101
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Chun J, Shapovalova Z, Dejgaard SY, Presley JF, Melançon P. Characterization of class I and II ADP-ribosylation factors (Arfs) in live cells: GDP-bound class II Arfs associate with the ER-Golgi intermediate compartment independently of GBF1. Mol Biol Cell 2008; 19:3488-500. [PMID: 18524849 DOI: 10.1091/mbc.e08-04-0373] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Despite extensive work on ADP-ribosylation factor (Arf) 1 at the Golgi complex, the functions of Arf2-5 in the secretory pathway, or for that of any Arf at the ER-Golgi intermediate compartment (ERGIC) remain uncharacterized. Here, we examined the recruitment of fluorescently tagged Arf1, -3, -4, and -5 onto peripheral ERGIC. Live cell imaging detected Arfs on peripheral puncta that also contained Golgi-specific brefeldin A (BFA) resistance factor (GBF) 1 and the ERGIC marker p58. Unexpectedly, BFA did not promote corecruitment of Arfs with GBF1 either at the Golgi complex or the ERGIC, but it uncovered striking differences between Arf1,3 and Arf4,5. Although Arf1,3 quickly dissociated from all endomembranes after BFA addition, Arf4,5 persisted on ERGIC structures, even after redistribution of GBF1 to separate compartments. The GDP-arrested Arf4(T31N) mutant localized to the ERGIC, even with BFA and Exo1 present. In addition, loss of Arf x GTP after treatment with Exo1 caused rapid release of all Arfs from the Golgi complex and led to GBF1 accumulation on both Golgi and ERGIC membranes. Our results demonstrate that GDP-bound Arf4,5 associate with ERGIC membranes through binding sites distinct from those responsible for GBF1 recruitment. Furthermore, they provide the first evidence that GBF1 accumulation on membranes may be caused by loss of Arf x GTP, rather than the formation of an Arf x GDP x BFA x GBF1 complex.
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Affiliation(s)
- Justin Chun
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
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102
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Enhanced exocytosis of the receptor BT-R1 induced by the Cry1Ab toxin of Bacillus thuringiensis directly correlates to the execution of cell death. Comp Biochem Physiol B Biochem Mol Biol 2008; 149:581-8. [DOI: 10.1016/j.cbpb.2007.12.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 12/06/2007] [Accepted: 12/09/2007] [Indexed: 11/22/2022]
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103
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Kirchhausen T, Macia E, Pelish HE. Use of dynasore, the small molecule inhibitor of dynamin, in the regulation of endocytosis. Methods Enzymol 2008; 438:77-93. [PMID: 18413242 DOI: 10.1016/s0076-6879(07)38006-3] [Citation(s) in RCA: 334] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The large GTPase dynamin is essential for clathrin-dependent coated-vesicle formation. Dynasore is a cell-permeable small molecule that inhibits the GTPase activity of dynamin1, dynamin2 and Drp1, the mitochondrial dynamin. Dynasore was discovered in a screen of approximately 16,000 compounds for inhibitors of the dynamin2 GTPase. Dynasore is a noncompetitive inhibitor of dynamin GTPase activity and blocks dynamin-dependent endocytosis in cells, including neurons. It is fast acting (seconds) and its inhibitory effect in cells can be reversed by washout. Here we present a detailed synthesis protocol for dynasore, and describe a series of experiments used to analyze the inhibitory effects of dynasore on dynamin in vitro and to study the effects of dynasore on endocytosis in cells.
