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Becchetti A. Interplay of Ca 2+ and K + signals in cell physiology and cancer. CURRENT TOPICS IN MEMBRANES 2023; 92:15-46. [PMID: 38007266 DOI: 10.1016/bs.ctm.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
The cytoplasmic Ca2+ concentration and the activity of K+ channels on the plasma membrane regulate cellular processes ranging from mitosis to oriented migration. The interplay between Ca2+ and K+ signals is intricate, and different cell types rely on peculiar cellular mechanisms. Derangement of these mechanisms accompanies the neoplastic progression. The calcium signals modulated by voltage-gated (KV) and calcium-dependent (KCa) K+ channel activity regulate progression of the cell division cycle, the release of growth factors, apoptosis, cell motility and migration. Moreover, KV channels regulate the cell response to the local microenvironment by assembling with cell adhesion and growth factor receptors. This chapter summarizes the pathophysiological roles of Ca2+ and K+ fluxes in normal and cancer cells, by concentrating on several biological systems in which these functions have been studied in depth, such as early embryos, mammalian cell lines, T lymphocytes, gliomas and colorectal cancer cells. A full understanding of the underlying mechanisms will offer a comprehensive view of the ion channel implication in cancer biology and suggest potential pharmacological targets for novel therapeutic approaches in oncology.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy.
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2
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Nugues C, Helassa N, Haynes LP. Mitosis, Focus on Calcium. Front Physiol 2022; 13:951979. [PMID: 35784871 PMCID: PMC9247304 DOI: 10.3389/fphys.2022.951979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 05/30/2022] [Indexed: 12/04/2022] Open
Abstract
The transformation of a single fertilised egg into an adult human consisting of tens of trillions of highly diverse cell types is a marvel of biology. The expansion is largely achieved by cell duplication through the process of mitosis. Mitosis is essential for normal growth, development, and tissue repair and is one of the most tightly regulated biological processes studied. This regulation is designed to ensure accurate segregation of chromosomes into each new daughter cell since errors in this process can lead to genetic imbalances, aneuploidy, that can lead to diseases including cancer. Understanding how mitosis operates and the molecular mechanisms that ensure its fidelity are therefore not only of significant intellectual value but provide unique insights into disease pathology. The purpose of this review is to revisit historical evidence that mitosis can be influenced by the ubiquitous second messenger calcium and to discuss this in the context of new findings revealing exciting new information about its role in cell division.
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Affiliation(s)
- Charlotte Nugues
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Nordine Helassa
- Department of Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
- *Correspondence: Nordine Helassa,
| | - Lee P. Haynes
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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3
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Ito D, Zitouni S, Jana SC, Duarte P, Surkont J, Carvalho-Santos Z, Pereira-Leal JB, Ferreira MG, Bettencourt-Dias M. Pericentrin-mediated SAS-6 recruitment promotes centriole assembly. eLife 2019; 8:41418. [PMID: 31182187 PMCID: PMC6559791 DOI: 10.7554/elife.41418] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 05/14/2019] [Indexed: 12/21/2022] Open
Abstract
The centrosome is composed of two centrioles surrounded by a microtubule-nucleating pericentriolar material (PCM). Although centrioles are known to regulate PCM assembly, it is less known whether and how the PCM contributes to centriole assembly. Here we investigate the interaction between centriole components and the PCM by taking advantage of fission yeast, which has a centriole-free, PCM-containing centrosome, the SPB. Surprisingly, we observed that several ectopically-expressed animal centriole components such as SAS-6 are recruited to the SPB. We revealed that a conserved PCM component, Pcp1/pericentrin, interacts with and recruits SAS-6. This interaction is conserved and important for centriole assembly, particularly its elongation. We further explored how yeasts kept this interaction even after centriole loss and showed that the conserved calmodulin-binding region of Pcp1/pericentrin is critical for SAS-6 interaction. Our work suggests that the PCM not only recruits and concentrates microtubule-nucleators, but also the centriole assembly machinery, promoting biogenesis close by.
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Affiliation(s)
- Daisuke Ito
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | | | - Paulo Duarte
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | | | - José B Pereira-Leal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Ophiomics, Precision Medicine, Lisboa, Portugal
| | - Miguel Godinho Ferreira
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.,Institute for Research on Cancer and Aging of Nice (IRCAN), INSERM U1081 UMR7284 CNRS, Nice, France
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4
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Jones MH, O'Toole ET, Fabritius AS, Muller EG, Meehl JB, Jaspersen SL, Winey M. Key phosphorylation events in Spc29 and Spc42 guide multiple steps of yeast centrosome duplication. Mol Biol Cell 2018; 29:2280-2291. [PMID: 30044722 PMCID: PMC6249810 DOI: 10.1091/mbc.e18-05-0296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Phosphorylation modulates many cellular processes during cell cycle progression. The yeast centrosome (called the spindle pole body, SPB) is regulated by the protein kinases Mps1 and Cdc28/Cdk1 as it nucleates microtubules to separate chromosomes during mitosis. Previously we completed an SPB phosphoproteome, identifying 297 sites on 17 of the 18 SPB components. Here we describe mutagenic analysis of phosphorylation events on Spc29 and Spc42, two SPB core components that were shown in the phosphoproteome to be heavily phosphorylated. Mutagenesis at multiple sites in Spc29 and Spc42 suggests that much of the phosphorylation on these two proteins is not essential but enhances several steps of mitosis. Of the 65 sites examined on both proteins, phosphorylation of the Mps1 sites Spc29-T18 and Spc29-T240 was shown to be critical for function. Interestingly, these two sites primarily influence distinct successive steps; Spc29-T240 is important for the interaction of Spc29 with Spc42, likely during satellite formation, and Spc29-T18 facilitates insertion of the new SPB into the nuclear envelope and promotes anaphase spindle elongation. Phosphorylation sites within Cdk1 motifs affect function to varying degrees, but mutations only have significant effects in the presence of an MPS1 mutation, supporting a theme of coregulation by these two kinases.
