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Srivastava P, Swaroop S, Diwakar K, Jaiswal A, Singh M. Gamma-Tubulin 1 (TUBG1) Mutation-Associated Lissencephaly and Microcephaly in an Indian Child: A Rare Case. Cureus 2024; 16:e62749. [PMID: 38912084 PMCID: PMC11191386 DOI: 10.7759/cureus.62749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2024] [Indexed: 06/25/2024] Open
Abstract
Malformations of cortical development (MCD) are a group of disorders affecting the normal development of the human cortex and are significant causes of delay in psychomotor development and epilepsy in children. Lissencephaly (smooth brain) forms a major group of brain malformations. Microtubules help in the migration of neuronal cells. Defect in tubulin gene alpha-tubulin (TUBA), beta-tubulin (TUBB), and gamma-tubulin (TUBG) leads to defective neuronal migration. This group of disorders is termed as "tubulinopathies." The important genes implicated in causing lissencephaly are LIS1, XLIS, and TUBA1A gene. Recently, a mutation in the TUBG1 gene is associated with it. Here, we report a one-and-a-half-year-old girl with global developmental delay, microcephaly, infantile-onset epilepsy, epileptic spasms, dysmorphism, and motor signs. There was no significant birth history. Neuroimaging (MRI) showed a broad thick gyri and a decreased number of sulci suggestive of lissencephaly/pachygyria spectrum. There was dilatation of the ventricles, and no grey matter heterotopia was noted. Sleep EEG showed multifocal epileptiform discharges. The child was treated with multiple anti-seizure medicines (ASMs). A genetic test, whole exome sequencing, was done to determine the etiology of MCD. A heterozygous missense variation in exon 6 of the TUBG1 gene was identified and reported as a "variant of unknown significance." Still, because the genotype matched with the clinical phenotype of the patient, it was considered clinically significant. Therefore, a complete diagnosis of TUBG1 mutation-associated cortical malformation (lissencephaly/pachygyria) with microcephaly and early-onset epilepsy was established. TUBG1 mutation is de novo in most cases, but parental testing is recommended. The parents of such patients need to be counseled about the need for prenatal testing and the risk of the disease to siblings. The overall prognosis in such cases is poor because of refractory seizures, physical limitations, and intellectual disability.
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Affiliation(s)
- Preeti Srivastava
- Department of Paediatrics, Tata Main Hospital, Jamshedpur, IND
- Department of Paediatrics, Manipal Tata Medical College, Manipal Institute of Higher Education (MAHE), Jamshedpur, IND
| | - Shikha Swaroop
- Department of Paediatrics, Manipal Tata Medical College, Manipal Institute of Higher Education (MAHE), Jamshedpur, IND
| | - Kumar Diwakar
- Department of Paediatrics, Manipal Tata Medical College, Manipal Institute of Higher Education (MAHE), Jamshedpur, IND
| | - Abhishek Jaiswal
- Department of Radiology, Meherbai Tata Memorial Hospital, Jamshedpur, IND
| | - Monika Singh
- Department of Paediatrics, Tata Main Hospital, Jamshedpur, IND
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Vottero P, Wang Q, Michalak M, Aminpour M, Tuszynski JA. Computational Analysis and Experimental Testing of the Molecular Mode of Action of Gatastatin and Its Derivatives. Cancers (Basel) 2023; 15:cancers15061714. [PMID: 36980600 PMCID: PMC10046562 DOI: 10.3390/cancers15061714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023] Open
Abstract
Given its critical role in cell mitosis, the tubulin γ chain represents a viable chemotherapeutic target to solve the specificity issues associated with targeting α and β tubulin. Since γ tubulin is overexpressed in glioblastoma multiforme (GBM) and some breast lesions, the glaziovianin A derivative gatastatin, presented as a γ-tubulin-specific inhibitor, could yield a successful therapeutic strategy. The present work aims to identify the binding sites and modes of gatastatin and its derivatives through molecular-docking simulations. Computational binding free energy predictions were compared to experimental microscale thermophoresis assay results. The computational simulations did not reveal a strong preference toward γ tubulin, suggesting that further derivatization may be needed to increase its specificity.
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Affiliation(s)
- Paola Vottero
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB T6G 2V2, Canada
| | - Qian Wang
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Maral Aminpour
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB T6G 2V2, Canada
| | - Jack Adam Tuszynski
- Department of Physics, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Dipartimento di Ingegneria Meccanica e Aerospaziale (DIMEAS), Politecnico di Torino, I-10129 Turin, Italy
- Correspondence:
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Wang ZJ, Dai ZZ, Hu MZ, Liu JN, Liang H, Shen MM, Zhu SJ, Sheng HJ, Gao J, Huang AL, Tang KF. Upregulation of TUBG1 expression promotes hepatocellular carcinoma development. MEDICAL ONCOLOGY (NORTHWOOD, LONDON, ENGLAND) 2023; 40:96. [PMID: 36792863 DOI: 10.1007/s12032-023-01966-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/01/2023] [Indexed: 02/17/2023]
Abstract
Tubulin γ-1 (TUBG1) is a highly conserved component of the centrosome and its deregulation is involved in the development of several types of cancer. However, the role of TUBG1 in hepatocellular carcinoma (HCC) remains unclear. In this study, we found that TUBG1 was upregulated in human HCC cells and tissues and that TUBG1 upregulation was associated with promoter hypomethylation in HCC tissues. TUBG1 knockdown suppressed the proliferation, invasion, and migration of HCC cells. While TUBG1 expression was positively correlated with CD4 + memory T lymphocyte infiltration, it was negatively correlated with CD4 + regulatory T-cell infiltration in human HCC tissues. Furthermore, TUBG1 expression was positively correlated with the expression of genes involved in cell division. Noticeably, high expression of TUBG1 was associated with poor prognosis in patients with HCC. Overall, our findings revealed that TUBG1 promotes hepatocarcinogenesis by increasing proliferation, invasion, and migration of HCC cells and may regulate T lymphocyte infiltration. The current findings provide important insights into TUBG1 regulation in HCC, which could provide new therapeutic targets for hepatocarcinoma which has a very high incidence and mortality rate worldwide.
