301
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Li N, Fassl A, Chick J, Inuzuka H, Li X, Mansour MR, Liu L, Wang H, King B, Shaik S, Gutierrez A, Ordureau A, Otto T, Kreslavsky T, Baitsch L, Bury L, Meyer CA, Ke N, Mulry KA, Kluk MJ, Roy M, Kim S, Zhang X, Geng Y, Zagozdzon A, Jenkinson S, Gale RE, Linch DC, Zhao JJ, Mullighan CG, Harper JW, Aster JC, Aifantis I, von Boehmer H, Gygi SP, Wei W, Look AT, Sicinski P. Cyclin C is a haploinsufficient tumour suppressor. Nat Cell Biol 2014; 16:1080-91. [PMID: 25344755 PMCID: PMC4235773 DOI: 10.1038/ncb3046] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 08/29/2014] [Indexed: 12/12/2022]
Abstract
Cyclin C was cloned as a growth-promoting G1 cyclin, and was also shown to regulate gene transcription. Here we report that in vivo cyclin C acts as a haploinsufficient tumour suppressor, by controlling Notch1 oncogene levels. Cyclin C activates an 'orphan' CDK19 kinase, as well as CDK8 and CDK3. These cyclin-C-CDK complexes phosphorylate the Notch1 intracellular domain (ICN1) and promote ICN1 degradation. Genetic ablation of cyclin C blocks ICN1 phosphorylation in vivo, thereby elevating ICN1 levels in cyclin-C-knockout mice. Cyclin C ablation or heterozygosity collaborates with other oncogenic lesions and accelerates development of T-cell acute lymphoblastic leukaemia (T-ALL). Furthermore, the cyclin C encoding gene CCNC is heterozygously deleted in a significant fraction of human T-ALLs, and these tumours express reduced cyclin C levels. We also describe point mutations in human T-ALL that render cyclin-C-CDK unable to phosphorylate ICN1. Hence, tumour cells may develop different strategies to evade inhibition by cyclin C.
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302
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Liew GM, Ye F, Nager AR, Murphy JP, Lee JS, Aguiar M, Breslow DK, Gygi SP, Nachury MV. The intraflagellar transport protein IFT27 promotes BBSome exit from cilia through the GTPase ARL6/BBS3. Dev Cell 2014; 31:265-278. [PMID: 25443296 DOI: 10.1016/j.devcel.2014.09.004] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/26/2014] [Accepted: 09/11/2014] [Indexed: 01/02/2023]
Abstract
The sorting of signaling receptors into and out of cilia relies on the BBSome, a complex of Bardet-Biedl syndrome (BBS) proteins, and on the intraflagellar transport (IFT) machinery. GTP loading onto the Arf-like GTPase ARL6/BBS3 drives assembly of a membrane-apposed BBSome coat that promotes cargo entry into cilia, yet how and where ARL6 is activated remains elusive. Here, we show that the Rab-like GTPase IFT27/RABL4, a known component of IFT complex B, promotes the exit of BBSome and associated cargoes from cilia. Unbiased proteomics and biochemical reconstitution assays show that, upon disengagement from the rest of IFT-B, IFT27 directly interacts with the nucleotide-free form of ARL6. Furthermore, IFT27 prevents aggregation of nucleotide-free ARL6 in solution. Thus, we propose that IFT27 separates from IFT-B inside cilia to promote ARL6 activation, BBSome coat assembly, and subsequent ciliary exit, mirroring the process by which BBSome mediates cargo entry into cilia.
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303
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Paulo JA, McAllister FE, Everley RA, Beausoleil SA, Banks AS, Gygi SP. Effects of MEK inhibitors GSK1120212 and PD0325901 in vivo using 10-plex quantitative proteomics and phosphoproteomics. Proteomics 2014; 15:462-73. [PMID: 25195567 DOI: 10.1002/pmic.201400154] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/05/2014] [Accepted: 09/01/2014] [Indexed: 12/11/2022]
Abstract
Multiplexed isobaric tag based quantitative proteomics and phosphoproteomics strategies can comprehensively analyze drug treatments effects on biological systems. Given the role of mitogen-activated protein/extracellular signal-regulated kinase (MEK) signaling in cancer and mitogen-activated protein kinase (MAPK)-dependent diseases, we sought to determine if this pathway could be inhibited safely by examining the downstream molecular consequences. We used a series of tandem mass tag 10-plex experiments to analyze the effect of two MEK inhibitors (GSK1120212 and PD0325901) on three tissues (kidney, liver, and pancreas) from nine mice. We quantified ∼ 6000 proteins in each tissue, but significant protein-level alterations were minimal with inhibitor treatment. Of particular interest was kidney tissue, as edema is an adverse effect of these inhibitors. From kidney tissue, we enriched phosphopeptides using titanium dioxide (TiO2 ) and quantified 10 562 phosphorylation events. Further analysis by phosphotyrosine peptide immunoprecipitation quantified an additional 592 phosphorylation events. Phosphorylation motif analysis revealed that the inhibitors decreased phosphorylation levels of proline-x-serine-proline (PxSP) and serine-proline (SP) sites, consistent with extracellular-signal-regulated kinase (ERK) inhibition. The MEK inhibitors had the greatest decrease on the phosphorylation of two proteins, Barttin and Slc12a3, which have roles in ion transport and fluid balance. Further studies will provide insight into the effect of these MEK inhibitors with respect to edema and other adverse events in mouse models and human patients.