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Affiliation(s)
- Michele Haltiner Jones
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Eileen T O'Toole
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Eric G Muller
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Janet B Meehl
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO 64110.,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160
| | - Mark Winey
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
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5
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Viswanath S, Bonomi M, Kim SJ, Klenchin VA, Taylor KC, Yabut KC, Umbreit NT, Van Epps HA, Meehl J, Jones MH, Russel D, Velazquez-Muriel JA, Winey M, Rayment I, Davis TN, Sali A, Muller EG. The molecular architecture of the yeast spindle pole body core determined by Bayesian integrative modeling. Mol Biol Cell 2017; 28:3298-3314. [PMID: 28814505 PMCID: PMC5687031 DOI: 10.1091/mbc.e17-06-0397] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/07/2017] [Accepted: 08/09/2017] [Indexed: 12/31/2022] Open
Abstract
A model of the core of the yeast spindle pole body (SPB) was created by a Bayesian modeling approach that integrated a diverse data set of biophysical, biochemical, and genetic information. The model led to a proposed pathway for the assembly of Spc110, a protein related to pericentrin, and a mechanism for how calmodulin strengthens the SPB during mitosis. Microtubule-organizing centers (MTOCs) form, anchor, and stabilize the polarized network of microtubules in a cell. The central MTOC is the centrosome that duplicates during the cell cycle and assembles a bipolar spindle during mitosis to capture and segregate sister chromatids. Yet, despite their importance in cell biology, the physical structure of MTOCs is poorly understood. Here we determine the molecular architecture of the core of the yeast spindle pole body (SPB) by Bayesian integrative structure modeling based on in vivo fluorescence resonance energy transfer (FRET), small-angle x-ray scattering (SAXS), x-ray crystallography, electron microscopy, and two-hybrid analysis. The model is validated by several methods that include a genetic analysis of the conserved PACT domain that recruits Spc110, a protein related to pericentrin, to the SPB. The model suggests that calmodulin can act as a protein cross-linker and Spc29 is an extended, flexible protein. The model led to the identification of a single, essential heptad in the coiled-coil of Spc110 and a minimal PACT domain. It also led to a proposed pathway for the integration of Spc110 into the SPB.
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Affiliation(s)
- Shruthi Viswanath
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158
| | - Massimiliano Bonomi
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158 .,Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK
| | - Seung Joong Kim
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158
| | - Vadim A Klenchin
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Keenan C Taylor
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - King C Yabut
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Neil T Umbreit
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | | | - Janet Meehl
- Department of Molecular, Cellular and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309
| | - Michele H Jones
- Department of Molecular, Cellular and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309
| | - Daniel Russel
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158
| | - Javier A Velazquez-Muriel
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158
| | - Mark Winey
- Department of Molecular, Cellular and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309
| | - Ivan Rayment
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Trisha N Davis
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94158
| | - Eric G Muller
- Department of Biochemistry, University of Washington, Seattle, WA 98195
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6
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Rüthnick D, Neuner A, Dietrich F, Kirrmaier D, Engel U, Knop M, Schiebel E. Characterization of spindle pole body duplication reveals a regulatory role for nuclear pore complexes. J Cell Biol 2017; 216:2425-2442. [PMID: 28659328 PMCID: PMC5551709 DOI: 10.1083/jcb.201612129] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/25/2017] [Accepted: 05/22/2017] [Indexed: 02/08/2023] Open
Abstract
The spindle pole body (SPB) of budding yeast duplicates once per cell cycle. In G1, the satellite, an SPB precursor, assembles next to the mother SPB (mSPB) on the cytoplasmic side of the nuclear envelope (NE). How the growing satellite subsequently inserts into the NE is an open question. To address this, we have uncoupled satellite growth from NE insertion. We show that the bridge structure that separates the mSPB from the satellite is a distance holder that prevents deleterious fusion of both structures. Binding of the γ-tubulin receptor Spc110 to the central plaque from within the nucleus is important for NE insertion of the new SPB. Moreover, we provide evidence that a nuclear pore complex associates with the duplicating SPB and helps to insert the SPB into the NE. After SPB insertion, membrane-associated proteins including the conserved Ndc1 encircle the SPB and retain it within the NE. Thus, uncoupling SPB growth from NE insertion unmasks functions of the duplication machinery.