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Affiliation(s)
- Zi-Jian Wang
- Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, 400016, People's Republic of China.,The First Clinical College, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Zhi-Zheng Dai
- Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Mei-Zhen Hu
- Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Jun-Nan Liu
- School of Basic Medicine, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Hang Liang
- School of Basic Medicine, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Mei-Mei Shen
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Shu-Juan Zhu
- School of Basic Medicine, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Hua-Jun Sheng
- School of Basic Medicine, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Jian Gao
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Ai-Long Huang
- Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, 400016, People's Republic of China
| | - Kai-Fu Tang
- Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing, 400016, People's Republic of China.
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Oakley BR. The ring saga: looking back at the discovery of γ-tubulin and γ-tubulin ring complexes. Mol Biol Cell 2022; 34:rt1. [PMID: 36520030 PMCID: PMC9816641 DOI: 10.1091/mbc.e22-07-0290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
For many years, two central, unanswered questions in cytoskeleton research were how microtubule assembly is nucleated and microtubule polarity established. The discoveries of γ-tubulin and γ-tubulin ring complexes were key advances that allowed these questions to be substantially answered. The discovery of γ-tubulin was the product of a genetic screen in Aspergillus nidulans for genes important for microtubule function. γ-Tubulin is a member of the tubulin superfamily of proteins, closely related to α- and β-tubulin but distinct from both. It is ubiquitous in eukaryotes, and in many organisms there are small families of γ-tubulin genes. γ-Tubulin and associated proteins form ring-like complexes that localize to microtubule-organizing centers (MTOCs) and play an important role in the nucleation of microtubule assembly from MTOCs and the establishment of microtubule polarity.
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Affiliation(s)
- Berl R. Oakley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045,*Address correspondence to: Berl R. Oakley ()
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5
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Zhang K, Yu M, Liu H, Hui Z, Yang N, Bi X, Sun L, Lin R, Lü G. Upregulated TUBG1 expression is correlated with poor prognosis in hepatocellular carcinoma. PeerJ 2022; 10:e14415. [PMID: 36523478 PMCID: PMC9745943 DOI: 10.7717/peerj.14415] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/28/2022] [Indexed: 12/11/2022] Open
Abstract
Background Hepatocellular carcinoma (HCC) development is a complex pathological process. Tubulin gamma 1 (TUBG1) plays an oncogenic role in several human cancers; however, its functional role in HCC tumorigenesis remains unknown. Methods Herein we first evaluated the gene expression levels of TUBG1 in HCC using data from The Cancer Genome Atlas and Gene Expression Profiling Interactive Analysis databases. We then elucidated the association between TUBG1 gene expression levels and survival rates of patients with HCC. Cell cycle, proliferation, transwell migration, and matrigel invasion assays were used to study the effects of TUBG1 on the malignant phenotypes of HCC cells. Results Based on the data obtained from the aforementioned databases and our in vitro experiments, TUBG1 was found to be overexpressed in HCC and patients with high TUBG1 expression levels showed a remarkably poor overall survival rate. In addition, the expression of TUBG1 significantly promoted the malignant phenotypes of HCC cells in vitro. Gene ontology term enrichment analysis revealed that co-regulated genes were enriched in biological processes mainly involved in chromosome segregation, chromosomal region, and chromatin binding; moreover, Kyoto Encyclopedia of Genes and Genome pathway analysis showed that they were mainly involved in cell cycle, oocyte meiosis, platinum drug resistance, and the p53 signaling pathway. Conclusions We report that TUBG1 is an important oncogene in HCC. It promotes HCC progression and may serve as a potential prognostic biomarker for HCC. Future studies are warranted to unveil molecular biological mechanisms underlying TUBG1 carcinogenesis.
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Affiliation(s)
- Kainan Zhang
- Xinjiang Medical University, Urumqi, Xinjiang, China,State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Mengsi Yu
- Department of Clinical Laboratory, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Hui Liu
- State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Zhao Hui
- Department of Clinical Laboratory, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Ning Yang
- State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Xiaojuan Bi
- State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Li Sun
- State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - RenYong Lin
- State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Guodong Lü
- State Key Laboratory of Pathogenesis, Prevention, and Treatment of Central Asian High Incidence Diseases, Clinical Medical Research Institute, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China,College of Pharmacy, Xinjiang Medical University, Urumqi, Xinjiang, China
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Sulimenko V, Dráberová E, Dráber P. γ-Tubulin in microtubule nucleation and beyond. Front Cell Dev Biol 2022; 10:880761. [PMID: 36158181 PMCID: PMC9503634 DOI: 10.3389/fcell.2022.880761] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 08/03/2022] [Indexed: 11/13/2022] Open
Abstract
Microtubules composed of αβ-tubulin dimers are dynamic cytoskeletal polymers that play key roles in essential cellular processes such as cell division, organelle positioning, intracellular transport, and cell migration. γ-Tubulin is a highly conserved member of the tubulin family that is required for microtubule nucleation. γ-Tubulin, together with its associated proteins, forms the γ-tubulin ring complex (γ-TuRC), that templates microtubules. Here we review recent advances in the structure of γ-TuRC, its activation, and centrosomal recruitment. This provides new mechanistic insights into the molecular mechanism of microtubule nucleation. Accumulating data suggest that γ-tubulin also has other, less well understood functions. We discuss emerging evidence that γ-tubulin can form oligomers and filaments, has specific nuclear functions, and might be involved in centrosomal cross-talk between microtubules and microfilaments.
