1
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Solon AL, Tan Z, Schutt KL, Jepsen L, Haynes SE, Nesvizhskii AI, Sept D, Stumpff J, Ohi R, Cianfrocco MA. Kinesin-binding protein remodels the kinesin motor to prevent microtubule binding. SCIENCE ADVANCES 2021; 7:eabj9812. [PMID: 34797717 PMCID: PMC8604404 DOI: 10.1126/sciadv.abj9812] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/29/2021] [Indexed: 05/30/2023]
Abstract
Kinesins are regulated in space and time to ensure activation only in the presence of cargo. Kinesin-binding protein (KIFBP), which is mutated in Goldberg-Shprintzen syndrome, binds to and inhibits the catalytic motor heads of 8 of 45 kinesin superfamily members, but the mechanism remains poorly defined. Here, we used cryo–electron microscopy and cross-linking mass spectrometry to determine high-resolution structures of KIFBP alone and in complex with two mitotic kinesins, revealing structural remodeling of kinesin by KIFBP. We find that KIFBP remodels kinesin motors and blocks microtubule binding (i) via allosteric changes to kinesin and (ii) by sterically blocking access to the microtubule. We identified two regions of KIFBP necessary for kinesin binding and cellular regulation during mitosis. Together, this work further elucidates the molecular mechanism of KIFBP-mediated kinesin inhibition and supports a model in which structural rearrangement of kinesin motor domains by KIFBP abrogates motor protein activity.
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Affiliation(s)
- April L. Solon
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Zhenyu Tan
- Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Katherine L. Schutt
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Lauren Jepsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Sarah E. Haynes
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Alexey I. Nesvizhskii
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - David Sept
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Michael A. Cianfrocco
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
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2
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Yang B, Lamb ML, Zhang T, Hennessy EJ, Grewal G, Sha L, Zambrowski M, Block MH, Dowling JE, Su N, Wu J, Deegan T, Mikule K, Wang W, Kaspera R, Chuaqui C, Chen H. Discovery of potent KIFC1 inhibitors using a method of integrated high-throughput synthesis and screening. J Med Chem 2014; 57:9958-70. [PMID: 25458601 DOI: 10.1021/jm501179r] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
KIFC1 (HSET), a member of the kinesin-14 family of motor proteins, plays an essential role in centrosomal bundling in cancer cells, but its function is not required for normal diploid cell division. To explore the potential of KIFC1 as a therapeutic target for human cancers, a series of potent KIFC1 inhibitors featuring a phenylalanine scaffold was developed from hits identified through high-throughput screening (HTS). Optimization of the initial hits combined both design-synthesis-test cycles and an integrated high-throughput synthesis and biochemical screening method. An important aspect of this integrated method was the utilization of DMSO stock solutions of compounds registered in the corporate compound collection as synthetic reactants. Using this method, over 1500 compounds selected for structural diversity were quickly assembled in assay-ready 384-well plates and were directly tested after the necessary dilutions. Our efforts led to the discovery of a potent KIFC1 inhibitor, AZ82, which demonstrated the desired centrosome declustering mode of action in cell studies.
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Affiliation(s)
- Bin Yang
- Oncology Innovative Medicine Unit, AstraZeneca R&D Boston , 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
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3
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Syred HM, Welburn J, Rappsilber J, Ohkura H. Cell cycle regulation of microtubule interactomes: multi-layered regulation is critical for the interphase/mitosis transition. Mol Cell Proteomics 2013; 12:3135-47. [PMID: 23893837 PMCID: PMC3820929 DOI: 10.1074/mcp.m113.028563] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 07/25/2013] [Indexed: 12/17/2022] Open
Abstract
Microtubules dramatically change their dynamics and organization at the entry into mitosis. Although this change is mediated by microtubule-associated proteins (MAPs), how MAPs themselves are regulated is not well understood. Here we used an integrated multi-level approach to establish the framework and biological significance of MAP regulation critical for the interphase/mitosis transition. Firstly, we applied quantitative proteomics to determine global cell cycle changes in the profiles of MAPs in human and Drosophila cells. This uncovered a wide range of cell cycle regulations of MAPs previously unidentified. Secondly, systematic studies of human kinesins highlighted an overlooked aspect of kinesins: most mitotic kinesins suppress their affinity to microtubules or reduce their protein levels in interphase in combination with nuclear localization. Thirdly, in-depth analysis of a novel Drosophila MAP (Mink) revealed that the suppression of the microtubule affinity of this mitotic MAP in combination with nuclear localization is essential for microtubule organization in interphase, and phosphorylation of Mink is needed for kinetochore-microtubule attachment in mitosis. Thus, this first comprehensive analysis of MAP regulation for the interphase/mitosis transition advances our understanding of kinesin biology and reveals the prevalence and importance of multi-layered MAP regulation.
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Affiliation(s)
- Heather M. Syred
- From the ‡Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Julie Welburn
- From the ‡Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Juri Rappsilber
- From the ‡Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Hiroyuki Ohkura
- From the ‡Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
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4
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Wu J, Mikule K, Wang W, Su N, Petteruti P, Gharahdaghi F, Code E, Zhu X, Jacques K, Lai Z, Yang B, Lamb ML, Chuaqui C, Keen N, Chen H. Discovery and mechanistic study of a small molecule inhibitor for motor protein KIFC1. ACS Chem Biol 2013; 8:2201-8. [PMID: 23895133 DOI: 10.1021/cb400186w] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Centrosome amplification is observed in many human cancers and has been proposed to be a driver of both genetic instability and tumorigenesis. Cancer cells have evolved mechanisms to bundle multiple centrosomes into two spindle poles to avoid multipolar mitosis that can lead to chromosomal segregation defects and eventually cell death. KIFC1, a kinesin-14 family protein, plays an essential role in centrosomal bundling in cancer cells, but its function is not required for normal diploid cell division, suggesting that KIFC1 is an attractive therapeutic target for human cancers. To this end, we have identified the first reported small molecule inhibitor AZ82 for KIFC1. AZ82 bound specifically to the KIFC1/microtubule (MT) binary complex and inhibited the MT-stimulated KIFC1 enzymatic activity in an ATP-competitive and MT-noncompetitive manner with a Ki of 0.043 μM. AZ82 effectively engaged with the minus end-directed KIFC1 motor inside cells to reverse the monopolar spindle phenotype induced by the inhibition of the plus end-directed kinesin Eg5. Treatment with AZ82 caused centrosome declustering in BT-549 breast cancer cells with amplified centrosomes. Consistent with genetic studies, our data confirmed that KIFC1 inhibition by a small molecule holds promise for targeting cancer cells with amplified centrosomes and provided evidence that functional suppression of KIFC1 by inhibiting its enzymatic activity could be an effective means for developing cancer therapeutics.
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Affiliation(s)
- Jiaquan Wu
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Keith Mikule
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Wenxian Wang
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Nancy Su
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Philip Petteruti
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Farzin Gharahdaghi
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Erin Code
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Xiahui Zhu
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Kelly Jacques
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Zhongwu Lai
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Bin Yang
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Michelle L. Lamb
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Claudio Chuaqui
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Nicholas Keen
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
| | - Huawei Chen
- Discovery Sciences and ‡Oncology Innovative Medicine Unit, AstraZeneca R&D Boston, Waltham, Massachusetts 02451, United States
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5
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Welburn JPI. The molecular basis for kinesin functional specificity during mitosis. Cytoskeleton (Hoboken) 2013; 70:476-93. [PMID: 24039047 PMCID: PMC4065354 DOI: 10.1002/cm.21135] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 07/24/2013] [Accepted: 08/21/2013] [Indexed: 12/13/2022]
Abstract
Microtubule-based motor proteins play key roles during mitosis to assemble the bipolar spindle, define the cell division axis, and align and segregate the chromosomes. The majority of mitotic motors are members of the kinesin superfamily. Despite sharing a conserved catalytic core, each kinesin has distinct functions and localization, and is uniquely regulated in time and space. These distinct behaviors and functional specificity are generated by variations in the enzymatic domain as well as the non-conserved regions outside of the kinesin motor domain and the stalk. These flanking regions can directly modulate the properties of the kinesin motor through dimerization or self-interactions, and can associate with extrinsic factors, such as microtubule or DNA binding proteins, to provide additional functional properties. This review discusses the recently identified molecular mechanisms that explain how the control and functional specification of mitotic kinesins is achieved. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Julie P I Welburn
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom
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6
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De S, Cipriano R, Jackson MW, Stark GR. Overexpression of kinesins mediates docetaxel resistance in breast cancer cells. Cancer Res 2009; 69:8035-42. [PMID: 19789344 DOI: 10.1158/0008-5472.can-09-1224] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Resistance to chemotherapy remains a major barrier to the successful treatment of cancer. To understand mechanisms underlying docetaxel resistance in breast cancer, we used an insertional mutagenesis strategy to identify proteins whose overexpression confers resistance. A strong promoter was inserted approximately randomly into the genomes of tumor-derived breast cancer cells, using a novel lentiviral vector. We isolated a docetaxel-resistant clone in which the level of the kinesin KIFC3 was elevated. When KIFC3 or the additional kinesins KIFC1, KIF1A, or KIF5A were overexpressed in the breast cancer cell lines MDA-MB231 and MDA-MB 468, the cells became more resistant to docetaxel. The binding of kinesins to microtubules opposes the stabilizing effect of docetaxel that prevents cytokinesis and leads to apoptosis. Our finding that kinesins can mediate docetaxel resistance might lead to novel therapeutic approaches in which kinesin inhibitors are paired with taxanes.