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Affiliation(s)
- Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, and IDI Immune Research Institute, Boston, Massachusetts, USA
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104
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Leimberg MJ, Prus E, Konijn AM, Fibach E. Macrophages function as a ferritin iron source for cultured human erythroid precursors. J Cell Biochem 2008; 103:1211-8. [PMID: 17902167 DOI: 10.1002/jcb.21499] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Iron is essential for the survival as well as the proliferation and maturation of developing erythroid precursors (EP) into hemoglobin-containing red blood cells. The transferrin-transferrin receptor pathway is the main route for erythroid iron uptake. Using a two-phase culture system, we have previously shown that placental ferritin as well as macrophages derived from peripheral blood monocytes could partially replace transferrin and support EP growth in a transferrin-free medium. We now demonstrate that in the absence of transferrin, ferritin synthesized and secreted by macrophages can serve as an iron source for EP. Macrophages trigger an increase in both the cytosolic and the mitochondrial labile iron pools, in heme and in hemoglobin synthesis, along with a decrease in surface transferrin receptors. Inhibiting macrophage exocytosis, binding extracellular ferritin with specific antibodies, inhibiting EP receptor-mediated endocytosis or acidification of EP lysosomes, all resulted in a decreased EP growth when co-cultured with macrophages under transferrin-free conditions. The results suggest that iron taken up by macrophages is incorporated mainly into their ferritin, which is subsequently secreted by exocytosis. Nearby EP are able to take up this ferritin probably through clathrin-dependent, receptor-mediated endocytosis into endosomes, which following acidification and proteolysis release the iron from the ferritin, making it available for regulatory and synthetic purposes. Thus, macrophages support EP development under transferrin-free conditions by delivering essential iron in the form of metabolizable ferritin.
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Affiliation(s)
- Moshe J Leimberg
- Department of Human Nutrition and Metabolism, Faculty of Medicine, The Hebrew University, Jerusalem, Israel
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105
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Affiliation(s)
- Daniel P Walsh
- Department of Chemistry, New York University, New York, New York 10003, USA
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106
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Starkuviene V, Pepperkok R. The potential of high-content high-throughput microscopy in drug discovery. Br J Pharmacol 2007; 152:62-71. [PMID: 17603554 PMCID: PMC1978277 DOI: 10.1038/sj.bjp.0707346] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Fluorescence microscopy is a powerful method to study protein function in its natural habitat, the living cell. With the availability of the green fluorescent protein and its spectral variants, almost any gene of interest can be fluorescently labelled in living cells opening the possibility to study protein localization, dynamics and interactions. The emergence of automated cellular systems allows rapid visualization of large groups of cells and phenotypic analysis in a quantitative manner. Here, we discuss recent advances in high-content high-throughput microscopy and its potential application to several steps of the drug discovery process.
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Affiliation(s)
- V Starkuviene
- Cell Biology and Cell Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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107
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Bartz R, Seemann J, Zehmer JK, Serrero G, Chapman KD, Anderson RG, Liu P. Evidence that mono-ADP-ribosylation of CtBP1/BARS regulates lipid storage. Mol Biol Cell 2007; 18:3015-25. [PMID: 17538025 PMCID: PMC1949384 DOI: 10.1091/mbc.e06-09-0869] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mono-ADP-ribosylation is emerging as an important posttranslational modification that modulates a variety of cell signaling pathways. Here, we present evidence that mono-ADP-ribosylation of the transcriptional corepressor C terminal binding protein, brefeldin A (BFA)-induced ADP-ribosylated substrate (CtBP1/BARS) regulates neutral lipid storage in droplets that are surrounded by a monolayer of phospholipid and associated proteins. CtBP1/BARS is an NAD-binding protein that becomes ribosylated when cells are exposed to BFA. Both endogenous lipid droplets and droplets enlarged by oleate treatment are lost after 12-h exposure to BFA. Lipid loss requires new protein synthesis, and it is blocked by multiple ribosylation inhibitors, but it is not stimulated by disruption of the Golgi apparatus or the endoplasmic reticulum unfolded protein response. Small interfering RNA knockdown of CtBP1/BARS mimics the effect of BFA, and mouse embryonic fibroblasts derived from embryos that are deficient in CtBP1/BARS seem to be defective in lipid accumulation. We conclude that mono-ADP-ribosylation of CtBP1/BARS inactivates its repressor function, which leads to the activation of genes that regulate neutral lipid storage.