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304
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Choi JH, Choi SS, Kim ES, Jedrychowski MP, Yang YR, Jang HJ, Suh PG, Banks AS, Gygi SP, Spiegelman BM. Thrap3 docks on phosphoserine 273 of PPARγ and controls diabetic gene programming. Genes Dev 2014; 28:2361-9. [PMID: 25316675 PMCID: PMC4215181 DOI: 10.1101/gad.249367.114] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphorylation of peroxisome proliferator-activated receptor γ (PPARγ) at Ser273 by cyclin-dependent kinase 5 (CDK5) in adipose tissue stimulates insulin resistance, but the underlying molecular mechanisms are unclear. We show here that Thrap3 (thyroid hormone receptor-associated protein 3) can directly interact with PPARγ when it is phosphorylated at Ser273, and this interaction controls the diabetic gene programming mediated by the phosphorylation of PPARγ. Knockdown of Thrap3 restores most of the genes dysregulated by CDK5 action on PPARγ in cultured adipocytes. Importantly, reduced expression of Thrap3 in fat tissue by antisense oligonucleotides (ASOs) regulates a specific set of genes, including the key adipokines adiponectin and adipsin, and effectively improves hyperglycemia and insulin resistance in high-fat-fed mice without affecting body weight. These data indicate that Thrap3 plays a crucial role in controlling diabetic gene programming and may provide opportunities for the development of new therapeutics for obesity and type 2 diabetes.
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305
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Sopko R, Foos M, Vinayagam A, Zhai B, Binari R, Hu Y, Randklev S, Perkins LA, Gygi SP, Perrimon N. Combining genetic perturbations and proteomics to examine kinase-phosphatase networks in Drosophila embryos. Dev Cell 2014; 31:114-27. [PMID: 25284370 DOI: 10.1016/j.devcel.2014.07.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/24/2014] [Accepted: 07/28/2014] [Indexed: 02/07/2023]
Abstract
Connecting phosphorylation events to kinases and phosphatases is key to understanding the molecular organization and signaling dynamics of networks. We have generated a validated set of transgenic RNA-interference reagents for knockdown and characterization of all protein kinases and phosphatases present during early Drosophila melanogaster development. These genetic tools enable collection of sufficient quantities of embryos depleted of single gene products for proteomics. As a demonstration of an application of the collection, we have used multiplexed isobaric labeling for quantitative proteomics to derive global phosphorylation signatures associated with kinase-depleted embryos to systematically link phosphosites with relevant kinases. We demonstrate how this strategy uncovers kinase consensus motifs and prioritizes phosphoproteins for kinase target validation. We validate this approach by providing auxiliary evidence for Wee kinase-directed regulation of the chromatin regulator Stonewall. Further, we show how correlative phosphorylation at the site level can indicate function, as exemplified by Sterile20-like kinase-dependent regulation of Stat92E.
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306
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Chantranupong L, Wolfson RL, Orozco JM, Saxton RA, Scaria SM, Bar-Peled L, Spooner E, Isasa M, Gygi SP, Sabatini DM. The Sestrins interact with GATOR2 to negatively regulate the amino-acid-sensing pathway upstream of mTORC1. Cell Rep 2014; 9:1-8. [PMID: 25263562 DOI: 10.1016/j.celrep.2014.09.014] [Citation(s) in RCA: 309] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/03/2014] [Accepted: 09/12/2014] [Indexed: 12/21/2022] Open
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) kinase is a major regulator of cell growth that responds to numerous environmental cues. A key input is amino acids, which act through the heterodimeric Rag GTPases (RagA or RagB bound to RagC or RagD) in order to promote the translocation of mTORC1 to the lysosomal surface, its site of activation. GATOR2 is a complex of unknown function that positively regulates mTORC1 signaling by acting upstream of or in parallel to GATOR1, which is a GTPase-activating protein (GAP) for RagA or RagB and an inhibitor of the amino-acid-sensing pathway. Here, we find that the Sestrins, a family of poorly understood growth regulators (Sestrin1-Sestrin3), interact with GATOR2 in an amino-acid-sensitive fashion. Sestrin2-mediated inhibition of mTORC1 signaling requires GATOR1 and the Rag GTPases, and the Sestrins regulate the localization of mTORC1 in response to amino acids. Thus, we identify the Sestrins as GATOR2-interacting proteins that regulate the amino-acid-sensing branch of the mTORC1 pathway.
