that S100A8, S100A9 and S100A8/9 cotransfomants form SDS-resistant non-toxic aggregates in yeast cells. Using fluorescently tagged proteins, we showed that S100A8 and S100A9 accumulate in foci. After prolonged induction, S100A8 foci localized to the cell vacuole, whereas the S100A9 foci remained in the cytoplasm when present alone, but entered the vacuole in cotransformants. Biochemical analysis of the proteins indicated that S100A8 and S100A9 alone or coexpressed together form amyloid-like aggregates in yeast. Expression of S100A8 and S100A9 in wild type yeast did not affect cell viability, but these proteins were toxic when expressed on a background of unrelated metastable temperature-sensitive mutant proteins, Cdc53-1p, Cdc34-2p, Srp1-31p and Sec27-1p. This finding suggests that the expression and aggregation of S100A8 and S100A9 may limit the capacity of the cellular proteostasis machinery. To test this hypothesis, we screened a set of chaperone deletion mutants and found that reducing the levels of the heat-shock proteins Hsp104p and Hsp70p was sufficient to induce S100A8 and S100A9 toxicity. This result indicates that the chaperone activity of the Hsp104/Hsp70 bi-chaperone system in wild type cells is sufficient to reduce S100A8 and S100A9 amyloid toxicity and preserve cellular proteostasis. Expression of human S100A8 and S100A9 in yeast thus provides a novel model system for the study of the interaction of amyloid deposits with the proteostasis machinery.
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Affiliation(s)
- Ekaterina Eremenko
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Anat Ben-Zvi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail: (AB); (DR)
| | | | - Dina Raveh
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail: (AB); (DR)
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12
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Abstract
Mating type in Saccharomyces cerevisiae is determined by two nonhomologous alleles, MATa and MATα. These sequences encode regulators of the two different haploid mating types and of the diploids formed by their conjugation. Analysis of the MATa1, MATα1, and MATα2 alleles provided one of the earliest models of cell-type specification by transcriptional activators and repressors. Remarkably, homothallic yeast cells can switch their mating type as often as every generation by a highly choreographed, site-specific homologous recombination event that replaces one MAT allele with different DNA sequences encoding the opposite MAT allele. This replacement process involves the participation of two intact but unexpressed copies of mating-type information at the heterochromatic loci, HMLα and HMRa, which are located at opposite ends of the same chromosome-encoding MAT. The study of MAT switching has yielded important insights into the control of cell lineage, the silencing of gene expression, the formation of heterochromatin, and the regulation of accessibility of the donor sequences. Real-time analysis of MAT switching has provided the most detailed description of the molecular events that occur during the homologous recombinational repair of a programmed double-strand chromosome break.
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13
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Transfer of Ho endonuclease and Ufo1 to the proteasome by the UbL-UbA shuttle protein, Ddi1, analysed by complex formation in vitro. PLoS One 2012; 7:e39210. [PMID: 22815701 PMCID: PMC3398040 DOI: 10.1371/journal.pone.0039210] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 05/21/2012] [Indexed: 01/20/2023] Open
Abstract
The F-box protein, Ufo1, recruits Ho endonuclease to the SCFUfo1 complex for ubiquitylation. Both ubiquitylated Ho and Ufo1 are transferred by the UbL-UbA protein, Ddi1, to the 19S Regulatory Particle (RP) of the proteasome for degradation. The Ddi1-UbL domain binds Rpn1 of the 19S RP, the Ddi1-UbA domain binds ubiquitin chains on the degradation substrate. Here we used complex reconstitution in vitro to identify stages in the transfer of Ho and Ufo1 from the SCFUfo1 complex to the proteasome. We report SCFUfo1 complex at the proteasome formed in the presence of Ho. Subsequently Ddi1 is recruited to this complex by interaction between the Ddi1-UbL domain and Ufo1. The core of Ddi1 binds both Ufo1 and Rpn1; this interaction confers specificity of SCFUfo1 for Ddi1. The substrate-shield model predicts that Ho would protect Ufo1 from degradation and we find that Ddi1 binds Ho, Ufo1, and Rpn1 simultaneously forming a complex for transfer of Ho to the 19S RP. In contrast, in the absence of Ho, Rpn1 displaces Ufo1 from Ddi1 indicating a higher affinity of the Ddi1-UbL for the 19S RP. However, at high Rpn1 levels there is synergistic binding of Ufo1 to Ddi1 that is dependent on the Ddi1-UbA domain. Our interpretation is that in the absence of substrate, the Ddi1-UbL binds Rpn1 while the Ddi1-UbA binds ubiquitin chains on Ufo1. This would promote degradation of Ufo1 and disassembly of SCFUfo1 complexes.
