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Power KM, Nguyen KC, Silva A, Singh S, Hall DH, Rongo C, Barr MM. NEKL-4 regulates microtubule stability and mitochondrial health in ciliated neurons. J Cell Biol 2024; 223:e202402006. [PMID: 38767515 PMCID: PMC11104396 DOI: 10.1083/jcb.202402006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/10/2024] [Accepted: 05/06/2024] [Indexed: 05/22/2024] Open
Abstract
Ciliopathies are often caused by defects in the ciliary microtubule core. Glutamylation is abundant in cilia, and its dysregulation may contribute to ciliopathies and neurodegeneration. Mutation of the deglutamylase CCP1 causes infantile-onset neurodegeneration. In C. elegans, ccpp-1 loss causes age-related ciliary degradation that is suppressed by a mutation in the conserved NEK10 homolog nekl-4. NEKL-4 is absent from cilia, yet it negatively regulates ciliary stability via an unknown, glutamylation-independent mechanism. We show that NEKL-4 was mitochondria-associated. Additionally, nekl-4 mutants had longer mitochondria, a higher baseline mitochondrial oxidation state, and suppressed ccpp-1∆ mutant lifespan extension in response to oxidative stress. A kinase-dead nekl-4(KD) mutant ectopically localized to ccpp-1∆ cilia and rescued degenerating microtubule doublet B-tubules. A nondegradable nekl-4(PEST∆) mutant resembled the ccpp-1∆ mutant with dye-filling defects and B-tubule breaks. The nekl-4(PEST∆) Dyf phenotype was suppressed by mutation in the depolymerizing kinesin-8 KLP-13/KIF19A. We conclude that NEKL-4 influences ciliary stability by activating ciliary kinesins and promoting mitochondrial homeostasis.
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Affiliation(s)
- Kaiden M. Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Ken C. Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Andriele Silva
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - Shaneen Singh
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - David H. Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Christopher Rongo
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, USA
| | - Maureen M. Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
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Power KM, Nguyen KC, Silva A, Singh S, Hall DH, Rongo C, Barr MM. NEKL-4 regulates microtubule stability and mitochondrial health in C. elegans ciliated neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580304. [PMID: 38405845 PMCID: PMC10888866 DOI: 10.1101/2024.02.14.580304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Ciliopathies are often caused by defects in the ciliary microtubule core. Glutamylation is abundant in cilia, and its dysregulation may contribute to ciliopathies and neurodegeneration. Mutation of the deglutamylase CCP1 causes infantile-onset neurodegeneration. In C. elegans, ccpp-1 loss causes age-related ciliary degradation that is suppressed by mutation in the conserved NEK10 homolog nekl-4. NEKL-4 is absent from cilia, yet negatively regulates ciliary stability via an unknown, glutamylation-independent mechanism. We show that NEKL-4 was mitochondria-associated. nekl-4 mutants had longer mitochondria, a higher baseline mitochondrial oxidation state, and suppressed ccpp-1 mutant lifespan extension in response to oxidative stress. A kinase-dead nekl-4(KD) mutant ectopically localized to ccpp-1 cilia and rescued degenerating microtubule doublet B-tubules. A nondegradable nekl-4(PESTΔ) mutant resembled the ccpp-1 mutant with dye filling defects and B-tubule breaks. The nekl-4(PESTΔ) Dyf phenotype was suppressed by mutation in the depolymerizing kinesin-8 KLP-13/KIF19A. We conclude that NEKL-4 influences ciliary stability by activating ciliary kinesins and promoting mitochondrial homeostasis.
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Affiliation(s)
- Kaiden M Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Ken C Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Andriele Silva
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY, United States of America
| | - Shaneen Singh
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY, United States of America
| | - David H Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Christopher Rongo
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, United States of America
| | - Maureen M Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
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3
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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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Melo-Hanchuk TD, Kobarg J. Polyglutamylase activity of tubulin tyrosine ligase-like 4 is negatively regulated by the never in mitosis gene A family kinase never in mitosis gene A -related kinase 5. World J Biol Chem 2021; 12:38-51. [PMID: 34084286 PMCID: PMC8160597 DOI: 10.4331/wjbc.v12.i3.38] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 01/06/2021] [Accepted: 02/25/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Tubulins, building blocks of microtubules, are modified substrates of diverse post-translational modifications including phosphorylation, polyglycylation and polyglutamylation. Polyglutamylation of microtubules, catalyzed by enzymes from the tubulin tyrosine ligase-like (TTLL) family, can regulate interactions with molecular motors and other proteins. Due to the diversity and functional importance of microtubule modifications, strict control of the TTLL enzymes has been suggested.