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Affiliation(s)
| | | | - Pavel Dráber
- *Correspondence: Vadym Sulimenko, ; Pavel Dráber,
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Dráber P, Dráberová E. Dysregulation of Microtubule Nucleating Proteins in Cancer Cells. Cancers (Basel) 2021; 13:cancers13225638. [PMID: 34830792 PMCID: PMC8616210 DOI: 10.3390/cancers13225638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary The dysfunction of microtubule nucleation in cancer cells changes the overall cytoskeleton organization and cellular physiology. This review focuses on the dysregulation of the γ-tubulin ring complex (γ-TuRC) proteins that are essential for microtubule nucleation. Recent research on the high-resolution structure of γ-TuRC has brought new insight into the microtubule nucleation mechanism. We discuss the effect of γ-TuRC protein overexpression on cancer cell behavior and new drugs directed to γ-tubulin that may offer a viable alternative to microtubule-targeting agents currently used in cancer chemotherapy. Abstract In cells, microtubules typically nucleate from microtubule organizing centers, such as centrosomes. γ-Tubulin, which forms multiprotein complexes, is essential for nucleation. The γ-tubulin ring complex (γ-TuRC) is an efficient microtubule nucleator that requires additional centrosomal proteins for its activation and targeting. Evidence suggests that there is a dysfunction of centrosomal microtubule nucleation in cancer cells. Despite decades of molecular analysis of γ-TuRC and its interacting factors, the mechanisms of microtubule nucleation in normal and cancer cells remains obscure. Here, we review recent work on the high-resolution structure of γ-TuRC, which brings new insight into the mechanism of microtubule nucleation. We discuss the effects of γ-TuRC protein dysregulation on cancer cell behavior and new compounds targeting γ-tubulin. Drugs inhibiting γ-TuRC functions could represent an alternative to microtubule targeting agents in cancer chemotherapy.
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8
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The γ-tubulin meshwork assists in the recruitment of PCNA to chromatin in mammalian cells. Commun Biol 2021; 4:767. [PMID: 34158617 PMCID: PMC8219688 DOI: 10.1038/s42003-021-02280-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 05/28/2021] [Indexed: 12/27/2022] Open
Abstract
Changes in the location of γ-tubulin ensure cell survival and preserve genome integrity. We investigated whether the nuclear accumulation of γ-tubulin facilitates the transport of proliferating cell nuclear antigen (PCNA) between the cytosolic and the nuclear compartment in mammalian cells. We found that the γ-tubulin meshwork assists in the recruitment of PCNA to chromatin. Also, decreased levels of γ-tubulin reduce the nuclear pool of PCNA. In addition, the γ-tubulin C terminus encodes a PCNA-interacting peptide (PIP) motif, and a γ-tubulin–PIP-mutant affects the nuclear accumulation of PCNA. In a cell-free system, PCNA and γ-tubulin formed a complex. In tumors, there is a significant positive correlation between TUBG1 and PCNA expression. Thus, we report a novel mechanism that constitutes the basis for tumor growth by which the γ-tubulin meshwork maintains indefinite proliferation by acting as an opportune scaffold for the transport of PCNA from the cytosol to the chromatin. Corvaisier et al discover that γ-tubulin and replication protein PCNA forms a complex and that this facilitates recruitment of PCNA to chromatin both during cell division and during the DSB repair response. They identify a PCNA binding motif in γ-tubulin, which when mutated affects replication fork progression, providing insights into the role of the nuclear γ-tubulin meshwork.
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Matboli M, Hasanin AH, Hussein R, El-Nakeep S, Habib EK, Ellackany R, Saleh LA. Cyanidin 3-glucoside modulated cell cycle progression in liver precancerous lesion, in vivo study. World J Gastroenterol 2021; 27:1435-1450. [PMID: 33911466 PMCID: PMC8047539 DOI: 10.3748/wjg.v27.i14.1435] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/22/2021] [Accepted: 03/26/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Cyanidin-3-O-glucoside (cyan) exhibits antioxidant and anticancer properties. The cell cycle proteins and antimitotic drugs might be promising therapeutic targets in hepatocellular carcinoma.
AIM To investigate the effect of cyan administration on cell cycle in hepatic precancerous lesion (PCL) induced by diethylnitrosamine/2-acetylaminofluorene (DEN/2-AAF) in Wistar rats.
METHODS In vivo, DEN/2-AAF-induced hepatic PCL, rats were treated with three doses of cyan (10, 15, and 20 mg/kg/d, for four consecutive days per week for 16 wk). Blood and liver tissue samples were collected for measurement of the followings; alpha fetoprotein (AFP) liver function and RNA panel differential expression was evaluated via real time polymerase chain reaction. Histopathological examination of liver sections stained with H&E and immunohistochemical study using glutathione S-transferase placental (GSTP) and proliferating cell nuclear antigen (PCNA) antibodies were assessed.
RESULTS Cyan administration mitigated the effect of DEN/2-AFF induced PCL, decreased AFP levels, and improved liver function. Remarkably, treatment with cyan dose dependently decreased the long non-coding RNA MALAT1 and tubulin gamma 1 mRNA expressions and increased the levels of miR-125b, all of which are involved in cell cycle and mitotic spindle assembly. Of note, cyan decreased GSTP foci percent area and PCNA positively stained nuclei.
CONCLUSION Our results indicated that cyan could be used as a potential therapeutic agent to inhibit liver carcinogenesis in rat model via modulation of cell cycle.
