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Danziger M, Xu F, Noble H, Yang P, Roque DM. Tubulin Complexity in Cancer and Metastasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1452:21-35. [PMID: 38805123 DOI: 10.1007/978-3-031-58311-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Tubulin plays a fundamental role in cellular function and as the subject for microtubule-active agents in the treatment of ovarian cancer. Microtubule-binding proteins (e.g., tau, MAP1/2/4, EB1, CLIP, TOG, survivin, stathmin) and posttranslational modifications (e.g., tyrosination, deglutamylation, acetylation, glycation, phosphorylation, polyamination) further diversify tubulin functionality and may permit additional opportunities to understand microtubule behavior in disease and to develop microtubule-modifying approaches to combat ovarian cancer. Tubulin-based structures that project from suspended ovarian cancer cells known as microtentacles may contribute to metastatic potential of ovarian cancer cells and could represent an exciting novel therapeutic target.
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Affiliation(s)
- Michael Danziger
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fuhua Xu
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Helen Noble
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Peixin Yang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dana M Roque
- Division of Gynecologic Oncology, Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.
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2
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Su Q, Baker L, Emery S, Balan B, Ansell B, Tichkule S, Mueller I, Svärd SG, Jex A. Transcriptomic analysis of albendazole resistance in human diarrheal parasite Giardia duodenalis. INTERNATIONAL JOURNAL FOR PARASITOLOGY: DRUGS AND DRUG RESISTANCE 2023; 22:9-19. [PMID: 37004489 PMCID: PMC10111952 DOI: 10.1016/j.ijpddr.2023.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/09/2023] [Accepted: 03/21/2023] [Indexed: 04/03/2023]
Abstract
Benzimidazole-2-carbamates (BZ, e.g., albendazole; ALB), which bind β-tubulin to disrupt microtubule polymerization, are one of two primary compound classes used to treat giardiasis. In most parasitic nematodes and fungi, BZ-resistance is caused by β-tubulin mutations and its molecular mode of action (MOA) is well studied. In contrast, in Giardia duodenalis BZ MOA or resistance is less well understood, may involve target-specific and broader impacts including cellular damage and oxidative stress, and its underlying cause is not clearly determined. Previously, we identified acquisition of a single nucleotide polymorphism, E198K, in β-tubulin in ALB-resistant (ALB-R) G. duodenalis WB-1B relative to ALB-sensitive (ALB-S) parental controls. E198K is linked to BZ-resistance in fungi and its allelic frequency correlated with the magnitude of BZ-resistance in G. duodenalis WB-1B. Here, we undertook detailed transcriptomic comparisons of these ALB-S and ALB-R G. duodenalis WB-1B cultures. The primary transcriptional changes with ALB-R in G. duodenalis WB-1B indicated increased protein degradation and turnover, and up-regulation of tubulin, and related genes, associated with the adhesive disc and basal bodies. These findings are consistent with previous observations noting focused disintegration of the disc and associated structures in Giardia duodenalis upon ALB exposure. We also saw transcriptional changes with ALB-R in G. duodenalis WB-1B consistent with prior observations of a shift from glycolysis to arginine metabolism for ATP production and possible changes to aspects of the vesicular trafficking system that require further investigation. Finally, we saw mixed transcriptional changes associated with DNA repair and oxidative stress responses in the G. duodenalis WB-1B line. These changes may be indicative of a role for H2O2 degradation in ALB-R, as has been observed in other G. duodenalis cell cultures. However, they were below the transcriptional fold-change threshold (log2FC > 1) typically employed in transcriptomic analyses and appear to be contradicted in ALB-R G. duodenalis WB-1B by down-regulation of the NAD scavenging and conversion pathways required to support these stress pathways and up-regulation of many highly oxidation sensitive iron-sulphur (FeS) cluster based metabolic enzymes.
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3
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Chen J, Roll-Mecak A. Glutamylation is a negative regulator of microtubule growth. Mol Biol Cell 2023; 34:ar70. [PMID: 37074962 PMCID: PMC10295482 DOI: 10.1091/mbc.e23-01-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/12/2023] [Accepted: 04/14/2023] [Indexed: 04/20/2023] Open
Abstract
Microtubules are noncovalent polymers built from αβ-tubulin dimers. The disordered C-terminal tubulin tails are functionalized with multiple glutamate chains of variable lengths added and removed by tubulin tyrosine ligases (TTLLs) and carboxypeptidases (CCPs). Glutamylation is abundant on stable microtubule arrays such as in axonemes and axons, and its dysregulation leads to human pathologies. Despite this, the effects of glutamylation on intrinsic microtubule dynamics are unclear. Here we generate tubulin with short and long glutamate chains and show that glutamylation slows the rate of microtubule growth and increases catastrophes as a function of glutamylation levels. This implies that the higher stability of glutamylated microtubules in cells is due to effectors. Interestingly, EB1 is minimally affected by glutamylation and thus can report on the growth rates of both unmodified and glutamylated microtubules. Finally, we show that glutamate removal by CCP1 and 5 is synergistic and occurs preferentially on soluble tubulin, unlike TTLL enzymes that prefer microtubules. This substrate preference establishes an asymmetry whereby once the microtubule depolymerizes, the released tubulin is reset to a less-modified state, while polymerized tubulin accumulates the glutamylation mark. Our work shows that a modification on the disordered tubulin tails can directly affect microtubule dynamics and furthers our understanding of the mechanistic underpinnings of the tubulin code.
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Affiliation(s)
- Jiayi Chen
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, and
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, and
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
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4
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Zhong Y, Yan W, Ruan J, Fang M, Yu C, Du S, Rai G, Tao D, Henderson MJ, Fang S. XBP1 variant 1 promotes mitosis of cancer cells involving upregulation of the polyglutamylase TTLL6. Hum Mol Genet 2022; 31:2639-2654. [PMID: 35333353 PMCID: PMC9396943 DOI: 10.1093/hmg/ddac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/19/2021] [Accepted: 01/10/2022] [Indexed: 11/15/2022] Open
Abstract
XBP1 variant 1 (Xv1) is the most abundant XBP1 variant and is highly enriched across cancer types but nearly none in normal tissues. Its expression is associated with poor patients' survival and is specifically required for survival of malignant cells, but the underlying mechanism is not known. Here we report that Xv1 upregulates the polyglutamylase tubulin tyrosine ligase-like 6 (TTLL6) and promotes mitosis of cancer cells. Like the canonical XBP1, Xv1 mRNA undergoes unconventional splicing by IRE1α under endoplasmic reticulum stress, but it is also constitutively spliced by IRE1β. The spliced Xv1 mRNA encodes the active form of Xv1 protein (Xv1s). RNA sequencing in HeLa cells revealed that Xv1s overexpression regulates expression of genes that are not involved in the canonical unfolded protein response, including TTLL6 as a highly upregulated gene. Gel shift assay and chromatin immunoprecipitation revealed that Xv1s bind to the TTLL6 promoter region. Knockdown of TTLL6 caused death of cancer cells but not benign and normal cells, similar to the effects of knocking down Xv1. Moreover, overexpression of TTLL6 partially rescued BT474 cells from apoptosis induced by either TTLL6 or Xv1 knockdown, supporting TTLL6 as an essential downstream effector of Xv1 in regulating cancer cell survival. TTLL6 is localized in the mitotic spindle of cancer cells. Xv1 or TTLL6 knockdown resulted in decreased spindle polyglutamylation and interpolar spindle, as well as congression failure, mitotic arrest and cell death. These findings suggest that Xv1 is essential for cancer cell mitosis, which is mediated, at least in part, by increasing TTLL6 expression.
