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Common Functions of Disordered Proteins across Evolutionary Distant Organisms. Int J Mol Sci 2020; 21:ijms21062105. [PMID: 32204351 PMCID: PMC7139818 DOI: 10.3390/ijms21062105] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/14/2022] Open
Abstract
Intrinsically disordered proteins and regions typically lack a well-defined structure and thus fall outside the scope of the classic sequence–structure–function relationship. Hence, classic sequence- or structure-based bioinformatic approaches are often not well suited to identify homology or predict the function of unknown intrinsically disordered proteins. Here, we give selected examples of intrinsic disorder in plant proteins and present how protein function is shared, altered or distinct in evolutionary distant organisms. Furthermore, we explore how examining the specific role of disorder across different phyla can provide a better understanding of the common features that protein disorder contributes to the respective biological mechanism.
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Shekhar-Guturja T, Gunaherath GMKB, Wijeratne EMK, Lambert JP, Averette AF, Lee SC, Kim T, Bahn YS, Tripodi F, Ammar R, Döhl K, Niewola-Staszkowska K, Schmitt L, Loewith RJ, Roth FP, Sanglard D, Andes D, Nislow C, Coccetti P, Gingras AC, Heitman J, Gunatilaka AAL, Cowen LE. Dual action antifungal small molecule modulates multidrug efflux and TOR signaling. Nat Chem Biol 2016; 12:867-75. [PMID: 27571477 PMCID: PMC5030160 DOI: 10.1038/nchembio.2165] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 06/03/2016] [Indexed: 12/26/2022]
Abstract
There is an urgent need for new strategies to treat invasive fungal infections, which are a leading cause of human mortality. Here, we establish two activities of the natural product beauvericin, which potentiates the activity of the most widely deployed class of antifungal against the leading human fungal pathogens, blocks the emergence of drug resistance, and renders antifungal-resistant pathogens responsive to treatment in mammalian infection models. Harnessing genome sequencing of beauvericin-resistant mutants, affinity purification of a biotinylated beauvericin analog, and biochemical and genetic assays reveals that beauvericin blocks multidrug efflux and inhibits the global regulator TORC1 kinase, thereby activating the protein kinase CK2 and inhibiting the molecular chaperone Hsp90. Substitutions in the multidrug transporter Pdr5 that enable beauvericin efflux impair antifungal efflux, thereby impeding resistance to the drug combination. Thus, dual targeting of multidrug efflux and TOR signaling provides a powerful, broadly effective therapeutic strategy for treating fungal infectious disease that evades resistance.
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Affiliation(s)
| | - G M Kamal B Gunaherath
- Natural Products Center, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona, USA
| | - E M Kithsiri Wijeratne
- Natural Products Center, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona, USA
| | - Jean-Philippe Lambert
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Anna F Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Soo Chan Lee
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Taeyup Kim
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Farida Tripodi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca and SYSBIO, Centre of Systems Biology, Milan, Italy
| | - Ron Ammar
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Katja Döhl
- Institute of Biochemistry, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | | | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Robbie J Loewith
- Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Frederick P Roth
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Dominique Sanglard
- Institute of Microbiology, University Hospital Lausanne and University Hospital Center, Lausanne, Switzerland
| | - David Andes
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA.,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Corey Nislow
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Paola Coccetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca and SYSBIO, Centre of Systems Biology, Milan, Italy
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - A A Leslie Gunatilaka
- Natural Products Center, School of Natural Resources and the Environment, College of Agriculture and Life Sciences, University of Arizona, Tucson, Arizona, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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3
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Li Z, Hao Y, Wang L, Xiang H, Zhou Z. Genome-wide identification and comprehensive analyses of the kinomes in four pathogenic microsporidia species. PLoS One 2014; 9:e115890. [PMID: 25549259 PMCID: PMC4280135 DOI: 10.1371/journal.pone.0115890] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/02/2014] [Indexed: 11/18/2022] Open
Abstract
