1
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Czajkowski ER, Zou Y, Divekar NS, Wignall SM. The doublecortin-family kinase ZYG-8DCLK1 regulates microtubule dynamics and motor-driven forces to promote the stability of C. elegans acentrosomal spindles. PLoS Genet 2024; 20:e1011373. [PMID: 39226307 PMCID: PMC11398696 DOI: 10.1371/journal.pgen.1011373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 09/13/2024] [Accepted: 07/23/2024] [Indexed: 09/05/2024] Open
Abstract
Although centrosomes help organize spindles in most cell types, oocytes of most species lack these structures. During acentrosomal spindle assembly in C. elegans oocytes, microtubule minus ends are sorted outwards away from the chromosomes where they form poles, but then these outward forces must be balanced to form a stable bipolar structure. Simultaneously, microtubule dynamics must be precisely controlled to maintain spindle length and organization. How forces and dynamics are tuned to create a stable bipolar structure is poorly understood. Here, we have gained insight into this question through studies of ZYG-8, a conserved doublecortin-family kinase; the mammalian homolog of this microtubule-associated protein is upregulated in many cancers and has been implicated in cell division, but the mechanisms by which it functions are poorly understood. We found that ZYG-8 depletion from oocytes resulted in overelongated spindles with pole and midspindle defects. Importantly, experiments with monopolar spindles revealed that ZYG-8 depletion led to excess outward forces within the spindle and suggested a potential role for this protein in regulating the force-generating motor BMK-1/kinesin-5. Further, we found that ZYG-8 is also required for proper microtubule dynamics within the oocyte spindle and that kinase activity is required for its function during both meiosis and mitosis. Altogether, our findings reveal new roles for ZYG-8 in oocytes and provide insights into how acentrosomal spindles are stabilized to promote faithful meiosis.
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Affiliation(s)
- Emily R Czajkowski
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Yuntong Zou
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Nikita S Divekar
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Sarah M Wignall
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
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2
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Parmar S, Gonzalez SJ, Heckel JM, Mukherjee S, McClellan M, Clarke DJ, Johansson M, Tank D, Geisness A, Wood DK, Gardner MK. Robust microtubule dynamics facilitate low-tension kinetochore detachment in metaphase. J Cell Biol 2023; 222:e202202085. [PMID: 37166419 PMCID: PMC10182774 DOI: 10.1083/jcb.202202085] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 02/07/2023] [Accepted: 04/24/2023] [Indexed: 05/12/2023] Open
Abstract
During mitosis, sister chromatids are stretched apart at their centromeres via their attachment to oppositely oriented kinetochore microtubules. This stretching generates inwardly directed tension across the separated sister centromeres. The cell leverages this tension signal to detect and then correct potential errors in chromosome segregation, via a mechanical tension signaling pathway that detaches improperly attached kinetochores from their microtubules. However, the sequence of events leading up to these detachment events remains unknown. In this study, we used microfluidics to sustain and observe low-tension budding yeast metaphase spindles over multiple hours, allowing us to elucidate the tension history prior to a detachment event. We found that, under conditions in which kinetochore phosphorylation weakens low-tension kinetochore-microtubule connections, the mechanical forces produced via the dynamic growth and shortening of microtubules is required to efficiently facilitate detachment events. Our findings underscore the critical role of robust kinetochore microtubule dynamics in ensuring the fidelity of chromosome segregation during mitosis.
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Affiliation(s)
- Sneha Parmar
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Samuel J. Gonzalez
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Julia M. Heckel
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Soumya Mukherjee
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Mark McClellan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Duncan J. Clarke
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Marnie Johansson
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Damien Tank
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Athena Geisness
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - David K. Wood
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Melissa K. Gardner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
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3
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Murase Y, Yamagishi M, Okada N, Toya M, Yajima J, Hamada T, Sato M. Fission yeast Dis1 is an unconventional TOG/XMAP215 that induces microtubule catastrophe to drive chromosome pulling. Commun Biol 2022; 5:1298. [PMID: 36435910 PMCID: PMC9701203 DOI: 10.1038/s42003-022-04271-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/16/2022] [Indexed: 11/28/2022] Open
Abstract
The shortening of microtubules attached to kinetochores is the driving force of chromosome movement during cell division. Specific kinesins are believed to shorten microtubules but are dispensable for viability in yeast, implying the existence of additional factors responsible for microtubule shortening. Here, we demonstrate that Dis1, a TOG/XMAP215 ortholog in fission yeast, promotes microtubule shortening to carry chromosomes. Although TOG/XMAP215 orthologs are generally accepted as microtubule polymerases, Dis1 promoted microtubule catastrophe in vitro and in vivo. Notably, microtubule catastrophe was promoted when the tip was attached to kinetochores, as they steadily anchored Dis1 at the kinetochore-microtubule interface. Engineered Dis1 oligomers artificially tethered at a chromosome arm region induced the shortening of microtubules in contact, frequently pulling the chromosome arm towards spindle poles. This effect was not brought by oligomerised Alp14. Thus, unlike Alp14 and other TOG/XMAP215 orthologs, Dis1 plays an unconventional role in promoting microtubule catastrophe, thereby driving chromosome movement.
