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Grazzini A, Cavanaugh AM. Fungal microtubule organizing centers are evolutionarily unstable structures. Fungal Genet Biol 2024; 172:103885. [PMID: 38485050 DOI: 10.1016/j.fgb.2024.103885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 03/24/2024]
Abstract
For most Eukaryotic species the requirements of cilia formation dictate the structure of microtubule organizing centers (MTOCs). In this study we find that loss of cilia corresponds to loss of evolutionary stability for fungal MTOCs. We used iterative search algorithms to identify proteins homologous to those found in Saccharomyces cerevisiae, and Schizosaccharomyces pombe MTOCs, and calculated site-specific rates of change for those proteins that were broadly phylogenetically distributed. Our results indicate that both the protein composition of MTOCs as well as the sequence of MTOC proteins are poorly conserved throughout the fungal kingdom. To begin to reconcile this rapid evolutionary change with the rigid structure and essential function of the S. cerevisiae MTOC we further analyzed how structural interfaces among proteins influence the rates of change for specific residues within a protein. We find that a more stable protein may stabilize portions of an interacting partner where the two proteins are in contact. In summary, while the protein composition and sequences of the MTOC may be rapidly changing the proteins within the structure have a stabilizing effect on one another. Further exploration of fungal MTOCs will expand our understanding of how changes in the functional needs of a cell have affected physical structures, proteomes, and protein sequences throughout fungal evolution.
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Affiliation(s)
- Adam Grazzini
- Department of Biology, Creighton University, Omaha, Nebraska, USA
| | - Ann M Cavanaugh
- Department of Biology, Creighton University, Omaha, Nebraska, USA.
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2
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Evans-Yamamoto D, Dubé AK, Saha G, Plante S, Bradley D, Gagnon-Arsenault I, Landry CR. Parallel Nonfunctionalization of CK1δ/ε Kinase Ohnologs Following a Whole-Genome Duplication Event. Mol Biol Evol 2023; 40:msad246. [PMID: 37979156 PMCID: PMC10699747 DOI: 10.1093/molbev/msad246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/07/2023] [Indexed: 11/20/2023] Open
Abstract
Whole-genome duplication (WGD) followed by speciation allows us to examine the parallel evolution of ohnolog pairs. In the yeast family Saccharomycetaceae, HRR25 is a rare case of repeated ohnolog maintenance. This gene has reverted to a single copy in Saccharomyces cerevisiae where it is now essential, but has been maintained as pairs in at least 7 species post-WGD. In S. cerevisiae, HRR25 encodes the casein kinase 1δ/ε and plays a role in a variety of functions through its kinase activity and protein-protein interactions (PPIs). We hypothesized that the maintenance of duplicated HRR25 ohnologs could be a result of repeated subfunctionalization. We tested this hypothesis through a functional complementation assay in S. cerevisiae, testing all pairwise combinations of 25 orthologs (including 7 ohnolog pairs). Contrary to our expectations, we observed no cases of pair-dependent complementation, which would have supported the subfunctionalization hypothesis. Instead, most post-WGD species have one ohnolog that failed to complement, suggesting their nonfunctionalization or neofunctionalization. The ohnologs incapable of complementation have undergone more rapid protein evolution, lost most PPIs that were observed for their functional counterparts and singletons from post-WGD and non-WGD species, and have nonconserved cellular localization, consistent with their ongoing loss of function. The analysis in Naumovozyma castellii shows that the noncomplementing ohnolog is expressed at a lower level and has become nonessential. Taken together, our results indicate that HRR25 orthologs are undergoing gradual nonfunctionalization.