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307
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Rhee DY, Cho DY, Zhai B, Slattery M, Ma L, Mintseris J, Wong CY, White KP, Celniker SE, Przytycka TM, Gygi SP, Obar RA, Artavanis-Tsakonas S. Transcription factor networks in Drosophila melanogaster. Cell Rep 2014; 8:2031-2043. [PMID: 25242320 DOI: 10.1016/j.celrep.2014.08.038] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/09/2014] [Accepted: 08/16/2014] [Indexed: 11/15/2022] Open
Abstract
Specific cellular fates and functions depend on differential gene expression, which occurs primarily at the transcriptional level and is controlled by complex regulatory networks of transcription factors (TFs). TFs act through combinatorial interactions with other TFs, cofactors, and chromatin-remodeling proteins. Here, we define protein-protein interactions using a coaffinity purification/mass spectrometry method and study 459 Drosophila melanogaster transcription-related factors, representing approximately half of the established catalog of TFs. We probe this network in vivo, demonstrating functional interactions for many interacting proteins, and test the predictive value of our data set. Building on these analyses, we combine regulatory network inference models with physical interactions to define an integrated network that connects combinatorial TF protein interactions to the transcriptional regulatory network of the cell. We use this integrated network as a tool to connect the functional network of genetic modifiers related to mastermind, a transcriptional cofactor of the Notch pathway.
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308
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Yamada T, Yang Y, Hemberg M, Yoshida T, Cho HY, Murphy JP, Fioravante D, Regehr WG, Gygi SP, Georgopoulos K, Bonni A. Promoter decommissioning by the NuRD chromatin remodeling complex triggers synaptic connectivity in the mammalian brain. Neuron 2014; 83:122-34. [PMID: 24991957 DOI: 10.1016/j.neuron.2014.05.039] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2014] [Indexed: 01/08/2023]
Abstract
Precise control of gene expression plays fundamental roles in brain development, but the roles of chromatin regulators in neuronal connectivity have remained poorly understood. We report that depletion of the NuRD complex by in vivo RNAi and conditional knockout of the core NuRD subunit Chd4 profoundly impairs the establishment of granule neuron parallel fiber/Purkinje cell synapses in the rodent cerebellar cortex in vivo. By interfacing genome-wide sequencing of transcripts and ChIP-seq analyses, we uncover a network of repressed genes and distinct histone modifications at target gene promoters that are developmentally regulated by the NuRD complex in the cerebellum in vivo. Finally, in a targeted in vivo RNAi screen of NuRD target genes, we identify a program of NuRD-repressed genes that operate as critical regulators of presynaptic differentiation in the cerebellar cortex. Our findings define NuRD-dependent promoter decommissioning as a developmentally regulated programming mechanism that drives synaptic connectivity in the mammalian brain.
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309
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Zheng X, Zhai B, Koivunen P, Shin SJ, Lu G, Liu J, Geisen C, Chakraborty AA, Moslehi JJ, Smalley DM, Wei X, Chen X, Chen Z, Beres JM, Zhang J, Tsao JL, Brenner MC, Zhang Y, Fan C, DePinho RA, Paik J, Gygi SP, Kaelin WG, Zhang Q. Prolyl hydroxylation by EglN2 destabilizes FOXO3a by blocking its interaction with the USP9x deubiquitinase. Genes Dev 2014; 28:1429-44. [PMID: 24990963 PMCID: PMC4083087 DOI: 10.1101/gad.242131.114] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The three EglN prolyl hydroxylases (EglN1, EglN2, and EglN3) regulate the stability of the HIF transcription factor. We recently showed that loss of EglN2, however, also leads to down-regulation of Cyclin D1 and decreased cell proliferation in a HIF-independent manner. Here we report that EglN2 can hydroxylate FOXO3a on two specific prolyl residues in vitro and in vivo. Hydroxylation of these sites prevents the binding of USP9x deubiquitinase, thereby promoting the proteasomal degradation of FOXO3a. FOXO transcription factors can repress Cyclin D1 transcription. Failure to hydroxylate FOXO3a promotes its accumulation in cells, which in turn suppresses Cyclin D1 expression. These findings provide new insights into post-transcriptional control of FOXO3a and provide a new avenue for pharmacologically altering Cyclin D1 activity.