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Affiliation(s)
- Sarmishtha De
- Department of Genetics and Pathology, Case Western Reserve University, Case Comprehensive Cancer Center, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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7
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Grishchuk EL, Spiridonov IS, McIntosh JR. Mitotic chromosome biorientation in fission yeast is enhanced by dynein and a minus-end-directed, kinesin-like protein. Mol Biol Cell 2007; 18:2216-25. [PMID: 17409356 PMCID: PMC1877089 DOI: 10.1091/mbc.e06-11-0987] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Chromosome biorientation, the attachment of sister kinetochores to sister spindle poles, is vitally important for accurate chromosome segregation. We have studied this process by following the congression of pole-proximal kinetochores and their subsequent anaphase segregation in fission yeast cells that carry deletions in any or all of this organism's minus end-directed, microtubule-dependent motors: two related kinesin 14s (Pkl1p and Klp2p) and dynein. None of these deletions abolished biorientation, but fewer chromosomes segregated normally without Pkl1p, and to a lesser degree without dynein, than in wild-type cells. In the absence of Pkl1p, which normally localizes to the spindle and its poles, the checkpoint that monitors chromosome biorientation was defective, leading to frequent precocious anaphase. Ultrastructural analysis of mutant mitotic spindles suggests that Pkl1p contributes to error-free biorientation by promoting normal spindle pole organization, whereas dynein helps to anchor a focused bundle of spindle microtubules at the pole.
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Affiliation(s)
- Ekaterina L Grishchuk
- Molecular, Cellular, and Developmental Biology Department, University of Colorado at Boulder, Boulder, CO 80309, USA.
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8
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Christodoulou A, Lederer CW, Surrey T, Vernos I, Santama N. Motor protein KIFC5A interacts with Nubp1 and Nubp2, and is implicated in the regulation of centrosome duplication. J Cell Sci 2006; 119:2035-47. [PMID: 16638812 DOI: 10.1242/jcs.02922] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Inhibition of motor protein activity has been linked with defects in the formation of poles in the spindle of dividing cells. However, the molecular mechanisms underlying the functional relationship between motor activity and centrosome dynamics have remained uncharacterised. Here, we characterise KIFC5A, a mouse kinesin-like protein that is highly expressed in dividing cells and tissues, and is subject to developmental and cell-type-specific regulation. KIFC5A is a minus-end-directed, microtubule-dependent motor that produces velocities of up to 1.26 μm minute-1 in gliding assays and possesses microtubule bundling activity. It is nuclear in interphase, localises to the centre of the two microtubule asters at the beginning of mitosis, and to spindle microtubules in later mitotic phases. Overexpression of KIFC5A in mouse cells causes the formation of aberrant, non-separated microtubule asters and mitotic arrest in a prometaphase-like state. KIFC5A knockdown partly rescues the phenotype caused by inhibition of plus-end-directed motor Eg5 by monastrol on the mitotic spindle, indicating that it is involved in the balance of forces determining bipolar spindle assembly and integrity. Silencing of KIFC5A also results in centrosome amplification detectable throughout the cell cycle. Supernumerary centrosomes arise primarily as a result of reduplication and partly as a result of cytokinesis defects. They contain duplicated centrioles and have the ability to organise microtubule asters, resulting in the formation of multipolar spindles. We show that KIFC5A interacts with nucleotide-binding proteins 1 and 2 (Nubp1 and Nubp2), which have extensive sequence similarity to prokaryotic division-site-determining protein MinD. Nubp1 and Nubp2 also interact with each other. Knockdown of Nubp1 or double knockdown of Nubp1 and Nubp2 (Nubp1&Nubp2) both phenocopy the KIFC5A silencing effect. These results implicate KIFC5A and the Nubp proteins in a common regulatory pathway involved in the control of centrosome duplication in mammalian cells.
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Affiliation(s)
- Andri Christodoulou
- Department of Biological Sciences, University of Cyprus and Cyprus Institute of Neurology and Genetics, PO Box 20537, 1678 Nicosia, Cyprus
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9
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Miki H, Okada Y, Hirokawa N. Analysis of the kinesin superfamily: insights into structure and function. Trends Cell Biol 2005; 15:467-76. [PMID: 16084724 DOI: 10.1016/j.tcb.2005.07.006] [Citation(s) in RCA: 515] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Revised: 06/13/2005] [Accepted: 07/26/2005] [Indexed: 11/25/2022]
Abstract
Kinesin superfamily proteins (KIFs) are key players or 'hub' proteins in the intracellular transport system, which is essential for cellular function and morphology. The KIF superfamily is also the first large protein family in mammals whose constituents have been completely identified and confirmed both in silico and in vivo. Numerous studies have revealed the structures and functions of individual family members; however, the relationships between members or a perspective of the whole superfamily structure until recently remained elusive. Here, we present a comprehensive summary based on a large, systematic phylogenetic analysis of the kinesin superfamily. All available sequences in public databases, including genomic information from all model organisms, were analyzed to yield the most complete phylogenetic kinesin tree thus far, comprising 14 families. This comprehensive classification builds on the recently proposed standardized nomenclature for kinesins and allows systematic analysis of the structural and functional relationships within the kinesin superfamily.
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Affiliation(s)
- Harukata Miki
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo, Japan
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10
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Robin G, DeBonis S, Dornier A, Cappello G, Ebel C, Wade RH, Thierry-Mieg D, Kozielski F. Essential kinesins: characterization of Caenorhabditis elegans KLP-15. Biochemistry 2005; 44:6526-36. [PMID: 15850386 DOI: 10.1021/bi048157h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinesins form a superfamily of molecular motors involved in cell division and intracellular transport. Twenty kinesins have been found in the Caenorhabditis elegans genome, and four of these belong to the kinesin-14 subfamily, i.e., kinesins with C-terminal motor domains. Three of these kinesin-14s, KLP-15, KLP-16, and KLP-17, form a distinct subgroup in which KLP-15 and KLP-16 are more than 90% identical and appear to be related by a relatively recent gene duplication. They are essential for meiotic spindle organization and chromosome segregation, and are mostly expressed in the germline. With 587 amino acids each, they are among the smallest kinesins known. Using bacterially expressed KLP-15 constructs with different length extensions preceding the motor domain, we have determined in vitro the following characteristic properties: ATPase activity, microtubule binding, oligomeric state, microtubule gliding activity, and direction of movement. The constructs exhibit a monomer-dimer equilibrium that depends on the length of the predicted alpha-helical coiled-coil region preceding the motor domain. The longest construct with the complete coiled-coil domain is a stable dimer, and the shortest construct with only seven amino acids preceding the motor domain is a monomer. In microtubule gliding assays, the monomer is immobile whereas the fully dimeric KLP-15 construct supports gliding at 2.3 microm/min and moves toward microtubule minus ends, like other members of the kinesin-14 subfamily studied to date.
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Affiliation(s)
- Gautier Robin
- Institut de Biologie Structurale, UMR 5075 CEA/CNRS/UJF, 41 rue Jules Horowitz, 38027 Grenoble Cedex 01, France
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11
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Goshima G, Vale RD. Cell cycle-dependent dynamics and regulation of mitotic kinesins in Drosophila S2 cells. Mol Biol Cell 2005; 16:3896-907. [PMID: 15958489 PMCID: PMC1182325 DOI: 10.1091/mbc.e05-02-0118] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Constructing a mitotic spindle requires the coordinated actions of several kinesin motor proteins. Here, we have visualized the dynamics of five green fluorescent protein (GFP)-tagged mitotic kinesins (class 5, 6, 8, 13, and 14) in live Drosophila Schneider cell line (S2), after first demonstrating that the GFP-tag does not interfere with the mitotic functions of these kinesins using an RNA interference (RNAi)-based rescue strategy. Class 8 (Klp67A) and class 14 (Ncd) kinesin are sequestered in an active form in the nucleus during interphase and engage their microtubule targets upon nuclear envelope breakdown (NEB). Relocalization of Klp67A to the cytoplasm using a nuclear export signal resulted in the disassembly of the interphase microtubule array, providing support for the hypothesis that this kinesin class possesses microtubule-destabilizing activity. The interactions of Kinesin-5 (Klp61F) and -6 (Pavarotti) with microtubules, on the other hand, are activated and inactivated by Cdc2 phosphorylation, respectively, as shown by examining localization after mutating Cdc2 consensus sites. The actions of microtubule-destabilizing kinesins (class 8 and 13 [Klp10A]) seem to be controlled by cell cycle-dependent changes in their localizations. Klp10A, concentrated on microtubule plus ends in interphase and prophase, relocalizes to centromeres and spindle poles upon NEB and remains at these sites throughout anaphase. Consistent with this localization, RNAi analysis showed that this kinesin contributes to chromosome-to-pole movement during anaphase A. Klp67A also becomes kinetochore associated upon NEB, but the majority of the population relocalizes to the central spindle by the timing of anaphase A onset, consistent with our RNAi result showing no effect of depleting this motor on anaphase A. These results reveal a diverse spectrum of regulatory mechanisms for controlling the localization and function of five mitotic kinesins at different stages of the cell cycle.