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Affiliation(s)
- Diana Rüthnick
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Annett Neuner
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Franziska Dietrich
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Daniel Kirrmaier
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Ulrike Engel
- Nikon Imaging Center at the University of Heidelberg, Bioquant, Heidelberg, Germany
| | - Michael Knop
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Elmar Schiebel
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
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7
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Galletta BJ, Guillen RX, Fagerstrom CJ, Brownlee CW, Lerit DA, Megraw TL, Rogers GC, Rusan NM. Drosophila pericentrin requires interaction with calmodulin for its function at centrosomes and neuronal basal bodies but not at sperm basal bodies. Mol Biol Cell 2014; 25:2682-94. [PMID: 25031429 PMCID: PMC4161505 DOI: 10.1091/mbc.e13-10-0617] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Pericentrin is a critical centrosomal protein required for organizing pericentriolar material (PCM) in mitosis. Mutations in pericentrin cause the human genetic disorder Majewski/microcephalic osteodysplastic primordial dwarfism type II, making a detailed understanding of its regulation extremely important. Germaine to pericentrin's function in organizing PCM is its ability to localize to the centrosome through the conserved C-terminal PACT domain. Here we use Drosophila pericentrin-like-protein (PLP) to understand how the PACT domain is regulated. We show that the interaction of PLP with calmodulin (CaM) at two highly conserved CaM-binding sites in the PACT domain controls the proper targeting of PLP to the centrosome. Disrupting the PLP-CaM interaction with single point mutations renders PLP inefficient in localizing to centrioles in cultured S2 cells and Drosophila neuroblasts. Although levels of PCM are unaffected, it is highly disorganized. We also demonstrate that basal body formation in the male testes and the production of functional sperm does not rely on the PLP-CaM interaction, whereas production of functional mechanosensory neurons does.
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Affiliation(s)
- Brian J Galletta
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Rodrigo X Guillen
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Carey J Fagerstrom
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Chris W Brownlee
- Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724
| | - Dorothy A Lerit
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32304
| | - Gregory C Rogers
- Department of Cellular and Molecular Medicine, University of Arizona Cancer Center, University of Arizona, Tucson, AZ 85724
| | - Nasser M Rusan
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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8
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Han HJ, Park HC, Byun HJ, Lee SM, Kim HS, Yun DJ, Cho MJ, Chung WS. The transcriptional repressor activity of ASYMMETRIC LEAVES1 is inhibited by direct interaction with calmodulin in Arabidopsis. PLANT, CELL & ENVIRONMENT 2012; 35:1969-82. [PMID: 22554014 DOI: 10.1111/j.1365-3040.2012.02530.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Calmodulin (CaM), a key Ca2+ sensor, regulates diverse cellular processes by modulating the activity of a variety of enzymes and proteins. However, little is known about the biological function of CaM in plant development. In this study, an ASYMMETRIC LEAVES1 (AS1) transcription factor was isolated as a CaM-binding protein. AS1 contains two putative CaM-binding domains (CaMBDs) at the N-terminus. Using domain mapping analysis, both predicted domains were identified as authentic Ca2+ -dependent CaMBDs. We identified three hydrophobic amino acid residues for CaM binding, Trp49 in CaMBDI, and Trp81 and Phe103 in CaMBDII. The interactions of AS1 with CaM were verified in yeast and plant cells. Based on electrophoretic mobility shift assays, CaM inhibited the DNA-binding activity of the AS1/AS2 complex to two cis-regulatory motifs in the KNAT1 promoter. Furthermore, CaM relieved the suppression of KNAT1 transcription by AS1 not only in transient expression assays of protoplasts but also by the overexpression of a CaM-binding negative form of AS1 in as1 mutant plant. Our study suggests that CaM, a calcium sensor, can be involved in the transcriptional control of meristem cell-specific genes by the inhibition of AS1 under the condition of higher levels of Ca2+ in plants.
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Affiliation(s)
- Hay Ju Han
- Division of Applied Life Science (BK21 program) and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea
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9
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A pericentrin-related protein homolog in Aspergillus nidulans plays important roles in nucleus positioning and cell polarity by affecting microtubule organization. EUKARYOTIC CELL 2012; 11:1520-30. [PMID: 23087372 DOI: 10.1128/ec.00203-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Pericentrin is a large coiled-coil protein in mammalian centrosomes that serves as a multifunctional scaffold for anchoring numerous proteins. Recent studies have linked numerous human disorders with mutated or elevated levels of pericentrin, suggesting unrecognized contributions of pericentrin-related proteins to the development of these disorders. In this study, we characterized AnPcpA, a putative homolog of pericentrin-related protein in the model filamentous fungus Aspergillus nidulans, and found that it is essential for conidial germination and hyphal development. Compared to the hyphal apex localization pattern of calmodulin (CaM), which has been identified as an interactive partner of the pericentrin homolog, GFP-AnPcpA fluorescence dots are associated mainly with nuclei, while the accumulation of CaM at the hyphal apex depends on the function of AnPcpA. In addition, the depletion of AnPcpA by an inducible alcA promoter repression results in severe growth defects and abnormal nuclear segregation. Most interestingly, in mature hyphal cells, knockdown of pericentrin was able to significantly induce changes in cell shape and cytoskeletal remodeling; it resulted in some enlarged compartments with condensed nuclei and anucleate small compartments as well. Moreover, defects in AnPcpA significantly disrupted the microtubule organization and nucleation, suggesting that AnPcpA may affect nucleus positioning by influencing microtubule organization.
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10
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Abstract
Microcephalic or Majewski's osteodysplastic primordial dwarfism type II (MOPD II) represents the most common type of primordial dwarfism. Adult height is typically about one meter and short stature is becoming mildly disproportionate over time with mild skeletal anomalies. Mental development is usually borderline or within the low normal range but cerebrovascular events that are common in childhood can result in significant cognitive impairment and cerebral palsy. Despite cerebrovascular insults, cardiomyopathy and early onset type 2 diabetes contribute to early mortality and morbidity. Common minor clinical features are truncal obesity, high pitched voice, microdontia and pigmentary changes. MOPD II is caused by autosomal recessive loss of function mutations in the PCNT gene encoding for a key centrosomal protein. There is clinical overlap with the so called Seckel syndrome, a heterogeneous group of entities with at least four different gene loci known to date.