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310
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Butovsky O, Jedrychowski MP, Moore CS, Cialic R, Lanser AJ, Gabriely G, Koeglsperger T, Dake B, Wu PM, Doykan CE, Fanek Z, Liu L, Chen Z, Rothstein JD, Ransohoff RM, Gygi SP, Antel JP, Weiner HL. Erratum: Corrigendum: Identification of a unique TGF-β–dependent molecular and functional signature in microglia. Nat Neurosci 2014. [DOI: 10.1038/nn0914-1286d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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311
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Lu G, Zhang Q, Huang Y, Song J, Tomaino R, Ehrenberger T, Lim E, Liu W, Bronson RT, Bowden M, Brock J, Krop IE, Dillon DA, Gygi SP, Mills GB, Richardson AL, Signoretti S, Yaffe MB, Kaelin WG. Phosphorylation of ETS1 by Src family kinases prevents its recognition by the COP1 tumor suppressor. Cancer Cell 2014; 26:222-34. [PMID: 25117710 PMCID: PMC4169234 DOI: 10.1016/j.ccr.2014.06.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 05/09/2014] [Accepted: 06/27/2014] [Indexed: 12/12/2022]
Abstract
Oncoproteins and tumor suppressors antagonistically converge on critical nodes governing neoplastic growth, invasion, and metastasis. We discovered that phosphorylation of the ETS1 and ETS2 transcriptional oncoproteins at specific serine or threonine residues creates binding sites for the COP1 tumor suppressor protein, which is an ubiquitin ligase component, leading to their destruction. In the case of ETS1, however, phosphorylation of a neighboring tyrosine residue by Src family kinases disrupts COP1 binding, thereby stabilizing ETS1. Src-dependent accumulation of ETS1 in breast cancer cells promotes anchorage-independent growth in vitro and tumor growth in vivo. These findings expand the list of potential COP1 substrates to include proteins whose COP1-binding sites are subject to regulatory phosphorylation and provide insights into transformation by Src family kinases.
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312
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Weekes MP, Tomasec P, Huttlin EL, Fielding CA, Nusinow D, Stanton RJ, Wang ECY, Aicheler R, Murrell I, Wilkinson GWG, Lehner PJ, Gygi SP. Quantitative temporal viromics: an approach to investigate host-pathogen interaction. Cell 2014; 157:1460-1472. [PMID: 24906157 PMCID: PMC4048463 DOI: 10.1016/j.cell.2014.04.028] [Citation(s) in RCA: 316] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 02/18/2014] [Accepted: 04/03/2014] [Indexed: 12/11/2022]
Abstract
A systematic quantitative analysis of temporal changes in host and viral proteins throughout the course of a productive infection could provide dynamic insights into virus-host interaction. We developed a proteomic technique called “quantitative temporal viromics” (QTV), which employs multiplexed tandem-mass-tag-based mass spectrometry. Human cytomegalovirus (HCMV) is not only an important pathogen but a paradigm of viral immune evasion. QTV detailed how HCMV orchestrates the expression of >8,000 cellular proteins, including 1,200 cell-surface proteins to manipulate signaling pathways and counterintrinsic, innate, and adaptive immune defenses. QTV predicted natural killer and T cell ligands, as well as 29 viral proteins present at the cell surface, potential therapeutic targets. Temporal profiles of >80% of HCMV canonical genes and 14 noncanonical HCMV open reading frames were defined. QTV is a powerful method that can yield important insights into viral infection and is applicable to any virus with a robust in vitro model. PaperClip
>8,000 proteins quantified over eight time points, including 1,200 cell-surface proteins Temporal profiles of 139/171 canonical HCMV proteins and 14 noncanonical HCMV ORFs Multiple families of cell-surface receptors selectively modulated by HCMV Multiple signaling pathways modulated during HCMV infection
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313
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Van Vranken JG, Bricker DK, Dephoure N, Gygi SP, Cox JE, Thummel CS, Rutter J. SDHAF4 promotes mitochondrial succinate dehydrogenase activity and prevents neurodegeneration. Cell Metab 2014; 20:241-52. [PMID: 24954416 PMCID: PMC4126880 DOI: 10.1016/j.cmet.2014.05.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/28/2014] [Accepted: 04/28/2014] [Indexed: 02/05/2023]
Abstract
Succinate dehydrogenase (SDH) occupies a central place in cellular energy production, linking the tricarboxylic cycle with the electron transport chain. As a result, a subset of cancers and neuromuscular disorders result from mutations affecting any of the four SDH structural subunits or either of two known SDH assembly factors. Herein we characterize an evolutionarily conserved SDH assembly factor designated Sdh8/SDHAF4, using yeast, Drosophila, and mammalian cells. Sdh8 interacts specifically with the catalytic Sdh1 subunit in the mitochondrial matrix, facilitating its association with Sdh2 and the subsequent assembly of the SDH holocomplex. These roles for Sdh8 are critical for preventing motility defects and neurodegeneration in Drosophila as well as the excess ROS generated by free Sdh1. These studies provide insights into the mechanisms by which SDH is assembled and raise the possibility that some forms of neuromuscular disease may be associated with mutations that affect this SDH assembly factor.