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Affiliation(s)
- Yuichi Murase
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan
| | - Masahiko Yamagishi
- grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, 153-8902 Tokyo Japan
| | - Naoyuki Okada
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan ,grid.5808.50000 0001 1503 7226Instituto de Biologia Molecular e Celular, Instituto de Investigacao e Inovacao em Saude (i3S), Universidade do Porto, 208 Rua Alfredo Allen, 4200-135 Porto, Portugal
| | - Mika Toya
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan ,grid.5290.e0000 0004 1936 9975Global Center for Science and Engineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 Japan ,grid.5290.e0000 0004 1936 9975Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 Japan
| | - Junichiro Yajima
- grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, 153-8902 Tokyo Japan ,grid.26999.3d0000 0001 2151 536XKomaba Institute for Science, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, 153-8902 Tokyo Japan ,grid.26999.3d0000 0001 2151 536XResearch Center for Complex Systems Biology, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, 153-8902 Tokyo Japan
| | - Takahiro Hamada
- grid.444568.f0000 0001 0672 2184Department of Bioscience, Faculty of Life Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama-shi 700-0005 Japan
| | - Masamitsu Sato
- grid.5290.e0000 0004 1936 9975Laboratory of Cytoskeletal Logistics, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan ,grid.5290.e0000 0004 1936 9975Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 Japan ,grid.5290.e0000 0004 1936 9975Institute for Medical-Oriented Structural Biology, Waseda University, 2-2 Wakamatsucho, Shinjuku-ku, Tokyo 162-8480 Japan
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4
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The TOG protein Stu2 is regulated by acetylation. PLoS Genet 2022; 18:e1010358. [PMID: 36084134 PMCID: PMC9491610 DOI: 10.1371/journal.pgen.1010358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 09/21/2022] [Accepted: 07/27/2022] [Indexed: 11/27/2022] Open
Abstract
Stu2 in S. cerevisiae is a member of the XMAP215/Dis1/CKAP5/ch-TOG family of MAPs and has multiple functions in controlling microtubules, including microtubule polymerization, microtubule depolymerization, linking chromosomes to the kinetochore, and assembly of γ-TuSCs at the SPB. Whereas phosphorylation has been shown to be critical for Stu2 localization at the kinetochore, other regulatory mechanisms that control Stu2 function are still poorly understood. Here, we show that a novel form of Stu2 regulation occurs through the acetylation of three lysine residues at K252, K469, and K870, which are located in three distinct domains of Stu2. Alteration of acetylation through acetyl-mimetic and acetyl-blocking mutations did not impact the essential function of Stu2. Instead, these mutations lead to a decrease in chromosome stability, as well as changes in resistance to the microtubule depolymerization drug, benomyl. In agreement with our in silico modeling, several acetylation-mimetic mutants displayed increased interactions with γ-tubulin. Taken together, these data suggest that Stu2 acetylation can govern multiple Stu2 functions, including chromosome stability and interactions at the SPB. Microtubules are proteinaceous polymers that play several important roles in cell division and segregation of the genetic material to each daughter cell. The functions of microtubules are critically dependent upon their dynamic properties in which tubulin subunits are added or removed from the microtubule end, allowing microtubules to grow or shorten in length. These dynamic properties are controlled by several types of microtubule associated proteins. In this study using bakers yeast, we describe our discovery of a previously unappreciated way to regulate the microtubule associated protein Stu2 by a modification called acetylation. When we created mutations in the Stu2 protein that can’t be properly acetylated, the cell lost some of its chromosomes. Some of these mutations actually caused the microtubules to be resistant to drugs that normally disassemble the microtubule polymer. As similar versions of the Stu2 protein are found in diverse organisms that range from yeast and fungus, to plants, insects, mammals and humans, our work could provide unique insights into how microtubules malfunction in some human diseases. With further studies, this may provide a new understanding of chromosome loss in birth defects and/or cancer.