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Affiliation(s)
- Anita Rauch
- Institute of Medical Genetics, Schorenstrasse 16, Schwerzenbach-Zurich, Switzerland.
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11
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Affiliation(s)
- Benedicte Delaval
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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12
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Rauch A, Thiel CT, Schindler D, Wick U, Crow YJ, Ekici AB, van Essen AJ, Goecke TO, Al-Gazali L, Chrzanowska KH, Zweier C, Brunner HG, Becker K, Curry CJ, Dallapiccola B, Devriendt K, Dorfler A, Kinning E, Megarbane A, Meinecke P, Semple RK, Spranger S, Toutain A, Trembath RC, Voss E, Wilson L, Hennekam R, de Zegher F, Dorr HG, Reis A. Mutations in the Pericentrin (PCNT) Gene Cause Primordial Dwarfism. Science 2008; 319:816-9. [DOI: 10.1126/science.1151174] [Citation(s) in RCA: 316] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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13
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Sun L, Hodeify R, Haun S, Charlesworth A, MacNicol AM, Ponnappan S, Ponnappan U, Prigent C, Machaca K. Ca2+ homeostasis regulates Xenopus oocyte maturation. Biol Reprod 2007; 78:726-35. [PMID: 18094360 DOI: 10.1095/biolreprod.107.063693] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In contrast to the well-defined role of Ca2+ signals during mitosis, the contribution of Ca2+ signaling to meiosis progression is controversial, despite several decades of investigating the role of Ca2+ and its effectors in vertebrate oocyte maturation. We have previously shown that during Xenopus oocyte maturation, Ca2+ signals are dispensable for entry into meiosis and for germinal vesicle breakdown. However, normal Ca2+ homeostasis is essential for completion of meiosis I and extrusion of the first polar body. In this study, we test the contribution of several downstream effectors in mediating the Ca2+ effects during oocyte maturation. We show that calmodulin and calcium-calmodulin-dependent protein kinase II (CAMK2) are not critical downstream Ca2+ effectors during meiotic maturation. In contrast, accumulation of Aurora kinase A (AURKA) protein is disrupted in cells deprived of Ca2+ signals. Since AURKA is required for bipolar spindle formation, failure to accumulate AURKA may contribute to the defective spindle phenotype following Ca2+ deprivation. These findings argue that Ca2+ homeostasis is important in establishing the oocyte's competence to undergo maturation in preparation for fertilization and embryonic development.
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Affiliation(s)
- Lu Sun
- Department of Physiology & Biophysics, and the Arkansas Cancer Research Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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14
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Batchelder EL, Thomas-Virnig CL, Hardin JD, White JG. Cytokinesis is not controlled by calmodulin or myosin light chain kinase in the Caenorhabditis elegans early embryo. FEBS Lett 2007; 581:4337-41. [PMID: 17716666 PMCID: PMC2144740 DOI: 10.1016/j.febslet.2007.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 07/27/2007] [Accepted: 08/03/2007] [Indexed: 12/16/2022]
Abstract
Furrow ingression in animal cell cytokinesis is controlled by phosphorylation of myosin II regulatory light chain (mRLC). In Caenorhabditis elegans embryos, Rho-dependent Kinase (RhoK) is involved in, but not absolutely required for, this phosphorylation. The calmodulin effector myosin light chain kinase (MLCK) can also phosphorylate mRLC and is widely regarded as a candidate for redundant function with RhoK. However, our results show that RNA mediated interference against C. elegans calmodulin and candidate MLCKs had no effect on cytokinesis in wild-type or RhoK mutant embryos, ruling out the calmodulin/MLCK pathway as the missing regulator of cytokinesis in the C. elegans early embryo.
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Affiliation(s)
- Ellen L Batchelder
- Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
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15
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Huisman SM, Smeets MFMA, Segal M. Phosphorylation of Spc110p by Cdc28p-Clb5p kinase contributes to correct spindle morphogenesis in S. cerevisiae. J Cell Sci 2007; 120:435-46. [PMID: 17213332 DOI: 10.1242/jcs.03342] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Spindle morphogenesis is regulated by cyclin-dependent kinases and monitored by checkpoint pathways to accurately coordinate chromosomal segregation with other events in the cell cycle. We have previously dissected the contribution of individual B-type cyclins to spindle morphogenesis in Saccharomyces cerevisiae. We showed that the S-phase cyclin Clb5p is required for coupling spindle assembly and orientation. Loss of Clb5p-dependent kinase abolishes intrinsic asymmetry between the spindle poles resulting in lethal translocation of the spindle into the bud with high penetrance in diploid cells. This phenotype was exploited in a screen for high dosage suppressors that yielded spc110(Delta)(13), encoding a truncation of the spindle pole body component Spc110p (the intranuclear receptor for the gamma-tubulin complex). We found that Clb5p-GFP was localised to the spindle poles and intranuclear microtubules and that Clb5p-dependent kinase promoted cell cycle dependent phosphorylation of Spc110p contributing to spindle integrity. Two cyclin-dependent kinase consensus sites were required for this phosphorylation and were critical for the activity of spc110(Delta)(13) as a suppressor. Together, our results point to the function of cyclin-dependent kinase phosphorylation of Spc110p and provide, in addition, support to a model for Clb5p control of spindle polarity at the level of astral microtubule organisation.