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Affiliation(s)
- Daniel Evans-Yamamoto
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa, 252-0882, Japan
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa, 252-0882, Japan
| | - Alexandre K Dubé
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
| | - Gourav Saha
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani K K Birla Goa Campus, South Goa, India
| | - Samuel Plante
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
| | - David Bradley
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
| | - Isabelle Gagnon-Arsenault
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
| | - Christian R Landry
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, Québec, QC, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec, QC, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, Québec, QC, G1V 0A6, Canada
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa, 252-0882, Japan
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3
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Evans-Yamamoto D, Dubé AK, Saha G, Plante S, Bradley D, Gagnon-Arsenault I, Landry CR. Parallel nonfunctionalization of CK1δ/ε kinase ohnologs following a whole-genome duplication event. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560513. [PMID: 37873368 PMCID: PMC10592909 DOI: 10.1101/2023.10.02.560513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Whole genome duplication (WGD) followed by speciation allows us to examine the parallel evolution of ohnolog pairs. In the yeast family Saccharomycetaceae, HRR25 is a rare case of repeated ohnolog maintenance. This gene has reverted to a single copy in S. cerevisiae where it is now essential, but has been maintained as pairs in at least 7 species post WGD. In S. cerevisiae, HRR25 encodes the casein kinase (CK) 1δ/ε and plays a role in a variety of functions through its kinase activity and protein-protein interactions (PPIs). We hypothesized that the maintenance of duplicated HRR25 ohnologs could be a result of repeated subfunctionalization. We tested this hypothesis through a functional complementation assay in S. cerevisiae, testing all pairwise combinations of 25 orthologs (including 7 ohnolog pairs). Contrary to our expectations, we observed no cases of pair-dependent complementation, which would have supported the subfunctionalization hypothesis. Instead, most post-WGD species have one ohnolog that failed to complement, suggesting their nonfunctionalization or neofunctionalization. The ohnologs incapable of complementation have undergone more rapid protein evolution, lost most PPIs that were observed for their functional counterparts and singletons from post and non-WGD species, and have non-conserved cellular localization, consistent with their ongoing loss of function. The analysis in N. castelli shows that the non-complementing ohnolog is expressed at a lower level and has become non-essential. Taken together, our results indicate that HRR25 orthologs are undergoing gradual nonfunctionalization.
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Affiliation(s)
- Daniel Evans-Yamamoto
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, 252-0882, Japan
- Institute for Advanced Biosciences, Keio University, Fujisawa, 252-0882, Japan
| | - Alexandre K Dubé
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
| | - Gourav Saha
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani K K Birla Goa campus, Zuarinagar, South Goa, Goa, India
- Current address: Department of Bioengineering, University of California, CA 90095, United States
| | - Samuel Plante
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
- Current address: Département de Biochimie, Université de Sherbrooke, Québec, J1K 0A5, Canada
| | - David Bradley
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
| | - Isabelle Gagnon-Arsenault
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
| | - Christian R Landry
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, G1V 0A6, Canada
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- Département de Biologie, Faculté des Sciences et de Génie, Université Laval, G1V 0A6, Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, G1V 0A6, Canada
- Centre de Recherche sur les Données Massives (CRDM), Université Laval, G1V 0A6, Canada
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Abstract
SignificanceMitosis is an essential process in all eukaryotes, but paradoxically, genes required for mitosis vary among species. The essentiality of many mitotic genes was bypassed by activating alternative mechanisms during evolution. However, bypass events have rarely been recapitulated experimentally. Here, using the fission yeast Schizosaccharomyces pombe, the essentiality of a kinase (Plo1) required for bipolar spindle formation was bypassed by other mutations, many of which are associated with glucose metabolism. The Plo1 bypass by the reduction in glucose uptake was dependent on another kinase (casein kinase I), which potentiated spindle microtubule formation. This study illustrates a rare experimental bypass of essentiality for mitotic genes and provides insights into the molecular diversity of mitosis.
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CK1 Is a Druggable Regulator of Microtubule Dynamics and Microtubule-Associated Processes. Cancers (Basel) 2022; 14:cancers14051345. [PMID: 35267653 PMCID: PMC8909099 DOI: 10.3390/cancers14051345] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/25/2022] [Accepted: 03/03/2022] [Indexed: 02/05/2023] Open
Abstract
Protein kinases of the Casein Kinase 1 family play a vital role in the regulation of numerous cellular processes. Apart from functions associated with regulation of proliferation, differentiation, or apoptosis, localization of several Casein Kinase 1 isoforms to the centrosome and microtubule asters also implicates regulatory functions in microtubule dynamic processes. Being localized to the spindle apparatus during mitosis Casein Kinase 1 directly modulates microtubule dynamics by phosphorylation of tubulin isoforms. Additionally, site-specific phosphorylation of microtubule-associated proteins can be related to the maintenance of genomic stability but also microtubule stabilization/destabilization, e.g., by hyper-phosphorylation of microtubule-associated protein 1A and RITA1. Consequently, approaches interfering with Casein Kinase 1-mediated microtubule-specific functions might be exploited as therapeutic strategies for the treatment of cancer. Currently pursued strategies include the development of Casein Kinase 1 isoform-specific small molecule inhibitors and therapeutically useful peptides specifically inhibiting kinase-substrate interactions.
