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Blank HM, Alonso A, Fabritius AS, Valk E, Loog M, Winey M, Polymenis M. Translational control of MPS1 links protein synthesis with the initiation of cell division and spindle pole body duplication in Saccharomyces cerevisiae. Genetics 2024:iyae069. [PMID: 38713088 DOI: 10.1093/genetics/iyae069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/10/2024] [Accepted: 04/23/2024] [Indexed: 05/08/2024] Open
Abstract
Protein synthesis underpins cell growth and controls when cells commit to a new round of cell division at a point in late G1 of the cell cycle called Start. Passage through Start also coincides with the duplication of the microtubule-organizing centers, the yeast spindle pole bodies, which will form the two poles of the mitotic spindle that segregates the chromosomes in mitosis. The conserved Mps1p kinase governs the duplication of the spindle pole body in Saccharomyces cerevisiae. Here, we show that the MPS1 transcript has a short upstream open reading frame that represses the synthesis of Mps1p. Mutating the MPS1 uORF makes the cells smaller, accelerates the appearance of Mps1p in late G1, and promotes completion of Start. Monitoring the spindle pole body in the cell cycle using structured illumination microscopy revealed that mutating the MPS1 uORF enabled cells to duplicate their spindle pole body earlier at a smaller cell size. The accelerated Start of MPS1 uORF mutants depends on the G1 cyclin Cln3p and the transcriptional repressor Whi5p but not on the Cln1,2p G1 cyclins. These results identify growth inputs in mechanisms that control duplication of the microtubule-organizing center and implicate these processes in the coupling of cell growth with division.
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Affiliation(s)
- Heidi M Blank
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843, USA
| | - Annabel Alonso
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Ervin Valk
- Institute of Technology, University of Tartu, Tartu, 50411, Estonia
| | - Mart Loog
- Institute of Technology, University of Tartu, Tartu, 50411, Estonia
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Michael Polymenis
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843, USA
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2
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Howard-Till RA, Kar UP, Fabritius AS, Winey M. Recent Advances in Ciliate Biology. Annu Rev Cell Dev Biol 2022; 38:75-102. [PMID: 35901313 DOI: 10.1146/annurev-cellbio-120420-020656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ciliates are a diverse group of unicellular eukaryotes that vary widely in size, shape, body plan, and ecological niche. Here, we review recent research advances achieved with ciliate models. Studies on patterning and regeneration have been revived in the giant ciliate Stentor, facilitated by modern omics methods. Cryo-electron microscopy and tomography have revolutionized the structural study of complex macromolecules such as telomerase, ribozymes, and axonemes. DNA elimination, gene scrambling, and mating type determination have been deciphered, revealing interesting adaptations of processes that have parallels in other kingdoms of life. Studies of common eukaryotic processes, such as intracellular trafficking, meiosis, and histone modification, reveal conservation as well as unique adaptations in these organisms that are evolutionarily distant from other models. Continual improvement of genetic and molecular tools makes ciliates accessible models for all levels of education and research. Such advances open new avenues of research and highlight the importance of ciliate research. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 38 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Rachel A Howard-Till
- Department of Molecular and Cellular Biology, University of California Davis, California, USA;
| | - Usha Pallabi Kar
- Department of Molecular and Cellular Biology, University of California Davis, California, USA;
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California Davis, California, USA;
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California Davis, California, USA;
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3
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Li S, Fernandez JJ, Fabritius AS, Agard DA, Winey M. Electron cryo-tomography structure of axonemal doublet microtubule from Tetrahymena thermophila. Life Sci Alliance 2022; 5:5/3/e202101225. [PMID: 34969817 PMCID: PMC8742875 DOI: 10.26508/lsa.202101225] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022] Open
Abstract
Doublet microtubules (DMTs) provide a scaffold for axoneme assembly in motile cilia. Aside from α/β tubulins, the DMT comprises a large number of non-tubulin proteins in the luminal wall of DMTs, collectively named the microtubule inner proteins (MIPs). We used cryoET to study axoneme DMT isolated from Tetrahymena We present the structures of DMT at nanometer and sub-nanometer resolution. The structures confirm that MIP RIB72A/B binds to the luminal wall of DMT by multiple DM10 domains. We found FAP115, an MIP-containing multiple EF-hand domains, located at the interface of four-tubulin dimers in the lumen of A-tubule. It contacts both lateral and longitudinal tubulin interfaces and playing a critical role in DMT stability. We observed substantial structure heterogeneity in DMT in an FAP115 knockout strain, showing extensive structural defects beyond the FAP115-binding site. The defects propagate along the axoneme. Finally, by comparing DMT structures from Tetrahymena and Chlamydomonas, we have identified a number of conserved MIPs as well as MIPs that are unique to each organism. This conservation and diversity of the DMT structures might be linked to their specific functions. Our work provides structural insights essential for understanding the roles of MIPs during motile cilium assembly and function, as well as their relationships to human ciliopathies.