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Affiliation(s)
- Stephen M Huisman
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
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16
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Niepel M, Strambio-de-Castillia C, Fasolo J, Chait BT, Rout MP. The nuclear pore complex-associated protein, Mlp2p, binds to the yeast spindle pole body and promotes its efficient assembly. ACTA ACUST UNITED AC 2005; 170:225-35. [PMID: 16027220 PMCID: PMC2171418 DOI: 10.1083/jcb.200504140] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The two yeast proteins Mlp1p and Mlp2p (homologues of the vertebrate protein Tpr) are filamentous proteins attached to the nuclear face of nuclear pore complexes. Here we perform a proteomic analysis, which reveals that the two Mlps have strikingly different interacting partners, testifying to their different roles within the cell. We find that Mlp2p binds directly to Spc110p, Spc42p, and Spc29p, which are three core components of the spindle pole body (SPB), the nuclear envelope–associated yeast spindle organizer. We further show that SPB function is compromised in mlp2 mutants. Cells lacking Mlp2p form significantly smaller SPBs, accumulate aberrant SPB component-containing structures inside the nucleus, and have stochastic failures of cell division. In addition, depletion of Mlp2p is synthetically lethal with mutants impaired in SPB assembly. Based on these data, we propose that Mlp2p links the SPB to the peripheral Mlp assembly, and that this linkage is required for efficient incorporation of components into the SPB.
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Affiliation(s)
- Mario Niepel
- The Rockefeller University, New York, NY 10021, USA
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17
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Kawaguchi SI, Zheng Y. Characterization of a Drosophila centrosome protein CP309 that shares homology with Kendrin and CG-NAP. Mol Biol Cell 2004; 15:37-45. [PMID: 14565985 PMCID: PMC307525 DOI: 10.1091/mbc.e03-03-0191] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2003] [Revised: 08/27/2003] [Accepted: 08/28/2003] [Indexed: 11/11/2022] Open
Abstract
The centrosome in animal cells provides a major microtubule-nucleating site that regulates the microtubule cytoskeleton temporally and spatially throughout the cell cycle. We report the identification in Drosophila melanogaster of a large coiled-coil centrosome protein that can bind to calmodulin. Biochemical studies reveal that this novel Drosophila centrosome protein, centrosome protein of 309 kDa (CP309), cofractionates with the gamma-tubulin ring complex and the centrosome-complementing activity. We show that CP309 is required for microtubule nucleation mediated by centrosomes and that it interacts with the gamma-tubulin small complex. These findings suggest that the microtubule-nucleating activity of the centrosome requires the function of CP309.
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Affiliation(s)
- Shin-ichi Kawaguchi
- Department of Embryology, Carnegie Institution of Washington and Howard Hughes Medical Institute, Baltimore, Maryland 21210, USA
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18
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Flory MR, Davis TN. Localization of calmodulin in budding yeast and fission yeast using green fluorescent protein. Methods Enzymol 2003; 302:87-102. [PMID: 12876765 DOI: 10.1016/s0076-6879(99)02012-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Affiliation(s)
- M R Flory
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195, USA
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19
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Okano H, Ohya Y. Binding of calmodulin to Nuf1p is required for karyogamy in Saccharomyces cerevisiae. Mol Genet Genomics 2003; 269:649-57. [PMID: 12836012 DOI: 10.1007/s00438-003-0853-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2003] [Accepted: 04/13/2003] [Indexed: 10/26/2022]
Abstract
The role of calmodulin (CaM) during mating in Saccharomyces cerevisiae was examined by using a set of Phe-to-Ala substitutions. We identified ten CaM mutants that exhibited significantly reduced mating efficiencies when crossed to a strain of the opposite mating type harboring the same CaM mutation. Most of the mating-defective CaM mutants were bilateral, i.e., they also exhibited mating defects, albeit minor ones, when crossed to the wild type. When strains carrying different bilateral CaM mutations were mated, the mating efficiencies recovered dramatically. We termed this phenomenon "intragenic mating complementation", and classified the mating-defective CaM mutations into two intragenic mating complementation groups. Two mutant alleles belonging to different groups showed minor defects in cell adhesion and cell fusion, but exhibited severe defects in karyogamy. CaM is known to bind to the essential spindle pole body component Nuf1p. This binding appears to be important for karyogamy because the nuf1(C911R) mutation, which impairs CaM-Nuf1p binding, resulted in a severe defect in karyogamy. Indeed, the two mating-defective CaM mutations were found to compromise formation of the CaM/Nuf1p complex, and the mating defects of these two CaM mutants were suppressible by a dominant, CaM-independent, mutation in NUF1. Taken together, these results suggest that loss of CaM binding to Nuf1p causes a defect in karyogamy, thereby inhibiting productive mating.