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Affiliation(s)
- Marwa Matboli
- Department of Biochemistry, Ain Shams Faculty of Medicine, Cairo 11318, Egypt
| | - Amany H Hasanin
- Department of Clinical Pharmacology, Ain Shams Faculty of Medicine, Cairo 11381, Egypt
| | - Reham Hussein
- Department of Clinical Pharmacology, Ain Shams Faculty of Medicine, Cairo 11381, Egypt
| | - Sarah El-Nakeep
- Department of General Internal Medicine, Ain Shams Faculty of Medicine, Cairo 11381, Egypt
| | - Eman K Habib
- Department of Anatomy & Embryology, Ain Shams Faculty of Medicine, Cairo 11318, Egypt
| | - Rawan Ellackany
- Department of Undergraduate, Faculty of Medicine, Modern University for Technology and Information, Cairo 11381, Egypt
| | - Lobna A Saleh
- Department of Clinical Pharmacology, Ain Shams Faculty of Medicine, Cairo 11381, Egypt
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A novel TUBG1 mutation with neurodevelopmental disorder caused by malformations of cortical development. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6644274. [PMID: 33728335 PMCID: PMC7935588 DOI: 10.1155/2021/6644274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/17/2021] [Accepted: 02/08/2021] [Indexed: 11/30/2022]
Abstract
Neurodevelopmental disorder caused by malformations of cortical development is a rare neurological disease. Heterozygous missense variants in the TUBG1 gene lead to malformations of human cortical development, which further result in intellectual disability, developmental retardation, and epilepsy. To the best of our knowledge, only thirteen patients and a total of nine pathogenic TUBG1 variants have been described in the published literature. This study reports the case details and genetic data analysis of a girl (aged 8 years, 9 months) with developmental delay, psychomotor regression, epilepsy, and left external ear deformity. A novel TUBG1 mutation was identified by whole-exome sequencing and Sanger sequencing, confirming that this mutation may be the cause of the neurodevelopmental disorders. This case report characterizes the phenotypic spectrum, molecular genetic findings, and functional consequences of novel pathogenic TUBG1 variants in neurodevelopmental disorders caused by cortical development malformations.
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Rashid NU, Luckett DJ, Chen J, Lawson MT, Wang L, Zhang Y, Laber EB, Liu Y, Yeh JJ, Zeng D, Kosorok MR. High-Dimensional Precision Medicine From Patient-Derived Xenografts. J Am Stat Assoc 2020; 116:1140-1154. [PMID: 34548714 PMCID: PMC8451968 DOI: 10.1080/01621459.2020.1828091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 08/28/2020] [Accepted: 09/18/2020] [Indexed: 12/26/2022]
Abstract
The complexity of human cancer often results in significant heterogeneity in response to treatment. Precision medicine offers the potential to improve patient outcomes by leveraging this heterogeneity. Individualized treatment rules (ITRs) formalize precision medicine as maps from the patient covariate space into the space of allowable treatments. The optimal ITR is that which maximizes the mean of a clinical outcome in a population of interest. Patient-derived xenograft (PDX) studies permit the evaluation of multiple treatments within a single tumor, and thus are ideally suited for estimating optimal ITRs. PDX data are characterized by correlated outcomes, a high-dimensional feature space, and a large number of treatments. Here we explore machine learning methods for estimating optimal ITRs from PDX data. We analyze data from a large PDX study to identify biomarkers that are informative for developing personalized treatment recommendations in multiple cancers. We estimate optimal ITRs using regression-based (Q-learning) and direct-search methods (outcome weighted learning). Finally, we implement a superlearner approach to combine multiple estimated ITRs and show that the resulting ITR performs better than any of the input ITRs, mitigating uncertainty regarding user choice. Our results indicate that PDX data are a valuable resource for developing individualized treatment strategies in oncology. Supplementary materials for this article are available online.
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Affiliation(s)
- Naim U. Rashid
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Daniel J. Luckett
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Jingxiang Chen
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Michael T. Lawson
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Longshaokan Wang
- Department of Statistics, North Carolina State University, Raleigh, NC, USA
| | - Yunshu Zhang
- Department of Statistics, North Carolina State University, Raleigh, NC, USA
| | - Eric B. Laber
- Department of Statistics, North Carolina State University, Raleigh, NC, USA
| | - Yufeng Liu
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Statistics and Operations Research, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Jen Jen Yeh
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Donglin Zeng
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Michael R. Kosorok
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Statistics and Operations Research, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Alvarado-Kristensson M. γ-tubulin as a signal-transducing molecule and meshwork with therapeutic potential. Signal Transduct Target Ther 2018; 3:24. [PMID: 30221013 PMCID: PMC6137058 DOI: 10.1038/s41392-018-0021-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/23/2018] [Accepted: 05/06/2018] [Indexed: 01/05/2023] Open
Abstract
Knowledge of γ-tubulin is increasing with regard to the cellular functions of this protein beyond its participation in microtubule nucleation. γ-Tubulin expression is altered in various malignancies, and changes in the TUBG1 gene have been found in patients suffering from brain malformations. This review recapitulates the known functions of γ-tubulin in cellular homeostasis and discusses the possible influence of the protein on disease development and cancer.
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Affiliation(s)
- Maria Alvarado-Kristensson
- Molecular Pathology, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, 20502 Sweden
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13
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Tubulinopathies continued: refining the phenotypic spectrum associated with variants in TUBG1. Eur J Hum Genet 2018; 26:1132-1142. [PMID: 29706637 PMCID: PMC6057922 DOI: 10.1038/s41431-018-0146-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 03/02/2018] [Accepted: 03/13/2018] [Indexed: 12/30/2022] Open
Abstract
Tubulinopathies are a heterogeneous group of conditions with a wide spectrum of clinical severity resulting from variants in genes of the tubulin superfamily. Variants in TUBG1 have been described in three patients with posterior predominant pachygyria and microcephaly. We here report eight additional patients with four novel heterozygous variants in TUBG1 identified by next-generation sequencing (NGS) analysis. All had severe motor and cognitive impairment and all except one developed seizures in early life. The core imaging features included a pachygyric cortex with posterior to anterior gradient, enlarged lateral ventricles most pronounced over the posterior horns, and variable degrees of reduced white matter volume. Basal ganglia, corpus callosum, brainstem, and cerebellum were often normal, in contrast to patients with variants in other tubulin genes where these structures are frequently malformed. The imaging phenotype associated with variants in TUBG1 is therefore more in line with the phenotype resulting from variants in LIS1 (a.k.a. PAFAH1B1). This difference may, at least in part, be explained by gamma-tubulin’s physiological function in microtubule nucleation, which differs from that of alpha and beta-tubulin.