AIM To characterize the interaction between never in mitosis gene A-related kinase 5 (NEK5) and TTLL4 proteins and the effects of TTLL4 phosphorylation.
METHODS The interaction between NEK5 and TTLL4 was identified by yeast two-hybrid screening using the C-terminus of NEK5 (a.a. 260–708) as bait and confirmed by immunoprecipitation. The phosphorylation sites of TTLL4 were identified by mass spectrometry and point mutations were introduced.
RESULTS Here, we show that NEK5 interacts with TTLL4 and regulates its polyglutamylation activity. We further show that NEK5 can also interact with TTLL5 and TTLL7. The silencing of NEK5 increases the levels of polyglutamylation of proteins by increasing the activity of TTLL4. The same effects were observed after the expression of the catalytically inactive form of NEK5. This regulation of TTLL4 activity involves its phosphorylation at Y815 and S1136 amino acid residues.
CONCLUSION Our results demonstrate, for the first time, the regulation of TTLL activity through phosphorylation, pointing to NEK5 as a potential effector kinase. We also suggest a general control of tubulin polyglutamylation through NEK family members in human cells.
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Affiliation(s)
| | - Jörg Kobarg
- Faculty of Pharmaceutical Sciences, University of Campinas, Campinas 13083-862, Brazil
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5
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Power KM, Akella JS, Gu A, Walsh JD, Bellotti S, Morash M, Zhang W, Ramadan YH, Ross N, Golden A, Smith HE, Barr MM, O’Hagan R. Mutation of NEKL-4/NEK10 and TTLL genes suppress neuronal ciliary degeneration caused by loss of CCPP-1 deglutamylase function. PLoS Genet 2020; 16:e1009052. [PMID: 33064774 PMCID: PMC7592914 DOI: 10.1371/journal.pgen.1009052] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/28/2020] [Accepted: 08/14/2020] [Indexed: 12/29/2022] Open
Abstract
Ciliary microtubules are subject to post-translational modifications that act as a "Tubulin Code" to regulate motor traffic, binding proteins and stability. In humans, loss of CCP1, a cytosolic carboxypeptidase and tubulin deglutamylating enzyme, causes infantile-onset neurodegeneration. In C. elegans, mutations in ccpp-1, the homolog of CCP1, result in progressive degeneration of neuronal cilia and loss of neuronal function. To identify genes that regulate microtubule glutamylation and ciliary integrity, we performed a forward genetic screen for suppressors of ciliary degeneration in ccpp-1 mutants. We isolated the ttll-5(my38) suppressor, a mutation in a tubulin tyrosine ligase-like glutamylase gene. We show that mutation in the ttll-4, ttll-5, or ttll-11 gene suppressed the hyperglutamylation-induced loss of ciliary dye filling and kinesin-2 mislocalization in ccpp-1 cilia. We also identified the nekl-4(my31) suppressor, an allele affecting the NIMA (Never in Mitosis A)-related kinase NEKL-4/NEK10. In humans, NEK10 mutation causes bronchiectasis, an airway and mucociliary transport disorder caused by defective motile cilia. C. elegans NEKL-4 localizes to the ciliary base but does not localize to cilia, suggesting an indirect role in ciliary processes. This work defines a pathway in which glutamylation, a component of the Tubulin Code, is written by TTLL-4, TTLL-5, and TTLL-11; is erased by CCPP-1; is read by ciliary kinesins; and its downstream effects are modulated by NEKL-4 activity. Identification of regulators of microtubule glutamylation in diverse cellular contexts is important to the development of effective therapies for disorders characterized by changes in microtubule glutamylation. By identifying C. elegans genes important for neuronal and ciliary stability, our work may inform research into the roles of the tubulin code in human ciliopathies and neurodegenerative diseases.