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314
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Dephoure N, Hwang S, O'Sullivan C, Dodgson SE, Gygi SP, Amon A, Torres EM. Quantitative proteomic analysis reveals posttranslational responses to aneuploidy in yeast. eLife 2014; 3:e03023. [PMID: 25073701 PMCID: PMC4129440 DOI: 10.7554/elife.03023] [Citation(s) in RCA: 181] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Aneuploidy causes severe developmental defects and is a near universal feature of tumor cells. Despite its profound effects, the cellular processes affected by aneuploidy are not well characterized. Here, we examined the consequences of aneuploidy on the proteome of aneuploid budding yeast strains. We show that although protein levels largely scale with gene copy number, subunits of multi-protein complexes are notable exceptions. Posttranslational mechanisms attenuate their expression when their encoding genes are in excess. Our proteomic analyses further revealed a novel aneuploidy-associated protein expression signature characteristic of altered metabolism and redox homeostasis. Indeed aneuploid cells harbor increased levels of reactive oxygen species (ROS). Interestingly, increased protein turnover attenuates ROS levels and this novel aneuploidy-associated signature and improves the fitness of most aneuploid strains. Our results show that aneuploidy causes alterations in metabolism and redox homeostasis. Cells respond to these alterations through both transcriptional and posttranscriptional mechanisms. DOI:http://dx.doi.org/10.7554/eLife.03023.001 Nearly all tumor cells contain abnormal number of chromosomes. This state is called aneuploidy, and can also cause embryos to be miscarried, or to be born with severe developmental disorders. Proteins are produced from the genes contained within chromosomes, and so cells with too many chromosomes produce too many of some proteins. How do these cells cope with this excess? Previous work identified one strategy where a gene called UBP6 is mutated to prevent it from working correctly. The UBP6 gene normally encodes a protein that removes a small tag (called ubiquitin) from other proteins. This tag normally marks other proteins that should be degraded; thus, if UBP6 is not working, more proteins are broken down. Dephoure et al. investigated the effect of aneuploidy on the proteins produced by 12 different types of yeast cell, which each had an extra chromosome. In general, the amount of each protein produced by these yeast increased depending on the number of extra copies of the matching genes found on the extra chromosome. However, this was not the case for around 20% of the proteins, which were found in lower amounts than expected. Dephoure et al. revealed that this was not because fewer proteins were made, but because more were broken down. These proteins may be targeted for degradation because they are unstable, as many of these proteins need to bind to other proteins to keep them stable—but these stabilizing proteins are not also over-produced. Aneuploidy in cells also has other effects, including changing the cells' metabolism so that the cells grow more slowly and do not respond as well to stress. However, Dephoure et al. found that, as well as reducing the number of proteins produced, deleting the UBP6 gene also increased the fitness of the cells. Targeting the protein encoded by the UBP6 gene, or others that also stop proteins being broken down, could therefore help to reduce the negative effects of aneuploidy for a cell. Whether targeting these genes or proteins could also help to treat the diseases and disorders that result from aneuploidy, such as Alzheimer's and Huntington's disease, remains to be investigated. DOI:http://dx.doi.org/10.7554/eLife.03023.002
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315
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Krutauz D, Reis N, Nakasone MA, Siman P, Zhang D, Kirkpatrick DS, Gygi SP, Brik A, Fushman D, Glickman MH. Extended ubiquitin species are protein-based DUB inhibitors. Nat Chem Biol 2014; 10:664-70. [PMID: 24997605 PMCID: PMC4466224 DOI: 10.1038/nchembio.1574] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 05/27/2014] [Indexed: 01/16/2023]
Abstract
A frameshift mutation in the transcript of the ubiquitin-B gene leads to a C-terminally extended ubiquitin (Ub), UBB(+1). UBB(+1) has been considered to inhibit proteasomes and as such to be the underlying cause for toxic protein buildup correlated with certain neuropathological conditions. We demonstrate that expression of extended Ub variants leads to accumulation of heterogeneously linked polyubiquitin conjugates, indicating a pervasive effect on Ub-dependent turnover. 20S proteasomes selectively proteolyzed Ub extensions, yet no evidence for inhibition of 26S holoenzymes was found. However, among susceptible targets for inhibition was Ubp6, the primary enzyme responsible for disassembly of Lys48 linkages at 26S proteasomes. Processing of Lys48 and Lys63 linkages by other deubiquitinating enzymes (DUBs) was also inhibited. Disruption of Ub-dependent degradation by extended Ub variants may therefore be attributed to their inhibitory effect on select DUBs, thus shifting research efforts related to protein accumulation in neurodegenerative processes from proteasomes to DUBs.
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316
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McAlister GC, Nusinow DP, Jedrychowski MP, Wühr M, Huttlin EL, Erickson BK, Rad R, Haas W, Gygi SP. MultiNotch MS3 enables accurate, sensitive, and multiplexed detection of differential expression across cancer cell line proteomes. Anal Chem 2014; 86:7150-8. [PMID: 24927332 PMCID: PMC4215866 DOI: 10.1021/ac502040v] [Citation(s) in RCA: 893] [Impact Index Per Article: 89.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Multiplexed quantitation via isobaric
chemical tags (e.g., tandem
mass tags (TMT) and isobaric tags for relative and absolute quantitation
(iTRAQ)) has the potential to revolutionize quantitative proteomics.