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Affiliation(s)
- Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Wenjing Yan
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jingjing Ruan
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Pulmonary Medicine, Anhui Medical University First Affiliated Hospital, Hefei, Anhui 230032, China
| | - Mike Fang
- Population and Quantitative Health Sciences Department, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Changjun Yu
- Department of General surgery, Anhui Medical University First Affiliated Hospital, Hefei, Anhui 230032, China
| | - Shaojun Du
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ganesha Rai
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Dingyin Tao
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Mark J Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Oncology, UM Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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5
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Gadadhar S, Hirschmugl T, Janke C. The tubulin code in mammalian sperm development and function. Semin Cell Dev Biol 2022; 137:26-37. [PMID: 35067438 DOI: 10.1016/j.semcdb.2021.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 01/11/2023]
Abstract
Microtubules are cytoskeletal elements that play key roles throughout the different steps of sperm development. As an integral part of the sperm flagellum, the molecular machine that generates sperm motility, microtubules are also essential for the progressive swimming of sperm to the oocyte, which is a prerequisite for fertilisation. Given the central role of microtubules in all steps of spermatogenesis, their functions need to be tightly controlled. Recent work has showcased tubulin posttranslational modifications as key players in sperm development and function, with aberrations often leading to male infertility with a broad spectrum of sperm defects. Posttranslational modifications are part of the tubulin code, a mechanism that can control microtubule functions by modulating the properties of their molecular building blocks, the tubulin proteins. Here we review the current knowledge on the implications of the tubulin code in sperm development and functions and its importance for male fertility.
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Affiliation(s)
- Sudarshan Gadadhar
- Institut Curie, Université PSL, CNRS UMR3348, F-91401 Orsay, France; Université Paris-Saclay, CNRS UMR3348, F-91401 Orsay, France.
| | | | - Carsten Janke
- Institut Curie, Université PSL, CNRS UMR3348, F-91401 Orsay, France; Université Paris-Saclay, CNRS UMR3348, F-91401 Orsay, France.
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6
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Joachimiak E, Wloga D. Tubulin post-translational modifications in protists - Tiny models for solving big questions. Semin Cell Dev Biol 2021; 137:3-15. [PMID: 34922809 DOI: 10.1016/j.semcdb.2021.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 11/09/2021] [Accepted: 12/01/2021] [Indexed: 11/15/2022]
Abstract
Protists are an exceptionally diverse group of mostly single-celled eukaryotes. The organization of the microtubular cytoskeleton in protists from various evolutionary lineages has different levels of sophistication, from a network of microtubules (MTs) supporting intracellular trafficking as in Dictyostelium, to complex structures such as basal bodies and cilia/flagella enabling cell motility, and lineage-specific adaptations such as the ventral disc in Giardia. MTs building these diverse structures have specific properties partly due to the presence of tubulin post-translational modifications (PTMs). Among them there are highly evolutionarily conserved PTMs: acetylation, detyrosination, (poly)glutamylation and (poly)glycylation. In some protists also less common tubulin PTMs were identified, including phosphorylation, methylation, Δ2-, Δ5- of α-tubulin, polyubiquitination, sumoylation, or S-palmitoylation. Not surprisingly, several single-celled organisms become models to study tubulin PTMs, including their effect on MT properties and discovery of the modifying enzymes. Here, we briefly summarize the current knowledge on tubulin PTMs in unicellular eukaryotes and highlight key findings in protists as model organisms.
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Affiliation(s)
- Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland.
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland.
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7
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Guichard P, Laporte MH, Hamel V. The centriolar tubulin code. Semin Cell Dev Biol 2021; 137:16-25. [PMID: 34896019 DOI: 10.1016/j.semcdb.2021.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/25/2022]
Abstract
Centrioles are microtubule-based cell organelles present in most eukaryotes. They participate in the control of cell division as part of the centrosome, the major microtubule-organizing center of the cell, and are also essential for the formation of primary and motile cilia. During centriole assembly as well as across its lifetime, centriolar tubulin display marks defined by post-translational modifications (PTMs), such as glutamylation or acetylation. To date, the functions of these PTMs at centrioles are not well understood, although pioneering experiments suggest a role in the stability of this organelle. Here, we review the current knowledge regarding PTMs at centrioles with a particular focus on a possible link between these modifications and centriole's architecture, and propose possible hypothesis regarding centriolar tubulin PTMs's function.
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Affiliation(s)
- Paul Guichard
- University of Geneva, Department of Cell Biology, Geneva, Switzerland.
| | - Marine H Laporte
- University of Geneva, Department of Cell Biology, Geneva, Switzerland
| | - Virginie Hamel
- University of Geneva, Department of Cell Biology, Geneva, Switzerland.
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8
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Ahn JI, Park JE, Meng L, Zhang L, Kim TS, Kruhlak MJ, Kim BY, Lee KS. Phase separation of the Cep63•Cep152 complex underlies the formation of dynamic supramolecular self-assemblies at human centrosomes. Cell Cycle 2020; 19:3437-3457. [PMID: 33208041 DOI: 10.1080/15384101.2020.1843777] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The centrosome is a unique membraneless organelle that plays a pivotal role in the orderly progression of the cell cycle in animal cells. It has been shown that two pericentriolar scaffold proteins, Cep63 and Cep152, generate a heterotetrameric complex to self-assemble into a higher-order cylindrical architecture around a centriole. However, the mechanisms underlying how they reach their threshold concentrations in the vast intracellular space and generate a self-assembled architecture remain mysterious. Here we demonstrate that, like liquid-like assemblies, Cep63 and Cep152 cooperatively generate amorphous aggregates capable of undergoing dynamic turnover and inter-aggregate fusion in vivo and a significant level of internal rearrangemefnt within a condensate in vitro. Consistently, 1,6-hexanediol, a liquid-liquid phase separation disruptor, greatly diminished the ability of endogenous Cep63 and Cep152 to localize to centrosomes. Interestingly, a purified Cep63•Cep152 complex generated either a cylindrical structure or a vesicle-like hollow sphere in a spatially controlled manner. It also formed condensate-like solid spheres in the presence of a macromolecular crowder. At the molecular level, two hydrophobic motifs, one each from Cep63 and Cep152, were required for generating phase-separating condensates and a high molecular-weight assembly. Thus, we propose that the self-assembly of the Cep63•Cep152 complex is triggered by an intrinsic property of the complex undergoing density transition through the hydrophobic-motif-mediated phase separation. Abbreviations: PCM, pericentriolar material; LLPS, liquid-liquid phase separation; MW, molecular-weight; CLEM, correlative light and electron microscopy; WT, wild-type; CMV, cytomegalovirus; FRAP, fluorescence recovery after photobleaching; FITC, fluorescein isothiocyanate; PCR, polymerase chain reaction; 3D-SIM, three-dimensional structured illumination microscopy; DMEM, Dulbecco's Modified Eagle Medium; PEI Max, Polyethylenimine Max; PBS, phosphate-buffered saline; RT, room temperature; DAPI, 4', 6-diamidino-2-phenylindole; AOTF, acousto-optic tunable filter; LB, Luria broth; OD, optical density; IPTG, isopropyl β-D-1-thiogalactopyranoside; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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Affiliation(s)
- Jong Il Ahn
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Jung-Eun Park
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Lingjun Meng
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Liang Zhang
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Tae-Sung Kim
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Michael J Kruhlak
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Bo Yeon Kim
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology , Ochang, Republic of Korea
| | - Kyung S Lee
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
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9
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The emerging role of tubulin posttranslational modifications in cilia and ciliopathies. BIOPHYSICS REPORTS 2020. [DOI: 10.1007/s41048-020-00111-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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10
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A Survey on Tubulin and Arginine Methyltransferase Families Sheds Light on P. lividus Embryo as Model System for Antiproliferative Drug Development. Int J Mol Sci 2019; 20:ijms20092136. [PMID: 31052191 PMCID: PMC6539552 DOI: 10.3390/ijms20092136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 04/27/2019] [Indexed: 01/18/2023] Open
Abstract
Tubulins and microtubules (MTs) represent targets for taxane-based chemotherapy. To date, several lines of evidence suggest that effectiveness of compounds binding tubulin often relies on different post-translational modifications on tubulins. Among them, methylation was recently associated to drug resistance mechanisms impairing taxanes binding. The sea urchin is recognized as a research model in several fields including fertilization, embryo development and toxicology. To date, some α- and β-tubulin genes have been identified in P. lividus, while no data are available in echinoderms for arginine methyl transferases (PRMT). To evaluate the exploiting of the sea urchin embryo in the field of antiproliferative drug development, we carried out a survey of the expressed α- and β-tubulin gene sets, together with a comprehensive analysis of the PRMT gene family and of the methylable arginine residues in P. lividus tubulins. Because of their specificities, the sea urchin embryo may represent an interesting tool for dissecting mechanisms of tubulin targeting drug action. Therefore, results herein reported provide evidences supporting the P. lividus embryo as animal system for testing antiproliferative drugs.