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14
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Lavut A, Raveh D. Sequestration of highly expressed mRNAs in cytoplasmic granules, P-bodies, and stress granules enhances cell viability. PLoS Genet 2012; 8:e1002527. [PMID: 22383896 PMCID: PMC3285586 DOI: 10.1371/journal.pgen.1002527] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 12/21/2011] [Indexed: 02/07/2023] Open
Abstract
Transcriptome analyses indicate that a core 10%–15% of the yeast genome is modulated by a variety of different stresses. However, not all the induced genes undergo translation, and null mutants of many induced genes do not show elevated sensitivity to the particular stress. Elucidation of the RNA lifecycle reveals accumulation of non-translating mRNAs in cytoplasmic granules, P-bodies, and stress granules for future regulation. P-bodies contain enzymes for mRNA degradation; under stress conditions mRNAs may be transferred to stress granules for storage and return to translation. Protein degradation by the ubiquitin-proteasome system is elevated by stress; and here we analyzed the steady state levels, decay, and subcellular localization of the mRNA of the gene encoding the F-box protein, UFO1, that is induced by stress. Using the MS2L mRNA reporter system UFO1 mRNA was observed in granules that colocalized with P-bodies and stress granules. These P-bodies stored diverse mRNAs. Granules of two mRNAs transported prior to translation, ASH1-MS2L and OXA1-MS2L, docked with P-bodies. HSP12 mRNA that gave rise to highly elevated protein levels was not observed in granules under these stress conditions. ecd3, pat1 double mutants that are defective in P-body formation were sensitive to mRNAs expressed ectopically from strong promoters. These highly expressed mRNAs showed elevated translation compared with wild-type cells, and the viability of the mutants was strongly reduced. ecd3, pat1 mutants also exhibited increased sensitivity to different stresses. Our interpretation is that sequestration of highly expressed mRNAs in P-bodies is essential for viability. Storage of mRNAs for future regulation may contribute to the discrepancy between the steady state levels of many stress-induced mRNAs and their proteins. Sorting of mRNAs for future translation or decay by individual cells could generate potentially different phenotypes in a genetically identical population and enhance its ability to withstand stress. 10%–15% of the yeast genome is modulated by stress; however, there is a discrepancy between the genes that are upregulated and the sensitivity of the null mutants of those genes to the stress. The question is: what happens to these highly expressed mRNAs? mRNAs have a complex lifecycle and non-translating mRNAs can be stored in cytoplasmic granules, processing P-bodies, and stress granules for decay or future translation, respectively. UFO1 encodes a component of the regulated protein degradation system, and its transcription is elevated by stress; however, the deletion mutants do not show enhanced sensitivity. UFO1 mRNA is stored in P-bodies and stress granules. Storage of mRNAs may contribute to the discrepancy between the steady state levels of stress-induced mRNAs and their proteins. To test this hypothesis, we expressed high levels of mRNA in cells unable to form P-bodies. We found that translation of these mRNAs was 3–8 fold higher than in wild-type cells. Furthermore high level expression of mRNA affected the viability of the mutants. The ability to store mRNAs for future translation or decay would generate different phenotypes in a genetically identical population and enhance its ability to withstand stress.
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Affiliation(s)
- Anna Lavut
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheba, Israel
| | - Dina Raveh
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheba, Israel
- * E-mail:
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15
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Abstract
DNA double-strand breaks (DSBs) have proven to be very potent initiators of recombination in yeast and other organisms. A single, site-specific DSB initiates homologous DNA repair events such as gene conversion, break-induced replication, and single-strand annealing, as well as nonhomologous end joining, microhomology-mediated end joining, and new telomere addition. When repair is either delayed or prevented, a single DSB can trigger checkpoint-mediated cell cycle arrest. In budding yeast, expressing the HO endonuclease under the control of a galactose-inducible promoter has been instrumental in the study of these processes by providing us a way to synchronously induce a DSB at a unique site in vivo. We describe how the HO endonuclease has been used to study the recombination events in mating-type (MAT) switching. Southern blots provide an overview of the process by allowing one to examine the formation of the DSB, DNA degradation at the break, and formation of the product. Denaturing gels and slot blots as well as PCR have provided important tools to follow the progression of resection in wild-type and mutant cells. PCR has also been important in allowing us to follow the kinetics of certain recombination intermediates such as the initiation of repair DNA synthesis or the removal of nonhomologous Y sequences during MAT switching. Finally chromatin immunoprecipitation has been used to follow the recruitment of key proteins to the DSB and in subsequent steps in DSB repair.