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Rajan TS, Scionti D, Diomede F, Piattelli A, Bramanti P, Mazzon E, Trubiani O. Prolonged Expansion Induces Spontaneous Neural Progenitor Differentiation from Human Gingiva-Derived Mesenchymal Stem Cells. Cell Reprogram 2017; 19:389-401. [PMID: 29058474 DOI: 10.1089/cell.2017.0012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Neural crest-derived mesenchymal stem cells (MSCs) obtained from dental tissues received considerable interest in regenerative medicine, particularly in nerve regeneration owing to their embryonic origin and ease of harvest. Proliferation efficacy and differentiation capacity into diverse cell lineages propose dental MSCs as an in vitro tool for disease modeling. In this study, we investigated the spontaneous differentiation efficiency of dental MSCs obtained from human gingiva tissue (hGMSCs) into neural progenitor cells after extended passaging. At passage 41, the morphology of hGMSCs changed from typical fibroblast-like shape into sphere-shaped cells with extending processes. Next-generation transcriptomics sequencing showed increased expression of neural progenitor markers such as NES, MEIS2, and MEST. In addition, de novo expression of neural precursor genes, such as NRN1, PHOX2B, VANGL2, and NTRK3, was noticed in passage 41. Immunocytochemistry results showed suppression of neurogenesis repressors TP53 and p21, whereas Western blot results revealed the expression of neurotrophic factors BDNF and NT3 at passage 41. Our results showed the spontaneous efficacy of hGMSCs to differentiate into neural precursor cells over prolonged passages and that these cells may assist in producing novel in vitro disease models that are associated with neural development.
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Affiliation(s)
| | - Domenico Scionti
- 1 Department of Experimental Neurology, IRCCS Centro Neurolesi "Bonino-Pulejo," Messina , Italy
| | - Francesca Diomede
- 2 Stem Cells and Regenerative Medicine Laboratory, Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
| | - Adriano Piattelli
- 2 Stem Cells and Regenerative Medicine Laboratory, Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
| | - Placido Bramanti
- 1 Department of Experimental Neurology, IRCCS Centro Neurolesi "Bonino-Pulejo," Messina , Italy
| | - Emanuela Mazzon
- 1 Department of Experimental Neurology, IRCCS Centro Neurolesi "Bonino-Pulejo," Messina , Italy
| | - Oriana Trubiani
- 2 Stem Cells and Regenerative Medicine Laboratory, Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio," Chieti-Pescara, Chieti, Italy
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15
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Dráberová E, Sulimenko V, Vinopal S, Sulimenko T, Sládková V, D'Agostino L, Sobol M, Hozák P, Křen L, Katsetos CD, Dráber P. Differential expression of human γ-tubulin isotypes during neuronal development and oxidative stress points to a γ-tubulin-2 prosurvival function. FASEB J 2017; 31:1828-1846. [PMID: 28119396 DOI: 10.1096/fj.201600846rr] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 01/03/2017] [Indexed: 12/11/2022]
Abstract
γ-Tubulins are highly conserved members of the tubulin superfamily essential for microtubule nucleation. Humans possess 2 γ-tubulin genes. It is thought that γ-tubulin-1 represents a ubiquitous isotype, whereas γ-tubulin-2 is found predominantly in the brain, where it may be endowed with divergent functions beyond microtubule nucleation. The molecular basis of the purported functional differences between γ-tubulins is unknown. We report discrimination of human γ-tubulins according to their electrophoretic and immunochemical properties. In vitro mutagenesis revealed that the differences in electrophoretic mobility originate in the C-terminal regions of the γ-tubulins. Using epitope mapping, we discovered mouse monoclonal antibodies that can discriminate between human γ-tubulin isotypes. Real time quantitative RT-PCR and 2-dimensional-PAGE showed that γ-tubulin-1 is the dominant isotype in fetal neurons. Although γ-tubulin-2 accumulates in the adult brain, γ-tubulin-1 remains the major isotype in various brain regions. Localization of γ-tubulin-1 in mature neurons was confirmed by immunohistochemistry and immunofluorescence microscopy on clinical samples and tissue microarrays. Differentiation of SH-SY5Y human neuroblastoma cells by all-trans retinoic acid, or oxidative stress induced by mitochondrial inhibitors, resulted in upregulation of γ-tubulin-2, whereas the expression of γ-tubulin-1 was unchanged. Fractionation experiments and immunoelectron microscopy revealed an association of γ-tubulins with mitochondrial membranes. These data indicate that in the face of predominant γ-tubulin-1 expression, the accumulation of γ-tubulin-2 in mature neurons and neuroblastoma cells during oxidative stress may denote a prosurvival role of γ-tubulin-2 in neurons.-Dráberová, E., Sulimenko, V., Vinopal, S., Sulimenko, T., Sládková, V., D'Agostino, L., Sobol, M., Hozák, P., Křen, L., Katsetos, C. D., Dráber, P. Differential expression of human γ-tubulin isotypes during neuronal development and oxidative stress points to γ-tubulin-2 prosurvival function.