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11
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Chawla DG, Shah RV, Barth ZK, Lee JD, Badecker KE, Naik A, Brewster MM, Salmon TP, Peel N. Caenorhabditis elegans glutamylating enzymes function redundantly in male mating. Biol Open 2016; 5:1290-8. [PMID: 27635036 PMCID: PMC5051658 DOI: 10.1242/bio.017442] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Microtubule glutamylation is an important modulator of microtubule function and has been implicated in the regulation of centriole stability, neuronal outgrowth and cilia motility. Glutamylation of the microtubules is catalyzed by a family of tubulin tyrosine ligase-like (TTLL) enzymes. Analysis of individual TTLL enzymes has led to an understanding of their specific functions, but how activities of the TTLL enzymes are coordinated to spatially and temporally regulate glutamylation remains relatively unexplored. We have undertaken an analysis of the glutamylating TTLL enzymes in C. elegans. We find that although all five TTLL enzymes are expressed in the embryo and adult worm, loss of individual enzymes does not perturb microtubule function in embryonic cell divisions. Moreover, normal dye-filling, osmotic avoidance and male mating behavior indicate the presence of functional amphid cilia and male-specific neurons. A ttll-4(tm3310); ttll-11(tm4059); ttll-5(tm3360) triple mutant, however, shows reduced male mating efficiency due to a defect in the response step, suggesting that these three enzymes function redundantly, and that glutamylation is required for proper function of the male-specific neurons. Summary: Although mutations in individual microtubule glutamylating enzymes do not disrupt essential microtubule functions in C. elegans, combining mutations in three enzymes uncovers a redundant function for glutamylation in male mating.
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Affiliation(s)
- Daniel G Chawla
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | - Ruchi V Shah
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | - Zachary K Barth
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | - Jessica D Lee
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | | | - Anar Naik
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | - Megan M Brewster
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | - Timothy P Salmon
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
| | - Nina Peel
- Department of Biology, The College of New Jersey, Ewing, NJ 08618, USA
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12
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Konno A, Ikegami K, Konishi Y, Yang HJ, Abe M, Yamazaki M, Sakimura K, Yao I, Shiba K, Inaba K, Setou M. Ttll9-/- mice sperm flagella show shortening of doublet 7, reduction of doublet 5 polyglutamylation and a stall in beating. J Cell Sci 2016; 129:2757-66. [PMID: 27257088 DOI: 10.1242/jcs.185983] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 05/31/2016] [Indexed: 12/27/2022] Open
Abstract
Nine outer doublet microtubules in axonemes of flagella and cilia are heterogeneous in structure and biochemical properties. In mammalian sperm flagella, one of the factors to generate the heterogeneity is tubulin polyglutamylation, although the importance of the heterogeneous modification is unclear. Here, we show that a tubulin polyglutamylase Ttll9 deficiency (Ttll9(-/-)) causes a unique set of phenotypes related to doublet heterogeneity. Ttll9(-/-) sperm axonemes had frequent loss of a doublet and reduced polyglutamylation. Intriguingly, the doublet loss selectively occurred at the distal region of doublet 7, and reduced polyglutamylation was observed preferentially on doublet 5. Ttll9(-/-) spermatozoa showed aberrant flagellar beating, characterized by frequent stalls after anti-hook bending. This abnormal motility could be attributed to the reduction of polyglutamylation on doublet 5, which probably occurred at a position involved in the switching of bending. These results indicate that mammalian Ttll9 plays essential roles in maintaining the normal structure and beating pattern of sperm flagella by establishing normal heterogeneous polyglutamylation patterns.
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Affiliation(s)
- Alu Konno
- Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan
| | - Koji Ikegami
- Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan
| | - Yoshiyuki Konishi
- Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan
| | - Hyun-Jeong Yang
- Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 9518585, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 9518585, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 9518585, Japan
| | - Ikuko Yao
- Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 4150025, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 4150025, Japan
| | - Mitsutoshi Setou
- Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan International Mass Imaging Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 4313192, Japan Department of Anatomy, The University of Hong Kong, 6/F, William MW Mong Block, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China Division of Neural Systematics, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 4440867, Japan Riken Center for Molecular Imaging Science, Kobe, Hyogo 6500047, Japan
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13
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Loss of RPGR glutamylation underlies the pathogenic mechanism of retinal dystrophy caused by TTLL5 mutations. Proc Natl Acad Sci U S A 2016; 113:E2925-34. [PMID: 27162334 DOI: 10.1073/pnas.1523201113] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mutations in the X-linked retinitis pigmentosa GTPase regulator (RPGR) gene are a major cause of retinitis pigmentosa, a blinding retinal disease resulting from photoreceptor degeneration. A photoreceptor specific ORF15 variant of RPGR (RPGR(ORF15)), carrying multiple Glu-Gly tandem repeats and a C-terminal basic domain of unknown function, localizes to the connecting cilium where it is thought to regulate cargo trafficking. Here we show that tubulin tyrosine ligase like-5 (TTLL5) glutamylates RPGR(ORF15) in its Glu-Gly-rich repetitive region containing motifs homologous to the α-tubulin C-terminal tail. The RPGR(ORF15) C-terminal basic domain binds to the noncatalytic cofactor interaction domain unique to TTLL5 among TTLL family glutamylases and targets TTLL5 to glutamylate RPGR. Only TTLL5 and not other TTLL family glutamylases interacts with RPGR(ORF15) when expressed transiently in cells. Consistent with this, a Ttll5 mutant mouse displays a complete loss of RPGR glutamylation without marked changes in tubulin glutamylation levels. The Ttll5 mutant mouse develops slow photoreceptor degeneration with early mislocalization of cone opsins, features resembling those of Rpgr-null mice. Moreover TTLL5 disease mutants that cause human retinal dystrophy show impaired glutamylation of RPGR(ORF15) Thus, RPGR(ORF15) is a novel glutamylation substrate, and this posttranslational modification is critical for its function in photoreceptors. Our study uncovers the pathogenic mechanism whereby absence of RPGR(ORF15) glutamylation leads to retinal pathology in patients with TTLL5 gene mutations and connects these two genes into a common disease pathway.