However, until recently the utility of these tags was questionable
due to reporter ion ratio distortion resulting from fragmentation
of coisolated interfering species. These interfering signals can be
negated through additional gas-phase manipulations (e.g., MS/MS/MS
(MS3) and proton-transfer reactions (PTR)). These methods, however,
have a significant sensitivity penalty. Using isolation waveforms
with multiple frequency notches (i.e., synchronous precursor selection,
SPS), we coisolated and cofragmented multiple MS2 fragment ions, thereby
increasing the number of reporter ions in the MS3 spectrum 10-fold
over the standard MS3 method (i.e., MultiNotch MS3). By increasing
the reporter ion signals, this method improves the dynamic range of
reporter ion quantitation, reduces reporter ion signal variance, and
ultimately produces more high-quality quantitative measurements. To
demonstrate utility, we analyzed biological triplicates of eight colon
cancer cell lines using the MultiNotch MS3 method. Across all the
replicates we quantified 8 378 proteins in union and 6 168
proteins in common. Taking into account that each of these quantified
proteins contains eight distinct cell-line measurements, this data
set encompasses 174 704 quantitative ratios each measured in
triplicate across the biological replicates. Herein, we demonstrate
that the MultiNotch MS3 method uniquely combines multiplexing capacity
with quantitative sensitivity and accuracy, drastically increasing
the informational value obtainable from proteomic experiments.
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317
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Ryu H, Gygi SP, Azuma Y, Arnaoutov A, Dasso M. SUMOylation of Psmd1 controls Adrm1 interaction with the proteasome. Cell Rep 2014; 7:1842-8. [PMID: 24910440 DOI: 10.1016/j.celrep.2014.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 01/17/2014] [Accepted: 05/05/2014] [Indexed: 12/21/2022] Open
Abstract
SUMOylation is the covalent conjugation of SUMO polypeptides to cellular target proteins. Psmd1 is a subunit of the proteasomal 19S regulatory particle that acts as a docking site for Adrm1, another proteasome subunit that recruits ubiquitinated substrates for proteolysis. Here, we show that the SUMO deconjugating enzyme xSENP1 specifically interacts with Psmd1 and that disruption of xSENP1 targeting delays mitotic exit. Psmd1 becomes SUMOylated through the action of the SUMO E3 enzyme PIASy. We mapped SUMOylation sites within Psmd1 and found that SUMOylation of a critical lysine immediately adjacent to the Adrm1-binding domain regulates the association of Adrm1 with Psmd1. Together, our findings suggest that the interaction of Psmd1 with Adrm1 is controlled by SUMOylation in a manner that may alter proteasome composition and function. These findings demonstrate a mechanism for regulation of ubiquitin-mediated protein degradation by ubiquitin-like proteins of the SUMO family.
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318
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Egan ED, Braun CR, Gygi SP, Moazed D. Post-transcriptional regulation of meiotic genes by a nuclear RNA silencing complex. RNA (NEW YORK, N.Y.) 2014; 20:867-81. [PMID: 24713849 PMCID: PMC4024641 DOI: 10.1261/rna.044479.114] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/03/2014] [Indexed: 05/24/2023]
Abstract
RNA is a central component of gene-silencing pathways that regulate diverse cellular processes. In the fission yeast Schizosaccharomyces pombe, an RNA-based mechanism represses meiotic gene expression during vegetative growth. This pathway depends on the zinc finger protein Red1, which is required to degrade meiotic mRNAs as well as to target histone H3 lysine 9 (H3K9) methylation, a repressive chromatin mark, to a subset of meiotic genes. However, the mechanism of Red1 function is unknown. Here we use affinity purification and mass spectrometry to identify a Red1-containing nuclear RNA silencing (NURS) complex. In addition to Red1, this complex includes the Mtl1, Red5, Ars2, Rmn1, and Iss10 proteins and associates with several other complexes that are involved in either signaling or mediating RNA silencing. By analyzing the effects of gene knockouts and inducible knockdown alleles, we show that NURS subunits regulate RNA degradation and H3K9 methylation at meiotic genes. We also identify roles for individual NURS subunits in interactions with Mmi1, an RNA-binding protein that marks meiotic RNAs for destruction, and the nuclear exosome RNA degradation complex. Finally, we show that the levels of H3K9 methylation at meiotic genes are not sufficient to restrict RNA polymerase II access or repress gene expression during vegetative growth. Our results demonstrate that Red1 partners with other proteins to silence meiotic gene expression at the post-transcriptional level. Conservation of a NURS-like complex in human cells suggests that this pathway plays an ancient and fundamental role in RNA silencing.