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Affiliation(s)
- Neal Sugawara
- Department of Biology, Brandeis University, Waltham, MA, USA
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16
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Bakhrat A, Eltzov E, Finkelstein Y, Marks RS, Raveh D. UV and arsenate toxicity: a specific and sensitive yeast bioluminescence assay. Cell Biol Toxicol 2011; 27:227-36. [DOI: 10.1007/s10565-011-9184-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 01/18/2011] [Indexed: 10/18/2022]
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17
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Voloshin O, Gocheva Y, Gutnick M, Movshovich N, Bakhrat A, Baranes-Bachar K, Bar-Zvi D, Parvari R, Gheber L, Raveh D. Tubulin chaperone E binds microtubules and proteasomes and protects against misfolded protein stress. Cell Mol Life Sci 2010; 67:2025-38. [PMID: 20204449 PMCID: PMC11115895 DOI: 10.1007/s00018-010-0308-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 01/10/2010] [Accepted: 02/09/2010] [Indexed: 11/29/2022]
Abstract
Mutation of tubulin chaperone E (TBCE) underlies hypoparathyroidism, retardation, and dysmorphism (HRD) syndrome with defective microtubule (MT) cytoskeleton. TBCE/yeast Pac2 comprises CAP-Gly, LRR (leucine-rich region), and UbL (ubiquitin-like) domains. TBCE folds alpha-tubulin and promotes alpha/beta dimerization. We show that Pac2 functions in MT dynamics: the CAP-Gly domain binds alpha-tubulin and MTs, and functions in suppression of benomyl sensitivity of pac2Delta mutants. Pac2 binds proteasomes: the LRR binds Rpn1, and the UbL binds Rpn10; the latter interaction mediates Pac2 turnover. The UbL also binds the Skp1-Cdc53-F-box (SCF) ubiquitin ligase complex; these competing interactions for the UbL may impact on MT dynamics. pac2Delta mutants are sensitive to misfolded protein stress. This is suppressed by ectopic PAC2 with both the CAP-Gly and UbL domains being essential. We propose a novel role for Pac2 in the misfolded protein stress response based on its ability to interact with both the MT cytoskeleton and the proteasomes.
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Affiliation(s)
- Olga Voloshin
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Yana Gocheva
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Marina Gutnick
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Natalia Movshovich
- Department of Clinical Biochemistry, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Anya Bakhrat
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Keren Baranes-Bachar
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Dudy Bar-Zvi
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Ruti Parvari
- National Institute of Biotechnology Negev and Department of Virology and Developmental Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Larisa Gheber
- Department of Clinical Biochemistry, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Dina Raveh
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
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18
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Baranes-Bachar K, Baranes-Bacher K, Khalaila I, Ivantsiv Y, Lavut A, Voloshin O, Raveh D. New interacting partners of the F-box protein Ufo1 of yeast. Yeast 2008; 25:733-43. [PMID: 18949821 DOI: 10.1002/yea.1615] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The yeast F-box protein Ufo1 recruits proteins for ubiquitylation by the SCF ubiquitin ligase complex preparing them for proteasomal degradation. Ufo1 has a role in maintenance of genome stability; its substrates include Ho endonuclease and Rad30 polymerase of error-prone DNA repair. Ufo1 is an unusual F-box protein, as it has three ubiquitin interacting motifs (UIMs). Deletion of the genomic UIMs is lethal; ectopic expression of UFO1 Delta UIMs extends protein half-life and arrests the cell cycle. A whole-genome study employing a TAP tag fused to the C-terminal UIMs did not identify Ufo1-interacting proteins. Here we therefore used stabilized N-terminally tagged Ufo1 Delta UIM as a strategy to identify Ufo1-interacting proteins by mass spectroscopy. We identified proteins that function in transcription, and an indirect interaction with Hsp70 molecular chaperones via the Skp1 adaptor; we also show that Ufo1 interacts with the 19S regulatory particle of the proteasome. Thus, our data augment the current network of known Ufo1 interacting proteins. We show directly that the UIMs are crucial for Ufo1 ubiquitylation in vivo, indicating that they facilitate turnover of SCF Ufo1 complexes. This allows recycling of the core subunits of the SCF complex and cell cycle progression.
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Affiliation(s)
- Keren Baranes-Bachar
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheba, Israel
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19
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Nuclear export of Ho endonuclease of yeast via Msn5. Curr Genet 2008; 54:271-81. [PMID: 18807043 DOI: 10.1007/s00294-008-0216-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/04/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
Abstract
Exportin-5, an evolutionarily conserved nuclear export factor of the beta-karyopherin family, exports phosphorylated proteins and small noncoding RNAs. Msn5, the yeast ortholog, exports primarily phosphorylated cargoes including Ho endonuclease and a number of transcription factors and regulatory proteins. The Msn5-mediated nuclear export of Ho is dependent on phosphorylation of Thr225 by kinases of the DNA damage response pathway. Although Msn5 has been the object of many studies, no NES sequence capable of binding the exportin and/or of leading to Msn5-dependent export of a heterologous protein has been identified. Here we report identification of a 13-residue Ho sequence that interacts with Msn5 in vitro and directs Msn5-dependent nuclear export of GFP in vivo. A single point mutation in this 13-mer Ho NES abrogates both interaction with Msn5 and nuclear export of Ho and of GFP. However, this mutation, or of T225A, both of which abrogate nuclear export of Ho, does not interfere with its interaction with Msn5 implying that the exportin makes multiple contacts with its cargo. This can explain the lack of a conserved NES in Msn5 cargoes. Our results identify essential criteria for Msn5-mediated nuclear export of Ho: phosphorylation on HoT225, and interaction with the 13-mer Ho NES sequence.