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Affiliation(s)
- Eduarda Dráberová
- Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Vadym Sulimenko
- Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Stanislav Vinopal
- Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Tetyana Sulimenko
- Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Vladimíra Sládková
- Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Luca D'Agostino
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children and Hahnemann University Hospital, Philadelphia, Pennsylvania, USA
| | - Margaryta Sobol
- Department of the Nucleus, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Pavel Hozák
- Department of the Nucleus, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Leoš Křen
- Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, St. Christopher's Hospital for Children and Hahnemann University Hospital, Philadelphia, Pennsylvania, USA; and
| | - Christos D Katsetos
- Department of Pediatrics, Drexel University College of Medicine, St. Christopher's Hospital for Children and Hahnemann University Hospital, Philadelphia, Pennsylvania, USA
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague, Czech Republic;
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16
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Ohashi T, Yamamoto T, Yamanashi Y, Ohsugi M. Human TUBG2 gene is expressed as two splice variant mRNA and involved in cell growth. FEBS Lett 2016; 590:1053-63. [PMID: 27015882 DOI: 10.1002/1873-3468.12163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/08/2016] [Accepted: 03/23/2016] [Indexed: 01/14/2023]
Abstract
In mammals, γ-tubulin, a key protein in microtubule nucleation, is encoded by two genes, TUBG1 and TUBG2. Human TUBG1 and TUBG2 mRNA are expressed ubiquitously and predominantly in preimplantation embryos and the brain, respectively, but specific detection of γ-tubulin2 protein expression is difficult due to their high sequence similarity. Here, we describe a protocol for differential detection of two human γ-tubulins by western blotting. In several cancer cell lines and the brain, expression of γ-tubulin2 along with γ-tubulin1 and a novel TUBG2 splice variant are identified. Contribution of ectopically expressed γ-tubulin2 in cancer growth was determined by depletion of γ-tubulin2.
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Affiliation(s)
- Tsubasa Ohashi
- Department of Life Sciences Graduate School of Arts and Sciences, The University of Tokyo, Japan
| | - Tadashi Yamamoto
- Cell Signal Unit, Okinawa Institute of Science and Technology, Japan.,RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, Japan
| | - Yuji Yamanashi
- Division of Genetics, Department of Cancer Biology, Institute of Medical Science, University of Tokyo, Japan
| | - Miho Ohsugi
- Department of Life Sciences Graduate School of Arts and Sciences, The University of Tokyo, Japan
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17
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Katsetos CD, Reginato MJ, Baas PW, D'Agostino L, Legido A, Tuszyn Ski JA, Dráberová E, Dráber P. Emerging microtubule targets in glioma therapy. Semin Pediatr Neurol 2015; 22:49-72. [PMID: 25976261 DOI: 10.1016/j.spen.2015.03.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.
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Affiliation(s)
- Christos D Katsetos
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA; Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA.
| | - Mauricio J Reginato
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA
| | - Luca D'Agostino
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Agustin Legido
- Department of Pediatrics, Drexel University College of Medicine, Section of Neurology and Pediatric Neuro-oncology Program, St Christopher's Hospital for Children, Philadelphia, PA
| | - Jack A Tuszyn Ski
- Department of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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18
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Abstract
Mitochondrial (mt) dysfunction in gliomas has been linked to abnormalities of mt energy metabolism, marked by a metabolic shift from oxidative phosphorylation to glycolysis ("Warburg effect"), disturbances in mt membrane potential regulation and apoptotic signaling, as well as to somatic mutations involving the Krebs cycle enzyme isocitrate dehydrogenase. Evolving biological concepts with potential therapeutic implications include interaction between microtubule proteins and mitochondria (mt) in the control of closure of voltage-dependent anion channels and in the regulation of mt dynamics and the mt-endoplasmic reticulum network. The cytoskeletal protein βIII-tubulin, which is overexpressed in malignant gliomas, has emerged as a prosurvival factor associated in part with mt and also as a marker of chemoresistance. Mt-targeted therapeutic strategies that are discussed include the following: (1) metabolic modulation with emphasis on dichloroacetate, a pyruvate dehydrogenase kinase inhibitor; (2) tumor cell death via apoptosis induced by tricyclic antidepressants, microtubule-modulating drugs, and small molecules or compounds capable of inflicting reactive oxygen species-dependent tumor cell death; and (3) pretreatment mt priming and mt-targeted prodrug cancer therapy.
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19
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Poirier K, Lebrun N, Broix L, Tian G, Saillour Y, Boscheron C, Parrini E, Valence S, Pierre BS, Oger M, Lacombe D, Geneviève D, Fontana E, Darra F, Cances C, Barth M, Bonneau D, Bernadina BD, N'guyen S, Gitiaux C, Parent P, des Portes V, Pedespan JM, Legrez V, Castelnau-Ptakine L, Nitschke P, Hieu T, Masson C, Zelenika D, Andrieux A, Francis F, Guerrini R, Cowan NJ, Bahi-Buisson N, Chelly J. Mutations in TUBG1, DYNC1H1, KIF5C and KIF2A cause malformations of cortical development and microcephaly. Nat Genet 2013; 45:639-47. [PMID: 23603762 DOI: 10.1038/ng.2613] [Citation(s) in RCA: 319] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/22/2013] [Indexed: 12/18/2022]
Abstract
The genetic causes of malformations of cortical development (MCD) remain largely unknown. Here we report the discovery of multiple pathogenic missense mutations in TUBG1, DYNC1H1 and KIF2A, as well as a single germline mosaic mutation in KIF5C, in subjects with MCD. We found a frequent recurrence of mutations in DYNC1H1, implying that this gene is a major locus for unexplained MCD. We further show that the mutations in KIF5C, KIF2A and DYNC1H1 affect ATP hydrolysis, productive protein folding and microtubule binding, respectively. In addition, we show that suppression of mouse Tubg1 expression in vivo interferes with proper neuronal migration, whereas expression of altered γ-tubulin proteins in Saccharomyces cerevisiae disrupts normal microtubule behavior. Our data reinforce the importance of centrosomal and microtubule-related proteins in cortical development and strongly suggest that microtubule-dependent mitotic and postmitotic processes are major contributors to the pathogenesis of MCD.