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319
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Chen YC, Umanah GKE, Dephoure N, Andrabi SA, Gygi SP, Dawson TM, Dawson VL, Rutter J. Msp1/ATAD1 maintains mitochondrial function by facilitating the degradation of mislocalized tail-anchored proteins. EMBO J 2014; 33:1548-64. [PMID: 24843043 DOI: 10.15252/embj.201487943] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The majority of ER-targeted tail-anchored (TA) proteins are inserted into membranes by the Guided Entry of Tail-anchored protein (GET) system. Disruption of this system causes a subset of TA proteins to mislocalize to mitochondria. We show that the AAA+ ATPase Msp1 limits the accumulation of mislocalized TA proteins on mitochondria. Deletion of MSP1 causes the Pex15 and Gos1 TA proteins to accumulate on mitochondria when the GET system is impaired. Likely as a result of failing to extract mislocalized TA proteins, yeast with combined mutation of the MSP1 gene and the GET system exhibit strong synergistic growth defects and severe mitochondrial damage, including loss of mitochondrial DNA and protein and aberrant mitochondrial morphology. Like yeast Msp1, human ATAD1 limits the mitochondrial mislocalization of PEX26 and GOS28, orthologs of Pex15 and Gos1, respectively. GOS28 protein level is also increased in ATAD1(-/-) mouse tissues. Therefore, we propose that yeast Msp1 and mammalian ATAD1 are conserved members of the mitochondrial protein quality control system that might promote the extraction and degradation of mislocalized TA proteins to maintain mitochondrial integrity.
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320
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Chung JJ, Shim SH, Everley RA, Gygi SP, Zhuang X, Clapham DE. Structurally distinct Ca(2+) signaling domains of sperm flagella orchestrate tyrosine phosphorylation and motility. Cell 2014; 157:808-22. [PMID: 24813608 PMCID: PMC4032590 DOI: 10.1016/j.cell.2014.02.056] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 01/21/2014] [Accepted: 02/24/2014] [Indexed: 11/23/2022]
Abstract
Spermatozoa must leave one organism, navigate long distances, and deliver their paternal DNA into a mature egg. For successful navigation and delivery, a sperm-specific calcium channel is activated in the mammalian flagellum. The genes encoding this channel (CatSpers) appear first in ancient uniflagellates, suggesting that sperm use adaptive strategies developed long ago for single-cell navigation. Here, using genetics, super-resolution fluorescence microscopy, and phosphoproteomics, we investigate the CatSper-dependent mechanisms underlying this flagellar switch. We find that the CatSper channel is required for four linear calcium domains that organize signaling proteins along the flagella. This unique structure focuses tyrosine phosphorylation in time and space as sperm acquire the capacity to fertilize. In heterogeneous sperm populations, we find unique molecular phenotypes, but only sperm with intact CatSper domains that organize time-dependent and spatially specific protein tyrosine phosphorylation successfully migrate. These findings illuminate flagellar adaptation, signal transduction cascade organization, and fertility.
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321
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Tabata M, Rodgers JT, Hall JA, Lee Y, Jedrychowski MP, Gygi SP, Puigserver P. Cdc2-like kinase 2 suppresses hepatic fatty acid oxidation and ketogenesis through disruption of the PGC-1α and MED1 complex. Diabetes 2014; 63:1519-32. [PMID: 24458359 PMCID: PMC3994960 DOI: 10.2337/db13-1304] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hepatic ketogenesis plays an important role in catabolism of fatty acids during fasting along with dietary lipid overload, but the mechanisms regulating this process remain poorly understood. Here, we show that Cdc2-like kinase 2 (Clk2) suppresses fatty acid oxidation and ketone body production during diet-induced obesity. In lean mice, hepatic Clk2 protein is very low during fasting and strongly increased during feeding; however, in diet-induced obese mice, Clk2 protein remains elevated through both fed and fasted states. Liver-specific Clk2 knockout mice fed a high-fat diet exhibit increased fasting levels of blood ketone bodies, reduced respiratory exchange ratio, and increased gene expression of fatty acid oxidation and ketogenic pathways. This effect of Clk2 is cell-autonomous, because manipulation of Clk2 in hepatocytes controls genes and rates of fatty acid utilization. Clk2 phosphorylation of peroxisome proliferator-activated receptor γ coactivator (PGC-1α) disrupts its interaction with Mediator subunit 1, which leads to a suppression of PGC-1α activation of peroxisome proliferator-activated receptor α target genes in fatty acid oxidation and ketogenesis. These data demonstrate the importance of Clk2 in the regulation of fatty acid metabolism in vivo and suggest that inhibition of hepatic Clk2 could provide new therapies in the treatment of fatty liver disease.
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322
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Zapata J, Dephoure N, Macdonough T, Yu Y, Parnell EJ, Mooring M, Gygi SP, Stillman DJ, Kellogg DR. PP2ARts1 is a master regulator of pathways that control cell size. ACTA ACUST UNITED AC 2014; 204:359-76. [PMID: 24493588 PMCID: PMC3912523 DOI: 10.1083/jcb.201309119] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cell size checkpoints ensure that passage through G1 and mitosis occurs only when sufficient growth has occurred. The mechanisms by which these checkpoints work are largely unknown. PP2A associated with the Rts1 regulatory subunit (PP2A(Rts1)) is required for cell size control in budding yeast, but the relevant targets are unknown. In this paper, we used quantitative proteome-wide mass spectrometry to identify proteins controlled by PP2A(Rts1). This revealed that PP2A(Rts1) controls the two key checkpoint pathways thought to regulate the cell cycle in response to cell growth. To investigate the role of PP2A(Rts1) in these pathways, we focused on the Ace2 transcription factor, which is thought to delay cell cycle entry by repressing transcription of the G1 cyclin CLN3. Diverse experiments suggest that PP2A(Rts1) promotes cell cycle entry by inhibiting the repressor functions of Ace2. We hypothesize that control of Ace2 by PP2A(Rts1) plays a role in mechanisms that link G1 cyclin accumulation to cell growth.