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20
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Towpik J, Graczyk D, Gajda A, Lefebvre O, Boguta M. Derepression of RNA polymerase III transcription by phosphorylation and nuclear export of its negative regulator, Maf1. J Biol Chem 2008; 283:17168-74. [PMID: 18445601 DOI: 10.1074/jbc.m709157200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Maf1 is the global repressor of RNA polymerase III (Pol III) in yeast Saccharomyces cerevisiae. Transcription regulation by Maf1 is important under stress conditions and during the switch between fermentation and respiration. Under repressive conditions on nonfermentable carbon sources, Maf1 is dephosphorylated and located predominantly in the nucleus. When cells were shifted to glucose medium, Maf1 became phosphorylated and concomitantly relocated to the cytoplasm. This relocation was dependent on Msn5, a carrier responsible for export of several other phosphoproteins out of the nucleus. Using coimmunoprecipitation, Maf1 was found to interact with Msn5. When msn5-Delta cells were transferred to glucose, Maf1 remained in the nucleus. Remarkably, despite constitutive presence in the nucleus, Maf1 was dephosphorylated and phosphorylated normally in the msn5-Delta mutant, and Pol III was under proper regulation. That phosphorylation of Maf1 and Pol III derepression are tightly linked was shown by studying tRNA transcription in Maf1 mutants with an altered pattern of phosphorylation. In summary, we conclude that phosphorylation of Maf1 inside the nucleus acts both directly by decreasing of Maf1-mediated repression of Pol III and indirectly by stimulation of Msn5 binding and export of nuclear Maf1 to the cytoplasm.
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Affiliation(s)
- Joanna Towpik
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawiñskiego 5a, 02-106 Warsaw, Poland
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21
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Quan X, Tsoulos P, Kuritzky A, Zhang R, Stochaj U. The carrier Msn5p/Kap142p promotes nuclear export of the hsp70 Ssa4p and relocates in response to stress. Mol Microbiol 2006; 62:592-609. [PMID: 17020589 DOI: 10.1111/j.1365-2958.2006.05395.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytoplasmic hsp70s like yeast Ssa4p shuttle between nucleus and cytoplasm under normal growth conditions but accumulate in nuclei upon stress. This nuclear accumulation is only transient, and Ssa4p relocates to the cytoplasm when cells recover. We show here that Ssa4p nuclear export is independent of Xpol/Crm1 and identify the importin-beta family member Msn5p/Kap142p as the exporter for Ssa4p. In growing cells and in vitro, Msn5p and Ssa4p generate genuine export complexes that require Ran/Gsp1p-GTP. Furthermore, nucleoporin Nup82p, which plays a role in Msn5p-mediated transport, is necessary for efficient export of Ssa4p. In living cells, stress not only regulates Ssa4p localization, but also controls the distribution of Msn5p. Msn5p is concentrated in nuclei of unstressed cells, but appears in the cytoplasm upon exposure to ethanol, heat, starvation or severe oxidative stress. In addition, growth on non-fermentable carbon sources relocates a portion of Msn5p to the cytoplasm and leads to a partial nuclear accumulation of Ssa4p. Taken together, growth and stress conditions that localize the transporter Msn5p to the cytoplasm also induce the nuclear accumulation of its cargo Ssa4p.