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Jing Z, Yin H, Wang P, Gao J, Yuan L. Centlein, a novel microtubule-associated protein stabilizing microtubules and involved in neurite formation. Biochem Biophys Res Commun 2016; 472:360-5. [DOI: 10.1016/j.bbrc.2016.02.079] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/19/2016] [Indexed: 11/24/2022]
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15
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Hu Z, Liang Y, He W, Pan J. Cilia disassembly with two distinct phases of regulation. Cell Rep 2015; 10:1803-10. [PMID: 25801021 DOI: 10.1016/j.celrep.2015.02.044] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/30/2014] [Accepted: 02/17/2015] [Indexed: 01/23/2023] Open
Abstract
Cilia and flagella are dynamic organelles that undergo assembly and disassembly during each cell cycle. They are structurally polarized, and the mechanisms by which these organelles are disassembled are incompletely understood. Here, we show that flagellar resorption occurs in two distinct phases of length-dependent regulation. A CDK-like kinase, encoded by flagellar shortening 1 (FLS1), is required for the normal rate of disassembly of only the distal part of the flagellum. Mechanistically, loss of function of FLS1 prevents the initial phosphorylation of CALK, an aurora-like kinase that regulates flagellar shortening, and induces the earlier onset of the inhibitory phosphorylation of CrKinesin13, a microtubule depolymerase, which is involved in flagellar shortening. In addition, CALK and CrKinesin13 phosphorylation can also be induced by the process of flagellar shortening itself, demonstrating an example of cilia-generated signaling not requiring the binding of a ligand or the stimulation of an ion channel.
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Lack of Cytosolic Carboxypeptidase 1 Leads to Subfertility due to the Reduced Number of Antral Follicles in pcd3J-/- Females. PLoS One 2015; 10:e0139557. [PMID: 26452267 PMCID: PMC4599934 DOI: 10.1371/journal.pone.0139557] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 09/15/2015] [Indexed: 11/19/2022] Open
Abstract
Females homozygous for the Purkinje cell degeneration mutation (pcd) are fertile, although the success rate is much lower than in the wild type. We performed detailed analysis of reproductive abnormalities of pcd females. The number of oocytes produced following exogenous gonadotropin treatment was much lower in pcd3J-/- females than in pcd3J+/+ females. Furthermore, the estrous cyclicity of pcd3J-/- females according to the appearance of the vagina was almost undetectable comparing to that of the wild type. Histological analyses and follicle counting of 4- and 8-week-old pcd3J-/- ovaries showed an increase in the number of secondary follicles and a decrease in the number of antral follicles, indicating that AGTPBP1/ CCP1 plays an important role in the development of secondary follicles into antral follicles. Consistent with a previous analysis of the pcd cerebellum, pcd3J-/- ovaries also showed a clear increase in the level of polyglutamylation. Gene expression analysis showed that both oocytes and cumulus cells express CCP1. However, Ccp4 and CCP6, which can compensate the function of CCP1, were not expressed in mouse ovaries. Failure of microtubule deglutamylation did not affect the structure and function of the meiotic spindle in properly aligning chromosomes in the center of the nucleus during meiosis in pcd3J-/- females. We also showed that the pituitary-derived growth and reproduction-related endocrine system functions normally in pcd3J-/- mice. The results of this study provide insight into additional functions of CCP1, which cannot be fully explained by the side chain deglutamylation of microtubules alone.
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Kashina A. Protein arginylation, a global biological regulator that targets actin cytoskeleton and the muscle. Anat Rec (Hoboken) 2015; 297:1630-6. [PMID: 25125176 DOI: 10.1002/ar.22969] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 03/14/2014] [Indexed: 12/20/2022]
Abstract
Posttranslational addition of Arg to proteins, mediated by arginyltransferase ATE1 has been first observed in 1963 and remained poorly understood for decades since its original discovery. Recent work demonstrated the global nature of arginylation and its essential role in multiple physiological pathways during embryogenesis and adulthood and identified over a hundred of proteins arginylated in vivo. Among these proteins, the prominent role belongs to the actin cytoskeleton and the muscle, and follow up studies strongly suggests that arginylation constitutes a novel biological regulator of contractility. This review presents an overview of the studies of protein arginylation that led to the discovery of its major role in the muscle.
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Affiliation(s)
- Anna Kashina
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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18
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Warburton-Pitt SRF, Silva M, Nguyen KCQ, Hall DH, Barr MM. The nphp-2 and arl-13 genetic modules interact to regulate ciliogenesis and ciliary microtubule patterning in C. elegans. PLoS Genet 2014; 10:e1004866. [PMID: 25501555 PMCID: PMC4263411 DOI: 10.1371/journal.pgen.1004866] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/31/2014] [Indexed: 12/14/2022] Open
Abstract
Cilia are microtubule-based cellular organelles that mediate signal transduction. Cilia are organized into several structurally and functionally distinct compartments: the basal body, the transition zone (TZ), and the cilia shaft. In vertebrates, the cystoprotein Inversin localizes to a portion of the cilia shaft adjacent to the TZ, a region termed the "Inversin compartment" (InvC). The mechanisms that establish and maintain the InvC are unknown. In the roundworm C. elegans, the cilia shafts of amphid channel and phasmid sensory cilia are subdivided into two regions defined by different microtubule ultrastructure: a proximal doublet-based region adjacent to the TZ, and a distal singlet-based region. It has been suggested that C. elegans cilia also possess an InvC, similarly to mammalian primary cilia. Here we explored the biogenesis, structure, and composition of the C. elegans ciliary doublet region and InvC. We show that the InvC is conserved and distinct from the doublet region. nphp-2 (the C. elegans Inversin homolog) and the doublet region genes arl-13, klp-11, and unc-119 are redundantly required for ciliogenesis. InvC and doublet region genes can be sorted into two modules-nphp-2+klp-11 and arl-13+unc-119-which are both antagonized by the hdac-6 deacetylase. The genes of this network modulate the sizes of the NPHP-2 InvC and ARL-13 doublet region. Glutamylation, a tubulin post-translational modification, is not required for ciliary targeting of InvC and doublet region components; rather, glutamylation is modulated by nphp-2, arl-13, and unc-119. The ciliary targeting and restricted localization of NPHP-2, ARL-13, and UNC-119 does not require TZ-, doublet region, and InvC-associated genes. NPHP-2 does require its calcium binding EF hand domain for targeting to the InvC. We conclude that the C. elegans InvC is distinct from the doublet region, and that components in these two regions interact to regulate ciliogenesis via cilia placement, ciliary microtubule ultrastructure, and protein localization.
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Affiliation(s)
- Simon R. F. Warburton-Pitt
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Malan Silva
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Ken C. Q. Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - David H. Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Maureen M. Barr
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
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Pathak N, Austin-Tse CA, Liu Y, Vasilyev A, Drummond IA. Cytoplasmic carboxypeptidase 5 regulates tubulin glutamylation and zebrafish cilia formation and function. Mol Biol Cell 2014; 25:1836-44. [PMID: 24743595 PMCID: PMC4055263 DOI: 10.1091/mbc.e13-01-0033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Glutamylation is a functionally important tubulin posttranslational modification enriched on stable microtubules of neuronal axons, mitotic spindles, centrioles, and cilia. In vertebrates, balanced activities of tubulin glutamyl ligase and cytoplasmic carboxypeptidase deglutamylase enzymes maintain organelle- and cell type-specific tubulin glutamylation patterns. Tubulin glutamylation in cilia is regulated via restricted subcellular localization or expression of tubulin glutamyl ligases (ttlls) and nonenzymatic proteins, including the zebrafish TPR repeat protein Fleer/Ift70. Here we analyze the expression patterns of ccp deglutamylase genes during zebrafish development and the effects of ccp gene knockdown on cilia formation, morphology, and tubulin glutamylation. The deglutamylases ccp2, ccp5, and ccp6 are expressed in ciliated cells, whereas ccp1 expression is restricted to the nervous system. Only ccp5 knockdown increases cilia tubulin glutamylation, induces ciliopathy phenotypes, including axis curvature, hydrocephalus, and pronephric cysts, and disrupts multicilia motility, suggesting that Ccp5 is the principal tubulin deglutamylase that maintains functional levels of cilia tubulin glutamylation. The ability of ccp5 knockdown to restore cilia tubulin glutamylation in fleer/ift70 mutants and rescue pronephric multicilia formation in both fleer- and ift88-deficient zebrafish indicates that tubulin glutamylation is a key driver of ciliogenesis.