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Affiliation(s)
- René Bartz
- *Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - Joachim Seemann
- *Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - John K. Zehmer
- *Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | | | - Kent D. Chapman
- Department of Biological Sciences, University of North Texas, Denton, TX 76203
| | - Richard G.W. Anderson
- *Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - Pingsheng Liu
- *Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
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108
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Chinnapen DJF, Chinnapen H, Saslowsky D, Lencer WI. Rafting with cholera toxin: endocytosis and trafficking from plasma membrane to ER. FEMS Microbiol Lett 2006; 266:129-37. [PMID: 17156122 PMCID: PMC3511785 DOI: 10.1111/j.1574-6968.2006.00545.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cholera toxin (CT), and members of the AB(5) family of toxins enter host cells and hijack the cell's endogenous pathways to induce toxicity. CT binds to a lipid receptor on the plasma membrane (PM), ganglioside GM1, which has the ability to associate with lipid rafts. The toxin can then enter the cell by various modes of receptor-mediated endocytosis and traffic in a retrograde manner from the PM to the Golgi and the endoplasmic reticulum (ER). Once in the ER, a portion of the toxin is unfolded and retro-translocated to the cytosol so as to induce disease. GM1 is the vehicle that carries CT from PM to ER. Thus, the toxin pathway from PM to ER is a lipid-based sorting pathway, which is potentially meditated by the determinants of the GM1 ganglioside structure itself.
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Affiliation(s)
- Daniel J.-F. Chinnapen
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | | | - David Saslowsky
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Wayne I. Lencer
- GI Cell Biology, Children’s Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- The Harvard Digestive Diseases Center, Boston, MA, USA
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109
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Klekota J, Brauner E, Roth FP, Schreiber SL. Using High-Throughput Screening Data To Discriminate Compounds with Single-Target Effects from Those with Side Effects. J Chem Inf Model 2006; 46:1549-62. [PMID: 16859287 DOI: 10.1021/ci050495h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The most desirable compound leads from high-throughput assays are those with novel biological activities resulting from their action on a single biological target. Valuable resources can be wasted on compound leads with significant 'side effects' on additional biological targets; therefore, technical refinements to identify compounds that primarily have effects resulting from a single target are needed. This study explores the use of multiple assays of a chemical library and a statistic based on entropy to identify lead compound classes that have patterns of assay activity resulting primarily from small molecule action on a single target. This statistic, called the coincidence score, discriminates with 88% accuracy compound classes known to act primarily on a single target from compound classes with significant side effects on nonhomologous targets. Furthermore, a significant number of the compound classes predicted to have primarily single-target effects contain known bioactive compounds. We also show that a compound's known biological target or mechanism of action can often be suggested by its pattern of activities in multiple assays.
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Affiliation(s)
- Justin Klekota
- Howard Hughes Medical Institute, 12 Oxford Street, Cambridge, Massachusetts 02138, Harvard Institute of Chemistry and Cell Biology, 250 Longwood Avenue, SGMB-604, Boston, Massachusetts 02115, USA.
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110
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Goess BC, Hannoush RN, Chan LK, Kirchhausen* T, Shair MD. Synthesis of a 10,000-membered library of molecules resembling carpanone and discovery of vesicular traffic inhibitors. J Am Chem Soc 2006; 128:5391-403. [PMID: 16620111 PMCID: PMC2785548 DOI: 10.1021/ja056338g] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Split-and-pool synthesis of a 10,000-membered library of molecules resembling the natural product carpanone has been achieved. The synthesis features development of solid-phase multicomponent reactions between nitrogen nucleophiles, enones, and hydroxylamines, and a solid-phase application of the Huisgen cycloaddition affording substituted triazoles. The synthesis was performed in high-capacity (500 microm) polystyrene beads using a one bead-one stock solution strategy that enabled phenotypic screens of the resulting library. Using whole-cell fluorescence imaging, we discovered a series of molecules from the carpanone-based library that inhibit exocytosis from the Golgi apparatus. The most potent member of this series has an IC(50) of 14 microM. We also report structure-activity relationships for the molecules exhibiting this interesting phenotype. These inhibitors of exocytosis may be useful reagents for the study of vesicular traffic.