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Affiliation(s)
- H Okano
- Bio-Mimetic Control Research Center, The Institute of Physical and Chemical Research RIKEN, Anagahora, 463-0003 Nagoya, Aichi, Japan
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20
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Euskirchen GM. Nnf1p, Dsn1p, Mtw1p, and Nsl1p: a new group of proteins important for chromosome segregation in Saccharomyces cerevisiae. EUKARYOTIC CELL 2002; 1:229-40. [PMID: 12455957 PMCID: PMC118027 DOI: 10.1128/ec.1.2.229-240.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previously, antibodies were raised against a nuclear envelope-enriched fraction of yeast, and the essential gene NNF1 was cloned by reverse genetics. Here it is shown that the conditional nnf1-17 mutant has decreased stability of a minichromosome in addition to mitotic spindle defects. I have identified the novel essential genes DSN1, DSN3, and NSL1 through genetic interactions with nnf1-17. Dsn3p was found to be equivalent to the kinetochore protein Mtw1p. By indirect immunofluorescence, all four proteins, Nnf1p, Mtw1p, Dsn1p, and Nsl1p, colocalize and are found in the region of the spindle poles. Based on the colocalization of these four proteins, the minichromosome instability and the spindle defects seen in nnf1 mutants, I propose that Nnf1p is part of a new group of proteins necessary for chromosome segregation.
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Affiliation(s)
- Ghia M Euskirchen
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
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21
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Schmalzigaug R, Ye Q, Berchtold MW. Calmodulin protects cells from death under normal growth conditions and mitogenic starvation but plays a mediating role in cell death upon B-cell receptor stimulation. Immunology 2001; 103:332-42. [PMID: 11454062 PMCID: PMC1783242 DOI: 10.1046/j.1365-2567.2001.01259.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Calmodulin (CaM) is the main intracellular Ca2+ sensor protein responsible for mediating Ca2+ triggered processes. Chicken DT40 lymphoma B cells express CaM from the two genes, CaMI and CaMII. Here we report the phenotypes of DT40 cells with the CaMII gene knocked out. The disruption of the CaMII gene causes the intracellular CaM level to decrease by 60%. CaMII-/- cells grow more slowly and die more frequently as compared to wild type (wt) cells but do not exhibit significant differences in their cell cycle profile. Both phenotypes are more pronounced at reduced serum concentrations. Upon stimulation of the B-cell receptor (BCR), the resting Ca2+ levels remain elevated after the initial transient in CaMII-/- cells. Despite higher Ca2+ resting levels, the CaMII-/- cells are partially protected from BCR induced apoptosis indicating that CaM plays a dual role in apoptotic processes.
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Affiliation(s)
- R Schmalzigaug
- Department of Molecular Cell Biology, Institute of Molecular Biology, University of Copenhagen, Denmark
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22
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Francis SE, Davis TN. The spindle pole body of Saccharomyces cerevisiae: architecture and assembly of the core components. Curr Top Dev Biol 2001; 49:105-32. [PMID: 11005016 DOI: 10.1016/s0070-2153(99)49006-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- S E Francis
- Department of Biochemistry, University of Washington, Seattle 98195, USA
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23
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Stirling DA, Stark MJ. Mutations in SPC110, encoding the yeast spindle pole body calmodulin-binding protein, cause defects in cell integrity as well as spindle formation. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1499:85-100. [PMID: 11118641 DOI: 10.1016/s0167-4889(00)00110-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The 110 kDa spindle pole body component, Spc110p, is an essential target of calmodulin in budding yeast. Cells with mutations which reduce calmodulin binding to Spc110p are unable to form a mitotic spindle and die. Here we show that these effects can be overcome either directly by increasing extracellular calcium or calmodulin expression, which reverse the primary spindle defect, or indirectly through increased extracellular osmolarity or high dosage of MID2 or SLG1/HCS77/WSC1 which preserve viability. We propose that overcoming a cell integrity defect associated with the mitotic arrest enables the defective spindle pole bodies to provide sufficient function for proliferation of a large proportion of mutant cells. Our findings demonstrate a role for calcium in the Spc110p-calmodulin interaction in vivo and have important general implications for the interpretation of genetic interactions involving cell integrity genes.
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Affiliation(s)
- D A Stirling
- Department of Biochemistry, University of Dundee, MSI/WTB Complex, DD1 5EH, Dundee, UK.
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24
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Flory MR, Moser MJ, Monnat RJ, Davis TN. Identification of a human centrosomal calmodulin-binding protein that shares homology with pericentrin. Proc Natl Acad Sci U S A 2000; 97:5919-23. [PMID: 10823944 PMCID: PMC18534 DOI: 10.1073/pnas.97.11.5919] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotic chromosome segregation depends on the mitotic spindle apparatus, a bipolar array of microtubules nucleated from centrosomes. Centrosomal microtubule nucleation requires attachment of gamma-tubulin ring complexes to a salt-insoluble centrosomal core, but the factor(s) underlying this attachment remains unknown. In budding yeast, this attachment is provided by the coiled-coil protein Spc110p, which links the yeast gamma-tubulin complex to the core of the yeast centrosome. Here, we show that the large coiled-coil protein kendrin is a human orthologue of Spc110p. We identified kendrin by its C-terminal calmodulin-binding site, which shares homology with the Spc110p calmodulin-binding site. Kendrin localizes specifically to centrosomes throughout the cell cycle. N-terminal regions of kendrin share significant sequence homology with pericentrin, a previously identified murine centrosome component known to interact with gamma-tubulin. In mitotic human breast carcinoma cells containing abundant centrosome-like structures, kendrin is found only at centrosomes associated with spindle microtubules.