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Affiliation(s)
- Narendra Pathak
- Nephrology Division, Massachusetts General Hospital, Charlestown, MA 02129
| | | | - Yan Liu
- Nephrology Division, Massachusetts General Hospital, Charlestown, MA 02129
| | - Aleksandr Vasilyev
- Department of Pathology, Massachusetts General Hospital, Charlestown, MA 02129
| | - Iain A Drummond
- Nephrology Division, Massachusetts General Hospital, Charlestown, MA 02129Department of Genetics, Harvard Medical School, Boston, MA 02115
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Ludueña RF. A Hypothesis on the Origin and Evolution of Tubulin. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 302:41-185. [DOI: 10.1016/b978-0-12-407699-0.00002-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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21
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Sperry AO. The dynamic cytoskeleton of the developing male germ cell. Biol Cell 2012; 104:297-305. [PMID: 22276751 DOI: 10.1111/boc.201100102] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 01/20/2012] [Indexed: 11/28/2022]
Abstract
Mammalian spermatogenesis is characterised by dramatic cellular change to transform the non-polar spermatogonium into a highly polarised and functional spermatozoon. The acquisition of cell polarity is a requisite step for formation of viable sperm. The polarity of the spermatozoon is clearly demonstrated by the acrosome at the apical pole of the cell and the flagellum at the opposite end. Spermatogenesis consists of three basic phases: mitosis, meiosis and spermiogenesis. The final phase represents the period of greatest cellular change where cell-type specific organelles such as the acrosome and the flagellum form, the nucleus migrates to the plasma membrane and elongates, chromatin condenses and residual cytoplasm is removed. An important feature of spermatogenesis is the change in the cytoskeleton that occurs throughout this pathway. In this review, the author will provide an overview of these transformations and provide insight into possible modes of regulation of these rearrangements during spermatogenesis. Although primary focus will be given to the microtubule cytoskeleton, the importance of actin filaments to the cellular transformation of the male germ cell will also be discussed.
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Affiliation(s)
- Ann O Sperry
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA.
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22
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The phosphorylation state of an aurora-like kinase marks the length of growing flagella in Chlamydomonas. Curr Biol 2011; 21:586-91. [PMID: 21458267 DOI: 10.1016/j.cub.2011.02.046] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 02/25/2011] [Accepted: 02/28/2011] [Indexed: 11/21/2022]
Abstract
Flagella and cilia are structurally polarized organelles whose lengths are precisely defined, and alterations in length are related to several human disorders. Intraflagellar transport (IFT) and protein signaling molecules are implicated in specifying flagellar and ciliary length, but evidence has been lacking for a flagellum and cilium length sensor that could participate in active length control or establishment of structural polarity. Previously, we showed that the phosphorylation state of the aurora-like protein kinase CALK in Chlamydomonas is a marker of the absence of flagella. Here we show that CALK phosphorylation state is also a marker for flagellar length. CALK is phosphorylated in cells without flagella, and during flagellar assembly it becomes dephosphorylated. Dephosphorylation is not simply a consequence of initiation of flagellar assembly or of time after experimentally induced flagellar loss, but instead requires flagella to be assembled to a threshold length. Analysis of cells with flagella of varying lengths shows that the threshold length for CALK dephosphorylation is ~6 μm (half length). Studies with short and long flagellar mutants indicate that cells detect absolute rather than relative flagellar length. Our results demonstrate that cells possess a mechanism for translating flagellar length into a posttranslational modification of a known flagellar regulatory protein.
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23
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Hermo L, Pelletier RM, Cyr DG, Smith CE. Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: changes in spermatid organelles associated with development of spermatozoa. Microsc Res Tech 2010; 73:279-319. [PMID: 19941292 DOI: 10.1002/jemt.20787] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Spermiogenesis is a long process whereby haploid spermatids derived from the meiotic divisions of spermatocytes undergo metamorphosis into spermatozoa. It is subdivided into distinct steps with 19 being identified in rats, 16 in mouse and 8 in humans. Spermiogenesis extends over 22.7 days in rats and 21.6 days in humans. In this part, we review several key events that take place during the development of spermatids from a structural and functional point of view. During early spermiogenesis, the Golgi apparatus forms the acrosome, a lysosome-like membrane bound organelle involved in fertilization. The endoplasmic reticulum undergoes several topographical and structural modifications including the formation of the radial body and annulate lamellae. The chromatoid body is fully developed and undergoes structural and functional modifications at this time. It is suspected to be involved in RNA storing and processing. The shape of the spermatid head undergoes extensive structural changes that are species-specific, and the nuclear chromatin becomes compacted to accommodate the stream-lined appearance of the sperm head. Microtubules become organized to form a curtain or manchette that associates with spermatids at specific steps of their development. It is involved in maintenance of the sperm head shape and trafficking of proteins in the spermatid cytoplasm. During spermiogenesis, many genes/proteins have been implicated in the diverse dynamic events occurring at this time of development of germ cells and the absence of some of these have been shown to result in subfertility or infertility.
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Affiliation(s)
- Louis Hermo
- Faculty of Medicine, Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada H3A 2B2.
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Redeker V. Mass spectrometry analysis of C-terminal posttranslational modifications of tubulins. Methods Cell Biol 2010; 95:77-103. [PMID: 20466131 DOI: 10.1016/s0091-679x(10)95006-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In mammalian brain and ciliary axonemes from ciliates, alpha- and beta-tubulins exhibit an extraordinary heterogeneity due to a combination of multigene family expression and numerous posttranslational modifications (PTMs). The combination of several PTMs located in the C-terminal tail of tubulins plays a major role in this important polymorphism of tubulin: polyglutamylation, polyglycylation, detyrosination, tyrosination, removal of the penultimate glutamate residue, and phosphorylation. In order to document the relationship and functions of these PTMs, we have developed a tubulin C-terminal Peptide Mass Fingerprinting (PMF) method. Using simplified microtubule proteins and tubulin C-terminal peptides purifications, direct matrix-assisted laser desorption ionization (MALDI) mass spectrometry (MS) analysis can generate a complete picture of all tubulin isotype-specific C-terminal peptides together with their respective PTMs. This chapter will illustrate the capability of this approach to compare tubulin isoform compositions and document the changes in PTMs between samples with different tubulin assembly properties or consecutively to inactivation of modification sites or modification enzymes. Complementary MS-based approaches useful to document the structure of the highly heterogeneous posttranslational polymodifications will also be presented.