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Affiliation(s)
- Gohta Goshima
- The Howard Hughes Medical Institute and the Department of Cellular and Molecular Pharmacology, University of California-San Francisco, San Francisco, CA 94107, USA
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12
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Ambrose JC, Li W, Marcus A, Ma H, Cyr R. A minus-end-directed kinesin with plus-end tracking protein activity is involved in spindle morphogenesis. Mol Biol Cell 2005; 16:1584-92. [PMID: 15659646 PMCID: PMC1073643 DOI: 10.1091/mbc.e04-10-0935] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Diverse kinesin motor proteins are involved in spindle function; however, the mechanisms by which they are targeted to specific sites within spindles are not well understood. Here, we show that a fusion between yellow fluorescent protein (YFP) and a minus-end-directed Kinesin-14 (C-terminal family) from Arabidopsis, ATK5, localizes to mitotic spindle midzones and regions rich in growing plus-ends within phragmoplasts. Notably, in Arabidopsis interphase cells, YFP::ATK5 localizes to microtubules with a preferential enrichment at growing plus-ends; indicating ATK5 is a plus-end tracking protein (+TIP). This +TIP activity is conferred by regions outside of the C-terminal motor domain, which reveals the presence of independent plus-end tracking and minus-end motor activities within ATK5. Furthermore, mitotic spindles of atk5 null mutant plants are abnormally broadened. Based on these data, we propose a model in which ATK5 uses plus-end tracking to reach spindle midzones, where it then organizes microtubules via minus-end-directed motor activity.
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Affiliation(s)
- J Christian Ambrose
- Department of Biology, The Pennsylvania State University, University Park, 16802, USA
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13
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Maiato H, Sampaio P, Sunkel CE. Microtubule-associated proteins and their essential roles during mitosis. ACTA ACUST UNITED AC 2005; 241:53-153. [PMID: 15548419 DOI: 10.1016/s0074-7696(04)41002-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Microtubules play essential roles during mitosis, including chromosome capture, congression, and segregation. In addition, microtubules are also required for successful cytokinesis. At the heart of these processes is the ability of microtubules to do work, a property that derives from their intrinsic dynamic behavior. However, if microtubule dynamics were not properly regulated, it is certain that microtubules alone could not accomplish any of these tasks. In vivo, the regulation of microtubule dynamics is the responsibility of microtubule-associated proteins. Among these, we can distinguish several classes according to their function: (1) promotion and stabilization of microtubule polymerization, (2) destabilization or severance of microtubules, (3) functioning as linkers between various structures, or (4) motility-related functions. Here we discuss how the various properties of microtubule-associated proteins can be used to assemble an efficient mitotic apparatus capable of ensuring the bona fide transmission of the genetic information in animal cells.
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Affiliation(s)
- Hélder Maiato
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal
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14
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Huang SC, Liu ES, Chan SH, Munagala ID, Cho HT, Jagadeeswaran R, Benz EJ. Mitotic regulation of protein 4.1R involves phosphorylation by cdc2 kinase. Mol Biol Cell 2004; 16:117-27. [PMID: 15525677 PMCID: PMC539157 DOI: 10.1091/mbc.e04-05-0426] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The nonerythrocyte isoform of the cytoskeletal protein 4.1R (4.1R) is associated with morphologically dynamic structures during cell division and has been implicated in mitotic spindle function. In this study, we define important 4.1R isoforms expressed in interphase and mitotic cells by RT-PCR and mini-cDNA library construction. Moreover, we show that 4.1R is phosphorylated by p34cdc2 kinase on residues Thr60 and Ser679 in a mitosis-specific manner. Phosphorylated 4.1R135 isoform(s) associate with tubulin and Nuclear Mitotic Apparatus protein (NuMA) in intact HeLa cells in vivo as well as with the microtubule-associated proteins in mitotic asters assembled in vitro. Recombinant 4.1R135 is readily phosphorylated in mitotic extracts and reconstitutes mitotic aster assemblies in 4.1R-immunodepleted extracts in vitro. Furthermore, phosphorylation of these residues appears to be essential for the targeting of 4.1R to the spindle poles and for mitotic microtubule aster assembly in vitro. Phosphorylation of 4.1R also enhances its association with NuMA and tubulin. Finally, we used siRNA inhibition to deplete 4.1R from HeLa cells and provide the first direct genetic evidence that 4.1R is required to efficiently focus mitotic spindle poles. Thus, we suggest that 4.1R is a member of the suite of direct cdc2 substrates that are required for the establishment of a bipolar spindle.
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Affiliation(s)
- Shu-Ching Huang
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02115, USA.
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15
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Wilson PG, Simmons R, Saighal S, Shigali S. Novel nuclear defects in KLP61F-deficient mutants in Drosophila are partially suppressed by loss of Ncd function. J Cell Sci 2004; 117:4921-33. [PMID: 15367580 DOI: 10.1242/jcs.01334] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
KLP61F in Drosophila and other BimC kinesins are essential for spindle bipolarity across species; loss of BimC function generates high frequencies of monopolar spindles. Concomitant loss of Kar3 kinesin function increases the frequency of bipolar spindles although the underlying mechanism is not known. Recent studies raise the question of whether BimC kinesins interact with a non-microtubule spindle matrix rather than spindle microtubules. Here we present cytological evidence that loss of KLP61F function generates novel defects during M-phase in the organization and integrity of the nuclear lamina, an integral component of the nuclear matrix. Larval neuroblasts and spermatocytes of klp61F mutants showed deep involutions in the nuclear lamina extending toward the centrally located centrosomes. Repositioning of centrosomes to form monopolar spindles probably does not cause invaginations as similar invaginations formed in spermatocytes lacking centrosomes entirely. Immunofluorescence microscopy indicated that non-claret disjunctional (Ncd) is a component of the nuclear matrix in somatic cells and spermatocytes. Loss of Ncd function increases the frequency of bipolar spindles in klp61F mutants. Nuclear defects were incompletely suppressed; micronuclei formed near telophase at the poles of bipolar spindle in klp61F ncd spermatocytes. Our results are consistent with a model in which KLP61F prevents Ncd-mediated collapse of a nonmicrotubule matrix derived from the interphase nucleus.
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Affiliation(s)
- Patricia G Wilson
- Georgia State University, Department of Biology, 24 Peachtree Center, Atlanta 30303, USA.
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16
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Chakravarty A, Howard L, Compton DA. A mechanistic model for the organization of microtubule asters by motor and non-motor proteins in a mammalian mitotic extract. Mol Biol Cell 2004; 15:2116-32. [PMID: 14978218 PMCID: PMC404009 DOI: 10.1091/mbc.e03-08-0579] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Revised: 01/30/2004] [Accepted: 01/30/2004] [Indexed: 11/11/2022] Open
Abstract
We used computer simulation to understand the functional relationships between motor (dynein, HSET, and Eg5) and non-motor (NuMA) proteins involved in microtubule aster organization. The simulation accurately predicted microtubule organization under all combinations of motor and non-motor proteins, provided that microtubule cross-links at minus-ends were dynamic, and dynein and HSET were restricted to cross-linking microtubules in parallel orientation only. A mechanistic model was derived from these data in which a combination of two aggregate properties, Net Minus-end-directed Force and microtubule Cross-linking Orientation Bias, determine microtubule organization. This model uses motor and non-motor proteins, accounts for motor antagonism, and predicts that alterations in microtubule Cross-linking Orientation Bias should compensate for imbalances in motor force during microtubule aster formation. We tested this prediction in the mammalian mitotic extract and, consistent with the model, found that increasing the contribution of microtubule cross-linking by NuMA compensated for the loss of Eg5 motor activity. Thus, this model proposes a precise mechanism of action of each noncentrosomal protein during microtubule aster organization and suggests that microtubule organization in spindles involves both motile forces from motors and static forces from non-motor cross-linking proteins.
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Affiliation(s)
- Arijit Chakravarty
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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17
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Fant X, Merdes A, Haren L. Cell and molecular biology of spindle poles and NuMA. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 238:1-57. [PMID: 15364196 DOI: 10.1016/s0074-7696(04)38001-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Mitotic and meiotic cells contain a bipolar spindle apparatus of microtubules and associated proteins. To arrange microtubules into focused spindle poles, different mechanisms are used by various organisms. Principally, two major pathways have been characterized: nucleation and anchorage of microtubules at preexisting centers such as centrosomes or spindle pole bodies, or microtubule growth off the surface of chromosomes, followed by sorting and focusing into spindle poles. These two mechanisms can even be found in cells of the same organism: whereas most somatic animal cells utilize the centrosome as an organizing center for spindle microtubules, female meiotic cells build an acentriolar spindle apparatus. Most interestingly, the molecular components that drive acentriolar spindle pole formation are also present in cells containing centrosomes. They include microtubule-dependent motor proteins and a variety of structural proteins that regulate microtubule orientation, anchoring, and stability. The first of these spindle pole proteins, NuMA, had already been identified more than 20 years ago. In addition, several new proteins have been characterized more recently. This review discusses their role during spindle formation and their regulation in the cell cycle.