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Affiliation(s)
- M R Flory
- Program in Molecular and Cellular Biology, Department of Pathology, University of Washington, Seattle, WA 98195, USA
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25
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Zhu G, Davis TN. The fork head transcription factor Hcm1p participates in the regulation of SPC110, which encodes the calmodulin-binding protein in the yeast spindle pole body. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1448:236-44. [PMID: 9920414 DOI: 10.1016/s0167-4889(98)00135-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We previously identified HCM1 as a dosage-dependent suppressor of a calmodulin temperature-sensitive mutant (cmd1-1). Calmodulin performs multiple functions in yeast. Here we demonstrate that the effects of HCM1 are specific to the role of calmodulin at the spindle pole body. Overexpression of HCM1 fully suppresses the temperature sensitivity of a calmodulin mutant (cmd1-3) that only has defects in assembly of the spindle pole body but does not suppress the temperature sensitivity of a calmodulin mutant (cmd1-8) that only affects other functions of calmodulin. The DNA binding specificity of Hcm1p was determined by a selection, amplification and binding protocol. The consensus sequence for an Hcmlp binding site is WAAYAAACAAW. Mutations in the DNA binding domain of Hcm1p abolish the ability of Hcmlp to specifically recognize this binding site and abolish the ability of Hcm1p to act as a suppressor of calmodulin mutants. The promoter of SPC110 contains a match to the consensus binding site. Deletion of HCM1 does not affect the basal level of SPC110 transcription, but reduces the induction that occurs late in G1 of the cell cycle.
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Affiliation(s)
- G Zhu
- Department of Biochemistry, University of Washington, Seattle 98195, USA
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26
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Nguyen T, Vinh DB, Crawford DK, Davis TN. A genetic analysis of interactions with Spc110p reveals distinct functions of Spc97p and Spc98p, components of the yeast gamma-tubulin complex. Mol Biol Cell 1998; 9:2201-16. [PMID: 9693376 PMCID: PMC25473 DOI: 10.1091/mbc.9.8.2201] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/1997] [Accepted: 06/05/1998] [Indexed: 11/11/2022] Open
Abstract
The spindle pole body (SPB) in Saccharomyces cerevisiae functions as the microtubule-organizing center. Spc110p is an essential structural component of the SPB and spans between the central and inner plaques of this multilamellar organelle. The amino terminus of Spc110p faces the inner plaque, the substructure from which spindle microtubules radiate. We have undertaken a synthetic lethal screen to identify mutations that enhance the phenotype of the temperature-sensitive spc110-221 allele, which encodes mutations in the amino terminus. The screen identified mutations in SPC97 and SPC98, two genes encoding components of the Tub4p complex in yeast. The spc98-63 allele is synthetic lethal only with spc110 alleles that encode mutations in the N terminus of Spc110p. In contrast, the spc97 alleles are synthetic lethal with spc110 alleles that encode mutations in either the N terminus or the C terminus. Using the two-hybrid assay, we show that the interactions of Spc110p with Spc97p and Spc98p are not equivalent. The N terminus of Spc110p displays a robust interaction with Spc98p in two different two-hybrid assays, while the interaction between Spc97p and Spc110p is not detectable in one strain and gives a weak signal in the other. Extra copies of SPC98 enhance the interaction between Spc97p and Spc110p, while extra copies of SPC97 interfere with the interaction between Spc98p and Spc110p. By testing the interactions between mutant proteins, we show that the lethal phenotype in spc98-63 spc110-221 cells is caused by the failure of Spc98-63p to interact with Spc110-221p. In contrast, the lethal phenotype in spc97-62 spc110-221 cells can be attributed to a decreased interaction between Spc97-62p and Spc98p. Together, these studies provide evidence that Spc110p directly links the Tub4p complex to the SPB. Moreover, an interaction between Spc98p and the amino-terminal region of Spc110p is a critical component of the linkage, whereas the interaction between Spc97p and Spc110p is dependent on Spc98p.
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Affiliation(s)
- T Nguyen
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195, USA
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27
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Abstract
The KlCMD1 gene was isolated from a Kluyveromyces lactis genomic library as a suppressor of the Saccharomyces cerevisiae temperature-sensitive mutant spc110-124, an allele previously shown to be suppressed by elevated copy number of the S. cerevisiae calmodulin gene CMD1. The KlCMD1 gene encodes a polypeptide which is 95% identical to S. cerevisiae calmodulin and 55% identical to calmodulin from Schizosaccharomyces pombe. Complementation of a S. cerevisiae cdm1 deletion mutant by KlCMD1 demonstrates that this gene encodes a functional calmodulin homologue. Multiple sequence alignment of calmodulins from yeast and multicellular eukaryotes shows that the K. lactis and S. cerevisiae calmodulins are considerably more closely related to each other than to other calmodulins, most of which have four functional Ca2+-binding EF hand domains. Thus like its S. cerevisiae counterpart Cmd1p, the KlCMD1 product is predicted to form only three Ca2+-binding motifs.
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Affiliation(s)
- T F Rayner
- Department of Biochemistry, University of Dundee, UK
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28
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May KM, Hyams JS. The yeast cytoskeleton: the closer We look, the more We See. Fungal Genet Biol 1998; 24:110-22. [PMID: 9742197 DOI: 10.1006/fgbi.1998.1073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
May, K. M., and Hyams, J. S. 1998. The yeast cytoskeleton: The closer we look, the more we see. Copyright 1998 Academic Press.