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Affiliation(s)
- Virginie Redeker
- Laboratoire d'Enzymologie et Biochimie Structurales, CNRS, 91198 Gif-sur-Yvette cedex, France
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25
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Fukushima N, Furuta D, Hidaka Y, Moriyama R, Tsujiuchi T. Post-translational modifications of tubulin in the nervous system. J Neurochem 2009; 109:683-93. [DOI: 10.1111/j.1471-4159.2009.06013.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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26
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Keller LC, Geimer S, Romijn E, Yates J, Zamora I, Marshall WF. Molecular architecture of the centriole proteome: the conserved WD40 domain protein POC1 is required for centriole duplication and length control. Mol Biol Cell 2009; 20:1150-66. [PMID: 19109428 PMCID: PMC2642750 DOI: 10.1091/mbc.e08-06-0619] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 11/12/2008] [Accepted: 12/08/2008] [Indexed: 12/11/2022] Open
Abstract
Centrioles are intriguing cylindrical organelles composed of triplet microtubules. Proteomic data suggest that a large number of proteins besides tubulin are necessary for the formation and maintenance of a centriole's complex structure. Expansion of the preexisting centriole proteome from the green alga Chlamydomonas reinhardtii revealed additional human disease genes, emphasizing the significance of centrioles in normal human tissue homeostasis. We found that two classes of ciliary disease genes were highly represented among the basal body proteome: cystic kidney disease (especially nephronophthisis) syndromes, including Meckel/Joubert-like and oral-facial-digital syndrome, caused by mutations in CEP290, MKS1, OFD1, and AHI1/Jouberin proteins and cone-rod dystrophy syndrome genes, including UNC-119/HRG4, NPHP4, and RPGR1. We further characterized proteome of the centriole (POC) 1, a highly abundant WD40 domain-containing centriole protein. We found that POC1 is recruited to nascent procentrioles and localizes in a highly asymmetrical pattern in mature centrioles corresponding to sites of basal-body fiber attachment. Knockdown of POC1 in human cells caused a reduction in centriole duplication, whereas overexpression caused the appearance of elongated centriole-like structures. Together, these data suggest that POC1 is involved in early steps of centriole duplication as well as in the later steps of centriole length control.
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Affiliation(s)
- Lani C. Keller
- *Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Stefan Geimer
- Zellbiologie/Elektronenmikroskopie, Universitaet Bayreuth, 95440 Bayreuth, Germany; and
| | - Edwin Romijn
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - John Yates
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Ivan Zamora
- *Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Wallace F. Marshall
- *Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
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Abstract
Centrioles perform the dual functions of organizing both centrosomes and cilia. The biogenesis of nascent centrioles is an essential cellular event that is tightly coupled to the cell cycle so that each cell contains only two or four centrioles at any given point in the cell cycle. The assembly of centrioles and their analogs, basal bodies, is well characterized at the ultrastructural level whereby structural modules are built into a functional organelle. Genetic studies in model organisms combined with proteomic, bioinformatic and identifying ciliary disease gene orthologs have revealed a wealth of molecules requiring further analysis to determine their roles in centriole duplication, assembly and function. Nonetheless, at this stage, our understanding of how molecular components interact to build new centrioles and basal bodies is limited. The ciliates, Tetrahymena and Paramecium, historically have been the subject of cytological and genetic study of basal bodies. Recent advances in the ciliate genetic and molecular toolkit have placed these model organisms in a favorable position to study the molecular mechanisms of centriole and basal body assembly.
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Affiliation(s)
- Chad G Pearson
- Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, 347 UCB, Porter Biosciences, Boulder, CO 80309-0347, USA.
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28
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Glutamylation on alpha-tubulin is not essential but affects the assembly and functions of a subset of microtubules in Tetrahymena thermophila. EUKARYOTIC CELL 2008; 7:1362-72. [PMID: 18586949 DOI: 10.1128/ec.00084-08] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Tubulin undergoes glutamylation, a conserved posttranslational modification of poorly understood function. We show here that in the ciliate Tetrahymena, most of the microtubule arrays contain glutamylated tubulin. However, the length of the polyglutamyl side chain is spatially regulated, with the longest side chains present on ciliary and basal body microtubules. We focused our efforts on the function of glutamylation on the alpha-tubulin subunit. By site-directed mutagenesis, we show that all six glutamates of the C-terminal tail domain of alpha-tubulin that provide potential sites for glutamylation are not essential but are needed for normal rates of cell multiplication and cilium-based functions (phagocytosis and cell motility). By comparative phylogeny and biochemical assays, we identify two conserved tubulin tyrosine ligase (TTL) domain proteins, Ttll1p and Ttll9p, as alpha-tubulin-preferring glutamyl ligase enzymes. In an in vitro microtubule glutamylation assay, Ttll1p showed a chain-initiating activity while Ttll9p had primarily a chain-elongating activity. GFP-Ttll1p localized mainly to basal bodies, while GFP-Ttll9p localized to cilia. Disruption of the TTLL1 and TTLL9 genes decreased the rates of cell multiplication and phagocytosis. Cells lacking both genes had fewer cortical microtubules and showed defects in the maturation of basal bodies. We conclude that glutamylation on alpha-tubulin is not essential but is required for efficiency of assembly and function of a subset of microtubule-based organelles. Furthermore, the spatial restriction of modifying enzymes appears to be a major mechanism that drives differential glutamylation at the subcellular level.
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Mencarelli C, Lupetti P, Dallai R. New insights into the cell biology of insect axonemes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 268:95-145. [PMID: 18703405 DOI: 10.1016/s1937-6448(08)00804-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Insects do not possess ciliated epithelia, and cilia/flagella are present in the sperm tail and--as modified cilia--in mechano- and chemosensory neurons. The core cytoskeletal component of these organelles, the axoneme, is a microtubule-based structure that has been conserved throughout evolution. However, in insects the sperm axoneme exhibits distinctive structural features; moreover, several insect groups are characterized by an unusual sperm axoneme variability. Besides the abundance of morphological data on insect sperm flagella, most of the available molecular information on the insect axoneme comes from genetic studies on Drosophila spermatogenesis, and only recently other insect species have been proposed as useful models. Here, we review the current knowledge on the cell biology of insect axoneme, including contributions from both Drosophila and other model insects.
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Affiliation(s)
- C Mencarelli
- Department of Evolutionary Biology, University of Siena, 53100 Siena, Italy
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30
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Abstract
Tubulin, the most abundant axonemal protein, is extensively modified by several highly conserved post-translational mechanisms including acetylation, detyrosination, glutamylation, and glycylation. We discuss the pathways that contribute to the assembly and maintenance of axonemal microtubules, with emphasis on the potential functions of post-translational modifications that affect tubulin. The recent identification of a number of tubulin modifying enzymes and mutational studies of modification sites on tubulin have allowed for significant functional insights. Polymeric modifications of tubulin (glutamylation and glycylation) have emerged as important determinants of the 9 + 2 axoneme assembly and motility.
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Affiliation(s)
- Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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31
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Sharma N, Bryant J, Wloga D, Donaldson R, Davis RC, Jerka-Dziadosz M, Gaertig J. Katanin regulates dynamics of microtubules and biogenesis of motile cilia. ACTA ACUST UNITED AC 2007; 178:1065-79. [PMID: 17846175 PMCID: PMC2064628 DOI: 10.1083/jcb.200704021] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The in vivo significance of microtubule severing and the mechanisms governing its spatial regulation are not well understood. In Tetrahymena, a cell type with elaborate microtubule arrays, we engineered null mutations in subunits of the microtubule-severing complex, katanin. We show that katanin activity is essential. The net effect of katanin on the polymer mass depends on the microtubule type and location. Although katanin reduces the polymer mass and destabilizes the internal network of microtubules, its activity increases the mass of ciliary microtubules. We also show that katanin reduces the levels of several types of post-translational modifications on tubulin of internal and cortical microtubules. Furthermore, katanin deficiencies phenocopy a mutation of β-tubulin that prevents deposition of polymodifications (glutamylation and glycylation) on microtubules. We propose that katanin preferentially severs older, post-translationally modified segments of microtubules.