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Affiliation(s)
- Karine Poirier
- Institut Cochin, Université Paris-Descartes, Centre National de la Recherche Scientifique CNRS, UMR 8104, Paris, France
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20
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Remy MH, Merdes A, Gregory-Pauron L. Assembly of Gamma-Tubulin Ring Complexes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:511-30. [DOI: 10.1016/b978-0-12-386931-9.00019-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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21
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Abbassi N, Chicha H, Rakib EM, Hannioui A, Alaoui M, Hajjaji A, Geffken D, Aiello C, Gangemi R, Rosano C, Viale M. Synthesis, antiproliferative and apoptotic activities of N-(6(4)-indazolyl)-benzenesulfonamide derivatives as potential anticancer agents. Eur J Med Chem 2012; 57:240-9. [PMID: 23072738 DOI: 10.1016/j.ejmech.2012.09.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 09/06/2012] [Accepted: 09/07/2012] [Indexed: 10/27/2022]
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22
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Dráber P, Sulimenko V, Dráberová E. Cytoskeleton in mast cell signaling. Front Immunol 2012; 3:130. [PMID: 22654883 PMCID: PMC3360219 DOI: 10.3389/fimmu.2012.00130] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 05/05/2012] [Indexed: 11/13/2022] Open
Abstract
Mast cell activation mediated by the high affinity receptor for IgE (FcεRI) is a key event in allergic response and inflammation. Other receptors on mast cells, as c-Kit for stem cell factor and G protein-coupled receptors (GPCRs) synergistically enhance the FcεRI-mediated release of inflammatory mediators. Activation of various signaling pathways in mast cells results in changes in cell morphology, adhesion to substrate, exocytosis, and migration. Reorganization of cytoskeleton is pivotal in all these processes. Cytoskeletal proteins also play an important role in initial stages of FcεRI and other surface receptors induced triggering. Highly dynamic microtubules formed by αβ-tubulin dimers as well as microfilaments build up from polymerized actin are affected in activated cells by kinases/phosphatases, Rho GTPases and changes in concentration of cytosolic Ca(2+). Also important are nucleation proteins; the γ-tubulin complexes in case of microtubules or Arp 2/3 complex with its nucleation promoting factors and formins in case of microfilaments. The dynamic nature of microtubules and microfilaments in activated cells depends on many associated/regulatory proteins. Changes in rigidity of activated mast cells reflect changes in intermediate filaments build up from vimentin. This review offers a critical appraisal of current knowledge on the role of cytoskeleton in mast cells signaling.
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Affiliation(s)
- Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
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23
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Friesen DE, Barakat KH, Semenchenko V, Perez-Pineiro R, Fenske BW, Mane J, Wishart DS, Tuszynski JA. Discovery of small molecule inhibitors that interact with γ-tubulin. Chem Biol Drug Des 2012; 79:639-52. [PMID: 22268380 DOI: 10.1111/j.1747-0285.2012.01340.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent studies have shown an overexpression of γ-tubulin in human glioblastomas and glioblastoma cell lines. As the 2-year survival rate for glioblastoma is very poor, potential benefit exists for discovering novel chemotherapeutic agents that can inhibit γ-tubulin, which is known to form a ring complex that acts as a microtubule nucleation center. We present experimental evidence that colchicine and combretastatin A-4 bind to γ-tubulin, which are to our knowledge the first drug-like compounds known to interact with γ-tubulin. Molecular dynamics simulations and docking studies were used to analyze the hypothesized γ-tubulin binding domain of these compounds. The suitability of the potential binding modes was evaluated and suggests the subsequent rational design of novel targeted inhibitors of γ-tubulin.
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24
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γ-Tubulin 2 nucleates microtubules and is downregulated in mouse early embryogenesis. PLoS One 2012; 7:e29919. [PMID: 22235350 PMCID: PMC3250491 DOI: 10.1371/journal.pone.0029919] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/06/2011] [Indexed: 01/09/2023] Open
Abstract
γ-Tubulin is the key protein for microtubule nucleation. Duplication of the γ-tubulin gene occurred several times during evolution, and in mammals γ-tubulin genes encode proteins which share ∼97% sequence identity. Previous analysis of Tubg1 and Tubg2 knock-out mice has suggested that γ-tubulins are not functionally equivalent. Tubg1 knock-out mice died at the blastocyst stage, whereas Tubg2 knock-out mice developed normally and were fertile. It was proposed that γ-tubulin 1 represents ubiquitous γ-tubulin, while γ-tubulin 2 may have some specific functions and cannot substitute for γ-tubulin 1 deficiency in blastocysts. The molecular basis of the suggested functional difference between γ-tubulins remains unknown. Here we show that exogenous γ-tubulin 2 is targeted to centrosomes and interacts with γ-tubulin complex proteins 2 and 4. Depletion of γ-tubulin 1 by RNAi in U2OS cells causes impaired microtubule nucleation and metaphase arrest. Wild-type phenotype in γ-tubulin 1-depleted cells is restored by expression of exogenous mouse or human γ-tubulin 2. Further, we show at both mRNA and protein levels using RT-qPCR and 2D-PAGE, respectively, that in contrast to Tubg1, the Tubg2 expression is dramatically reduced in mouse blastocysts. This indicates that γ-tubulin 2 cannot rescue γ-tubulin 1 deficiency in knock-out blastocysts, owing to its very low amount. The combined data suggest that γ-tubulin 2 is able to nucleate microtubules and substitute for γ-tubulin 1. We propose that mammalian γ-tubulins are functionally redundant with respect to the nucleation activity.