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Affiliation(s)
- KM May
- Department of Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
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29
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Wigge PA, Jensen ON, Holmes S, Souès S, Mann M, Kilmartin JV. Analysis of the Saccharomyces spindle pole by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. J Cell Biol 1998; 141:967-77. [PMID: 9585415 PMCID: PMC2132767 DOI: 10.1083/jcb.141.4.967] [Citation(s) in RCA: 265] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A highly enriched spindle pole preparation was prepared from budding yeast and fractionated by SDS gel electrophoresis. Forty-five of the gel bands that appeared enriched in this fraction were analyzed by high-mass accuracy matrix-assisted laser desorption/ ionization (MALDI) peptide mass mapping combined with sequence database searching. This identified twelve of the known spindle pole components and an additional eleven gene products that had not previously been localized to the spindle pole. Immunoelectron microscopy localized eight of these components to different parts of the spindle. One of the gene products, Ndc80p, shows homology to human HEC protein (Chen, Y., D.J. Riley, P-L. Chen, and W-H. Lee. 1997. Mol. Cell Biol. 17:6049-6056) and temperature-sensitive mutants show defects in chromosome segregation. This is the first report of the identification of the components of a large cellular organelle by MALDI peptide mapping alone.
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MESH Headings
- Amino Acid Sequence
- Chromosomes, Fungal/physiology
- Chromosomes, Fungal/ultrastructure
- Cloning, Molecular
- Cytoskeletal Proteins
- Databases, Factual
- Humans
- Kinetochores
- Microscopy, Immunoelectron
- Models, Biological
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Neoplasm Proteins/chemistry
- Nuclear Proteins/analysis
- Nuclear Proteins/biosynthesis
- Nuclear Proteins/chemistry
- Peptide Library
- Peptide Mapping
- Saccharomyces cerevisiae/physiology
- Saccharomyces cerevisiae/ultrastructure
- Saccharomyces cerevisiae Proteins
- Schizosaccharomyces
- Sequence Alignment
- Sequence Homology, Amino Acid
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods
- Spindle Apparatus/physiology
- Spindle Apparatus/ultrastructure
- Temperature
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Affiliation(s)
- P A Wigge
- Medical Research Council (MRC) Laboratory of Molecular Biology, Cambridge CB2 2QH, United Kingdom
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30
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Sundberg HA, Davis TN. A mutational analysis identifies three functional regions of the spindle pole component Spc110p in Saccharomyces cerevisiae. Mol Biol Cell 1997; 8:2575-90. [PMID: 9398677 PMCID: PMC25729 DOI: 10.1091/mbc.8.12.2575] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/1997] [Accepted: 09/08/1997] [Indexed: 02/05/2023] Open
Abstract
The central coiled coil of the essential spindle pole component Spc110p spans the distance between the central and inner plaques of the Saccharomyces cerevisiae spindle pole body (SPB). The carboxy terminus of Spc110p, which binds calmodulin, resides at the central plaque, and the amino terminus resides at the inner plaque from which nuclear microtubules originate. To dissect the functions of Spc110p, we created temperature-sensitive mutations in the amino and carboxy termini. Analysis of the temperature-sensitive spc110 mutations and intragenic complementation analysis of the spc110 alleles defined three functional regions of Spc110p. Region I is located at the amino terminus. Region II is located at the carboxy-terminal end of the coiled coil, and region III is the previously defined calmodulin-binding site. Overexpression of SPC98 suppresses the temperature sensitivity conferred by mutations in region I but not the phenotypes conferred by mutations in the other two regions, suggesting that the amino terminus of Spc110p is involved in an interaction with the gamma-tubulin complex composed of Spc97p, Spc98p, and Tub4p. Mutations in region II lead to loss of SPB integrity during mitosis, suggesting that this region is required for the stable attachment of Spc110p to the central plaque. Our results strongly argue that Spc110p links the gamma-tubulin complex to the central plaque of the SPB.
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Affiliation(s)
- H A Sundberg
- Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350, USA
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31
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Saunders RD, Avides MC, Howard T, Gonzalez C, Glover DM. The Drosophila gene abnormal spindle encodes a novel microtubule-associated protein that associates with the polar regions of the mitotic spindle. J Cell Biol 1997; 137:881-90. [PMID: 9151690 PMCID: PMC2139842 DOI: 10.1083/jcb.137.4.881] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
abnormal spindle, a gene required for normal spindle structure and function in Drosophila melanogaster, lies immediately adjacent the gene tolloid at 96A/B. It encodes a 220-kD polypeptide with a predicted pI of 10.8. The recessive mutant allele asp1 directs the synthesis of a COOH terminally truncated or internally deleted peptide of approximately 124 kD. Wild-type Asp protein copurifies with microtubules and is not released by salt concentrations known to dissociate most other microtubule-associated proteins. The bacterially expressed NH2-terminal 512-amino acid peptide, which has a number of potential phosphorylation sites for p34(cdc2) and MAP kinases, strongly binds to microtubules. The central 579-amino acid segment of the molecule contains one short motif homologous to sequences in a number of actin bundling proteins and a second motif present at the calmodulin binding sites of several proteins. Immunofluorescence studies show that the wild-type Asp protein is localized to the polar regions of the spindle immediately surrounding the centrosome. These findings are discussed in relation to the known spindle abnormalities in asp mutants.
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Affiliation(s)
- R D Saunders
- Cancer Research Campaign, Cell Cycle Genetics Group, Department of Anatomy and Physiology, University of Dundee, Dundee DD1 4HN, Scotland
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