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Affiliation(s)
- XinXin Quan
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
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22
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Ding B, Liu CJ, Huang Y, Yu J, Kong W, Lengyel P. p204 protein overcomes the inhibition of the differentiation of P19 murine embryonal carcinoma cells to beating cardiac myocytes by Id proteins. J Biol Chem 2006; 281:14893-906. [PMID: 16556596 DOI: 10.1074/jbc.m511748200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We reported in the accompanying article (Ding, B., Liu, C., Huang, Y., Hickey, R. P., Yu, J., Kong, W., and Lengyel, P. (2006) J. Biol. Chem. 281, 14882-14892) that (i) the p204 protein is required for the differentiation of murine P19 embryonal carcinoma stem cells to beating cardiac myocytes, and (ii) the expression of p204 in the differentiating P19 cells is synergistically transactivated by the cardiac transcription factors Gata4, Nkx2.5, and Tbx5. Here we report that endogenous or ectopic inhibitor of differentiation (Id) proteins inhibited the differentiation of P19 cells to myocytes. This was in consequence of the binding of Id1, Id2, or Id3 protein to the Gata4 and Nkx2.5 proteins and the resulting inhibitions (i) of the binding of these transcription factors to each other and to DNA and (ii) of their synergistic transactivation of the expression of various genes, including atrial natriuretic factor and Ifi204 (encoding p204). p204 overcame this inhibition by Id proteins in consequence of (i) binding and sequestering Id proteins, (ii) accelerating their ubiquitination and degradation by proteasomes, and (iii) decreasing the level of Id proteins in the nucleus by increasing their translocation from the nucleus to the cytoplasm. Points (ii) and (iii) depended on the presence of the nuclear export signal in p204. In the course of the differentiation, Gata4, Nkx2.5, and p204 were components of a positive feedback loop. This loop arose in consequence of it that p204 overcame the inhibition of the synergistic activity of Gata4 and Nkx2.5 by the Id proteins.
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Affiliation(s)
- Bo Ding
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar Street, New Haven, CT 06520-8024, USA
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23
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Ivantsiv Y, Kaplun L, Tzirkin-Goldin R, Shabek N, Raveh D. Unique role for the UbL-UbA protein Ddi1 in turnover of SCFUfo1 complexes. Mol Cell Biol 2006; 26:1579-88. [PMID: 16478980 PMCID: PMC1430233 DOI: 10.1128/mcb.26.5.1579-1588.2006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 07/10/2005] [Accepted: 11/18/2005] [Indexed: 01/21/2023] Open
Abstract
SCF complexes are E3 ubiquitin-protein ligases that mediate degradation of regulatory and signaling proteins and control G1/S cell cycle progression by degradation of G1 cyclins and the cyclin-dependent kinase inhibitor, Sic1. Interchangeable F-box proteins bind the core SCF components; each recruits a specific subset of substrates for ubiquitylation. The F-box proteins themselves are rapidly turned over by autoubiquitylation, allowing rapid recycling of SCF complexes. Here we report a role for the UbL-UbA protein Ddi1 in the turnover of the F-box protein, Ufo1. Ufo1 is unique among F-box proteins in having a domain comprising multiple ubiquitin-interacting motifs (UIMs) that mediate its turnover. Deleting the UIMs leads to stabilization of Ufo1 and to cell cycle arrest at G1/S of cells with long buds resembling skp1 mutants. Cells accumulate substrates of other F-box proteins, indicating that the SCF pathway of substrate ubiquitylation is inhibited. Ufo1 interacts with Ddi1 via its UIMs, and Deltaddi1 cells arrest when full-length UFO1 is overexpressed. These results imply a role for the UIMs in turnover of SCF(Ufo1) complexes that is dependent on Ddi1, a novel activity for an UbL-UbA protein.
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Affiliation(s)
- Yelena Ivantsiv
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheba 84105, Israel
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24
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Bakhrat A, Baranes K, Krichevsky O, Rom I, Schlenstedt G, Pietrokovski S, Raveh D. Nuclear import of ho endonuclease utilizes two nuclear localization signals and four importins of the ribosomal import system. J Biol Chem 2006; 281:12218-26. [PMID: 16507575 DOI: 10.1074/jbc.m600238200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activity of Ho, the yeast mating switch endonuclease, is restricted to a narrow time window of the cell cycle. Ho is unstable and despite being a nuclear protein is exported to the cytoplasm for proteasomal degradation. We report here the molecular basis for the highly efficient nuclear import of Ho and the relation between its short half-life and passage through the nucleus. The Ho nuclear import machinery is functionally redundant, being based on two bipartite nuclear localization signals, recognized by four importins of the ribosomal import system. Ho degradation is regulated by the DNA damage response and Ho retained in the cytoplasm is stabilized, implying that Ho acquires its crucial degradation signals in the nucleus. Ho arose by domestication of a fungal VMA1 intein. A comparison of the primary sequences of Ho and fungal VMA1 inteins shows that the Ho nuclear localization signals are highly conserved in all Ho proteins, but are absent from VMA1 inteins. Thus adoption of a highly efficient import strategy occurred very early in the evolution of Ho. This may have been a crucial factor in establishment of homothallism in yeast, and a key event in the rise of the Saccharomyces sensu stricto.
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Affiliation(s)
- Anya Bakhrat
- Department of Life Sciences, Ben Gurion University of the Negev, P. O. Box 653, 84105 Beersheba, Israel
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25
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Abstract
The 26S proteasome is responsible for regulated proteolysis of most intracellular proteins yet the focus of intense regulatory action itself. Proteasome abundance is responsive to cell needs or stress conditions, and dynamically localized to concentrations of substrates. Proteasomes are continually assembled and disassembled, and their subunits subject to a variety of posttranslational modifications. Furthermore, as robust and multi-tasking as this complex is, it does not function alone. A spattering of closely associating proteins enhances complex stability, fine-tunes activity, assists in substrate-binding, recycling of ubiquitin, and more. HEAT repeat caps activate proteasomes, yet share remarkable features with nuclear importins. Fascinating cross talk even occurs with ribosomes through common maturation factors. The dynamics of proteasome configurations and how they relate to diverse activities is the topic of this review.