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5
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Meyer RE, Tipton AR, LaVictoire R, Gorbsky GJ, Dawson DS. Mps1 promotes poleward chromosome movements in meiotic prometaphase. Mol Biol Cell 2021; 32:1020-1032. [PMID: 33788584 PMCID: PMC8101486 DOI: 10.1091/mbc.e20-08-0525-t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In prophase of meiosis I, homologous chromosomes pair and become connected by cross-overs. Chiasmata, the connections formed by cross-overs, enable the chromosome pair, called a bivalent, to attach as a single unit to the spindle. When the meiotic spindle forms in prometaphase, most bivalents are associated with one spindle pole and then go through a series of oscillations on the spindle, attaching to and detaching from microtubules until the partners of the bivalent become bioriented—attached to microtubules from opposite sides of the spindle. The conserved kinase, Mps1, is essential for the bivalents to be pulled by microtubules across the spindle in prometaphase. Here we show that MPS1 is needed for efficient triggering of the migration of microtubule-attached kinetochores toward the poles and promotes microtubule depolymerization. Our data support the model Mps1 acts at the kinetochore to coordinate the successful attachment of a microtubule and the triggering of microtubule depolymerization to then move the chromosome.
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Affiliation(s)
- Régis E Meyer
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104
| | - Aaron R Tipton
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104
| | - Rebecca LaVictoire
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104
| | - Gary J Gorbsky
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Dean S Dawson
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
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6
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Zahm JA, Stewart MG, Carrier JS, Harrison SC, Miller MP. Structural basis of Stu2 recruitment to yeast kinetochores. eLife 2021; 10:e65389. [PMID: 33591274 PMCID: PMC7909949 DOI: 10.7554/elife.65389] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/15/2021] [Indexed: 12/02/2022] Open
Abstract
Chromosome segregation during cell division requires engagement of kinetochores of sister chromatids with microtubules emanating from opposite poles. As the corresponding microtubules shorten, these 'bioriented' sister kinetochores experience tension-dependent stabilization of microtubule attachments. The yeast XMAP215 family member and microtubule polymerase, Stu2, associates with kinetochores and contributes to tension-dependent stabilization in vitro. We show here that a C-terminal segment of Stu2 binds the four-way junction of the Ndc80 complex (Ndc80c) and that residues conserved both in yeast Stu2 orthologs and in their metazoan counterparts make specific contacts with Ndc80 and Spc24. Mutations that perturb this interaction prevent association of Stu2 with kinetochores, impair cell viability, produce biorientation defects, and delay cell cycle progression. Ectopic tethering of the mutant Stu2 species to the Ndc80c junction restores wild-type function in vivo. These findings show that the role of Stu2 in tension-sensing depends on its association with kinetochores by binding with Ndc80c.
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Affiliation(s)
- Jacob A Zahm
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Howard Hughes Medical InstituteBostonUnited States
| | - Michael G Stewart
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Joseph S Carrier
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, and Howard Hughes Medical InstituteBostonUnited States
| | - Matthew P Miller
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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7
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Miller MP, Evans RK, Zelter A, Geyer EA, MacCoss MJ, Rice LM, Davis TN, Asbury CL, Biggins S. Kinetochore-associated Stu2 promotes chromosome biorientation in vivo. PLoS Genet 2019; 15:e1008423. [PMID: 31584935 PMCID: PMC6795502 DOI: 10.1371/journal.pgen.1008423] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/16/2019] [Accepted: 09/13/2019] [Indexed: 12/31/2022] Open
Abstract
Accurate segregation of chromosomes to daughter cells is a critical aspect of cell division. It requires the kinetochores on duplicated chromosomes to biorient, attaching to microtubules from opposite poles of the cell. Bioriented attachments come under tension, while incorrect attachments lack tension and must be released to allow proper attachments to form. A well-studied error correction pathway is mediated by the Aurora B kinase, which destabilizes low tension-bearing attachments. We recently discovered that in vitro, kinetochores display an additional intrinsic tension-sensing pathway that utilizes Stu2. The contribution of kinetochore-associated Stu2 to error correction in cells, however, was unknown. Here, we identify a Stu2 mutant that abolishes its kinetochore function and show that it causes biorientation defects in vivo. We also show that this Stu2-mediated pathway functions together with the Aurora B-mediated pathway. Altogether, our work indicates that cells employ multiple pathways to ensure biorientation and the accuracy of chromosome segregation. The precise regulation of cell division is critical to processes such as self-renewal, proliferation and development. A key event in the cell cycle is the partitioning of every pair of duplicated chromosomes to daughter cells. Defects in chromosome partitioning lead to aneuploidy, a condition that is a common hallmark of cancer cells and the cause of some birth defects. Chromosomes segregate using their kinetochores, the specialized protein structures that are assembled on centromeric DNA sequences and attach to spindle microtubules. Here, we report that a protein that associates with kinetochores called Stu2 ensures that each kinetochore attaches to the proper microtubules. We identified a Stu2 mutant that does not associate with kinetochores and found that it generates aneuploidy. Together, our work identifies a previously unknown mechanism where cells ensure that chromosomes are accurately inherited during cell division.