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Abstract
As one of four filament types, microtubules are a core component of the cytoskeleton and are essential for cell function. Yet how microtubules are nucleated from their building blocks, the αβ-tubulin heterodimer, has remained a fundamental open question since the discovery of tubulin 50 years ago. Recent structural studies have shed light on how γ-tubulin and the γ-tubulin complex proteins (GCPs) GCP2 to GCP6 form the γ-tubulin ring complex (γ-TuRC). In parallel, functional and single-molecule studies have informed on how the γ-TuRC nucleates microtubules in real time, how this process is regulated in the cell and how it compares to other modes of nucleation. Another recent surprise has been the identification of a second essential nucleation factor, which turns out to be the well-characterized microtubule polymerase XMAP215 (also known as CKAP5, a homolog of chTOG, Stu2 and Alp14). This discovery helps to explain why the observed nucleation activity of the γ-TuRC in vitro is relatively low. Taken together, research in recent years has afforded important insight into how microtubules are made in the cell and provides a basis for an exciting era in the cytoskeleton field.
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Affiliation(s)
- Akanksha Thawani
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sabine Petry
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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7
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Aquino Perez C, Burocziova M, Jenikova G, Macurek L. CK1-mediated phosphorylation of FAM110A promotes its interaction with mitotic spindle and controls chromosomal alignment. EMBO Rep 2021; 22:e51847. [PMID: 34080749 DOI: 10.15252/embr.202051847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/14/2021] [Accepted: 05/05/2021] [Indexed: 01/10/2023] Open
Abstract
Progression through the cell cycle is driven by cyclin-dependent kinases that control gene expression, orchestration of mitotic spindle, and cell division. To identify new regulators of the cell cycle, we performed transcriptomic analysis of human non-transformed cells expressing a fluorescent ubiquitination-based cell cycle indicator and identified 701 transcripts differentially expressed in G1 and G2 cells. Family with sequence similarity 110 member A (FAM110A) protein is highly expressed in G2 cells and localized at mitotic spindle and spindle poles during mitosis. Depletion of FAM110A impairs chromosomal alignment, delays metaphase-to-anaphase transition, and affects spindle positioning. Using mass spectrometry and immunoprecipitation, we identified casein kinase I (CK1) in complex with FAM110A during mitosis. CK1 phosphorylates the C-terminal domain of FAM110A in vitro, and inhibition of CK1 reduces phosphorylation of mitotic FAM110A. Wild-type FAM110A, but not the FAM110A-S252-S255A mutant deficient in CK1 phosphorylation, rescues the chromosomal alignment, duration of mitosis, and orientation of the mitotic spindle after depletion of endogenous FAM110A. We propose that CK1 regulates chromosomal alignment by phosphorylating FAM110A and promoting its interaction with mitotic spindle.
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Affiliation(s)
- Cecilia Aquino Perez
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Monika Burocziova
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Gabriela Jenikova
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Libor Macurek
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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8
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Brilot AF, Lyon AS, Zelter A, Viswanath S, Maxwell A, MacCoss MJ, Muller EG, Sali A, Davis TN, Agard DA. CM1-driven assembly and activation of yeast γ-tubulin small complex underlies microtubule nucleation. eLife 2021; 10:e65168. [PMID: 33949948 PMCID: PMC8099430 DOI: 10.7554/elife.65168] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/12/2021] [Indexed: 01/08/2023] Open
Abstract
Microtubule (MT) nucleation is regulated by the γ-tubulin ring complex (γTuRC), conserved from yeast to humans. In Saccharomyces cerevisiae, γTuRC is composed of seven identical γ-tubulin small complex (γTuSC) sub-assemblies, which associate helically to template MT growth. γTuRC assembly provides a key point of regulation for the MT cytoskeleton. Here, we combine crosslinking mass spectrometry, X-ray crystallography, and cryo-EM structures of both monomeric and dimeric γTuSCs, and open and closed helical γTuRC assemblies in complex with Spc110p to elucidate the mechanisms of γTuRC assembly. γTuRC assembly is substantially aided by the evolutionarily conserved CM1 motif in Spc110p spanning a pair of adjacent γTuSCs. By providing the highest resolution and most complete views of any γTuSC assembly, our structures allow phosphorylation sites to be mapped, surprisingly suggesting that they are mostly inhibitory. A comparison of our structures with the CM1 binding site in the human γTuRC structure at the interface between GCP2 and GCP6 allows for the interpretation of significant structural changes arising from CM1 helix binding to metazoan γTuRC.