Microsporidia have attracted considerable attention because they infect a wide range of hosts, from invertebrates to vertebrates, and cause serious human diseases and major economic losses in the livestock industry. There are no prospective drugs to counteract this pathogen. Eukaryotic protein kinases (ePKs) play a central role in regulating many essential cellular processes and are therefore potential drug targets. In this study, a comprehensive summary and comparative analysis of the protein kinases in four microsporidia–Enterocytozoon bieneusi, Encephalitozoon cuniculi, Nosema bombycis and Nosema ceranae–was performed. The results show that there are 34 ePKs and 4 atypical protein kinases (aPKs) in E. bieneusi, 29 ePKs and 6 aPKs in E. cuniculi, 41 ePKs and 5 aPKs in N. bombycis, and 27 ePKs and 4 aPKs in N. ceranae. These data support the previous conclusion that the microsporidian kinome is the smallest eukaryotic kinome. Microsporidian kinomes contain only serine-threonine kinases and do not contain receptor-like and tyrosine kinases. Many of the kinases related to nutrient and energy signaling and the stress response have been lost in microsporidian kinomes. However, cell cycle-, development- and growth-related kinases, which are important to parasites, are well conserved. This reduction of the microsporidian kinome is in good agreement with genome compaction, but kinome density is negatively correlated with proteome size. Furthermore, the protein kinases in each microsporidian genome are under strong purifying selection pressure. No remarkable differences in kinase family classification, domain features, gain and/or loss, and selective pressure were observed in these four species. Although microsporidia adapt to different host types, the coevolution of microsporidia and their hosts was not clearly reflected in the protein kinases. Overall, this study enriches and updates the microsporidian protein kinase database and may provide valuable information and candidate targets for the design of treatments for pathogenic diseases.
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Affiliation(s)
- Zhi Li
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Youjin Hao
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Linling Wang
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Heng Xiang
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Zeyang Zhou
- College of Life Sciences, Chongqing Normal University, Chongqing, China
- The State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- * E-mail:
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Snf1/AMPK promotes SBF and MBF-dependent transcription in budding yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:3254-3264. [DOI: 10.1016/j.bbamcr.2013.09.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 09/20/2013] [Accepted: 09/23/2013] [Indexed: 01/11/2023]
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Protein kinase CK2 holoenzyme promotes start-specific transcription in Saccharomyces cerevisiae. EUKARYOTIC CELL 2013; 12:1271-80. [PMID: 23873864 DOI: 10.1128/ec.00117-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Saccharomyces cerevisiae, the entrance into S phase requires the activation of a specific burst of transcription, which depends on SBF (SCB binding factor, Swi4/Swi6) and MBF (MCB binding factor, Mbp1/Swi6) complexes. CK2 is a pleiotropic kinase involved in several cellular processes, including the regulation of the cell cycle. CK2 is composed of two catalytic subunits (α and α') and two regulatory subunits (β and β'), both of which are required to form the active holoenzyme. Here we investigate the function of the CK2 holoenzyme in Start-specific transcription. The ckb1Δ ckb2Δ mutant strain, bearing deletions of both genes encoding CK2 regulatory subunits, shows a delay of S-phase entrance due to a severe reduction of the expression of SBF- and MBF-dependent genes. This transcriptional defect is caused by an impaired recruitment of Swi6 and Swi4 to G1 gene promoters. Moreover, CK2 α and β' subunits interact with RNA polymerase II, whose binding to G1 promoters is positively regulated by the CK2 holoenzyme. Collectively, these findings suggest a novel role for the CK2 holoenzyme in the activation of G1 transcription.
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Cirulli C, Coccetti P, Alberghina L, Tripodi F. A surface-activated chemical ionization approach allows quantitative phosphorylation analysis of the cyclin-dependent kinase inhibitor Sic1 phosphorylated on Ser201. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:1527-1532. [PMID: 22638969 DOI: 10.1002/rcm.6251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RATIONALE Quantitative phosphoproteomics represents a front line for functional proteomics and hence for systems biology. Here we present a new application of the surface-activated chemical ionization (SACI) technology for quantitative phosphoproteomics analysis. The main advantages of SACI-MS technology are high sensitivity, quantitative accuracy and matrix effect reduction, which allow quantitative estimations. METHODS A SACI-MS approach was used to investigate the quantitative in vivo phosphorylation of the cyclin-dependent kinase inhibitor Sic1, a low-abundance protein of Saccharomyces cerevisiae, which is phosphorylated on Ser201 by casein kinase 2 (CK2) and compared its phosphorylation status in cells growing in two different carbon sources (glucose or ethanol). RESULTS Our relative quantification indicated that the Sic1-Ser201 phosphorylation level is about 2-fold higher in ethanol- than in glucose-growing cells, proportional to the Sic1 protein level. This finding is coherent with results of western blot analysis using anti-phospho-Ser201-specific antibody, validating the results obtained with this new SACI approach. CONCLUSIONS The findings presented in this paper indicate that the innovative LC/SACI-MS method, coupled with immunoprecipitation, is a powerful device to obtain quantitative information on the phosphorylation state of low abundance proteins.