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Affiliation(s)
- Neeraj Sharma
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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Pathak N, Obara T, Mangos S, Liu Y, Drummond IA. The zebrafish fleer gene encodes an essential regulator of cilia tubulin polyglutamylation. Mol Biol Cell 2007; 18:4353-64. [PMID: 17761526 PMCID: PMC2043541 DOI: 10.1091/mbc.e07-06-0537] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cilia and basal bodies are essential organelles for a broad spectrum of functions, including the development of left-right asymmetry, kidney function, cerebrospinal fluid transport, generation of photoreceptor outer segments, and hedgehog signaling. Zebrafish fleer (flr) mutants exhibit kidney cysts, randomized left-right asymmetry, hydrocephalus, and rod outer segment defects, suggesting a pleiotropic defect in ciliogenesis. Positional cloning flr identified a tetratricopeptide repeat protein homologous to the Caenorhabditis elegans protein DYF1 that was highly expressed in ciliated cells. flr pronephric cilia were shortened and showed a reduced beat amplitude, and olfactory cilia were absent in mutants. flr cilia exhibited ultrastructural defects in microtubule B-tubules, similar to axonemes that lack tubulin posttranslational modifications (polyglutamylation or polyglycylation). flr cilia showed a dramatic reduction in cilia polyglutamylated tubulin, indicating that flr encodes a novel modulator of tubulin polyglutamylation. We also found that the C. elegans flr homologue, dyf-1, is also required for tubulin polyglutamylation in sensory neuron cilia. Knockdown of zebrafish Ttll6, a tubulin polyglutamylase, specifically eliminated tubulin polyglutamylation and cilia formation in olfactory placodes, similar to flr mutants. These results are the first in vivo evidence that tubulin polyglutamylation is required for vertebrate cilia motility and structure, and, when compromised, results in failed ciliogenesis.
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Affiliation(s)
- Narendra Pathak
- Nephrology Division, Massachusetts General Hospital, Charlestown, MA 02129, USA
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Chernyavsky AI, Arredondo J, Vetter DE, Grando SA. Central role of alpha9 acetylcholine receptor in coordinating keratinocyte adhesion and motility at the initiation of epithelialization. Exp Cell Res 2007; 313:3542-55. [PMID: 17706194 PMCID: PMC2682983 DOI: 10.1016/j.yexcr.2007.07.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2007] [Revised: 07/13/2007] [Accepted: 07/13/2007] [Indexed: 11/24/2022]
Abstract
Epithelialization, a major component of wound healing, depends on keratinocyte adhesion and migration. Initiation of migration relies upon the ability of keratinocytes to free themselves from neighboring cells and basement membrane. The local cytotransmitter acetylcholine (ACh) controls keratinocyte adhesion and locomotion through different classes of ACh receptors (AChR). In this study, we explored signaling pathways downstream of the alpha9 AChR subtype that had been shown to control cell shape and cytoplasm mobility. Inactivation of alpha9 signaling by pharmacologic antagonism and RNA interference in keratinocyte cultures and null mutation in knockout mice delayed wound re-epithelialization in vitro and in vivo, respectively, and diminished the extent of colony scattering and cell outgrowth from the megacolony. Although keratinocytes at the leading edge elongated, produced filopodia and moved out, most of them remained anchored to the substrate by long cytoplasmic processes that stretched during their migration instead of retracting the uropod. Since the velocity of keratinocyte migration was not altered, we investigated the role of alpha9 in assembly/disassembly of the cell-cell and cell-matrix adhesion complexes. Stimulation of alpha9 upregulated in a time-dependent fashion phosphorylation of the adhesion molecules comprising focal adhesions (FAK, paxillin) and intercellular junctions (beta-catenin, desmoglein 3) as well as cytokeratins. Stimulation of alpha9 was associated with activation of phospholipase C, Src, EGF receptor kinase, protein kinase C, Rac and Rho, whereas inhibition of this receptor interfered with phosphorylation of adhesion and cytoskeletal proteins, and also altered cell-cell cohesion. We conclude that signaling through alpha9 AChR is critical for completion of the very early stages of epithelialization. By activating alpha9 AChR, ACh can control the dynamics and strength of cell-cell cohesion, disabling of a trailing uropod and disassembly and reassembly of focal adhesions, thus facilitating crawling locomotion.
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Affiliation(s)
- Alex I Chernyavsky
- Department of Dermatology, University of California Irvine, C340 Medical Sciences I, Irvine, CA 92697, USA
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van Dijk J, Rogowski K, Miro J, Lacroix B, Eddé B, Janke C. A targeted multienzyme mechanism for selective microtubule polyglutamylation. Mol Cell 2007; 26:437-48. [PMID: 17499049 DOI: 10.1016/j.molcel.2007.04.012] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 02/26/2007] [Accepted: 04/18/2007] [Indexed: 12/14/2022]
Abstract
Polyglutamylases are enzymes that form polyglutamate side chains of variable lengths on proteins. Polyglutamylation of tubulin is believed to regulate interactions of microtubules (MTs) with MT-associated proteins and molecular motors. Subpopulations of MTs are differentially polyglutamylated, yet only one modifying enzyme has been discovered in mammals. In an attempt to better understand the heterogeneous appearance of tubulin polyglutamylation, we searched for additional enzymes and report here the identification of six mammalian polyglutamylases. Each of them has a characteristic mode of catalysis and generates distinct patterns of modification on MTs, which can be further diversified by cooperation of multiple enzymes. Polyglutamylases are restricted to confined tissues and subtypes of MTs by differential expression and localization. In conclusion, we propose a multienzyme mechanism of polyglutamylation that can explain how the diversity of polyglutamylation on selected types of MTs is controlled at the molecular level.
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Libusová L, Dráber P. Multiple tubulin forms in ciliated protozoan Tetrahymena and Paramecium species. PROTOPLASMA 2006; 227:65-76. [PMID: 16736248 DOI: 10.1007/s00709-005-0152-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2005] [Accepted: 08/26/2005] [Indexed: 05/09/2023]
Abstract
Tetrahymena and Paramecium species are widely used representatives of the phylum Ciliata. Ciliates are particularly suitable model organisms for studying the functional heterogeneity of tubulins, since they provide a wide range of different microtubular structures in a single cell. Sequencing projects of the genomes of members of these two genera are in progress. Nearly all members of the tubulin superfamily (alpha-, beta-, gamma-, delta-, epsilon-, eta-, theta-, iota-, and kappa-tubulins) have been identified in Paramecium tetraurelia. In Tetrahymena spp., the functional consequences of different posttranslational tubulin modifications (acetylation, tyrosination and detyrosination, phosphorylation, glutamylation, and glycylation) have been studied by different approaches. These model organisms provide the opportunity to determine the function of tubulins found in ciliates, as well as in humans, but absent in some other model organisms. They also give us an opportunity to explore the mechanisms underlying microtubule diversity. Here we review current knowledge concerning the diversity of microtubular structures, tubulin genes, and posttranslational modifications in Tetrahymena and Paramecium species.
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Affiliation(s)
- L Libusová
- Department of Animal Physiology and Developmental Biology, Faculty of Sciences, Charles University, Prague, Czech Republic
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Lakämper S, Meyhöfer E. Back on track – On the role of the microtubule for kinesin motility and cellular function. J Muscle Res Cell Motil 2006; 27:161-71. [PMID: 16453157 DOI: 10.1007/s10974-005-9052-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 12/08/2005] [Indexed: 10/25/2022]
Abstract
The evolution of cytoskeletal filaments (actin- and intermediate-filaments, and the microtubules) and their associated motor- and non-motor-proteins has enabled the eukaryotic cell to achieve complex organizational and structural tasks. This ability to control cellular transport processes and structures allowed for the development of such complex cellular organelles like cilia or flagella in single-cell organisms and made possible the development and differentiation of multi-cellular organisms with highly specialized, polarized cells. Also, the faithful segregation of large amounts of genetic information during cell division relies crucially on the reorganization and control of the cytoskeleton, making the cytoskeleton a key prerequisite for the development of highly complex genomes. Therefore, it is not surprising that the eukaryotic cell continuously invests considerable resources in the establishment, maintenance, modification and rearrangement of the cytoskeletal filaments and the regulation of its interaction with accessory proteins. Here we review the literature on the interaction between microtubules and motor-proteins of the kinesin-family. Our particular interest is the role of the microtubule in the regulation of kinesin motility and cellular function. After an introduction of the kinesin-microtubule interaction we focus on two interrelated aspects: (1) the active allosteric participation of the microtubule during the interaction with kinesins in general and (2) the possible regulatory role of post-translational modifications of the microtubule in the kinesin-microtubule interaction.