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Affiliation(s)
- Axel F Brilot
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
| | - Andrew S Lyon
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
| | - Alex Zelter
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - Shruthi Viswanath
- Department of Bioengineering and Therapeutic Sciences, University of California at San FranciscoSan FranciscoUnited States
| | - Alison Maxwell
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
| | - Michael J MacCoss
- Department of Genome Sciences, University of WashingtonSeattleUnited States
| | - Eric G Muller
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California at San FranciscoSan FranciscoUnited States
| | - Trisha N Davis
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
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9
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Nejedlá M, Klebanovych A, Sulimenko V, Sulimenko T, Dráberová E, Dráber P, Karlsson R. The actin regulator profilin 1 is functionally associated with the mammalian centrosome. Life Sci Alliance 2020; 4:4/1/e202000655. [PMID: 33184056 PMCID: PMC7668531 DOI: 10.26508/lsa.202000655] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 12/16/2022] Open
Abstract
The actin regulator profilin 1 recently shown to control microtubule elongation at the cell periphery is found to interact with the γ-tubulin ring complex and tune centrosomal microtubule nucleation. Profilin 1 is a crucial actin regulator, interacting with monomeric actin and several actin-binding proteins controlling actin polymerization. Recently, it has become evident that this profilin isoform associates with microtubules via formins and interferes with microtubule elongation at the cell periphery. Recruitment of microtubule-associated profilin upon extensive actin polymerizations, for example, at the cell edge, enhances microtubule growth, indicating that profilin contributes to the coordination of actin and microtubule organization. Here, we provide further evidence for the profilin-microtubule connection by demonstrating that it also functions in centrosomes where it impacts on microtubule nucleation.
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Affiliation(s)
- Michaela Nejedlá
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Anastasiya Klebanovych
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tetyana Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Roger Karlsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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10
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Zupa E, Zheng A, Neuner A, Würtz M, Liu P, Böhler A, Schiebel E, Pfeffer S. The cryo-EM structure of a γ-TuSC elucidates architecture and regulation of minimal microtubule nucleation systems. Nat Commun 2020; 11:5705. [PMID: 33177498 PMCID: PMC7658347 DOI: 10.1038/s41467-020-19456-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/15/2020] [Indexed: 11/23/2022] Open
Abstract
The nucleation of microtubules from αβ-tubulin subunits is mediated by γ-tubulin complexes, which vary in composition across organisms. Aiming to understand how de novo microtubule formation is achieved and regulated by a minimal microtubule nucleation system, we here determined the cryo-electron microscopy structure of the heterotetrameric γ-tubulin small complex (γ-TuSC) from C. albicans at near-atomic resolution. Compared to the vertebrate γ-tubulin ring complex (γ-TuRC), we observed a vastly remodeled interface between the SPC/GCP-γ-tubulin spokes, which stabilizes the complex and defines the γ-tubulin arrangement. The relative positioning of γ-tubulin subunits indicates that a conformational rearrangement of the complex is required for microtubule nucleation activity, which follows opposing directionality as predicted for the vertebrate γ-TuRC. Collectively, our data suggest that the assembly and regulation mechanisms of γ-tubulin complexes fundamentally differ between the microtubule nucleation systems in lower and higher eukaryotes. The nucleation of microtubules from αβ-tubulin subunits is mediated by γtubulin complexes, which vary in composition across organisms. Here, authors present the cryo-EM structure of the heterotetrameric γ-tubulin small complex (γ-TuSC) from C. albicans at near-atomic resolution.