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Affiliation(s)
- Sam Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Jose-Jesus Fernandez
- Nanomaterials and Nanotechnology Research Center (CINN-CSIC), Health Research Institute of Asturias (ISPA), Oviedo, Spain
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, USA
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA, USA
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Fabritius AS, Bayless BA, Li S, Stoddard D, Heydeck W, Ebmeier CC, Anderson L, Gunnels T, Nachiappan C, Whittall JB, Old W, Agard DA, Nicastro D, Winey M. Proteomic analysis of microtubule inner proteins (MIPs) in Rib72 null Tetrahymena cells reveals functional MIPs. Mol Biol Cell 2021; 32:br8. [PMID: 34406789 PMCID: PMC8693976 DOI: 10.1091/mbc.e20-12-0786] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The core structure of motile cilia and flagella, the axoneme, is built from a stable population of doublet microtubules. This unique stability is brought about, at least in part, by a network of microtubule inner proteins (MIPs) that are bound to the luminal side of the microtubule walls. Rib72A and Rib72B were identified as MIPs in the motile cilia of the protist Tetrahymena thermophila. Loss of these proteins leads to ciliary defects and loss of additional MIPs. We performed mass spectrometry coupled with proteomic analysis and bioinformatics to identify the MIPs lost in RIB72A/B knockout Tetrahymena axonemes. We identified a number of candidate MIPs and pursued one, Fap115, for functional characterization. We find that loss of Fap115 results in disrupted cell swimming and aberrant ciliary beating. Cryo-electron tomography reveals that Fap115 localizes to MIP6a in the A-tubule of the doublet microtubules. Overall, our results highlight the complex relationship between MIPs, ciliary structure, and ciliary function.
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Affiliation(s)
- Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616
| | - Brian A Bayless
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616.,Department of Biology, Santa Clara University, Santa Clara, CA 95053
| | - Sam Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158
| | - Daniel Stoddard
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Westley Heydeck
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - Christopher C Ebmeier
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - Lauren Anderson
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616
| | - Tess Gunnels
- Department of Biology, Santa Clara University, Santa Clara, CA 95053
| | | | - Justen B Whittall
- Department of Biology, Santa Clara University, Santa Clara, CA 95053
| | - William Old
- Department of Molecular Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616
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Heydeck W, Bayless BA, Stemm-Wolf AJ, O'Toole ET, Fabritius AS, Ozzello C, Nguyen M, Winey M. Tetrahymena Poc5 is a transient basal body component that is important for basal body maturation. J Cell Sci 2020; 133:jcs.240838. [PMID: 32350068 DOI: 10.1242/jcs.240838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 04/06/2020] [Indexed: 01/26/2023] Open
Abstract
Basal bodies (BBs) are microtubule-based organelles that act as a template for and stabilize cilia at the cell surface. Centrins ubiquitously associate with BBs and function in BB assembly, maturation and stability. Human POC5 (hPOC5) is a highly conserved centrin-binding protein that binds centrins through Sfi1p-like repeats and is required for building full-length, mature centrioles. Here, we use the BB-rich cytoskeleton of Tetrahymena thermophila to characterize Poc5 BB functions. Tetrahymena Poc5 (TtPoc5) uniquely incorporates into assembling BBs and is then removed from mature BBs prior to ciliogenesis. Complete genomic knockout of TtPOC5 leads to a significantly increased production of BBs, yet a markedly reduced ciliary density, both of which are rescued by reintroduction of TtPoc5. A second Tetrahymena POC5-like gene, SFR1, is similarly implicated in modulating BB production. When TtPOC5 and SFR1 are co-deleted, cell viability is compromised and BB overproduction is exacerbated. Overproduced BBs display defective transition zone formation and a diminished capacity for ciliogenesis. This study uncovers a requirement for Poc5 in building mature BBs, providing a possible functional link between hPOC5 mutations and impaired cilia.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Westley Heydeck
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Brian A Bayless
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Alexander J Stemm-Wolf
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eileen T O'Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Courtney Ozzello
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Marina Nguyen
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Mark Winey
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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6