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Affiliation(s)
- Stefan Lakämper
- Physics of Complex Systems, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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Dallai R, Lupetti P, Mencarelli C. Unusual Axonemes of Hexapod Spermatozoa. INTERNATIONAL REVIEW OF CYTOLOGY 2006; 254:45-99. [PMID: 17147997 DOI: 10.1016/s0074-7696(06)54002-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hexapod spermatozoa exhibit a great variation in their axoneme structure. The 9+2 pattern organization is present in a few basal taxa and in some derived groups. In most hexapods, a crown of nine accessory microtubules surrounds the 9+2 array, giving rise to the so-called 9+9+2 pattern. This general organization, however, displays a number of modifications in several taxa. In this review, the main variations concerning the number and localization of the accessory tubules, microtubular doublets, central microtubules, dynein arms, and axonemal length are summarized. We discuss the phylogenetic significance of all this structural information as well as the current hypotheses relating the sperm size and sperm polymorphism with reproductive success of some hexapod species. Also described are the biochemical data and the motility patterns which are currently known on some peculiar aberrant axonemes, in light of the contribution these models may give to the comprehension of the general functioning of the conventional 9+2 axoneme. Finally, we summarize methodological developments for the study of axoneme ultrastructure and the new opportunities for the molecular analysis of hexapod axonemes.
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Affiliation(s)
- Romano Dallai
- Department of Evolutionary Biology, University of Siena, Via A Moro 2, I-53100 Siena, Italy
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Mirouse V, Dastugue B, Couderc JL. The Drosophila Toucan protein is a new mitotic microtubule-associated protein required for spindle microtubule stability. Genes Cells 2005; 10:37-46. [PMID: 15670212 DOI: 10.1111/j.1365-2443.2004.00813.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mitotic spindle dynamics are highly dependent on proteins that interact with microtubules to influence their organization or stability. Here, we show that the Drosophila Toucan protein interacts directly with microtubules. Its localization to the microtubule network when it is expressed in mammalian cells and its direct interaction with microtubules in vitro are dependent on its central basic domain. Moreover, Toc expression in mammalian cells strongly protects microtubules from depolymerization. By using in vivo inducible RNAi in syncytial embryos, we generated a dose-sensitive loss of function of toucan, demonstrating that this technique is an efficient method for inactivating a maternal transcript. This enabled us to accurately characterize several new mitotic defects from the early to the late phases of mitosis, depending on Toucan depletion level. Toucan is required for metaphase spindle formation and centrosome anchoring to the poles. Then, during anaphase, Toc depletion affects kinetochore microtubules and therefore chromosome segregation. Toc is also necessary for central spindle formation by the interpolar microtubules. In contrast, astral microtubules are not disturbed by Toc depletion. Taken together, our results show that Toucan is a microtubule-associated protein specifically required for the stability of spindle microtubules throughout mitosis.
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Affiliation(s)
- Vincent Mirouse
- Institut National de la Santé et de la Recherche Médicale UMR384, Laboratoire de Biochimie, UFR Médecine, 28, place Henri Dunant, 63001 Clermont-Fd, France
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Mencarelli C, Caroti D, Bré MH, Levilliers N, Mercati D, Robbins LG, Dallai R. Glutamylated and glycylated tubulin isoforms in the aberrant sperm axoneme of the gall-midge fly, Asphondylia ruebsaameni. ACTA ACUST UNITED AC 2005; 58:160-74. [PMID: 15146535 DOI: 10.1002/cm.20000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The axonemal organization expressed in the sperm flagella of the cecidomyiid dipteran Asphondylia ruebsaameni is unconventional, being characterized by the presence of an exceedingly high number of microtubular doublets and by the absence of both the inner dynein arms and the central pair/radial spoke complex. Consequently, its motility, both in vivo and in vitro, is also peculiar. Using monoclonal antibodies directed against posttranslational modifications, we have analyzed the presence and distribution of glutamylated and glycylated tubulin isoforms in this aberrant axonemal structure, and compared them with those of a reference insect species (Apis mellifera), endowed with a conventional axoneme. Our results have shown that the unorthodox structure and motility of the Asphondylia axoneme are concomitant with: (1). a very low glutamylation extent in the alpha-tubulin subunit, (2). a high level of glutamylation in the beta-subunit, (3). an extremely low total extent of glycylation, with regard to both monoglycylated and polyglycylated sites, either in alpha- or in beta-tubulin, (4). the presence of a strong labeling of glutamylated tubulin isoforms at the proximal end of the axoneme, and (5). a uniform distribution of glutamylated as well as glycylated isoforms along the rest of the axoneme. Thus, our data indicate that tubulin molecular heterogeneity is much lower in the Asphondylia axoneme than in the conventional 9+2 axoneme with regard to both isoform content and isoform distribution along the axoneme.
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Abstract
Eukaryotic cilia and flagella are cytoskeletal organelles that are remarkably conserved from protists to mammals. Their basic unit is the axoneme, a well-defined cylindrical structure composed of microtubules and up to 250 associated proteins. These complex organelles are assembled by a dynamic process called intraflagellar transport. Flagella and cilia perform diverse motility and sensitivity functions in many different organisms. Trypanosomes are flagellated protozoa, responsible for various tropical diseases such as sleeping sickness and Chagas disease. In this review, we first describe general knowledge on the flagellum: its occurrence in the living world, its molecular composition, and its mode of assembly, with special emphasis on the exciting developments that followed the discovery of intraflagellar transport. We then present recent progress regarding the characteristics of the trypanosome flagellum, highlighting the original contributions brought by this organism. The most striking phenomenon is the involvement of the flagellum in several aspects of the trypanosome cell cycle, including cell morphogenesis, basal body migration, and cytokinesis.
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Affiliation(s)
- Linda Kohl
- INSERM U565, CNRS UMR5153, and MNHN USM 0503, Muséum National d'Histoire Naturelle, 75231 Paris, France
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Regnard C, Fesquet D, Janke C, Boucher D, Desbruyéres E, Koulakoff A, Insina C, Travo P, Eddé B. Characterisation of PGs1, a subunit of a protein complex co-purifying with tubulin polyglutamylase. J Cell Sci 2003; 116:4181-90. [PMID: 12972506 DOI: 10.1242/jcs.00743] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Polyglutamylation is a post-translational modification initially discovered on tubulin. It has been implicated in multiple microtubule functions, including neuronal differentiation, axonemal beating and stability of the centrioles, and shown to modulate the interaction between tubulin and microtubule associated proteins. The enzymes catalysing this modification are not yet known. Starting with a partially purified fraction of mouse brain tubulin polyglutamylase, monoclonal antibodies were raised and used to further purify the enzyme by immunoprecipitation. The purified enzyme complex (Mr 360x103) displayed at least three major polypeptides of 32, 50 and 80x103, present in stochiometric amounts. We show that the 32x103 subunit is encoded by the mouse gene GTRGEO22, the mutation of which has recently been implicated in multiple defects in mice, including male sterility. We demonstrate that this subunit, called PGs1, has no catalytic activity on its own, but is implicated in the localisation of the enzyme at major sites of polyglutamylation, i.e. neurones, axonemes and centrioles.
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Affiliation(s)
- Catherine Regnard
- Centre de Recherches de Biochimie Macromoléculaire, CNRS, 34293 Montpellier, France
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