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Affiliation(s)
- Erik Zupa
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Anjun Zheng
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Annett Neuner
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Martin Würtz
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Peng Liu
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Anna Böhler
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
| | - Elmar Schiebel
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany.
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11
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Bhondeley M, Liu Z. Mitochondrial Biogenesis Is Positively Regulated by Casein Kinase I Hrr25 Through Phosphorylation of Puf3 in Saccharomyces cerevisiae. Genetics 2020; 215:463-482. [PMID: 32317286 PMCID: PMC7268985 DOI: 10.1534/genetics.120.303191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 04/20/2020] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial biogenesis requires coordinated expression of genes encoding mitochondrial proteins, which in Saccharomyces cerevisiae is achieved in part via post-transcriptional control by the Pumilio RNA-binding domain protein Puf3 Puf3 binds to the 3'-UTR of many messenger RNAs (mRNAs) that encode mitochondrial proteins, regulating their turnover, translation, and/or mitochondrial targeting. Puf3 hyperphosphorylation correlates with increased mitochondrial biogenesis; however, the kinase responsible for Puf3 phosphorylation is unclear. Here, we show that the casein kinase I protein Hrr25 negatively regulates Puf3 by mediating its phosphorylation. An hrr25 mutation results in reduced phosphorylation of Puf3 in vivo and a puf3 deletion mutation reverses growth defects of hrr25 mutant cells grown on medium with a nonfermentable carbon source. We show that Hrr25 directly phosphorylates Puf3, and that the interaction between Puf3 and Hrr25 is mediated through the N-terminal domain of Puf3 and the kinase domain of Hrr25 We further found that an hrr25 mutation reduces GFP expression from GFP reporter constructs carrying the 3'-UTR of Puf3 targets. Downregulation of GFP expression due to an hrr25 mutation can be reversed either by puf3Δ or by mutations to the Puf3-binding sites in the 3'-UTR of the GFP reporter constructs. Together, our data indicate that Hrr25 is a positive regulator of mitochondrial biogenesis by phosphorylating Puf3 and inhibiting its function in downregulating target mRNAs encoding mitochondrial proteins.
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Affiliation(s)
- Manika Bhondeley
- Department of Biological Sciences, University of New Orleans, Louisiana 70148
| | - Zhengchang Liu
- Department of Biological Sciences, University of New Orleans, Louisiana 70148
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12
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Xu P, Ianes C, Gärtner F, Liu C, Burster T, Bakulev V, Rachidi N, Knippschild U, Bischof J. Structure, regulation, and (patho-)physiological functions of the stress-induced protein kinase CK1 delta (CSNK1D). Gene 2019; 715:144005. [PMID: 31376410 DOI: 10.1016/j.gene.2019.144005] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 12/11/2022]
Abstract
Members of the highly conserved pleiotropic CK1 family of serine/threonine-specific kinases are tightly regulated in the cell and play crucial regulatory roles in multiple cellular processes from protozoa to human. Since their dysregulation as well as mutations within their coding regions contribute to the development of various different pathologies, including cancer and neurodegenerative diseases, they have become interesting new drug targets within the last decade. However, to develop optimized CK1 isoform-specific therapeutics in personalized therapy concepts, a detailed knowledge of the regulation and functions of the different CK1 isoforms, their various splice variants and orthologs is mandatory. In this review we will focus on the stress-induced CK1 isoform delta (CK1δ), thereby addressing its regulation, physiological functions, the consequences of its deregulation for the development and progression of diseases, and its potential as therapeutic drug target.
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Affiliation(s)
- Pengfei Xu
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Chiara Ianes
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Fabian Gärtner
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Congxing Liu
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Timo Burster
- Department of Biology, School of Science and Technology, Nazarbayev University, 53 Kabanbay Batyr Ave, Nur-Sultan 020000, Kazakhstan.
| | - Vasiliy Bakulev
- Ural Federal University named after the first President of Russia B. N. Eltsin, Technology for Organic Synthesis Laboratory, 19 Mirastr., 620002 Ekaterinburg, Russia.
| | - Najma Rachidi
- Unité de Parasitologie Moléculaire et Signalisation, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201, 25-28 Rue du Dr Roux, 75015 Paris, France.