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Affiliation(s)
- Xavier Fant
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, United Kingdom
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18
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Abstract
Spindle microtubules interact with mitotic chromosomes, binding to their kinetochores to generate forces that are important for accurate chromosome segregation. Motor enzymes localized both at kinetochores and spindle poles help to form the biologically significant attachments between spindle fibers and their cargo, but microtubule-associated proteins without motor activity contribute to these junctions in important ways. This review examines the molecules necessary for chromosome-microtubule interaction in a range of well-studied organisms, using biological diversity to identify the factors that are essential for organized chromosome movement. We conclude that microtubule dynamics and the proteins that control them are likely to be more important for mitosis than the current enthusiasm for motor enzymes would suggest.
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Affiliation(s)
- J Richard McIntosh
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder 80309-0347, USA.
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19
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Haren L, Merdes A. Direct binding of NuMA to tubulin is mediated by a novel sequence motif in the tail domain that bundles and stabilizes microtubules. J Cell Sci 2002; 115:1815-24. [PMID: 11956313 DOI: 10.1242/jcs.115.9.1815] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In mitosis, NuMA localises to spindle poles where it contributes to the formation and maintenance of focussed microtubule arrays. Previous work has shown that NuMA is transported to the poles by dynein and dynactin. So far, it is unclear how NuMA accumulates at the spindle poles following transport and how it remains associated throughout mitosis. We show here that NuMA can bind to microtubules independently of dynein/dynactin. We characterise a 100-residue domain located within the C-terminal tail of NuMA that mediates a direct interaction with tubulin in vitro and that is necessary for NuMA association with tubulin in vivo. Moreover, this domain induces bundling and stabilisation of microtubules when expressed in cultured cells and leads to formation of abnormal mitotic spindles with increased microtubule asters or multiple poles. Our results suggest that NuMA organises the poles by stable crosslinking of the microtubule fibers.
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Affiliation(s)
- Laurence Haren
- Wellcome Trust Centre for Cell Biology, Institute of Cell and Molecular Biology, University of Edinburgh, King's Buildings, Edinburgh, EH9 3JR, UK
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20
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Ohta T, Essner R, Ryu JH, Palazzo RE, Uetake Y, Kuriyama R. Characterization of Cep135, a novel coiled-coil centrosomal protein involved in microtubule organization in mammalian cells. J Cell Biol 2002; 156:87-99. [PMID: 11781336 PMCID: PMC2173569 DOI: 10.1083/jcb.200108088] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
By using monoclonal antibodies raised against isolated clam centrosomes, we have identified a novel 135-kD centrosomal protein (Cep135), present in a wide range of organisms. Cep135 is located at the centrosome throughout the cell cycle, and localization is independent of the microtubule network. It distributes throughout the centrosomal area in association with the electron-dense material surrounding centrioles. Sequence analysis of cDNA isolated from CHO cells predicted a protein of 1,145-amino acid residues with extensive alpha-helical domains. Expression of a series of deletion constructs revealed the presence of three independent centrosome-targeting domains. Overexpression of Cep135 resulted in the accumulation of unique whorl-like particles in both the centrosome and the cytoplasm. Although their size, shape, and number varied according to the level of protein expression, these whorls were composed of parallel dense lines arranged in a 6-nm space. Altered levels of Cep135 by protein overexpression and/or suppression of endogenous Cep135 by RNA interference caused disorganization of interphase and mitotic spindle microtubules. Thus, Cep135 may play an important role in the centrosomal function of organizing microtubules in mammalian cells.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- CHO Cells
- Centrosome/chemistry
- Centrosome/immunology
- Centrosome/metabolism
- Centrosome/ultrastructure
- Cloning, Molecular
- Cricetinae
- Cytoplasm/metabolism
- Cytoplasm/ultrastructure
- Fibroblasts
- Interphase/drug effects
- Mice
- Microscopy, Immunoelectron
- Microtubule-Associated Proteins/chemistry
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/immunology
- Microtubule-Associated Proteins/metabolism
- Microtubules/drug effects
- Microtubules/metabolism
- Microtubules/ultrastructure
- Molecular Weight
- Nocodazole/pharmacology
- Peptides/chemistry
- Peptides/genetics
- Peptides/metabolism
- Protein Structure, Secondary
- Protein Structure, Tertiary
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Double-Stranded/pharmacology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Deletion
- Spindle Apparatus/chemistry
- Spindle Apparatus/drug effects
- Spindle Apparatus/metabolism
- Spindle Apparatus/ultrastructure
- Transfection
- Xenopus
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Affiliation(s)
- Toshiro Ohta
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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21
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DeLuca JG, Newton CN, Himes RH, Jordan MA, Wilson L. Purification and characterization of native conventional kinesin, HSET, and CENP-E from mitotic hela cells. J Biol Chem 2001; 276:28014-21. [PMID: 11382767 DOI: 10.1074/jbc.m102801200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have developed a strategy for the purification of native microtubule motor proteins from mitotic HeLa cells and describe here the purification and characterization of human conventional kinesin and two human kinesin-related proteins, HSET and CENP-E. We found that the 120-kDa HeLa cell conventional kinesin is an active motor that induces microtubule gliding at approximately 30 microm/min at room temperature. This active form of HeLa cell kinesin does not contain light chains, although light chains were detected in other fractions. HSET, a member of the C-terminal kinesin subfamily, was also purified in native form for the first time, and the protein migrates as a single band at approximately 75 kDa. The purified HSET is an active motor that induces microtubule gliding at a rate of approximately 5 microm/min, and microtubules glide for an average of 3 microm before ceasing movement. Finally, we purified native CENP-E, a kinesin-related protein that has been implicated in chromosome congression during mitosis, and we found that this form of CENP-E does not induce microtubule gliding but is able to bind to microtubules.
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Affiliation(s)
- J G DeLuca
- Department of Molecular, Cellular, and Developmental Biology and the Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA
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22
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Reddy ASN, Day IS. Kinesins in the Arabidopsis genome: a comparative analysis among eukaryotes. BMC Genomics 2001; 2:2. [PMID: 11472632 PMCID: PMC35278 DOI: 10.1186/1471-2164-2-2] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2001] [Accepted: 06/25/2001] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Kinesins constitute a superfamily of microtubule motor proteins that are found in eukaryotic organisms. Members of the kinesin superfamily perform many diverse cellular functions such as transport of vesicles and organelles, spindle formation and elongation, chromosome segregation, microtubule dynamics and morphogenesis. Only a few kinesins have been characterized in plants including Arabidopsis thaliana. Because of the diverse cellular functions in which kinesins are involved, the number, types and characteristics of kinesins present in the Arabidopsis genome would provide valuable information for many researchers. RESULTS Here we have analyzed the recently completed Arabidopsis genome sequence and identified sixty-one kinesin genes in the Arabidopsis genome. Among the five completed eukaryotic genomes the Arabidopsis genome has the highest percentage of kinesin genes. Further analyses of the kinesin gene products have resulted in identification of several interesting domains in Arabidopsis kinesins that provide clues in understanding their functions. A phylogenetic analysis of all Arabidopsis kinesin motor domain sequences with 113 motor domain sequences from other organisms has revealed that Arabidopsis has seven of the nine recognized subfamilies of kinesins whereas some kinesins do not fall into any known family. CONCLUSION There are groups of Arabidopsis kinesins that are not present in yeast, Caenorhabditis elegans and Drosophila melanogaster that may, therefore, represent new subfamilies specific to plants. The domains present in different kinesins may provide clues about their functions in cellular processes. The comparative analysis presented here provides a framework for future functional studies with Arabidopsis kinesins.
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Affiliation(s)
- Anireddy SN Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Irene S Day
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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23
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Miki H, Setou M, Kaneshiro K, Hirokawa N. All kinesin superfamily protein, KIF, genes in mouse and human. Proc Natl Acad Sci U S A 2001; 98:7004-11. [PMID: 11416179 PMCID: PMC34614 DOI: 10.1073/pnas.111145398] [Citation(s) in RCA: 438] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Intracellular transport is essential for morphogenesis and functioning of the cell. The kinesin superfamily proteins (KIFs) have been shown to transport membranous organelles and protein complexes in a microtubule- and ATP-dependent manner. More than 30 KIFs have been reported in mice. However, the nomenclature of KIFs has not been clearly established, resulting in various designations and redundant names for a single KIF. Here, we report the identification and classification of all KIFs in mouse and human genome transcripts. Previously unidentified murine KIFs were found by a PCR-based search. The identification of all KIFs was confirmed by a database search of the total human genome. As a result, there are a total of 45 KIFs. The nomenclature of all KIFs is presented. To understand the function of KIFs in intracellular transport in a single tissue, we focused on the brain. The expression of 38 KIFs was detected in brain tissue by Northern blotting or PCR using cDNA. The brain, mainly composed of highly differentiated and polarized cells such as neurons and glia, requires a highly complex intracellular transport system as indicated by the increased number of KIFs for their sophisticated functions. It is becoming increasingly clear that the cell uses a number of KIFs and tightly controls the direction, destination, and velocity of transportation of various important functional molecules, including mRNA. This report will set the foundation of KIF and intracellular transport research.