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Affiliation(s)
- Claudia Cirulli
- Università degli Studi di Milano-Bicocca, Dipartimento di Biotecnologie e Bioscienze, Piazza della Scienza 2, 20126 Milano, Italy.
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Barberis M. Sic1 as a timer of Clb cyclin waves in the yeast cell cycle--design principle of not just an inhibitor. FEBS J 2012; 279:3386-410. [PMID: 22356687 DOI: 10.1111/j.1742-4658.2012.08542.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cellular systems biology aims to uncover design principles that describe the properties of biological networks through interaction of their components in space and time. The cell cycle is a complex system regulated by molecules that are integrated into functional modules to ensure genome integrity and faithful cell division. In budding yeast, cyclin-dependent kinases (Cdk1/Clb) drive cell cycle progression, being activated and inactivated in a precise temporal sequence. In this module, which we refer to as the 'Clb module', different Cdk1/Clb complexes are regulated to generate waves of Clb activity, a functional property of cell cycle control. The inhibitor Sic1 plays a critical role in the Clb module by binding to and blocking Cdk1/Clb activity, ultimately setting the timing of DNA replication and mitosis. Fifteen years of research subsequent to the identification of Sic1 have lead to the development of an integrative approach that addresses its role in regulating the Clb module. Sic1 is an intrinsically disordered protein and achieves its inhibitory function by cooperative binding, where different structural regions stretch on the Cdk1/Clb surface. Moreover, Sic1 promotes S phase entry, facilitating Cdk1/Clb5 nuclear transport, and therefore revealing a double function of inhibitor/activator that rationalizes a mechanism to prevent precocious DNA replication. Interestingly, the investigation of Clb temporal dynamics by mathematical modelling and experimental validation provides evidence that Sic1 acts as a timer to coordinate oscillations of Clb cyclin waves. Here we review these findings, focusing on the design principle underlying the Clb module, which highlights the role of Sic1 in regulating phase-specific Cdk1/Clb activities.
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Affiliation(s)
- Matteo Barberis
- Institute for Biology, Theoretical Biophysics, Humboldt University Berlin, Germany.
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Molecular systems biology of Sic1 in yeast cell cycle regulation through multiscale modeling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 736:135-67. [PMID: 22161326 DOI: 10.1007/978-1-4419-7210-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell cycle control is highly regulated to guarantee the precise timing of events essential for cell growth, i.e., DNA replication onset and cell division. Failure of this control plays a role in cancer and molecules called cyclin-dependent kinase (Cdk) inhibitors (Ckis) exploit a critical function in cell cycle timing. Here we present a multiscale modeling where experimental and computational studies have been employed to investigate structure, function and temporal dynamics of the Cki Sic1 that regulates cell cycle progression in Saccharomyces cerevisiae. Structural analyses reveal molecular details of the interaction between Sic1 and Cdk/cyclin complexes, and biochemical investigation reveals Sic1 function in analogy to its human counterpart p27(Kip1), whose deregulation leads to failure in timing of kinase activation and, therefore, to cancer. Following these findings, a bottom-up systems biology approach has been developed to characterize modular networks addressing Sic1 regulatory function. Through complementary experimentation and modeling, we suggest a mechanism that underlies Sic1 function in controlling temporal waves of cyclins to ensure correct timing of the phase-specific Cdk activities.