| | - Uwe Knippschild
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
| | - Joachim Bischof
- Department of General and Visceral Surgery, Surgery Center, Ulm University Hospital, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
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13
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It is all about the process(ing): P-body granules and the regulation of signal transduction. Curr Genet 2019; 66:73-77. [PMID: 31317215 DOI: 10.1007/s00294-019-01016-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 12/21/2022]
Abstract
The eukaryotic cell is subdivided into distinct functional domains by the presence of both membrane-bound and membraneless organelles. The latter include cytoplasmic granules, like the Processing-body (P-body), that are induced in response to stress and contain specific sets of mRNAs and proteins. Although P-bodies have been evolutionarily conserved, we do not yet understand the full extent of their biological functions in the cell. Early studies suggested that these structures might be sites of mRNA decay as the first protein constituents identified were enzymes involved in mRNA processing. However, more recent work indicates that this is not likely to be the primary function of these granules and has even suggested that P-bodies are sites of long-term mRNA storage. Interestingly, P-bodies and other ribonucleoprotein granules have been found to also contain a variety of signaling molecules, including protein kinases and phosphatases key to the normal control of cell growth and survival. Therefore, P-bodies could have a role in the modulation of cell signaling during particular types of stress. This review discusses both the general implications of such a proposal and one particular example that illustrates how the granule recruitment of a protein kinase can impact overall cell physiology.
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14
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(-)-Epigallocatechin-3-gallate and hydroxytyrosol improved antioxidative and anti-inflammatory responses in bovine mammary epithelial cells. Animal 2019; 13:2847-2856. [DOI: 10.1017/s1751731119001356] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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15
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Fong KK, Zelter A, Graczyk B, Hoyt JM, Riffle M, Johnson R, MacCoss MJ, Davis TN. Novel phosphorylation states of the yeast spindle pole body. Biol Open 2018; 7:bio.033647. [PMID: 29903865 PMCID: PMC6215409 DOI: 10.1242/bio.033647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Phosphorylation regulates yeast spindle pole body (SPB) duplication and separation and likely regulates microtubule nucleation. We report a phosphoproteomic analysis using tandem mass spectrometry of enriched Saccharomyces cerevisiae SPBs for two cell cycle arrests, G1/S and the mitotic checkpoint, expanding on previously reported phosphoproteomic data sets. We present a novel phosphoproteomic state of SPBs arrested in G1/S by a cdc4-1 temperature-sensitive mutation, with particular focus on phosphorylation events on the γ-tubulin small complex (γ-TuSC). The cdc4-1 arrest is the earliest arrest at which microtubule nucleation has occurred at the newly duplicated SPB. Several novel phosphorylation sites were identified in G1/S and during mitosis on the microtubule nucleating γ-TuSC. These sites were analyzed in vivo by fluorescence microscopy and were shown to be required for proper regulation of spindle length. Additionally, in vivo analysis of two mitotic sites in Spc97 found that phosphorylation of at least one of these sites is required for progression through the cell cycle. This phosphoproteomic data set not only broadens the scope of the phosphoproteome of SPBs, it also identifies several γ-TuSC phosphorylation sites that influence microtubule formation. Summary: A phosphoproteome of yeast spindle pole bodies in G1/S or M phase identifies phosphorylation sites involved in spindle length control and provides direction for future phosphorylation analyses of spindle pole components.
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Affiliation(s)
- Kimberly K Fong
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Alex Zelter
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Beth Graczyk
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Jill M Hoyt
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Michael Riffle
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Richard Johnson
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Trisha N Davis
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
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16
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Elmore ZC, Guillen RX, Gould KL. The kinase domain of CK1 enzymes contains the localization cue essential for compartmentalized signaling at the spindle pole. Mol Biol Cell 2018; 29:1664-1674. [PMID: 29742018 PMCID: PMC6080649 DOI: 10.1091/mbc.e18-02-0129] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
CK1 protein kinases contribute to multiple biological processes, but how they are tailored to function in compartmentalized signaling events is largely unknown. Hhp1 and Hhp2 (Hhp1/2) are the soluble CK1 family members in Schizosaccharomyces pombe. One of their functions is to inhibit the septation initiation network (SIN) during a mitotic checkpoint arrest. The SIN is assembled by Sid4 at spindle pole bodies (SPBs), and though Hhp1/2 colocalize there, it is not known how they are targeted there or whether their SPB localization is required for SIN inhibition. Here, we establish that Hhp1/2 localize throughout the cell cycle to SPBs, as well as to the nucleus, cell tips, and division site. We find that their catalytic domains but not their enzymatic function are used for SPB targeting and that this targeting strategy is conserved in human CK1δ/ε localization to centrosomes. Further, we pinpoint amino acids in the Hhp1 catalytic domain required for SPB interaction; mutation of these residues disrupts Hhp1 association with the core SPB protein Ppc89, and the inhibition of cytokinesis in the setting of spindle stress. Taken together, these data have enabled us to define a molecular mechanism used by CK1 enzymes to target a specific cellular locale for compartmentalized signaling.