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Affiliation(s)
| | - Rami N. Hannoush
- Contribution from the Department of Chemistry & Chemical Biology, HarVard University, Cambridge, Massachusetts 02138, Harvard Institute of Chemistry & Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and the Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115
| | - Lawrence K. Chan
- Contribution from the Department of Chemistry & Chemical Biology, HarVard University, Cambridge, Massachusetts 02138, Harvard Institute of Chemistry & Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and the Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115
| | - Tomas Kirchhausen*
- Contribution from the Department of Chemistry & Chemical Biology, HarVard University, Cambridge, Massachusetts 02138, Harvard Institute of Chemistry & Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and the Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115
| | - Matthew D. Shair
- Contribution from the Department of Chemistry & Chemical Biology, HarVard University, Cambridge, Massachusetts 02138, Harvard Institute of Chemistry & Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, and the Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115
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111
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Pelish HE, Peterson JR, Salvarezza SB, Rodriguez-Boulan E, Chen JL, Stamnes M, Macia E, Feng Y, Shair MD, Kirchhausen T. Secramine inhibits Cdc42-dependent functions in cells and Cdc42 activation in vitro. Nat Chem Biol 2005; 2:39-46. [PMID: 16408091 DOI: 10.1038/nchembio751] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 10/31/2005] [Indexed: 01/06/2023]
Abstract
Inspired by the usefulness of small molecules to study membrane traffic, we used high-throughput synthesis and phenotypic screening to discover secramine, a molecule that inhibits membrane traffic out of the Golgi apparatus by an unknown mechanism. We report here that secramine inhibits activation of the Rho GTPase Cdc42, a protein involved in membrane traffic, by a mechanism dependent upon the guanine dissociation inhibitor RhoGDI. RhoGDI binds Cdc42 and antagonizes its membrane association, nucleotide exchange and effector binding. In vitro, secramine inhibits Cdc42 binding to membranes, GTP and effectors in a RhoGDI-dependent manner. In cells, secramine mimics the effects of dominant-negative Cdc42 expression on protein export from the Golgi and on Golgi polarization in migrating cells. RhoGDI-dependent Cdc42 inhibition by secramine illustrates a new way to inhibit Rho GTPases with small molecules and provides a new means to study Cdc42, RhoGDI and the cellular processes they mediate.
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Affiliation(s)
- Henry E Pelish
- Department of Cell Biology and the CBR Institute for Biomedical Research, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115, USA
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112
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Klekota J, Brauner E, Schreiber SL. Identifying Biologically Active Compound Classes Using Phenotypic Screening Data and Sampling Statistics. J Chem Inf Model 2005; 45:1824-36. [PMID: 16309290 DOI: 10.1021/ci050087d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Scoring the activity of compounds in phenotypic high-throughput assays presents a unique challenge because of the limited resolution and inherent measurement error of these assays. Techniques that leverage the structural similarity of compounds within an assay can be used to improve the hit-recovery rate from screening data. A technique is presented that uses clustering and sampling statistics to predict likely compound activity by scoring entire structural classes. A set of phenotypic assays performed against a commercially available compound library was used as a test set. Using the class-scoring technique, the resultant activity prediction scores were more reproducible than individual assay measurements, and class scoring recovered known active compounds more efficiently than individual assay measurements because class scoring had fewer false positives. Known biologically active compounds were recovered 87% of the time using class scores, suggesting a low false-negative rate that compared well to individual assay measurements. In addition, many weak and potentially novel classes of active compounds, overlooked by individual assay measurements, were suggested.
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Affiliation(s)
- Justin Klekota
- Howard Hughes Medical Institute, Harvard Institute of Chemistry and Cell Biology, Broad Institute of Harvard and MIT, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
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113
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Abstract
Automated fluorescence microscopy provides a powerful tool for analyzing the physiological state of single cells with high throughput and high information content. Here I discuss two types of experiments in which this technology was used to discover and characterize bioactive small molecules. In phenotypic-screening experiments, the goal is to find "hits" with specific effects on cells by screening large libraries of small molecules. An example is screening for small molecules that perturb mitosis by novel mechanisms. In cytological-profiling experiments, the goal is to characterize the bioactivity of a limited number of small molecules in considerable depth, and thus understand their mechanism and toxicities at the cellular level. I discuss an example in which 100 small molecules with known bioactivity were profiled by using multiple fluorescent probes, and clustered into mechanistic classes by automated statistical analysis.