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Affiliation(s)
- Kade M. Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Jyothi S. Akella
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Amanda Gu
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Jonathon D. Walsh
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Sebastian Bellotti
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Margaret Morash
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Winnie Zhang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Yasmin H. Ramadan
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Nicole Ross
- Biology Department, Montclair State University, Montclair, NJ, United States of America
| | - Andy Golden
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Harold E. Smith
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Maureen M. Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, United States of America
| | - Robert O’Hagan
- Biology Department, Montclair State University, Montclair, NJ, United States of America
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Ohta S, Hamada M, Sato N, Toramoto I. Polyglutamylated Tubulin Binding Protein C1orf96/CSAP Is Involved in Microtubule Stabilization in Mitotic Spindles. PLoS One 2015; 10:e0142798. [PMID: 26562023 PMCID: PMC4642972 DOI: 10.1371/journal.pone.0142798] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/27/2015] [Indexed: 12/13/2022] Open
Abstract
The centrosome-associated C1orf96/Centriole, Cilia and Spindle-Associated Protein (CSAP) targets polyglutamylated tubulin in mitotic microtubules (MTs). Loss of CSAP causes critical defects in brain development; however, it is unclear how CSAP association with MTs affects mitosis progression. In this study, we explored the molecular mechanisms of the interaction of CSAP with mitotic spindles. Loss of CSAP caused MT instability in mitotic spindles and resulted in mislocalization of Nuclear protein that associates with the Mitotic Apparatus (NuMA), with defective MT dynamics. Thus, CSAP overload in the spindles caused extensive MT stabilization and recruitment of NuMA. Moreover, MT stabilization by CSAP led to high levels of polyglutamylation on MTs. MT depolymerization by cold or nocodazole treatment was inhibited by CSAP binding. Live-cell imaging analysis suggested that CSAP-dependent MT-stabilization led to centrosome-free MT aster formation immediately upon nuclear envelope breakdown without γ-tubulin. We therefore propose that CSAP associates with MTs around centrosomes to stabilize MTs during mitosis, ensuring proper bipolar spindle formation and maintenance.
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Affiliation(s)
- Shinya Ohta
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
- * E-mail:
| | - Mayako Hamada
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
| | - Nobuko Sato
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
| | - Iyo Toramoto
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
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7
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Cohen S, Aizer A, Shav-Tal Y, Yanai A, Motro B. Nek7 kinase accelerates microtubule dynamic instability. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1104-13. [PMID: 23313050 DOI: 10.1016/j.bbamcr.2012.12.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 12/27/2012] [Accepted: 12/28/2012] [Indexed: 12/19/2022]
Abstract
The NIMA-related kinases (NRK or Nek) are emerging as conserved and crucial regulators of mitosis and cilia formation. The microtubule (MT) network has long been suspected as a major target of the Neks. However, the underlying mechanism remains unclear. Using the PlusTipTracker software, recently developed by the Danuser group, we followed the consequences of alterations in Nek7 levels on MT dynamic instability. siRNA-mediated downregulation of Nek7 in HeLa cells resulted in lower speeds of MT growth and catastrophe, reduction of the relative time spent in catastrophe, and considerably lowered the overall MT dynamicity. Co-expression of Nek7 with the siRNA treatment rescued the MT phenotypes, while ectopic overexpression of Nek7 yielded inverse characteristics compared to Nek7 downregulation. MT dynamics in mouse embryonic fibroblasts derived from targeted null mutants for Nek7 recapitulated the siRNA downregulation phenotypes. Precise MT dynamic instability is critical for accurate shaping of the mitotic spindle and for cilium formation, and higher MT dynamicity is associated with tumorigenicity. Thus, our results can supply a mechanistic explanation for Nek involvement in these processes.