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Affiliation(s)
- Matthew P. Miller
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Rena K. Evans
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Alex Zelter
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States of America
| | - Elisabeth A. Geyer
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michael J. MacCoss
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Luke M. Rice
- Departments of Biophysics and Biochemistry, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Trisha N. Davis
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States of America
| | - Charles L. Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington, United States of America
| | - Sue Biggins
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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8
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Slater PG, Cammarata GM, Samuelson AG, Magee A, Hu Y, Lowery LA. XMAP215 promotes microtubule-F-actin interactions to regulate growth cone microtubules during axon guidance in Xenopus laevis. J Cell Sci 2019; 132:jcs.224311. [PMID: 30890650 DOI: 10.1242/jcs.224311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 03/08/2019] [Indexed: 12/24/2022] Open
Abstract
It has long been established that neuronal growth cone navigation depends on changes in microtubule (MT) and F-actin architecture downstream of guidance cues. However, the mechanisms by which MTs and F-actin are dually coordinated remain a fundamentally unresolved question. Here, we report that the well-characterized MT polymerase, XMAP215 (also known as CKAP5), plays an important role in mediating MT-F-actin interaction within the growth cone. We demonstrate that XMAP215 regulates MT-F-actin alignment through its N-terminal TOG 1-5 domains. Additionally, we show that XMAP215 directly binds to F-actin in vitro and co-localizes with F-actin in the growth cone periphery. We also find that XMAP215 is required for regulation of growth cone morphology and response to the guidance cue, Ephrin A5. Our findings provide the first strong evidence that XMAP215 coordinates MT and F-actin interaction in vivo We suggest a model in which XMAP215 regulates MT extension along F-actin bundles into the growth cone periphery and that these interactions may be important to control cytoskeletal dynamics downstream of guidance cues. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Paula G Slater
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | | | - Alexandra Magee
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | - Yuhan Hu
- Department of Cell Biology, Yale University, New Haven, CT 06520, USA
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9
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Greenlee M, Alonso A, Rahman M, Meednu N, Davis K, Tabb V, Cook R, Miller RK. The TOG protein Stu2/XMAP215 interacts covalently and noncovalently with SUMO. Cytoskeleton (Hoboken) 2018; 75:290-306. [PMID: 29729126 PMCID: PMC6712953 DOI: 10.1002/cm.21449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 04/27/2018] [Accepted: 04/30/2018] [Indexed: 01/21/2023]
Abstract
Stu2p is the yeast member of the XMAP215/Dis1/ch‐TOG family of microtubule‐associated proteins that promote microtubule polymerization. However, the factors that regulate its activity are not clearly understood. Here we report that Stu2p in the budding yeast Saccharomyces cerevisiae interacts with SUMO by covalent and noncovalent mechanisms. Stu2p interacted by two‐hybrid analysis with the yeast SUMO Smt3p, its E2 Ubc9p, and the E3 Nfi1p. A region of Stu2p containing the dimerization domain was both necessary and sufficient for interaction with SUMO and Ubc9p. Stu2p was found to be sumoylated both in vitro and in vivo. Stu2p copurified with SUMO in a pull‐down assay and vice versa. Stu2p also bound to a nonconjugatable form of SUMO, suggesting that Stu2p can interact noncovalently with SUMO. In addition, Stu2p interacted with the STUbL enzyme Ris1p. Stu2p also copurified with ubiquitin in a pull‐down assay, suggesting that it can be modified by both SUMO and ubiquitin. Tubulin, a major binding partner of Stu2p, also interacted noncovalently with SUMO. By two‐hybrid analysis, the beta‐tubulin Tub2p interacted with SUMO independently of the microtubule stressor, benomyl. Together, these findings raise the possibility that the microtubule polymerization activities mediated by Stu2p are regulated through sumoylation pathways.
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Affiliation(s)
- Matt Greenlee
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
| | - Annabel Alonso
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
| | - Maliha Rahman
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
| | - Nida Meednu
- Department of Biology, University of Rochester, Rochester, New York, 14627
| | - Kayla Davis
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
| | - Victoria Tabb
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
| | - River Cook
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
| | - Rita K Miller
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, 74078
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