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Affiliation(s)
- Timothy J Mitchison
- Dept. Systems Biology and Institute of Chemistry and Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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114
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Zhou X, Cao X, Perlman Z, Wong STC. A computerized cellular imaging system for high content analysis in Monastrol suppressor screens. J Biomed Inform 2005; 39:115-25. [PMID: 16011909 DOI: 10.1016/j.jbi.2005.05.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2004] [Revised: 05/05/2005] [Accepted: 05/19/2005] [Indexed: 10/25/2022]
Abstract
In this paper, we describe a new bioimage informatics system developed for high content screening (HCS) applications with the goal to extract and analyze phenotypic features of hundreds of thousands of mitotic cells simultaneously. The system introduces the algorithm of multi-phenotypic mitotic analysis (MMA) and integrates that with algorithms of correlation analysis and compound clustering used in gene microarray studies. The HCS-MMA system combines different phenotypic information of cellular images obtained from three-channel acquisitions to distinguish and label individual cells at various phases of mitosis. The proposed system can also be used to extract and count the number of cells in each phase in cell-based assay experiments and archive the extracted data into a structured database for more sophisticated statistical and data analysis. To recognize different mitotic phases, binary patterns are set up based on a known biological mitotic spindle model to characterize cellular morphology of actin, microtubules, and DNA. To illustrate its utility, the HCS-MMA system has been applied to screen the quantitative response of 320 different drug compounds in suppressing Monastrol. The results are validated and evaluated by comparing the performance of HCS-MMA with visual analysis, as well as clustering of the drug compounds under evaluation.
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Affiliation(s)
- Xiaobo Zhou
- Harvard Center for Neurodegeneration and Repair-Center for Bioinformatics, Harvard Medical School, 1249 Boylston, Boston, MA 02215, USA.
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115
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Haggarty SJ. The principle of complementarity: chemical versus biological space. Curr Opin Chem Biol 2005; 9:296-303. [PMID: 15939332 DOI: 10.1016/j.cbpa.2005.04.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Accepted: 04/15/2005] [Indexed: 02/07/2023]
Abstract
Chemical genomics aims to systematically explore the interactions between small molecules and biological systems. These efforts aim to annotate genomes using the language of chemistry, and to provide information-rich profiles of chemical and biological systems. Here, I describe recent conceptual and experimental advances toward the goal of mapping multidimensional chemical and biological descriptor spaces. In doing so, I will focus on the complementary nature of these efforts, the importance of recognizing the distinction between computed versus observed descriptors, and highlight recent 'landmark' examples of small molecules discovered using phenotypic screens. Future computation and experimental advances will be needed to fully realize the goals of chemical genomics. For those willing to consider both local and global properties of chemical and biological space, and to venture into uncharted territory, there promises to be new vistas and principles to be discovered.
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Affiliation(s)
- Stephen J Haggarty
- Eli & Edythe L Broad Institute, 320 Charles Street, Cambridge, MA 02141, USA.
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116
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Cerny J, Feng Y, Yu A, Miyake K, Borgonovo B, Klumperman J, Meldolesi J, McNeil PL, Kirchhausen T. The small chemical vacuolin-1 inhibits Ca(2+)-dependent lysosomal exocytosis but not cell resealing. EMBO Rep 2005; 5:883-8. [PMID: 15332114 PMCID: PMC1299144 DOI: 10.1038/sj.embor.7400243] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Revised: 07/09/2004] [Accepted: 07/29/2004] [Indexed: 11/08/2022] Open
Abstract
Resealing after wounding, the process of repair following plasma membrane damage, requires exocytosis. Vacuolins are molecules that induce rapid formation of large, swollen structures derived from endosomes and lysosomes by homotypic fusion combined with uncontrolled fusion of the inner and limiting membranes of these organelles. Vacuolin-1, the most potent compound, blocks the Ca(2+)-dependent exocytosis of lysosomes induced by ionomycin or plasma membrane wounding, without affecting the process of resealing. In contrast, other cell structures and membrane trafficking functions including exocytosis of enlargeosomes are unaffected. Because cells heal normally in the presence of vacuolin-1, we suggest that lysosomes are dispensable for resealing.