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8
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Chang J, Baloh RH, Milbrandt J. The NIMA-family kinase Nek3 regulates microtubule acetylation in neurons. J Cell Sci 2009; 122:2274-82. [PMID: 19509051 DOI: 10.1242/jcs.048975] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
NIMA-related kinases (Neks) belong to a large family of Ser/Thr kinases that have critical roles in coordinating microtubule dynamics during ciliogenesis and mitotic progression. The Nek kinases are also expressed in neurons, whose axonal projections are, similarly to cilia, microtubule-abundant structures that extend from the cell body. We therefore investigated whether Nek kinases have additional, non-mitotic roles in neurons. We found that Nek3 influences neuronal morphogenesis and polarity through effects on microtubules. Nek3 is expressed in the cytoplasm and axons of neurons and is phosphorylated at Thr475 located in the C-terminal PEST domain, which regulates its catalytic activity. Although exogenous expression of wild-type or phosphomimic (T475D) Nek3 in cultured neurons has no discernible impact, expression of a phospho-defective mutant (T475A) or PEST-truncated Nek3 leads to distorted neuronal morphology with disturbed polarity and deacetylation of microtubules via HDAC6 in its kinase-dependent manner. Thus, the phosphorylation at Thr475 serves as a regulatory switch that alters Nek3 function. The deacetylation of microtubules in neurons by unphosphorylated Nek3 raises the possibility that it could have a role in disorders where axonal degeneration is an important component.
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Affiliation(s)
- Jufang Chang
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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9
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Alexander JP, Ryan TJ, Ballou DP, Coward JK. Gamma-glutamyl hydrolase: kinetic characterization of isopeptide hydrolysis using fluorogenic substrates. Biochemistry 2008; 47:1228-39. [PMID: 18171026 DOI: 10.1021/bi701607v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gamma-glutamyl hydrolase, a cysteine peptidase, catalyzes the hydrolysis of poly-gamma-glutamate derivatives of folate cofactors and many antifolate drugs. We have used internally quenched fluorogenic derivatives of glutamyl-gamma-glutamate and (4,4-difluoro)glutamyl-gamma-glutamate to examine the effect of fluorine substitution adjacent to the scissile isopeptide bond. Using a newly developed continuous fluorescence assay, the hydrolysis of both substrates could be described by Michaelis-Menten kinetics. Fluorine substitution resulted in a significant decrease in observed rates of hydrolysis under steady-state conditions due primarily to a approximately 15-fold increase in Km. Using stopped-flow techniques, hydrolysis of the non-fluorinated isopeptide was characterized by a burst phase followed by a steady-state rate, indicating that formation of the acyl enzyme is not rate-limiting for hydrolysis of this isopeptide. This conclusion was confirmed by analysis of the progress curves over a wide range of substrate concentration, which demonstrated that the acylation rate (k2) is approximately 10-fold higher than the deacylation rate (k3). The increased value of Km associated with the difluoro derivative limited the ability to obtain comparable pre-steady-state kinetics data at saturating concentration of substrate due to inner filter effects. However, even under nonsaturating conditions, a modest burst was observed for the difluoro derivative. These data indicate that either deacylation or rearrangement of the enzyme-product complex is rate-limiting in this isopeptide hydrolysis reaction.
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Affiliation(s)
- Jessica P Alexander
- Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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10
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Westermann S. Stefan Westermann: a close look at kinetochore function. Interviewed by Caitlin Sedwick. J Cell Biol 2007; 179:810-1. [PMID: 18056405 PMCID: PMC2099201 DOI: 10.1083/jcb.1795pi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stefan Westermann is probing the structure and function of the yeast kinetochore.
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11
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Pradel LC, Bonhivers M, Landrein N, Robinson DR. NIMA-related kinase TbNRKC is involved in basal body separation in Trypanosoma brucei. J Cell Sci 2006; 119:1852-63. [PMID: 16608878 DOI: 10.1242/jcs.02900] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The NIMA-related kinase 2 (NEK 2) has important cell cycle functions related to centriole integrity and splitting. Trypanosoma brucei does not possess centrioles, however, cytokinesis is coupled to basal body separation events. Here we report the first functional characterisation of a T. brucei basal body-cytoskeletal NIMA-related kinase (NRK) protein, TbNRKC. The TbNRKC kinase domain has high amino acid identity with the human NEK1 kinase domain (50%) but also shares 42% identity with human NEK2. TbNRKC is expressed in bloodstream and procyclic cells and functions as a bona fide kinase in vitro. Remarkably, RNAi knockdown of TbNRKC and overexpression of kinase-dead TbNRKC in procyclic forms induces the accumulation of cells with four basal bodies, whereas overexpression of active protein produces supernumary basal bodies and blocks cytokinesis. TbNRKC is located on mature and immature basal bodies and is the first T. brucei NRK to be found associated with the basal body cytokinesis pathway.