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9
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Sic1 plays a role in timing and oscillatory behaviour of B-type cyclins. Biotechnol Adv 2012; 30:108-30. [DOI: 10.1016/j.biotechadv.2011.09.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 08/18/2011] [Accepted: 09/12/2011] [Indexed: 12/23/2022]
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10
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Kõivomägi M, Valk E, Venta R, Iofik A, Lepiku M, Morgan DO, Loog M. Dynamics of Cdk1 substrate specificity during the cell cycle. Mol Cell 2011; 42:610-23. [PMID: 21658602 PMCID: PMC3115021 DOI: 10.1016/j.molcel.2011.05.016] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 01/25/2011] [Accepted: 05/23/2011] [Indexed: 11/30/2022]
Abstract
Cdk specificity is determined by the intrinsic selectivity of the active site and by substrate docking sites on the cyclin subunit. There is a long-standing debate about the relative importance of these factors in the timing of Cdk1 substrate phosphorylation. We analyzed major budding yeast cyclins (the G1/S-cyclin Cln2, S-cyclin Clb5, G2/M-cyclin Clb3, and M-cyclin Clb2) and found that the activity of Cdk1 toward the consensus motif increased gradually in the sequence Cln2-Clb5-Clb3-Clb2, in parallel with cell cycle progression. Further, we identified a docking element that compensates for the weak intrinsic specificity of Cln2 toward G1-specific targets. In addition, Cln2-Cdk1 showed distinct consensus site specificity, suggesting that cyclins do not merely activate Cdk1 but also modulate its active-site specificity. Finally, we identified several Cln2-, Clb3-, and Clb2-specific Cdk1 targets. We propose that robust timing and ordering of cell cycle events depend on gradual changes in the substrate specificity of Cdk1.
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Affiliation(s)
- Mardo Kõivomägi
- Institute of Technology, University of Tartu, Tartu 50411, Estonia.
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11
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Tripodi F, Cirulli C, Reghellin V, Brambilla L, Marin O, Coccetti P. Nutritional modulation of CK2 in Saccharomyces cerevisiae: regulating the activity of a constitutive enzyme. Mol Cell Biochem 2011; 356:269-75. [PMID: 21750980 DOI: 10.1007/s11010-011-0958-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 06/24/2011] [Indexed: 02/02/2023]
Abstract
CK2 is a highly conserved protein kinase involved in different cellular processes, which shows a higher activity in actively proliferating mammalian cells and in various types of cancer and cancer cell lines. We recently demonstrated that CK2 activity is strongly influenced by growth rate in yeast cells as well. Here, we extend our previous findings and show that, in cells grown in either glucose or ethanol-supplemented media, CK2 presents no alteration in K(m) for both the ATP and the peptide substrate RRRADDSDDDDD, while a significant increase in V (max) is observed. In chemostat-grown cells, no difference of CK2 activity was observed in cells grown at the same dilution rate in media supplemented with either ethanol or glucose, excluding the contribution of carbon metabolism on CK2 activity. By using the eIF2β-derived peptide, which can be phosphorylated by the holoenzyme but not by the free catalytic subunits, we show that the holoenzyme activity requires the concurrent presence of both β and β' encoding genes. Finally, conditions of nitrogen deprivation leading to a G0-like arrest result in a decrease of total CK2 activity, but have no effect on the activity of the holoenzyme. These findings newly indicate a regulatory role of β and β' subunits of CK2 in the nutrient response.
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Affiliation(s)
- Farida Tripodi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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New insight into the role of the Cdc34 ubiquitin-conjugating enzyme in cell cycle regulation via Ace2 and Sic1. Genetics 2010; 187:701-15. [PMID: 21196523 DOI: 10.1534/genetics.110.125302] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Cdc34 ubiquitin-conjugating enzyme plays a central role in progression of the cell cycle. Through analysis of the phenotype of a mutant missing a highly conserved sequence motif within the catalytic domain of Cdc34, we discovered previously unrecognized levels of regulation of the Ace2 transcription factor and the cyclin-dependent protein kinase inhibitor Sic1. In cells carrying the Cdc34(tm) mutation, which alters the conserved sequence, the cyclin-dependent protein kinase inhibitor Sic1, an SCF(Cdc4) substrate, has a shorter half-life, while the cyclin Cln1, an SCF(Grr1) substrate, has a longer half-life than in wild-type cells. Expression of the SIC1 gene cluster, which is regulated by Swi5 and Ace2 transcription factors, is induced in CDC34(tm) cells. Levels of Swi5, Ace2, and the SCF(Grr1) targets Cln1 and Cln2 are elevated in Cdc34(tm) cells, and loss of Grr1 causes an increase in Ace2 levels. Sic1 levels are similar in CDC34(tm) ace2Δ and wild-type cells, explaining a paradoxical increase in the steady-state level of Sic1 protein despite its reduced half-life. A screen for mutations that interact with CDC34(tm) uncovered novel regulators of Sic1, including genes encoding the polyubiquitin chain receptors Rad23 and Rpn10.