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Affiliation(s)
- Jan Cerny
- Department of Cell Biology and The CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Physiology of Animals and Developmental Biology, Charles University, Prague 2, Czech Republic
| | - Yan Feng
- Institute of Chemistry and Cell Biology, ICCB, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Anan Yu
- Department of Cell Biology and The CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Katsuya Miyake
- Department of Cellular Biology and Anatomy and Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
| | - Barbara Borgonovo
- Department of Neuroscience, DIBIT, Vitasalute San Raffaele University and San Raffaele Institute, Via Olgettina 58, 20132 Milano, Italy
| | - Judith Klumperman
- Department of Cell Biology, University Medical Centre and Institute for Biomembranes, Heidelberglaan 100, 3584 Utrecht, The Netherlands
| | - Jacopo Meldolesi
- Department of Neuroscience, DIBIT, Vitasalute San Raffaele University and San Raffaele Institute, Via Olgettina 58, 20132 Milano, Italy
| | - Paul L McNeil
- Department of Cellular Biology and Anatomy and Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
| | - Tomas Kirchhausen
- Department of Cell Biology and The CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts 02115, USA
- Institute of Chemistry and Cell Biology, ICCB, Harvard Medical School, Boston, Massachusetts 02115, USA
- Tel: +1 617 278 3140; Fax: +1 617 278 3131; E-mail:
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117
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Yarrow JC, Totsukawa G, Charras GT, Mitchison TJ. Screening for Cell Migration Inhibitors via Automated Microscopy Reveals a Rho-Kinase Inhibitor. ACTA ACUST UNITED AC 2005; 12:385-95. [PMID: 15797222 DOI: 10.1016/j.chembiol.2005.01.015] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Revised: 12/31/2004] [Accepted: 01/04/2005] [Indexed: 01/22/2023]
Abstract
Small-molecule kinase inhibitors are predominantly discovered in pure protein assays. We have discovered an inhibitor of Rho-kinase (ROCK) through an image-based, high-throughput screen of cell monolayer wound healing. Using automated microscopy, we screened a library of approximately 16,000 compounds finding many that affected cell migration or cell morphology as well as compounds that blocked mitotic progression. We tested approximately 200 compounds in a series of subassays and chose one, 3-(4-pyridyl)indole (Rockout), for more detailed characterization. Rockout inhibits blebbing and causes dissolution of actin stress fibers, phenocopying Rho-kinase inhibitors. Testing Rho-kinase activity in vitro, Rockout inhibits with an IC50 of 25 microM ( approximately 5-fold less potent than Y-27632) but has a similar specificity profile. We also profile the wound healing assay with a library of compounds with known bioactivities, revealing multiple pathways involved in the biology.
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Affiliation(s)
- Justin C Yarrow
- Department of Systems Biology, Boston, Massachusetts 02115, USA.
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118
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Nieland TJF, Feng Y, Brown JX, Chuang TD, Buckett PD, Wang J, Xie XS, McGraw TE, Kirchhausen T, Wessling-Resnick M. Chemical genetic screening identifies sulfonamides that raise organellar pH and interfere with membrane traffic. Traffic 2005; 5:478-92. [PMID: 15180825 PMCID: PMC2494881 DOI: 10.1111/j.1398-9219.2004.00193.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Chemical genetics seeks to identify small molecules that afford functional dissection of cell biological pathways. Previous screens for small molecule inhibitors of exocytic membrane traffic yielded the identification and characterization of several compounds that block traffic from the Golgi to the cell surface as well as transport from the endoplasmic reticulum to the Golgi network [Feng et al. Proc Natl Acad Sci USA 2003;100:6469-6474; Yarrow et al. Comb Chem High Throughput Screen 2003;6:279-286; Feng et al. EMBO Reports 2004: in press]. Here, we screened these inhibitors for potential effects on endocytic membrane traffic. Two structurally related sulfonamides were found to be potent and reversible inhibitors of transferrin-mediated iron uptake. These inhibitors do not block endoplasmic reticulum-to-Golgi transport, but do disrupt Golgi-to-cell surface traffic. The compounds are members of a novel class of sulfonamides that elevate endosomal and lysosomal pH, down-regulate cell surface receptors, and impair recycling of internalized transferrin receptors to the plasma membrane. In vitro experiments revealed that the sulfonamides directly inhibit adenosine triphosphate (ATP) hydrolysis by the V-ATPase and that they also possess a potent proton ionophore activity. While maintenance of organellar pH is known to be a critical factor in both endocytosis and exocytosis, the precise role of acidification, beyond the uncoupling of ligands from their receptors, remains largely unknown. Identification of this novel class of sulfonamide inhibitors provides new chemical tools to better understand the function of organelle pH in membrane traffic and the activity of V-ATPases in particular.