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Affiliation(s)
- H Miki
- Department of Cell Biology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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24
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Abstract
Molecular motors that hydrolyze ATP and use the derived energy to generate force are involved in a variety of diverse cellular functions. Genetic, biochemical, and cellular localization data have implicated motors in a variety of functions such as vesicle and organelle transport, cytoskeleton dynamics, morphogenesis, polarized growth, cell movements, spindle formation, chromosome movement, nuclear fusion, and signal transduction. In non-plant systems three families of molecular motors (kinesins, dyneins, and myosins) have been well characterized. These motors use microtubules (in the case of kinesines and dyneins) or actin filaments (in the case of myosins) as tracks to transport cargo materials intracellularly. During the last decade tremendous progress has been made in understanding the structure and function of various motors in animals. These studies are yielding interesting insights into the functions of molecular motors and the origin of different families of motors. Furthermore, the paradigm that motors bind cargo and move along cytoskeletal tracks does not explain the functions of some of the motors. Relatively little is known about the molecular motors and their roles in plants. In recent years, by using biochemical, cell biological, molecular, and genetic approaches a few molecular motors have been isolated and characterized from plants. These studies indicate that some of the motors in plants have novel features and regulatory mechanisms. The role of molecular motors in plant cell division, cell expansion, cytoplasmic streaming, cell-to-cell communication, membrane trafficking, and morphogenesis is beginning to be understood. Analyses of the Arabidopsis genome sequence database (51% of genome) with conserved motor domains of kinesin and myosin families indicates the presence of a large number (about 40) of molecular motors and the functions of many of these motors remain to be discovered. It is likely that many more motors with novel regulatory mechanisms that perform plant-specific functions are yet to be discovered. Although the identification of motors in plants, especially in Arabidopsis, is progressing at a rapid pace because of the ongoing plant genome sequencing projects, only a few plant motors have been characterized in any detail. Elucidation of function and regulation of this multitude of motors in a given species is going to be a challenging and exciting area of research in plant cell biology. Structural features of some plant motors suggest calcium, through calmodulin, is likely to play a key role in regulating the function of both microtubule- and actin-based motors in plants.
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Affiliation(s)
- A S Reddy
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins 80523, USA
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25
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Abstract
Chromosome segregation during mitosis and meiosis is driven by a complex superstructure called the spindle. Microtubules are the primary structural component of spindles, and spindle assembly and function are intimately linked to the intrinsic dynamics of microtubules. This review summarizes spindle structure and highlights recent findings regarding the mechanisms and molecules involved in organizing microtubules into spindles. In addition, mechanisms for chromosome movement and segregation are discussed.
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Affiliation(s)
- D A Compton
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
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26
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Abstract
Anchorage of microtubule minus ends at spindle poles has been proposed to bear the load of poleward forces exerted by kinetochore-associated motors so that chromosomes move toward the poles rather than the poles toward the chromosomes. To test this hypothesis, we monitored chromosome movement during mitosis after perturbation of nuclear mitotic apparatus protein (NuMA) and the human homologue of the KIN C motor family (HSET), two noncentrosomal proteins involved in spindle pole organization in animal cells. Perturbation of NuMA alone disrupts spindle pole organization and delays anaphase onset, but does not alter the velocity of oscillatory chromosome movement in prometaphase. Perturbation of HSET alone increases the duration of prometaphase, but does not alter the velocity of chromosome movement in prometaphase or anaphase. In contrast, simultaneous perturbation of both HSET and NuMA severely suppresses directed chromosome movement in prometaphase. Chromosomes coalesce near the center of these cells on bi-oriented spindles that lack organized poles. Immunofluorescence and electron microscopy verify microtubule attachment to sister kinetochores, but this attachment fails to generate proper tension across sister kinetochores. These results demonstrate that anchorage of microtubule minus ends at spindle poles mediated by overlapping mechanisms involving both NuMA and HSET is essential for chromosome movement during mitosis.
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Affiliation(s)
- Michael B. Gordon
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Louisa Howard
- Rippel Electron Microscope Facility, Dartmouth College, Hanover, New Hampshire 03755
| | - Duane A. Compton
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
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27
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Yang Z, Xia C, Roberts EA, Bush K, Nigam SK, Goldstein LS. Molecular cloning and functional analysis of mouse C-terminal kinesin motor KifC3. Mol Cell Biol 2001; 21:765-70. [PMID: 11154264 PMCID: PMC86668 DOI: 10.1128/mcb.21.3.765-770.2001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Proteins of the kinesin superfamily define a class of microtubule-dependent motors that play crucial roles in cell division and intracellular transport. To study the molecular mechanism of intracellular transport involving microtubule-dependent motors, a cDNA encoding a new kinesin-like protein called KifC3 was cloned from a mouse brain cDNA library. Sequence and secondary structure analysis revealed that KifC3 is a member of the C-terminal motor family. In contrast to other mouse C-terminal motors, KifC3 is apparently ubiquitous and may have a general role in intracellular transport. To understand the in vivo function of the KifC3 gene, we used homologous recombination in embryonic stem cells to construct knockout mouse strains for the KifC3 gene. Homozygous mutants of the KifC3 gene are viable, reproduce normally, and apparently develop normally. These results suggest that KifC3 is dispensable for normal development and reproduction in the mouse.
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Affiliation(s)
- Z Yang
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093, USA
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28
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Abstract
The mitotic spindle uses microtubule-based motor proteins to assemble itself and to segregate sister chromatids. It is becoming clear that motors invoke several distinct mechanisms to generate the forces that drive mitosis. Moreover, in carrying out its function, the spindle appears to pass through a series of transient steady-state structures, each established by a delicate balance of forces generated by multiple complementary and antagonistic motors. Transitions from one steady state to the next can occur when a change in the activity of a subset of mitotic motors tips the balance.
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Affiliation(s)
- D J Sharp
- Section of Molecular and Cellular Biology, University of California-Davis, 95616, USA
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29
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Funabiki H, Murray AW. The Xenopus chromokinesin Xkid is essential for metaphase chromosome alignment and must be degraded to allow anaphase chromosome movement. Cell 2000; 102:411-24. [PMID: 10966104 DOI: 10.1016/s0092-8674(00)00047-7] [Citation(s) in RCA: 241] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
At anaphase, the linkage betweeh sister chromatids is dissolved and the separated sisters move toward opposite poles of the spindle. We developed a method to purify metaphase and anaphase chromosomes from frog egg extracts and identified proteins that leave chromosomes at anaphase using a new form of expression screening. This approach identified Xkid, a Xenopus homolog of human Kid (kinesin-like DNA binding protein) as a protein that is degraded in anaphase by ubiquitin-mediated proteolysis. Immunodepleting Xkid from egg extracts prevented normal chromosome alignment on the metaphase spindle. Adding a mild excess of wild-type or nondegradable Xkid to egg extracts prevented the separated chromosomes from moving toward the poles. We propose that Xkid provides the metaphase force that pushes chromosome arms toward the equator of the spindle and that its destruction is needed for anaphase chromosome movement.
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Affiliation(s)
- H Funabiki
- Department of Physiology, University of California, San Francisco 94143, USA.
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30
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Sültmann H, Murray BW, Klein J. Identification of seven genes in the major histocompatibility complex class I region of the zebrafish. Scand J Immunol 2000; 51:577-85. [PMID: 10849368 DOI: 10.1046/j.1365-3083.2000.00729.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Physical linkage of genes whose products are involved in similar physiological pathways may have functional significance. The identification of conserved gene linkage in distantly related organisms can therefore strengthen the hypothesis of selection acting towards keeping genes on a chromosome. We used the cDNA selection technique and the polymerase chain reaction (PCR) with generic primers for the identification of new genes on the genomic clones bearing the major histocompatibility complex (Mhc) class I genes of the zebrafish (Danio rerio). We found six new genes (BING1, DAXX, TAPBP, KNSL2, TAP2B and KE6) whose orthologues are known to be linked to the Mhc class II region in humans and mice. In addition, a new zebrafish Mhc class I gene, termed Dare-UFA, was detected. By contrast, a search for the human leucocyte antigen (HLA)-linked BING3, KE3 and SACM2L genes revealed that these loci are not located on the class I clones of the zebrafish. The zebrafish class I region contains repetitive elements with similarity to the DANA, SATA and LINE repeats, as well as Tc1 transposable elements. Our findings indicate a high degree of linkage conservation between the zebrafish class I and the mammalian class II regions.
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Affiliation(s)
- H Sültmann
- Max-Planck-Institut für Biologie, Abteilung Immungenetik, Tübingen, Germany
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31
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Navolanic PM, Sperry AO. Identification of isoforms of a mitotic motor in mammalian spermatogenesis. Biol Reprod 2000; 62:1360-9. [PMID: 10775188 DOI: 10.1095/biolreprod62.5.1360] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have isolated the full-length coding sequence for mouse KIFC5A (kinesin family c-terminal 5A) cDNA, encoding a motor protein found in the testes. The complete sequence of the KIFC5A cDNA is homologous to a group of carboxyl-terminal motors, including hamster CHO2, human HSET, and mouse KIFC1 and KIFC4. The KIFC5A and KIFC1 cDNAs are nearly identical except for the presence of two additional sequence blocks in the 5'-end of KIFC5A and a number of single base-pair differences in their motor domains. Polymerase chain reaction amplification and sequencing of the 5'-end of KIFC5A identified 3 distinct RNA species in testes and other tissues. Sequence comparison and genetic mapping confirmed the existence of a small multi-gene family in the mouse and suggest possible mechanisms of alternative splicing, genetic duplication, and separate genetic loci in the generation of these motors. In order to examine the possible role of these motors in germ cells of the testes, an antibody to a shared epitope was used to localize this group of proteins to different spermatogenic cell types. These experiments suggest that KIFC5-like motor proteins are associated with multiple microtubule complexes in male germ cells, including the meiotic spindle, the manchette, and the flagella.