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Affiliation(s)
- Michael H Glickman
- Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel
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26
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Kaplun L, Tzirkin R, Bakhrat A, Shabek N, Ivantsiv Y, Raveh D. The DNA damage-inducible UbL-UbA protein Ddi1 participates in Mec1-mediated degradation of Ho endonuclease. Mol Cell Biol 2005; 25:5355-62. [PMID: 15964793 PMCID: PMC1156969 DOI: 10.1128/mcb.25.13.5355-5362.2005] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2005] [Revised: 02/10/2005] [Accepted: 03/23/2005] [Indexed: 11/20/2022] Open
Abstract
Ho endonuclease initiates a mating type switch by making a double-strand break at the mating type locus, MAT. Ho is marked by phosphorylation for rapid destruction by functions of the DNA damage response, MEC1, RAD9, and CHK1. Phosphorylated Ho is recruited for ubiquitylation via the SCF ubiquitin ligase complex by the F-box protein, Ufo1. Here we identify a further DNA damage-inducible protein, the UbL-UbA protein Ddi1, specifically required for Ho degradation. Ho interacts only with Ddi1; it does not interact with the other UbL-UbA proteins, Rad23 or Dsk2. Ho must be ubiquitylated to interact with Ddi1, and there is no interaction when Ho is produced in mec1 or Deltaufo1 mutants that do not support its degradation. Ddi1 binds the proteasome via its N-terminal ubiquitin-like domain (UbL) and interacts with ubiquitylated Ho via its ubiquitin-associated domain (UbA); both domains of Ddi1 are required for association of ubiquitylated Ho with the proteasome. Despite being a nuclear protein, Ho is exported to the cytoplasm for degradation. In the absence of Ddi1, ubiquitylated Ho is stabilized and accumulates in the cytoplasm. These results establish a role for Ddi1 in the degradation of a natural ubiquitylated substrate. The specific interaction between Ho and Ddi1 identifies an additional function associated with DNA damage involved in its degradation.
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Affiliation(s)
- Ludmila Kaplun
- Department of Life Sciences, Ben Gurion University of Negev, P.O. Box 653, Beersheba 84105, Israel
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27
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Abstract
Cullin-RING complexes comprise the largest known class of ubiquitin ligases. Owing to the great diversity of their substrate-receptor subunits, it is possible that there are hundreds of distinct cullin-RING ubiquitin ligases in eukaryotic cells, which establishes these enzymes as key mediators of post-translational protein regulation. In this review, we focus on the composition, regulation and function of cullin-RING ligases, and describe how these enzymes can be characterized by a set of general principles.
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Affiliation(s)
- Matthew D Petroski
- Division of Biology and Howard Hughes Medical Institute, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
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28
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Willems AR, Schwab M, Tyers M. A hitchhiker's guide to the cullin ubiquitin ligases: SCF and its kin. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1695:133-70. [PMID: 15571813 DOI: 10.1016/j.bbamcr.2004.09.027] [Citation(s) in RCA: 371] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The SCF (Skp1-Cullin-F-box) E3 ubiquitin ligase family was discovered through genetic requirements for cell cycle progression in budding yeast. In these multisubunit enzymes, an invariant core complex, composed of the Skp1 linker protein, the Cdc53/Cul1 scaffold protein and the Rbx1/Roc1/Hrt1 RING domain protein, engages one of a suite of substrate adaptors called F-box proteins that in turn recruit substrates for ubiquitination by an associated E2 enzyme. The cullin-RING domain-adaptor architecture has diversified through evolution, such that in total many hundreds of distinct SCF and SCF-like complexes enable degradation of myriad substrates. Substrate recognition by adaptors often depends on posttranslational modification of the substrate, which thus places substrate stability under dynamic regulation by intracellular signaling events. SCF complexes control cell proliferation through degradation of critical regulators such as cyclins, CDK inhibitors and transcription factors. A plethora of other processes in development and disease are controlled by other SCF-like complexes, including those based on Cul2-SOCS-box adaptor protein and Cul3-BTB domain adaptor protein combinations. Recent structural insights into SCF-like complexes have begun to illuminate aspects of substrate recognition and catalytic reaction mechanisms.