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Affiliation(s)
- Thomas J. F. Nieland
- Harvard Medical School, Department of Cell Biology and The CBR Institute for Biomedical Research, 200 Longwood Avenue, Boston MA, 02115, USA
- Harvard Institute of Chemistry and Cell Biology, 250 Longwood Avenue, Boston, MA, 02115, USA
| | - Yan Feng
- Harvard Institute of Chemistry and Cell Biology, 250 Longwood Avenue, Boston, MA, 02115, USA
| | - Jing Xu Brown
- Harvard School of Public Health, Department of Genetics and Complex Diseases, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Tuan Daniel Chuang
- Cornell University, Weill Medical College, Department of Biochemistry, 1300 York Avenue, New York, NY 10021, USA
| | - Peter D. Buckett
- Harvard School of Public Health, Department of Genetics and Complex Diseases, 665 Huntington Avenue, Boston, MA 02115, USA
| | - Jin Wang
- University of Texas South-western Medical Center, Eugene McDermott Center for Human Growth and Development, 5323 Harry Hines Blvd., Dallas, TX 75390–8591, USA
| | - Xiao-Song Xie
- University of Texas South-western Medical Center, Eugene McDermott Center for Human Growth and Development, 5323 Harry Hines Blvd., Dallas, TX 75390–8591, USA
| | - Timothy E. McGraw
- Cornell University, Weill Medical College, Department of Biochemistry, 1300 York Avenue, New York, NY 10021, USA
| | - Tomas Kirchhausen
- Harvard Medical School, Department of Cell Biology and The CBR Institute for Biomedical Research, 200 Longwood Avenue, Boston MA, 02115, USA
- Harvard Institute of Chemistry and Cell Biology, 250 Longwood Avenue, Boston, MA, 02115, USA
- Corresponding authors: Tomas Kirchhausen, and Marianne Wessling-Resnick, .
| | - Marianne Wessling-Resnick
- Harvard School of Public Health, Department of Genetics and Complex Diseases, 665 Huntington Avenue, Boston, MA 02115, USA
- Corresponding authors: Tomas Kirchhausen, and Marianne Wessling-Resnick, .
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119
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Altan-Bonnet N, Sougrat R, Lippincott-Schwartz J. Molecular basis for Golgi maintenance and biogenesis. Curr Opin Cell Biol 2005; 16:364-72. [PMID: 15261668 DOI: 10.1016/j.ceb.2004.06.011] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Golgi apparatus contains thousands of different types of integral and peripheral membrane proteins, perhaps more than any other intracellular organelle. To understand these proteins' roles in Golgi function and in broader cellular processes, it is useful to categorize them according to their contribution to Golgi creation and maintenance. This is because all of the Golgi's functions derive from its ability to maintain steady-state pools of particular proteins and lipids, which in turn relies on the Golgi's dynamic character - that is, its ongoing state of transformation and outgrowth from the endoplasmic reticulum. Here, we categorize the expanding list of Golgi-associated proteins on the basis of their role in Golgi reformation after the Golgi has been disassembled. Information gained on how different proteins participate in this process can provide important insights for understanding the Golgi's global functions within cells.
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Affiliation(s)
- Nihal Altan-Bonnet
- Cell biology and Metabolism Branch, National Institutes of Child Health and Development, National Institutes of Health, Bethesda, Maryland, MD 20892, USA
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120
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Westwood NJ. Chemical genetics: how does it function? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2004; 362:2761-2774. [PMID: 15539369 DOI: 10.1098/rsta.2004.1467] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article highlights recent successes in the field of chemical genetics. It discusses the challenges inherent in this interdisciplinary research field and focuses on the essential role that the biologically aware synthetic chemist can play.