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Affiliation(s)
- P M Navolanic
- Department of Pharmacology, East Carolina University School of Medicine, Greenville, North Carolina 27858, USA
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32
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Chang BD, Broude EV, Fang J, Kalinichenko TV, Abdryashitov R, Poole JC, Roninson IB. p21Waf1/Cip1/Sdi1-induced growth arrest is associated with depletion of mitosis-control proteins and leads to abnormal mitosis and endoreduplication in recovering cells. Oncogene 2000; 19:2165-70. [PMID: 10815808 DOI: 10.1038/sj.onc.1203573] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/1999] [Revised: 01/10/2000] [Accepted: 02/13/2000] [Indexed: 11/09/2022]
Abstract
Induction of a cyclin-dependent kinase inhibitor p21Waf1/ Cip1/Sdi1 is an integral part of cell growth arrest associated with senescence and damage response. p21 overexpression from an inducible promoter resulted in senescence-like growth arrest in a human fibrosarcoma cell line. After release from p21-induced growth arrest, cells re-entered the cell cycle but displayed growth retardation, cell death and decreased clonogenicity. The failure to form colonies was associated with abnormal mitosis and endoreduplication in the recovering cells and was correlated with the induced level of p21 and the duration of p21 induction. p21 induction was found to inhibit the expression of multiple proteins involved in the execution and control of mitosis. p21-induced depletion of the cellular pools of mitosis-control proteins was followed by asynchronous resynthesis of such proteins after release from p21, which explains the observed mitotic abnormalities. Genetic destabilization in cells recovering from p21-induced growth arrest may conceivably play a role in carcinogenesis and tumor progression.
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Affiliation(s)
- B D Chang
- Department of Molecular Genetics (M/C 669), University of Illinois at Chicago, 60607-7170, USA
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33
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Abstract
The budding yeast Saccharomyces cerevisiae provides a unique opportunity for study of the microtubule-based motor proteins that participate in mitotic spindle function. The genome of Saccharomyces encodes a relatively small and genetically tractable set of microtubule-based motor proteins. The single cytoplasmic dynein and five of the six kinesin-related proteins encoded have been implicated in mitotic spindle function. Each motor protein is unique in amino acid sequence. On account of functional overlap, no single motor is uniquely required for cell viability, however. The ability to create and analyze multiple mutants has allowed experimental dissection of the roles performed by each mitotic motor. Some of the motors operate within the nucleus to assemble and elongate the bipolar spindle (kinesin-related Cin8p, Kip1p, Kip3p and Kar3p). Others operate on the cytoplasmic microtubules to effect spindle and nuclear positioning within the cell (dynein and kinesin-related Kip2p, Kip3p and Kar3p). The six motors apparently contribute three fundamental activities to spindle function: motility, microtubule cross-linking and regulation of microtubule dynamics.
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Affiliation(s)
- E R Hildebrandt
- Department of Biology, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
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34
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Goldstein LS, Philp AV. The road less traveled: emerging principles of kinesin motor utilization. Annu Rev Cell Dev Biol 1999; 15:141-83. [PMID: 10611960 DOI: 10.1146/annurev.cellbio.15.1.141] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Proteins of the kinesin superfamily utilize a conserved catalytic motor domain to generate movements in a wide variety of cellular processes. In this review, we discuss the rapid expansion in our understanding of how eukaryotic cells take advantage of these proteins to generate force and movement in diverse functional contexts. We summarize several recent examples revealing that the simplest view of a kinesin motor protein binding to and translocating a cargo along a microtubule track is inadequate. In fact, this paradigm captures only a small subset of the many ways in which cells harness force production of the generation of intracellular movements and functions. We also highlight several situations where the catalytic kinesin motor domain may not be used to generate movement, but instead may be used in other biochemical and functional contexts. Finally, we review some recent ideas about kinesin motor regulation, redundancy, and cargo attachment strategies.
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Affiliation(s)
- L S Goldstein
- Howard Hughes Medical Institute, Department of Pharmacology, University of California San Diego, La Jolla 92093-0683, USA.
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35
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Rogers GC, Hart CL, Wedaman KP, Scholey JM. Identification of kinesin-C, a calmodulin-binding carboxy-terminal kinesin in animal (Strongylocentrotus purpuratus) cells. J Mol Biol 1999; 294:1-8. [PMID: 10556023 DOI: 10.1006/jmbi.1999.3249] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several novel members of the kinesin superfamily, until now identified only in plants, are unique in their ability to bind calmodulin in the presence of Ca(2+). Here, we identify the first such kinesin in an animal system. Sequence analysis of this new motor, called kinesin-C, predicts that it is a large carboxy-terminal kinesin, 1624 amino acid residues in length, with a predicted molecular mass of 181 kDa. Kinesin-C is predicted to contain a kinesin motor domain at its carboxy terminus, linked to a segment of alpha-helical coiled-coil 950 amino acid residues long, ending with an amino-terminal proline-rich tail domain. A putative calmodulin-binding domain resides at the extreme carboxy terminus of the motor polypeptide, and recombinant kinesin-C binds to a calmodulin-affinity column in a Ca(2+)-dependent fashion. The presence of this novel calmodulin-binding motor in sea urchin embryos suggests that it plays a critical role in Ca(2+)-dependent events during early sea urchin development.
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Affiliation(s)
- G C Rogers
- Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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36
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Matuliene J, Essner R, Ryu J, Hamaguchi Y, Baas PW, Haraguchi T, Hiraoka Y, Kuriyama R. Function of a minus-end-directed kinesin-like motor protein in mammalian cells. J Cell Sci 1999; 112 ( Pt 22):4041-50. [PMID: 10547364 DOI: 10.1242/jcs.112.22.4041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CHO2 is a mammalian minus-end-directed kinesin-like motor protein present in interphase centrosomes/nuclei and mitotic spindle fibers/poles. Expression of HA- or GFP-tagged subfragments in transfected CHO cells revealed the presence of the nuclear localization site at the N-terminal tail. This domain becomes associated with spindle fibers during mitosis, indicating that the tail is capable of interaction with microtubules in vivo. While the central stalk diffusely distributes in the entire cytoplasm of cells, the motor domain co-localizes with microtubules throughout the cell cycle, which is eliminated by mutation of the ATP-binding consensus motif from GKT to AAA. Overexpression of the full-length CHO2 causes mitotic arrest and spindle abnormality. The effect of protein expression was first seen around the polar region where microtubule tended to be bundled together. A higher level of protein expression induces more elongated spindles which eventually become disorganized by loosing the structural integrity between microtubule bundles. Live cell observation demonstrated that GFP-labeled microtubule bundles underwent continuous changes in their relative position to one another through repeated attachment and detachment at one end; this results in the formation of irregular number of microtubule focal points in mitotic arrested cells. Thus the primary action of CHO2 appears to cross-link microtubules and move toward the minus-end direction to maintain association of the microtubule end at the pole. In contrast to the full-length of CHO2, overexpression of neither truncated nor mutant polypeptides resulted in significant effects on mitosis and mitotic spindles, suggesting that the function of CHO2 in mammalian cells may be redundant with other motor molecules during cell division.
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Affiliation(s)
- J Matuliene
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN55455, USA
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Mountain V, Simerly C, Howard L, Ando A, Schatten G, Compton DA. The kinesin-related protein, HSET, opposes the activity of Eg5 and cross-links microtubules in the mammalian mitotic spindle. J Cell Biol 1999; 147:351-66. [PMID: 10525540 PMCID: PMC2174226 DOI: 10.1083/jcb.147.2.351] [Citation(s) in RCA: 252] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have prepared antibodies specific for HSET, the human homologue of the KAR3 family of minus end-directed motors. Immuno-EM with these antibodies indicates that HSET frequently localizes between microtubules within the mammalian metaphase spindle consistent with a microtubule cross-linking function. Microinjection experiments show that HSET activity is essential for meiotic spindle organization in murine oocytes and taxol-induced aster assembly in cultured cells. However, inhibition of HSET did not affect mitotic spindle architecture or function in cultured cells, indicating that centrosomes mask the role of HSET during mitosis. We also show that (acentrosomal) microtubule asters fail to assemble in vitro without HSET activity, but simultaneous inhibition of HSET and Eg5, a plus end-directed motor, redresses the balance of forces acting on microtubules and restores aster organization. In vivo, centrosomes fail to separate and monopolar spindles assemble without Eg5 activity. Simultaneous inhibition of HSET and Eg5 restores centrosome separation and, in some cases, bipolar spindle formation. Thus, through microtubule cross-linking and oppositely oriented motor activity, HSET and Eg5 participate in spindle assembly and promote spindle bipolarity, although the activity of HSET is not essential for spindle assembly and function in cultured cells because of centrosomes.