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Jones MH, O'Toole ET, Fabritius AS, Muller EG, Meehl JB, Jaspersen SL, Winey M. Key phosphorylation events in Spc29 and Spc42 guide multiple steps of yeast centrosome duplication. Mol Biol Cell 2018; 29:2280-2291. [PMID: 30044722 PMCID: PMC6249810 DOI: 10.1091/mbc.e18-05-0296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Phosphorylation modulates many cellular processes during cell cycle progression. The yeast centrosome (called the spindle pole body, SPB) is regulated by the protein kinases Mps1 and Cdc28/Cdk1 as it nucleates microtubules to separate chromosomes during mitosis. Previously we completed an SPB phosphoproteome, identifying 297 sites on 17 of the 18 SPB components. Here we describe mutagenic analysis of phosphorylation events on Spc29 and Spc42, two SPB core components that were shown in the phosphoproteome to be heavily phosphorylated. Mutagenesis at multiple sites in Spc29 and Spc42 suggests that much of the phosphorylation on these two proteins is not essential but enhances several steps of mitosis. Of the 65 sites examined on both proteins, phosphorylation of the Mps1 sites Spc29-T18 and Spc29-T240 was shown to be critical for function. Interestingly, these two sites primarily influence distinct successive steps; Spc29-T240 is important for the interaction of Spc29 with Spc42, likely during satellite formation, and Spc29-T18 facilitates insertion of the new SPB into the nuclear envelope and promotes anaphase spindle elongation. Phosphorylation sites within Cdk1 motifs affect function to varying degrees, but mutations only have significant effects in the presence of an MPS1 mutation, supporting a theme of coregulation by these two kinases.
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Affiliation(s)
- Michele Haltiner Jones
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Eileen T O'Toole
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Eric G Muller
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Janet B Meehl
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Sue L Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO 64110.,Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160
| | - Mark Winey
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
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7
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Jaramillo-Lambert A, Fabritius AS, Hansen TJ, Smith HE, Golden A. The Identification of a Novel Mutant Allele of topoisomerase II in Caenorhabditis elegans Reveals a Unique Role in Chromosome Segregation During Spermatogenesis. Genetics 2016; 204:1407-1422. [PMID: 27707787 PMCID: PMC5161275 DOI: 10.1534/genetics.116.195099] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/30/2016] [Indexed: 01/03/2023] Open
Abstract
Topoisomerase II alleviates DNA entanglements that are generated during mitotic DNA replication, transcription, and sister chromatid separation. In contrast to mitosis, meiosis has two rounds of chromosome segregation following one round of DNA replication. In meiosis II, sister chromatids segregate from each other, similar to mitosis. Meiosis I, on the other hand, segregates homologs, which requires pairing, synapsis, and recombination. The exact role that topoisomerase II plays during meiosis is unknown. In a screen reexamining Caenorhabditis elegans legacy mutants isolated 30 years ago, we identified a novel allele of the gene encoding topoisomerase II, top-2(it7). In this study, we demonstrate that top-2(it7) males produce dead embryos, even when fertilizing wild-type oocytes. Characterization of early embryonic events indicates that fertilization is successful and sperm components are transmitted to the embryo. However, sperm chromatin is not detected in these fertilized embryos. Examination of top-2(it7) spermatogenic germ lines reveals that the sperm DNA fails to segregate properly during anaphase I of meiosis, resulting in anucleate sperm. top-2(it7) chromosome-segregation defects observed during anaphase I are not due to residual entanglements incurred during meiotic DNA replication and are not dependent on SPO-11-induced double-strand DNA breaks. Finally, we show that TOP-2 associates with chromosomes in meiotic prophase and that chromosome association is disrupted in the germ lines of top-2(it7) mutants.
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Affiliation(s)
- Aimee Jaramillo-Lambert
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Amy S Fabritius
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Tyler J Hansen
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Harold E Smith
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Andy Golden
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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Fabritius AS, Ellefson ML, McNally FJ. Nuclear and spindle positioning during oocyte meiosis. Curr Opin Cell Biol 2010; 23:78-84. [PMID: 20708397 DOI: 10.1016/j.ceb.2010.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/16/2010] [Accepted: 07/19/2010] [Indexed: 10/19/2022]
Abstract
Female meiosis is unique in that an asymmetrically positioned meiotic spindle expels chromosomes into tiny, non-developing polar bodies. The extrusion of chromosomes into polar bodies is always mediated by meiotic spindles that are attached to the oocyte cortex by one pole. The asymmetric, cortical positioning of the oocyte meiotic spindle preserves the volume and contents of the oocyte. Recent work in C. elegans and mouse has provided mechanistic details of spindle positioning in oocytes.
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Affiliation(s)
- Amy S Fabritius
- Department of Molecular and Cellular Biology, University of California-Davis, Davis, CA 95616, United States
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