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Affiliation(s)
- Lydie C Pradel
- Laboratoire de Génomique Fonctionnelle des Trypanosomatides, CNRS UMR 5162, Université Bordeaux 2, 146 rue Léo Saignat, Bât. 3A, 33076 Bordeaux CEDEX, France
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12
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Hagiwara H, Tajika Y, Matsuzaki T, Suzuki T, Aoki T, Takata K. Localization of Golgi 58K protein (formiminotransferase cyclodeaminase) to the centrosome. Histochem Cell Biol 2006; 126:251-9. [PMID: 16534631 DOI: 10.1007/s00418-006-0166-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2006] [Indexed: 10/24/2022]
Abstract
In vertebrate cells, the centrosome consists of a pair of centrioles and surrounding pericentriolar material. Using anti-Golgi 58K protein antibodies that recognize formiminotransferase cyclodeaminase (FTCD), we investigated its localization to the centrosome in various cultured cells and human oviductal secretory cells by immunohistochemistry. In addition to the Golgi apparatus, FTCD was localized to the centrosome, more abundantly around the mother centriole. The centrosome localization of FTCD continued throughout the cell cycle and was not disrupted after Golgi fragmentation, which was induced by colcemid and brefeldin A. Centriole microtubules are polyglutamylated and stable against tubulin depolymerizing drugs. FTCD in the centrosome may be associated with polyglutamylated residues of centriole microtubules and may play a role in providing centrioles with glutamate produced by cyclodeaminase domains of FTCD.
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Affiliation(s)
- Haruo Hagiwara
- Department of Anatomy and Cell Biology, Gunma University Graduate School of Medicine, 3-39-22, Showa-machi, Maebashi, Gunma 371-8511, Japan.
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13
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Bradley BA, Wagner JJD, Quarmby LM. Identification and sequence analysis of six new members of the NIMA-related kinase family in Chlamydomonas. J Eukaryot Microbiol 2004; 51:66-72. [PMID: 15068267 DOI: 10.1111/j.1550-7408.2004.tb00164.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NIMA kinases are an evolutionarily conserved protein family with enigmatic roles in the regulation of mitosis. We report six new members of this family in Chlamydomonas, in addition to the previously identified NIMA-related kinase, Fa2p. Chlamydomonas NIMA-related kinases (CNKs) 1-6 were sequenced from subclones generated by RT-PCR using information from EST libraries and the recently sequenced Chlamydomonas genome. Phylogenetic and bioinformatic approaches were used to determine the relationships of the six new members with known members of the NIMA-related kinase family. Although humans express at least eleven NIMA-related kinases, the eukaryotic microbes that have been studied to date express only one or two members of the family. Thus, the discovery that Chlamydomonas expresses a total of at least seven NIMA-related kinases is intriguing. Our analyses suggest that members of this family may play roles in the assembly and function of cilia.
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Affiliation(s)
- Brian A Bradley
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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14
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Westermann S, Weber K. Post-translational modifications regulate microtubule function. Nat Rev Mol Cell Biol 2004; 4:938-47. [PMID: 14685172 DOI: 10.1038/nrm1260] [Citation(s) in RCA: 525] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Stefan Westermann
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
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15
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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: 44] [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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Gull K. Host-parasite interactions and trypanosome morphogenesis: a flagellar pocketful of goodies. Curr Opin Microbiol 2003; 6:365-70. [PMID: 12941406 DOI: 10.1016/s1369-5274(03)00092-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Trypanosomes are characterised by the possession of a single flagellum and a subpellicular microtubule cytoskeleton. The flagellum is more than an organelle for motility; its position and polarity along with the sub-pellicular cytoskeleton enables the morphogenesis of a distinct flagellar pocket and the flagellar basal body is responsible for positioning and segregating the kinetoplast--the mitochondrial genome. Recent work has highlighted the molecules and morphogenesis of these cytoskeletal/flagellum structures and how dynamic events, occurring in the flagellar pocket and kinetoplast, are critical for host-parasite interactions.
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Affiliation(s)
- Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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Watt F. Best Paper Award 2002. J Cell Sci 2003. [DOI: 10.1242/jcs.116.7.1155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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