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Varedi K. SM, Ventura AC, Merajver SD, Lin XN. Multisite phosphorylation provides an effective and flexible mechanism for switch-like protein degradation. PLoS One 2010; 5:e14029. [PMID: 21179196 PMCID: PMC3001445 DOI: 10.1371/journal.pone.0014029] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 10/20/2010] [Indexed: 12/12/2022] Open
Abstract
Phosphorylation-triggered degradation is a common strategy for elimination of regulatory proteins in many important cell signaling processes. Interesting examples include cyclin-dependent kinase inhibitors such as p27 in human and Sic1 in yeast, which play crucial roles during the G1/S transition in the cell cycle. In this work, we have modeled and analyzed the dynamics of multisite-phosphorylation-triggered protein degradation systematically. Inspired by experimental observations on the Sic1 protein and a previous intriguing theoretical conjecture, we develop a model to examine in detail the degradation dynamics of a protein featuring multiple phosphorylation sites and a threshold site number for elimination in response to a kinase signal. Our model explains the role of multiple phosphorylation sites, compared to a single site, in the regulation of protein degradation. A single-site protein cannot convert a graded input of kinase increase to much sharper output, whereas multisite phosphorylation is capable of generating a highly switch-like temporal profile of the substrate protein with two characteristics: a temporal threshold and rapid decrease beyond the threshold. We introduce a measure termed temporal response coefficient to quantify the extent to which a response in the time domain is switch-like and further investigate how this property is determined by various factors including the kinase input, the total number of sites, the threshold site number for elimination, the order of phosphorylation, the kinetic parameters, and site preference. Some interesting and experimentally verifiable predictions include that the non-degradable fraction of the substrate protein exhibits a more switch-like temporal profile; a sequential system is more switch-like, while a random system has the advantage of increased robustness; all the parameters, including the total number of sites, the threshold site number for elimination and the kinetic parameters synergistically determine the exact extent to which the degradation profile is switch-like. Our results suggest design principles for protein degradation switches which might be a widespread mechanism for precise regulation of cellular processes such as cell cycle progression.
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Affiliation(s)
- S. Marjan Varedi K.
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Alejandra C. Ventura
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sofia D. Merajver
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan, United States of America
- Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Xiaoxia Nina Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
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14
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CK2 activity is modulated by growth rate in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2010; 398:44-50. [DOI: 10.1016/j.bbrc.2010.06.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 06/05/2010] [Indexed: 02/02/2023]
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15
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Ruzzene M, Di Maira G, Tosoni K, Pinna LA. Assessment of CK2 constitutive activity in cancer cells. Methods Enzymol 2010; 484:495-514. [PMID: 21036247 DOI: 10.1016/b978-0-12-381298-8.00024-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
At variance with the great majority of protein kinases that become active only in response to specific stimuli and whose implication in tumors is caused by genetic alterations conferring to them unscheduled activity, the highly pleiotropic Ser/Thr-specific protein kinase CK2 is constitutively active even under normal conditions and no gain-of-function CK2 mutants are known. Nevertheless, CK2 level is abnormally high in cancer cells where it is believed to generate an environment favorable to the development of malignancy, through a mechanism denoted as "non-oncogene addiction." This makes CK2 not only an appealing target to counteract different kinds of tumors but also a valuable marker of cells predisposed to undergo neoplastic transformation owing to the presence in them of CK2 level exceeding a critical threshold. Such a prognostic exploitation of CK2 would imply the availability of methods suitable for the reliable, sensitive, and specific quantification of its activity in biological samples and in living cells. The aim of this chapter is to describe a number of procedures applicable to the quantitative determination of CK2 activity and to provide experimental details designed for rendering these assays as sensitive and selective as possible even in the presence of many other protein kinases. The procedures described roughly fall in three categories: (i) in vitro quantification of CK2 activity in crude biological samples and cell lysates; (ii) in-cell assay of endogenous CK2 activity based on the phosphorylation of reporter substrates; (iii) identification of CK2 targets in malignant and normal cells.