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Affiliation(s)
- Vicki Mountain
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Calvin Simerly
- Departments of Cell-Developmental Biology, Obstetrics-Gynecology, and Oregon Regional Primate Research Center, Oregon Health Sciences University, Beaverton, Oregon 97006
| | - Louisa Howard
- Rippel Electron Microscope Facility, Dartmouth College, Hanover, New Hampshire 03755
| | - Asako Ando
- Department of Genetic Information, Division of Molecular Life Science, University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan
| | - Gerald Schatten
- Departments of Cell-Developmental Biology, Obstetrics-Gynecology, and Oregon Regional Primate Research Center, Oregon Health Sciences University, Beaverton, Oregon 97006
| | - Duane A. Compton
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
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Tsakraklides V, Krogh K, Wang L, Bizario JC, Larson RE, Espreafico EM, Wolenski JS. Subcellular localization of GFP-myosin-V in live mouse melanocytes. J Cell Sci 1999; 112 ( Pt 17):2853-65. [PMID: 10444380 DOI: 10.1242/jcs.112.17.2853] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Class-V myosins are two-headed actin-based mechanoenzymes that function in the transport and subcellular localization of organelles and possibly in the outgrowth of cellular processes. To determine which domains of myosin-V are involved in intracellular localization of this motor protein, we have expressed fusions of the green fluorescent protein with segments from two distinct myosin-V heavy chains. The expression patterns of constructs encoding four different domains of chick brain myosin-Va were compared to a single construct encoding the globular tail region of mouse myosin-Vb. In transfected mouse melanocytes, expression of the NH(2)-terminal head (catalytic domain) of chick brain myosin-Va codistributed with actin filaments throughout the cytoplasm. A similar construct encoding the myosin-Va head with the associated neck (light chain binding sites), also codistributed with actin filaments. The GFP-head-neck peptide was also highly concentrated in the tips of filopodia in B16 melanocytes wild type for myosin-Va (MYO5a gene), but was concentrated throughout the entire filopodia of S91-6 melanocytes derived from dilute mice with mutations in the MYO5a gene. Evidence is also presented that the globular tail of myosin-Va, but not myosin-Vb, targets this motor molecule to the centrosome as confirmed by colocalization in cells stained with antibodies to (gamma)-tubulin. Expression of the GFP-myosin-Va globular tail causes displacement of endogenous myosin-V from centrosomes as visualized by immunolabeling with antibodies to the head domain of myosin-V. Treatment with the microtubule-disrupting drug nocodazole markedly reduces myosin-V staining at the centrosome. In contrast, there was no detectable diminution of myosin-V staining at the centrosome in cells treated with the actin filament-disrupting drug cytochalasin D. Thus, while localization of the myosin-V motor domain to actin-rich regions is consistent with conventional models of actomyosin-based motility, localization to the centrosome occurs in the complete absence of the myosin-V motor domain and is dependent on intact microtubules.
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Affiliation(s)
- V Tsakraklides
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8103, USA
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39
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Abstract
Many of the kinesin microtubule motor proteins discovered during the past 8-9 years have roles in spindle assembly and function or chromosome movement during meiosis or mitosis. The discovery of kinesin motor proteins with a clear involvement in spindle and chromosome motility, together with recent evidence that cytoplasmic dynein plays a role in chromosome distribution, has attracted great interest. The identification of microtubule motors that function in chromosome distribution represents a major advance in understanding the forces that underlie chromosome and spindle movements during cell division.
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Affiliation(s)
- S A Endow
- Department of Microbiology, Duke University Medical Center, Durham, NC USA.
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40
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Mattagajasingh SN, Huang SC, Hartenstein JS, Snyder M, Marchesi VT, Benz EJ. A nonerythroid isoform of protein 4.1R interacts with the nuclear mitotic apparatus (NuMA) protein. J Biophys Biochem Cytol 1999; 145:29-43. [PMID: 10189366 PMCID: PMC2148212 DOI: 10.1083/jcb.145.1.29] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Red blood cell protein 4.1 (4.1R) is an 80- kD erythrocyte phosphoprotein that stabilizes the spectrin/actin cytoskeleton. In nonerythroid cells, multiple 4.1R isoforms arise from a single gene by alternative splicing and predominantly code for a 135-kD isoform. This isoform contains a 209 amino acid extension at its NH2 terminus (head piece; HP). Immunoreactive epitopes specific for HP have been detected within the cell nucleus, nuclear matrix, centrosomes, and parts of the mitotic apparatus in dividing cells. Using a yeast two-hybrid system, in vitro binding assays, coimmunolocalization, and coimmunoprecipitation studies, we show that a 135-kD 4.1R isoform specifically interacts with the nuclear mitotic apparatus (NuMA) protein. NuMA and 4.1R partially colocalize in the interphase nucleus of MDCK cells and redistribute to the spindle poles early in mitosis. Protein 4.1R associates with NuMA in the interphase nucleus and forms a complex with spindle pole organizing proteins, NuMA, dynein, and dynactin during cell division. Overexpression of a 135-kD isoform of 4.1R alters the normal distribution of NuMA in the interphase nucleus. The minimal sequence sufficient for this interaction has been mapped to the amino acids encoded by exons 20 and 21 of 4.1R and residues 1788-1810 of NuMA. Our results not only suggest that 4.1R could, possibly, play an important role in organizing the nuclear architecture, mitotic spindle, and spindle poles, but also could define a novel role for its 22-24-kD domain.
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Affiliation(s)
- S N Mattagajasingh
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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41
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Affiliation(s)
- R Kuriyama
- Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis 55455, USA
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42
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Sheetz MP, Pfister KK, Bulinski JC, Cotman CW. Mechanisms of trafficking in axons and dendrites: implications for development and neurodegeneration. Prog Neurobiol 1998; 55:577-94. [PMID: 9670219 DOI: 10.1016/s0301-0082(98)00021-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the area of routing and sorting of dendritic traffic, the current phenomenological data beg questions about the cellular mechanisms utilized not only to transport material but also to modulate activity in a process, even apoptosis. To aid in formulating testable hypotheses, many plausible models are developed here and linked with some of the preliminary data that supports them. We first assume that in long dendrites the sorting of membranous proteins into transport vesicles also involves the linkage of motor proteins to the vesicles. Second, we assume that the cytoskeleton in dendrites is altered from the cytoskeleton in axons and the cell body. Viral glycoproteins, MAP2 and specific mRNA sorting into dendrites provide the simplest models for analyzing vesicular, cytoskeletal and RNA sorting. In the case of viral glycoproteins, initial sorting appears to occur at the Golgi but additional routing steps involve further complexities that could best be served by an additional sorting step at the junction of the cell body and the process. Transport of the specialized cytoskeletal proteins and specific mRNAs as well as vesicular material could be controlled by a similar gatekeeper at the mouth of a process. Studies of the microtubule-organelle motor complex, regulation of microtubule-based motility by microtubule-associated proteins, and slow axonal transport all provide insights into important aspects of the routing and sorting. These processes are in turn controlled by extracellular signals such as those generated by matrix molecules or their hydrolysis products in the case of amyloid precursor protein (APP). Routing and sorting mechanisms may be central to the development of Alzheimer's disease in view of evidence that APP processing is affected, transport is disturbed, and intracellular vesicles (early endosomes) hypertrophied. Further it is possible that routing mechanisms play a role in cell-cell interactions as, for example, the possibility that pathogenic/cellular stress signals may be passed along circuits transsynaptically.
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Affiliation(s)
- M P Sheetz
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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43
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Narasimhulu SB, Reddy AS. Characterization of microtubule binding domains in the Arabidopsis kinesin-like calmodulin binding protein. THE PLANT CELL 1998; 10:957-65. [PMID: 9634584 PMCID: PMC144043 DOI: 10.1105/tpc.10.6.957] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The kinesin-like calmodulin binding protein (KCBP) is a new member of the kinesin superfamily that appears to be present only in plants. The KCBP is unique in its ability to interact with calmodulin in a Ca2+-dependent manner. To study the interaction of the KCBP with microtubules, we expressed different regions of the Arabidopsis KCBP and used the purified proteins in cosedimentation assays with microtubules. The motor domain with or without the calmodulin binding domain bound to microtubules. The binding of the motor domain containing the calmodulin binding region to microtubules was inhibited by Ca2+-calmodulin. This Ca2+-calmodulin regulation of motor domain interactions with microtubules was abolished in the presence of antibodies specific to the calmodulin binding region. In addition, the binding of the motor domain lacking the calmodulin binding region to microtubules was not inhibited in the presence of Ca2+-calmodulin, suggesting an essential role for the calmodulin binding region in Ca2+-calmodulin modulation. Results of the cosedimentation assays with the N-terminal tail suggest the presence of a second microtubule binding site on the KCBP. However, the interaction of the N-terminal tail region of the KCBP with microtubules was insensitive to ATP. These data on the interaction of the KCBP with microtubules provide new insights into the functioning of the KCBP in plants.