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Affiliation(s)
- Zachary C Elmore
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Rodrigo X Guillen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
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17
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Xiang X. Nuclear movement in fungi. Semin Cell Dev Biol 2017; 82:3-16. [PMID: 29241689 DOI: 10.1016/j.semcdb.2017.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/17/2017] [Accepted: 10/23/2017] [Indexed: 12/22/2022]
Abstract
Nuclear movement within a cell occurs in a variety of eukaryotic organisms including yeasts and filamentous fungi. Fungal molecular genetic studies identified the minus-end-directed microtubule motor cytoplasmic dynein as a critical protein for nuclear movement or orientation of the mitotic spindle contained in the nucleus. Studies in the budding yeast first indicated that dynein anchored at the cortex via its anchoring protein Num1 exerts pulling force on an astral microtubule to orient the anaphase spindle across the mother-daughter axis before nuclear division. Prior to anaphase, myosin V interacts with the plus end of an astral microtubule via Kar9-Bim1/EB1 and pulls the plus end along the actin cables to move the nucleus/spindle close to the bud neck. In addition, pushing or pulling forces generated from cortex-linked polymerization or depolymerization of microtubules drive nuclear movements in yeasts and possibly also in filamentous fungi. In filamentous fungi, multiple nuclei within a hyphal segment undergo dynein-dependent back-and-forth movements and their positioning is also influenced by cytoplasmic streaming toward the hyphal tip. In addition, nuclear movement occurs at various stages of fungal development and fungal infection of plant tissues. This review discusses our current understanding on the mechanisms of nuclear movement in fungal organisms, the importance of nuclear positioning and the regulatory strategies that ensure the proper positioning of nucleus/spindle.
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Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences - F. Edward Hébert School of Medicine, Bethesda, MD, USA.
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18
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Lengefeld J, Yen E, Chen X, Leary A, Vogel J, Barral Y. Spatial cues and not spindle pole maturation drive the asymmetry of astral microtubules between new and preexisting spindle poles. Mol Biol Cell 2017; 29:10-28. [PMID: 29142076 PMCID: PMC5746063 DOI: 10.1091/mbc.e16-10-0725] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/31/2017] [Accepted: 11/07/2017] [Indexed: 11/17/2022] Open
Abstract
The distinct behavior of the spindle pole bodies (SPBs) during spindle orientation in yeast metaphase does not result from them being differently mature, but astral microtubule organization correlates with the subcellular position rather than the age of the SPBs. In many asymmetrically dividing cells, the microtubule-organizing centers (MTOCs; mammalian centrosome and yeast spindle pole body [SPB]) nucleate more astral microtubules on one of the two spindle poles than the other. This differential activity generally correlates with the age of MTOCs and contributes to orienting the mitotic spindle within the cell. The asymmetry might result from the two MTOCs being in distinctive maturation states. We investigated this model in budding yeast. Using fluorophores with different maturation kinetics to label the outer plaque components of the SPB, we found that the Cnm67 protein is mobile, whereas Spc72 is not. However, these two proteins were rapidly as abundant on both SPBs, indicating that SPBs mature more rapidly than anticipated. Superresolution microscopy confirmed this finding for Spc72 and for the γ-tubulin complex. Moreover, astral microtubule number and length correlated with the subcellular localization of SPBs rather than their age. Kar9-dependent orientation of the spindle drove the differential activity of the SPBs in astral microtubule organization rather than intrinsic differences between the spindle poles. Together, our data establish that Kar9 and spatial cues, rather than the kinetics of SPB maturation, control the asymmetry of astral microtubule organization between the preexisting and new SPBs.