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Affiliation(s)
- Maria Ruzzene
- Department of Biological Chemistry, and VIMM (Venetian Institute of Molecular Medicine), University ofPadova, Padova, Italy
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16
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Brocca S, Samalíková M, Uversky VN, Lotti M, Vanoni M, Alberghina L, Grandori R. Order propensity of an intrinsically disordered protein, the cyclin-dependent-kinase inhibitor Sic1. Proteins 2009; 76:731-46. [PMID: 19280601 DOI: 10.1002/prot.22385] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Intrinsically disordered proteins (IDPs) carry out important biological functions and offer an instructive model system for folding and binding studies. However, their structural characterization in the absence of interactors is hindered by their highly dynamic conformation. The cyclin-dependent-kinase inhibitor (Cki) Sic1 from Saccharomyces cerevisiae is a key regulator of the yeast cell cycle, which controls entrance into S phase and coordination between cell growth and proliferation. Its last 70 out of 284 residues display functional and structural homology to the inhibitory domain of mammalian p21 and p27. Sic1 has escaped systematic structural characterization until now. Here, complementary biophysical methods are applied to the study of conformational properties of pure Sic1 in solution. Based on sequence analysis, gel filtration, circular dichroism (CD), electrospray-ionization mass spectrometry (ESI-MS), and limited proteolysis, it can be concluded that the whole molecule exists in a highly disordered state and can, therefore, be classified as an IDP. However, the results of these experiments indicate, at the same time, that the protein displays some content in secondary and tertiary structure, having properties similar to those of molten globules or premolten globules. Proteolysis-hypersensitive sites cluster at the N-terminus and in the middle of the molecule, whereas the most structured region resides at the C-terminus, including part of the inhibitory domain and the casein-kinase-2 (CK2) phosphorylation target S201. The mutations S201A and S201E, which are known to affect Sic1 function, do not have significant effects on the conformational properties of the pure protein.
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Affiliation(s)
- Stefania Brocca
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
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17
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Alberghina L, Coccetti P, Orlandi I. Systems biology of the cell cycle of Saccharomyces cerevisiae: From network mining to system-level properties. Biotechnol Adv 2009; 27:960-978. [PMID: 19465107 DOI: 10.1016/j.biotechadv.2009.05.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Following a brief description of the operational procedures of systems biology (SB), the cell cycle of budding yeast is discussed as a successful example of a top-down SB analysis. After the reconstruction of the steps that have led to the identification of a sizer plus timer network in the G1 to S transition, it is shown that basic functions of the cell cycle (the setting of the critical cell size and the accuracy of DNA replication) are system-level properties, detected only by integrating molecular analysis with modelling and simulation of their underlying networks. A detailed network structure of a second relevant regulatory step of the cell cycle, the exit from mitosis, derived from extensive data mining, is constructed and discussed. To reach a quantitative understanding of how nutrients control, through signalling, metabolism and transcription, cell growth and cycle is a very relevant aim of SB. Since we know that about 900 gene products are required for cell cycle execution and control in budding yeast, it is quite clear that a purely systematic approach would require too much time. Therefore lines for a modular SB approach, which prioritises molecular and computational investigations for faster cell cycle understanding, are proposed. The relevance of the insight coming from the cell cycle SB studies in developing a new framework for tackling very complex biological processes, such as cancer and aging, is discussed.
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Affiliation(s)
- Lilia Alberghina
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.zza della Scienza 2, 20126 Milano, Italy.