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Affiliation(s)
- S B Narasimhulu
- Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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44
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Abstract
Spindle poles are discernible by light microscopy as the sites where microtubules converge at the ends of both mitotic and meiotic spindles. In most cell types centrosomes are present at spindle poles due to their dominant role in microtubule nucleation. However, in some specialized cell types microtubules converge into spindle poles in the absence of centrosomes. Thus, spindle poles in centrosomal and acentrosomal cell types are structurally different, and it is this structural dichotomy that has created confusion as to the mechanism by which microtubules are organized into spindle poles. This review summarizes a series of recent articles that begin to resolve this confusion by demonstrating that spindle poles are organized through a common mechanism by a conserved group of non-centrosomal proteins in the presence or absence of centrosomes.
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Affiliation(s)
- D A Compton
- Department of Biochemistry, Dartmouth Medical School, Room 411, Hanover, NH 03755, USA.
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45
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Allersma MW, Gittes F, deCastro MJ, Stewart RJ, Schmidt CF. Two-dimensional tracking of ncd motility by back focal plane interferometry. Biophys J 1998; 74:1074-85. [PMID: 9533719 PMCID: PMC1302587 DOI: 10.1016/s0006-3495(98)74031-7] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A technique for detecting the displacement of micron-sized optically trapped probes using far-field interference is introduced, theoretically explained, and used to study the motility of the ncd motor protein. Bead motions in the focal plane relative to the optical trap were detected by measuring laser intensity shifts in the back-focal plane of the microscope condenser by projection on a quadrant diode. This detection method is two-dimensional, largely independent of the position of the trap in the field of view and has approximately 10-micros time resolution. The high resolution makes it possible to apply spectral analysis to measure dynamic parameters such as local viscosity and attachment compliance. A simple quantitative theory for back-focal-plane detection was derived that shows that the laser intensity shifts are caused primarily by a far-field interference effect. The theory predicts the detector response to bead displacement, without adjustable parameters, with good accuracy. To demonstrate the potential of the method, the ATP-dependent motility of ncd, a kinesin-related motor protein, was observed with an in vitro bead assay. A fusion protein consisting of truncated ncd (amino acids 195-685) fused with glutathione-S-transferase was adsorbed to silica beads, and the axial and lateral motions of the beads along the microtubule surface were observed with high spatial and temporal resolution. The average axial velocity of the ncd-coated beads was 230 +/- 30 nm/s (average +/- SD). Spectral analysis of bead motion showed the increase in viscous drag near the surface; we also found that any elastic constraints of the moving motors are much smaller than the constraints due to binding in the presence of the nonhydrolyzable nucleotide adenylylimidodiphosphate.
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Affiliation(s)
- M W Allersma
- Department of Physics, University of Michigan, Ann Arbor 48109, USA
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46
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Yang Z, Hanlon DW, Marszalek JR, Goldstein LS. Identification, partial characterization, and genetic mapping of kinesin-like protein genes in mouse. Genomics 1997; 45:123-31. [PMID: 9339368 DOI: 10.1006/geno.1997.4901] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Microtubule-dependent motors of the kinesin superfamily have undergone structural and functional diversification during evolution and play crucial roles in cell division and intracellular transport. Degenerate oligonucleotides homologous to highly conserved regions of sequence within the motor domain were used in a polymerase chain reaction to isolate five new members (KIF3C, KIFC2, KIFC3, KIFC4, and KIF22) of the kinesin superfamily from a mouse brain cDNA library. Northern analysis showed that KIF3C and KIFC2 are expressed mainly in neural tissues, that KIFC4 and KIF22 are expressed primarily in proliferative tissues and cell lines, and that KIFC3 is apparently ubiquitous. To elucidate the organization of genes encoding kinesin-like motors in the mouse genome and to explore the potential associations of these genes with classical mouse mutations or human genetic diseases, these new genes as well as genes encoding the previously reported KIF3A and KIF3B motors were mapped to mouse chromosomes by using an interspecific backcross panel of DNAs from The Jackson Laboratory. The data indicate that the gene KIFC4 is present in three copies in the mouse genome on chromosomes 13 (KIFC4A), 10 (KIFC4B), and 17 (KIFC4C). The gene KIF22 is present in two copies on chromosomes 7 (KIF22A) and 1 (KIF22B). The genes KIF3A, KIF3B, KIF3C, KIFC2, and KIFC3 are each single loci and map to chromosomes 11, 2, 12, 15, and 8, respectively.
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Affiliation(s)
- Z Yang
- Howard Hughes Medical Institute, Department of Pharmacology, University of California at San Diego, La Jolla 92093-0683, USA
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47
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Case RB, Pierce DW, Hom-Booher N, Hart CL, Vale RD. The directional preference of kinesin motors is specified by an element outside of the motor catalytic domain. Cell 1997; 90:959-66. [PMID: 9298907 DOI: 10.1016/s0092-8674(00)80360-8] [Citation(s) in RCA: 258] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Members of the kinesin superfamily share a similar motor catalytic domain yet move either toward the plus end (e.g., conventional kinesin) or the minus end (e.g., Ncd) of microtubules. The structural features that determine the polarity of movement have remained enigmatic. Here, we show that kinesin's catalytic domain (316 residues) in a dimeric construct (560 residues) can be replaced with the catalytic domain of Ncd and that the resultant motor moves in the kinesin direction. We also demonstrate that this chimera does not move processively over many tubulin subunits, which is similar to Ncd but differs from the highly processive motion of conventional kinesin. These findings reveal that the catalytic domain contributes to motor processivity but does not control the polarity of movement. We propose that a region adjacent to the catalytic domain serves as a mechanical transducer that determines directionality.
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Affiliation(s)
- R B Case
- Department of Pharmacology, University of California, San Francisco 94143, USA
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48
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Abstract
How do cells order their cytoplasm? While microtubule organizing centers have long been considered essential to conferring order by virtue of their microtubule nucleating activity, attention has currently refocused on the role that microtubule motors play in organizing microtubules. An intriguing set of recent findings reveals that cell fragments, lacking microtubule organizing centers, rapidly organize microtubules into a radial array during organelle transport driven by the microtubule motor, cytoplasmic dynein. Further, interaction of radial microtubules with the cell surface centers the array, revealing that centering information resides not with centrosomes but with organized microtubules.
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Affiliation(s)
- L T Haimo
- Department of Biology, University of California, Riverside 92521, USA.
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49
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Hanlon DW, Yang Z, Goldstein LS. Characterization of KIFC2, a neuronal kinesin superfamily member in mouse. Neuron 1997; 18:439-51. [PMID: 9115737 DOI: 10.1016/s0896-6273(00)81244-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Members of the kinesin superfamily of microtubule-associated proteins are involved in a variety of intracellular processes including cell division and organelle transport. In the case of axonal transport, all kinesin superfamily members reported thus far appear to play a role in anterograde transport, while a different type of microtubule motor, dynein, appears to function in retrograde transport. To better understand the role of kinesins in axonal transport, we cloned and characterized KIFC2, a novel kinesin superfamily member from mouse brain. KIFC2 encodes a 792 amino acid protein, which contains the conserved motor domain at the C-terminal end of the protein and is most similar to members of the KAR3 family involved in cell division. However, expression analysis localized KIFC2 mRNA to nonproliferative neuronal cells in the central nervous system, and immunolocalization studies demonstrated that KIFC2 is present in axons and dendrites of neurons in the central and peripheral nervous systems. Immunolocalization and biochemical fractionation studies suggest that KIFC2 localizes with some, but not all, axonally transported organelles. Finally, ligation of mouse peripheral nerves showed that KIFC2 accumulates at the proximal and distal sides of an axonal ligature. Taken together, the data suggest that, unlike other C-terminal motor proteins that appear to be involved in cell division, KIFC2 may play a role in retrograde axonal transport.
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Affiliation(s)
- D W Hanlon
- Department of Pharmacology, University of California, San Diego, La Jolla 92093-0683, USA
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50
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Saito N, Okada Y, Noda Y, Kinoshita Y, Kondo S, Hirokawa N. KIFC2 is a novel neuron-specific C-terminal type kinesin superfamily motor for dendritic transport of multivesicular body-like organelles. Neuron 1997; 18:425-38. [PMID: 9115736 DOI: 10.1016/s0896-6273(00)81243-x] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have cloned two novel C-terminal motor domain-type kinesin superfamily motor proteins (KIFCs) from mouse brain by utilizing a KIFC-specific consensus sequence. The first protein was the murine homologue of CHO2 antigen, a member of the kar3-type mitotic motor subfamily, and we designated this protein KIFC1. The other protein, KIFC2 (792 amino acids), is novel, with no significant similarity to known kinesin superfamily proteins (KIFs). KIFC2 was specifically expressed in adult neurons, and was immunofluorescently localized to punctate structures in cell bodies and dendrites, but was not detected in axons. Electron microscopic analysis of the immunoisolated KIFC2-bound organelles revealed that KIFC2 associates with multivesicular body (mvb)-like organelles, suggesting that KIFC2 functions as the motor for the transport of mvb-like organelles in dendrites.
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Affiliation(s)
- N Saito
- Department of Anatomy and Cell Biology, Faculty of Medicine, University of Tokyo, Hongo, Japan
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