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Affiliation(s)
- Nicholas J Westwood
- School of Chemistry and Centre for Biomolecular Sciences, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
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121
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Zouhar J, Hicks GR, Raikhel NV. Sorting inhibitors (Sortins): Chemical compounds to study vacuolar sorting in Arabidopsis. Proc Natl Acad Sci U S A 2004; 101:9497-501. [PMID: 15190181 PMCID: PMC439005 DOI: 10.1073/pnas.0402121101] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chemical genomics is an interdisciplinary approach that unites the power of chemical screens and genomics strategies to dissect biological processes such as endomembrane trafficking. We have taken advantage of the evolutionary conservation between plants and Saccharomyces cerevisiae to identify such chemicals. Using S. cerevisiae, we screened a library of diverse chemical structures for compounds that induce the secretion of carboxypeptidase Y, which is normally targeted to the vacuole. Among 4,800 chemicals screened, 14 compounds, termed sorting inhibitors (Sortins), were identified that stimulated secretion in yeast. In Arabidopsis seedlings, application of Sortin1 and -2 led to reversible defects in vacuole biogenesis and root development. Sortin1 was found to redirect the vacuolar destination of plant carboxypeptidase Y and other proteins in Arabidopsis suspension cells and cause these proteins to be secreted. Sortin1 treatment of whole Arabidopsis seedlings also resulted in carboxypeptidase Y secretion, indicating that the drug has a similar mode of action in cells and intact plants. We have demonstrated that screening of a simple eukaryote, in which vacuolar biogenesis is not essential, can be a powerful tool to find chemicals that interfere with vacuolar delivery of proteins in plants, where vacuole biogenesis is essential. Our studies were done by using a sublethal dose of Sortin1, demonstrating the powerful ability of the chemical to control the induced phenotype in a manner that would be difficult to achieve using conventional genetics.
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Affiliation(s)
- Jan Zouhar
- Center for Plant Cell Biology and Department of Botany and Plant Sciences, University of California, Riverside, 92521, USA
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122
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Feng Y, Jadhav AP, Rodighiero C, Fujinaga Y, Kirchhausen T, Lencer WI. Retrograde transport of cholera toxin from the plasma membrane to the endoplasmic reticulum requires the trans-Golgi network but not the Golgi apparatus in Exo2-treated cells. EMBO Rep 2004; 5:596-601. [PMID: 15153932 PMCID: PMC1299072 DOI: 10.1038/sj.embor.7400152] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 03/11/2004] [Accepted: 03/15/2004] [Indexed: 11/08/2022] Open
Abstract
Cholera toxin (CT) follows a glycolipid-dependent entry pathway from the plasma membrane through the trans-Golgi network (TGN) to the endoplasmic reticulum (ER) where it is retro-translocated into the cytosol to induce toxicity. Whether access to the Golgi apparatus is necessary for transport to the ER is not known. Exo2 is a small chemical that rapidly blocks anterograde traffic from the ER to the Golgi and selectively disrupts the Golgi apparatus but not the TGN. Here we use Exo2 to determine the role of the Golgi apparatus in CT trafficking. We find that under the condition of complete Golgi ablation by Exo2, CT reaches the TGN and moves efficiently into the ER without loss in toxicity. We propose that even in the absence of Exo2 the glycolipid pathway that carries the toxin from plasma membrane into the ER bypasses the Golgi apparatus entirely.
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Affiliation(s)
- Yan Feng
- Department of Cell Biology, Institute of Chemistry and Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Ashutosh P Jadhav
- Department of Cell Biology, Institute of Chemistry and Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- The CBR Institute for Biomedical Research, Boston, Massachusetts 02115, USA
| | - Chiara Rodighiero
- Department of Gastrointestinal Cell Biology, Children's Hospital, Harvard Digestive Disease Center, Boston, Massachusetts 02115, USA
| | - Yukako Fujinaga
- Department of Gastrointestinal Cell Biology, Children's Hospital, Harvard Digestive Disease Center, Boston, Massachusetts 02115, USA
| | - Tomas Kirchhausen
- Department of Cell Biology, Institute of Chemistry and Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- The CBR Institute for Biomedical Research, Boston, Massachusetts 02115, USA
- Tel: +1 617 278 3140; Fax: +1 617 278 3131; E-mail:
| | - Wayne I Lencer
- Department of Gastrointestinal Cell Biology, Children's Hospital, Harvard Digestive Disease Center, Boston, Massachusetts 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Tel:+1 617 355 8599; Fax:+1 617 730 0498; E-mail:
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123
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Feng Y. A marriage of chemistry and biology. CHINESE SCIENCE BULLETIN-CHINESE 2003. [DOI: 10.1007/bf03184204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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