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Affiliation(s)
- Andrew R Willems
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Canada, M5G 1X5
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Spielewoy N, Flick K, Kalashnikova TI, Walker JR, Wittenberg C. Regulation and recognition of SCFGrr1 targets in the glucose and amino acid signaling pathways. Mol Cell Biol 2004; 24:8994-9005. [PMID: 15456873 PMCID: PMC517892 DOI: 10.1128/mcb.24.20.8994-9005.2004] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SCFGrr1, one of several members of the SCF family of E3 ubiquitin ligases in budding Saccharomyces cerevisiae, is required for both regulation of the cell cycle and nutritionally controlled transcription. In addition to its role in degradation of Gic2 and the CDK targets Cln1 and Cln2, Grr1 is also required for induction of glucose- and amino acid-regulated genes. Induction of HXT genes by glucose requires the Grr1-dependent degradation of Mth1. We show that Mth1 is ubiquitinated in vivo and degraded via the proteasome. Furthermore, phosphorylated Mth1, targeted by the casein kinases Yck1/2, binds to Grr1. That binding depends upon the Grr1 leucine-rich repeat (LRR) domain but not upon the F-box or basic residues within the LRR that are required for recognition of Cln2 and Gic2. Those observations extend to a large number of Grr1-dependent genes, some targets of the amino acid-regulated SPS signaling system, which are properly regulated in the absence of those basic LRR residues. Finally, we show that regulation of the SPS targets requires the Yck1/2 casein kinases. We propose that casein kinase I plays a similar role in both nutritional signaling pathways by phosphorylating pathway components and targeting them for ubiquitination by SCFGrr1.
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Affiliation(s)
- Nathalie Spielewoy
- Department of Molecular Biology, MB-3, The Scripps Research Institute, 10550 North Torrey Pines Rd., La Jolla, CA 92037, USA
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Laney JD, Hochstrasser M. Ubiquitin-dependent control of development in Saccharomyces cerevisiae. Curr Opin Microbiol 2004; 7:647-54. [PMID: 15556038 DOI: 10.1016/j.mib.2004.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In response to external environmental stimuli and intrinsic developmental cues, yeast cells reset their gene expression programs and change phenotype. These switches in cellular state require the dismantling of an initial regulatory program, in addition to the induction of different sets of genes to specify the new cell phenotype. Recent experiments examining the role of protein degradation in these transitions have highlighted the importance of inactivating previously utilized regulators and have led to advances in our understanding of how cells change from one phenotypic state to another.
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Affiliation(s)
- Jeffrey D Laney
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Box G-J2, Providence, Rhode Island 02912, USA.
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Bose S, Dutko JA, Zitomer RS. Genetic factors that regulate the attenuation of the general stress response of yeast. Genetics 2004; 169:1215-26. [PMID: 15545648 PMCID: PMC1449543 DOI: 10.1534/genetics.104.034603] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The general stress response of yeast involves the induction of approximately 200 genes in response to any one of several stresses. These genes are activated by Msn2 and repressed by the Srb10 kinase, a member of the mediator complex. Normally, Msn2 is exported from the nucleus, and Srb10 represses STRE gene expression. Under stress, Msn2 relocalizes to the nucleus and, with the relief of Srb10 repression, activates transcription. The stress response is rapid, but quickly attenuated. We show here that this attenuation is due to a nuclear-dependent degradation of Msn2. Msn2 rapidly disappeared from cells after heat or osmotic shock. This disappearance was not due to a change in MSN2 RNA levels, which remain constant during stress. Pulse-chase experiments confirmed the stress-dependent Msn2 degradation. The levels of Msn2 were significantly reduced in msn5 deletion cells that have been shown to constitutively retain Msn2 in the nucleus. The degradation was Srb10-dependent; Msn2 was not degraded in an srb10 deletion mutant. An Msn2 internal deletion mutant was insensitive to Srb10 repression, but was degraded by the Srb10-dependent mechanism. Thus, this mutation uncoupled Srb10 repression from degradation.
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Affiliation(s)
- Sohini Bose
- Department of Biological Sciences, University at Albany/SUNY, New York 12222, USA
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Bakhrat A, Jurica MS, Stoddard BL, Raveh D. Homology modeling and mutational analysis of Ho endonuclease of yeast. Genetics 2004; 166:721-8. [PMID: 15020462 PMCID: PMC1470740 DOI: 10.1534/genetics.166.2.721] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ho endonuclease is a LAGLIDADG homing endonuclease that initiates mating-type interconversion in yeast. Ho is encoded by a free-standing gene but shows 50% primary sequence similarity to the intein (protein-intron encoded) PI-SceI. Ho is unique among LAGLIDADG endonucleases in having a 120-residue C-terminal putative zinc finger domain. The crystal structure of PI-SceI revealed a bipartite enzyme with a protein-splicing domain (Hint) and intervening endonuclease domain. We made a homology model for Ho on the basis of the PI-SceI structure and performed mutational analysis of putative critical residues, using a mating-type switch as a bioassay for activity and GFP-fusion proteins to detect nuclear localization. We found that residues of the N-terminal sequence of the Hint domain are important for Ho activity, in particular the DNA recognition region. C-terminal residues of the Hint domain are dispensable for Ho activity; however, the C-terminal putative zinc finger domain is essential. Mutational analysis indicated that residues in Ho that are conserved relative to catalytic, active-site residues in PI-SceI and other related homing endonucleases are essential for Ho activity. Our results indicate that in addition to the conserved catalytic residues, Hint domain residues and the zinc finger domain have evolved a critical role in Ho activity.