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323
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Murphy JP, Everley RA, Coloff JL, Gygi SP. Combining amine metabolomics and quantitative proteomics of cancer cells using derivatization with isobaric tags. Anal Chem 2014; 86:3585-93. [PMID: 24611633 PMCID: PMC3983006 DOI: 10.1021/ac500153a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
![]()
Quantitative metabolomics and proteomics
technologies are powerful
approaches to explore cellular metabolic regulation. Unfortunately,
combining the two technologies typically requires different LC-MS
setups for sensitive measurement of metabolites and peptides. One
approach to enhance the analysis of certain classes of metabolites
is by derivatization with various types of tags to increase ionization
and chromatographic efficiency. We demonstrate here that derivatization
of amine metabolites with tandem mass tags (TMT), typically used in
multiplexed peptide quantitation, facilitates amino acid analysis
by standard nanoflow reversed-phase LC-MS setups used for proteomics.
We demonstrate that this approach offers the potential to perform
experiments at the MS1-level using duplex tags or at the MS2-level
using novel 10-plex reporter ion-containing isobaric tags for multiplexed
amine metabolite analysis. We also demonstrate absolute quantitative
measurements of amino acids conducted in parallel with multiplexed
quantitative proteomics, using similar LC-MS setups to explore cellular
amino acid regulation. We further show that the approach can also
be used to determine intracellular metabolic labeling of amino acids
from glucose carbons.
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324
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Engel U, Zhan Y, Long JB, Boyle SN, Ballif BA, Dorey K, Gygi SP, Koleske AJ, Vanvactor D. Abelson phosphorylation of CLASP2 modulates its association with microtubules and actin. Cytoskeleton (Hoboken) 2014; 71:195-209. [PMID: 24520051 PMCID: PMC4054870 DOI: 10.1002/cm.21164] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 12/21/2013] [Accepted: 12/30/2013] [Indexed: 11/20/2022]
Abstract
The Abelson (Abl) non-receptor tyrosine kinase regulates the cytoskeleton during multiple stages of neural development, from neurulation, to the articulation of axons and dendrites, to synapse formation and maintenance. We previously showed that Abl is genetically linked to the microtubule (MT) plus end tracking protein (+TIP) CLASP in Drosophila. Here we show in vertebrate cells that Abl binds to CLASP and phosphorylates it in response to serum or PDGF stimulation. In vitro, Abl phosphorylates CLASP with a Km of 1.89 µM, indicating that CLASP is a bona fide substrate. Abl-phosphorylated tyrosine residues that we detect in CLASP by mass spectrometry lie within previously mapped F-actin and MT plus end interaction domains. Using purified proteins, we find that Abl phosphorylation modulates direct binding between purified CLASP2 with both MTs and actin. Consistent with these observations, Abl-induced phosphorylation of CLASP2 modulates its localization as well as the distribution of F-actin structures in spinal cord growth cones. Our data suggest that the functional relationship between Abl and CLASP2 is conserved and provides a means to control the CLASP2 association with the cytoskeleton. © 2014 The Authors. Cytoskeleton Published by Wiley Periodicals, Inc.
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325
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Raju RM, Jedrychowski MP, Wei JR, Pinkham JT, Park AS, O'Brien K, Rehren G, Schnappinger D, Gygi SP, Rubin EJ. Post-translational regulation via Clp protease is critical for survival of Mycobacterium tuberculosis. PLoS Pathog 2014; 10:e1003994. [PMID: 24603869 PMCID: PMC3946367 DOI: 10.1371/journal.ppat.1003994] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 01/29/2014] [Indexed: 01/22/2023] Open
Abstract
Unlike most bacterial species, Mycobacterium tuberculosis depends on the Clp proteolysis system for survival even in in vitro conditions. We hypothesized that Clp is required for the physiologic turnover of mycobacterial proteins whose accumulation is deleterious to bacterial growth and survival. To identify cellular substrates, we employed quantitative proteomics and transcriptomics to identify the set of proteins that accumulated upon the loss of functional Clp protease. Among the set of potential Clp substrates uncovered, we were able to unambiguously identify WhiB1, an essential transcriptional repressor capable of auto-repression, as a substrate of the mycobacterial Clp protease. Dysregulation of WhiB1 turnover had a toxic effect that was not rescued by repression of whiB1 transcription. Thus, under normal growth conditions, Clp protease is the predominant regulatory check on the levels of potentially toxic cellular proteins. Our findings add to the growing evidence of how post-translational regulation plays a critical role in the regulation of bacterial physiology.
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