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Affiliation(s)
- Jette Lengefeld
- Department of Biology, Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Eric Yen
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Xiuzhen Chen
- Department of Biology, Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Allen Leary
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Jackie Vogel
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Yves Barral
- Department of Biology, Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
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19
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Cavanaugh AM, Jaspersen SL. Big Lessons from Little Yeast: Budding and Fission Yeast Centrosome Structure, Duplication, and Function. Annu Rev Genet 2017; 51:361-383. [PMID: 28934593 DOI: 10.1146/annurev-genet-120116-024733] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Centrosomes are a functionally conserved feature of eukaryotic cells that play an important role in cell division. The conserved γ-tubulin complex organizes spindle and astral microtubules, which, in turn, separate replicated chromosomes accurately into daughter cells. Like DNA, centrosomes are duplicated once each cell cycle. Although in some cell types it is possible for cell division to occur in the absence of centrosomes, these divisions typically result in defects in chromosome number and stability. In single-celled organisms such as fungi, centrosomes [known as spindle pole bodies (SPBs)] are essential for cell division. SPBs also must be inserted into the membrane because fungi undergo a closed mitosis in which the nuclear envelope (NE) remains intact. This poorly understood process involves events similar or identical to those needed for de novo nuclear pore complex assembly. Here, we review how analysis of fungal SPBs has advanced our understanding of centrosomes and NE events.
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Affiliation(s)
- Ann M Cavanaugh
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA; .,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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20
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Abstract
Clathrin-mediated endocytosis is an essential cellular process that involves the concerted assembly and disassembly of many different proteins at the plasma membrane. In yeast, live-cell imaging has shown that the spatiotemporal dynamics of these proteins is highly stereotypical. Recent work has focused on determining how the timing and functions of endocytic proteins are regulated. In this Cell Science at a Glance article and accompanying poster, we review our current knowledge of the timeline of endocytic site maturation and discuss recent works focusing on how phosphorylation, ubiquitylation and lipids regulate various aspects of the process.
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Affiliation(s)
- Rebecca Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Yidi Sun
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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21
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Ye Q, Ur SN, Su TY, Corbett KD. Structure of the Saccharomyces cerevisiae Hrr25:Mam1 monopolin subcomplex reveals a novel kinase regulator. EMBO J 2016; 35:2139-2151. [PMID: 27491543 DOI: 10.15252/embj.201694082] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/20/2016] [Indexed: 11/09/2022] Open
Abstract
In budding yeast, the monopolin complex mediates sister kinetochore cross-linking and co-orientation in meiosis I. The CK1δ kinase Hrr25 is critical for sister kinetochore co-orientation, but its roles are not well understood. Here, we present the structures of Hrr25 and its complex with the monopolin subunit Mam1. Hrr25 possesses a "central domain" that packs tightly against the kinase C-lobe, adjacent to the binding site for Mam1. Together, the Hrr25 central domain and Mam1 form a novel, contiguous embellishment to the Hrr25 kinase domain that affects Hrr25 conformational dynamics and enzyme kinetics. Mam1 binds a hydrophobic surface on the Hrr25 N-lobe that is conserved in CK1δ-family kinases, suggesting a role for this surface in recruitment and/or regulation of these enzymes throughout eukaryotes. Finally, using purified proteins, we find that Hrr25 phosphorylates the kinetochore receptor for monopolin, Dsn1. Together with our new structural insights into the fully assembled monopolin complex, this finding suggests that tightly localized Hrr25 activity modulates monopolin complex-kinetochore interactions through phosphorylation of both kinetochore and monopolin complex components.
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Affiliation(s)
- Qiaozhen Ye
- Ludwig Institute for Cancer Research, San Diego Branch, San Diego, La Jolla, CA, USA
| | - Sarah N Ur
- Ludwig Institute for Cancer Research, San Diego Branch, San Diego, La Jolla, CA, USA
| | - Tiffany Y Su
- Ludwig Institute for Cancer Research, San Diego Branch, San Diego, La Jolla, CA, USA
| | - Kevin D Corbett
- Ludwig Institute for Cancer Research, San Diego Branch, San Diego, La Jolla, CA, USA Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
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