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Affiliation(s)
- Anya Bakhrat
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, 84105 Israel
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Mosammaparast N, Pemberton LF. Karyopherins: from nuclear-transport mediators to nuclear-function regulators. Trends Cell Biol 2004; 14:547-56. [PMID: 15450977 DOI: 10.1016/j.tcb.2004.09.004] [Citation(s) in RCA: 258] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The karyopherin beta (or importin beta) family comprises soluble transport factors that mediate the movement of proteins and RNAs between the nucleus and cytoplasm. Recent studies have extended the role of karyopherins to regulating assembly of the nuclear pore complex (NPC), assembly of the nuclear envelope, mitosis and replication. New data also address how karyopherins specifically recognize and transport many distinct cargoes and traverse the NPC. These data raise the possibility that, although there might be a universal mechanism for nuclear transport, specific interactions between karyopherins and components of the NPC might function to regulate differentially the ability of the different karyopherins to cross the NPC.
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Affiliation(s)
- Nima Mosammaparast
- Center for Cell Signaling and Department of Microbiology, University of Virginia, Charlottesville, VA 22908, USA
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Smith S, Hwang JY, Banerjee S, Majeed A, Gupta A, Myung K. Mutator genes for suppression of gross chromosomal rearrangements identified by a genome-wide screening in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2004; 101:9039-44. [PMID: 15184655 PMCID: PMC428469 DOI: 10.1073/pnas.0403093101] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Different types of gross chromosomal rearrangements (GCRs), including translocations, interstitial deletions, terminal deletions with de novo telomere additions, and chromosome fusions, are observed in many cancers. Multiple pathways, such as S-phase checkpoints, DNA replication, recombination, chromatin remodeling, and telomere maintenance that suppress GCRs have been identified. To experimentally expand our knowledge of other pathway(s) that suppress GCRs, we developed a generally applicable genome-wide screening method. In this screen, we identified 10 genes (ALO1, CDC50, CSM2, ELG1, ESC1, MMS4, RAD5, RAD18, TSA1, and UFO1) that encode proteins functioning in the suppression of GCRs. Moreover, the breakpoint junctions of GCRs from these GCR mutator mutants were determined with modified breakpoint-mapping methods. We also identified nine genes (AKR1, BFR1, HTZ1, IES6, NPL6, RPL13B, RPL27A, RPL35A, and SHU2) whose mutations generated growth defects with the pif1Delta mutation. In addition, we found that some of these mutations changed the telomere size.
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Affiliation(s)
- Stephanie Smith
- Genome Instability Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, 49 Convent Drive, Bethesda, MD 20892, USA
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Bakhrat A, Jurica MS, Stoddard BL, Raveh D. Homology Modeling and Mutational Analysis of Ho Endonuclease of Yeast. Genetics 2004. [DOI: 10.1093/genetics/166.2.721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Ho endonuclease is a LAGLIDADG homing endonuclease that initiates mating-type interconversion in yeast. Ho is encoded by a free-standing gene but shows 50% primary sequence similarity to the intein (protein-intron encoded) PI-SceI. Ho is unique among LAGLIDADG endonucleases in having a 120-residue C-terminal putative zinc finger domain. The crystal structure of PI-SceI revealed a bipartite enzyme with a protein-splicing domain (Hint) and intervening endonuclease domain. We made a homology model for Ho on the basis of the PI-SceI structure and performed mutational analysis of putative critical residues, using a mating-type switch as a bioassay for activity and GFP-fusion proteins to detect nuclear localization. We found that residues of the N-terminal sequence of the Hint domain are important for Ho activity, in particular the DNA recognition region. C-terminal residues of the Hint domain are dispensable for Ho activity; however, the C-terminal putative zinc finger domain is essential. Mutational analysis indicated that residues in Ho that are conserved relative to catalytic, active-site residues in PI-SceI and other related homing endonucleases are essential for Ho activity. Our results indicate that in addition to the conserved catalytic residues, Hint domain residues and the zinc finger domain have evolved a critical role in Ho activity.
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Affiliation(s)
- Anya Bakhrat
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, 84105 Israel
| | - Melissa S Jurica
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Dina Raveh
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, 84105 Israel
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