| | - Paola Coccetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.zza della Scienza 2, 20126 Milano, Italy
| | - Ivan Orlandi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, P.zza della Scienza 2, 20126 Milano, Italy
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Angermayr M, Hochleitner E, Lottspeich F, Bandlow W. Protein kinase CK2 activates the atypical Rio1p kinase and promotes its cell-cycle phase-dependent degradation in yeast. FEBS J 2007; 274:4654-67. [PMID: 17725716 DOI: 10.1111/j.1742-4658.2007.05993.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Using co-immunoprecipitation combined with MS analysis, we identified the alpha' subunit of casein kinase 2 (CK2) as an interaction partner of the atypical Rio1 protein kinase in yeast. Co-purification of Rio1p with CK2 from Deltacka1 or Deltacka2 mutant extracts shows that Rio1p preferentially interacts with Cka2p in vitro. The C-terminal domain of Rio1p is essential and sufficient for this interaction. Six C-terminally located clustered serines were identified as the only CK2 sites present in Rio1p. Replacement of all six serine residues by aspartate, mimicking constitutive phosphorylation, stimulates Rio1p kinase activity about twofold in vitro compared with wild-type or the corresponding (S > A)(6) mutant proteins. Both mutant alleles (S > A)(6) or (S > D)(6) complement in vivo, however, growth of the RIO1 (S > A)(6) mutant is greatly retarded and shows a cell-cycle phenotype, whereas the behaviour of the RIO1 (S > D)(6) mutant is indistinguishable from wild-type. This suggests that phosphorylation by protein kinase CK2 leads to moderate activation of Rio1p in vivo and promotes cell proliferation. Physiological studies indicate that phosphorylation by CK2 renders the Rio1 protein kinase susceptible to proteolytic degradation at the G(1)/S transition in the cell-division cycle, whereas the non-phosphorylated version is resistant.
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Affiliation(s)
- Michaela Angermayr
- Department Biologie I, Bereich Genetik, Ludwig-Maximilians-Universität München, Germany.
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19
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Tripodi F, Zinzalla V, Vanoni M, Alberghina L, Coccetti P. In CK2 inactivated cells the cyclin dependent kinase inhibitor Sic1 is involved in cell-cycle arrest before the onset of S phase. Biochem Biophys Res Commun 2007; 359:921-7. [PMID: 17574209 DOI: 10.1016/j.bbrc.2007.05.195] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 05/29/2007] [Indexed: 11/28/2022]
Abstract
Protein kinase CK2 is a heterotetramer composed of two catalytic and two regulatory subunits. In Saccharomyces cerevisiae the catalytic subunits (alpha and alpha') are encoded by the CKA1, CKA2 genes. cka1Deltacka2(ts) mutants arrest cell cycle in both G1 and G2/M at 37 degrees C. Hence, it has been proposed that CK2 plays an important role in cell-cycle progression and several cell-cycle proteins have been reported to be CK2 substrates. We have previously shown that Sic1, the inhibitor of Clb5-Cdc28 complexes required for the G1/S transition, is a physiologically relevant CK2 substrate. Here we show that CK2 inactivation up-regulates Sic1 level resulting in severe down-regulation of Clb5-Cdc28 kinase activity. Concurrent inactivation of Sic1 and CK2 leads to accumulation of cells with a post-synthetic DNA content and short/elongated spindles, typical of cells arrested in mitosis. These findings indicate that Sic1 plays a major role during G1 arrest of CK2-inactivated cells.
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Affiliation(s)
- Farida Tripodi
- Dipartimento di Biotecnologie e Bioscienze, Università Milano-Bicocca, P.zza della Scienza 2, 20126 Milano, Italy
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Pathak R, Blank HM, Guo J, Ellis S, Polymenis M. The Dcr2p phosphatase destabilizes Sic1p in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2007; 361:700-4. [PMID: 17673172 PMCID: PMC2031908 DOI: 10.1016/j.bbrc.2007.07.092] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Accepted: 07/19/2007] [Indexed: 01/20/2023]
Abstract
Initiation of cell division is controlled by an irreversible switch. In Saccharomyces cerevisiae degradation of the Sic1p protein, an inhibitor of mitotic cyclin/cyclin-dependent kinase complexes, takes place before initiation of DNA replication, at a point called START. Sic1p is phosphorylated by multiple kinases, which can differentially affect the stability of Sic1p. How phosphorylations that stabilize Sic1p are reversed is unknown. Here we show that the Dcr2p phosphatase functionally and physically interacts with Sic1p. Over-expression of Dcr2p destabilizes Sic1p and leads to phenotypes associated with destabilized Sic1p, such as genome instability. Our results identify a novel factor that affects the stability of Sic1p, possibly contributing to mechanisms that trigger initiation of cell division.
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Affiliation(s)
| | | | | | | | - Michael Polymenis
- *To whom correspondence should be addressed. Tel: 1-979-458-3259; FAX: 1-979-845-4946, e-mail:
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21
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Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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