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25
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Hořejší B, Vinopal S, Sládková V, Dráberová E, Sulimenko V, Sulimenko T, Vosecká V, Philimonenko A, Hozák P, Katsetos CD, Dráber P. Nuclear γ-tubulin associates with nucleoli and interacts with tumor suppressor protein C53. J Cell Physiol 2011; 227:367-82. [PMID: 21465471 DOI: 10.1002/jcp.22772] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
γ-Tubulin is assumed to be a typical cytosolic protein necessary for nucleation of microtubules from microtubule organizing centers. Using immunolocalization and cell fractionation techniques in combination with siRNAi and expression of FLAG-tagged constructs, we have obtained evidence that γ-tubulin is also present in nucleoli of mammalian interphase cells of diverse cellular origins. Immunoelectron microscopy has revealed γ-tubulin localization outside fibrillar centers where transcription of ribosomal DNA takes place. γ-Tubulin was associated with nucleolar remnants after nuclear envelope breakdown and could be translocated to nucleoli during mitosis. Pretreatment of cells with leptomycin B did not affect the distribution of nuclear γ-tubulin, making it unlikely that rapid active transport via nuclear pores participates in the transport of γ-tubulin into the nucleus. This finding was confirmed by heterokaryon assay and time-lapse imaging of photoconvertible protein Dendra2 tagged to γ-tubulin. Immunoprecipitation from nuclear extracts combined with mass spectrometry revealed an association of γ-tubulin with tumor suppressor protein C53 located at multiple subcellular compartments including nucleoli. The notion of an interaction between γ-tubulin and C53 was corroborated by pull-down and co-immunoprecipitation experiments. Overexpression of γ-tubulin antagonized the inhibitory effect of C53 on DNA damage G(2) /M checkpoint activation. The combined results indicate that aside from its known role in microtubule nucleation, γ-tubulin may also have nuclear-specific function(s).
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Affiliation(s)
- Barbora Hořejší
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Czech Republic
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26
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Balbi A, Anzaldi M, Macciò C, Aiello C, Mazzei M, Gangemi R, Castagnola P, Miele M, Rosano C, Viale M. Synthesis and biological evaluation of novel pyrazole derivatives with anticancer activity. Eur J Med Chem 2011; 46:5293-309. [PMID: 21920636 DOI: 10.1016/j.ejmech.2011.08.014] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 07/19/2011] [Accepted: 08/09/2011] [Indexed: 11/24/2022]
Abstract
We synthesized thirty-six novel pyrazole derivatives and studied their antiproliferative activity in human ovarian adenocarcinoma A2780 cells, human lung carcinoma A549 cells, and murine P388 leukemia cells. Four of these substances were selected because of their higher antiproliferative activity and further analyses showed that they were all able to induce apoptosis, although to a different extent. The expression of p53 and p21(waf1), which induce apoptosis and cell cycle arrest, was evaluated by western blot analysis in cells treated with compound 12d. The analysis of the cell cycle showed that all the selected compounds cause a partial G2/M block and the formation of polyploid cells. Furthermore, the four selected compounds were tested for their interaction with the microtubular cytoskeletal system by docking analysis, tubulin polymerization assay and immunofluorescence staining, demonstrating that the compound 12d, unlike the other active derivatives, was able to significantly bind dimers of α- and β-tubulin, probably causing a molecular distortion resulting in the disassembly of microtubules.
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Affiliation(s)
- Alessandro Balbi
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Genova, V.le Benedetto XV 3, 16132 Genova, Italy.
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27
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Caracciolo V, D'Agostino L, Dráberová E, Sládková V, Crozier-Fitzgerald C, Agamanolis DP, de Chadarévian JP, Legido A, Giordano A, Dráber P, Katsetos CD. Differential expression and cellular distribution of gamma-tubulin and betaIII-tubulin in medulloblastomas and human medulloblastoma cell lines. J Cell Physiol 2010; 223:519-29. [PMID: 20162618 DOI: 10.1002/jcp.22077] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In previous studies, we have shown overexpression and ectopic subcellular distribution of gamma-tubulin and betaIII-tubulin in human glioblastomas and glioblastoma cell lines (Katsetos et al., 2006, J Neuropathol Exp Neurol 65:455-467; Katsetos et al., 2007, Neurochem Res 32:1387-1398). Here we determined the expression of gamma-tubulin in surgically excised medulloblastomas (n = 20) and in the human medulloblastoma cell lines D283 Med and DAOY. In clinical tissue samples, the immunohistochemical distribution of gamma-tubulin labeling was pervasive and inversely related to neuritogenesis. Overexpression of gamma-tubulin was widespread in poorly differentiated, proliferating tumor cells but was significantly diminished in quiescent differentiating tumor cells undergoing neuritogenesis, highlighted by betaIII-tubulin immunolabeling. By quantitative real-time PCR, gamma-tubulin transcripts for TUBG1, TUBG2, and TUBB3 genes were detected in both cell lines but expression was less prominent when compared with the human glioblastoma cell lines. Immunoblotting revealed comparable amounts of gamma-tubulin and betaIII-tubulin in different phases of cell cycle; however, a larger amount of gamma-tubulin was detected in D283 Med when compared with DAOY cells. Interphase D283 Med cells exhibited predominantly diffuse cytoplasmic gamma-tubulin localization, in addition to the expected centrosome-associated distribution. Robust betaIII-tubulin immunoreactivity was detected in mitotic spindles of DAOY cells. Our data indicate that overexpression of gamma-tubulin may be linked to phenotypic dedifferentiation (anaplasia) and tumor progression in medulloblastomas and may potentially serve as a promising tumor marker.
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Affiliation(s)
- Valentina Caracciolo
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania, USA
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28
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Katsetos CD, Dráberová E, Legido A, Dráber P. Tubulin targets in the pathobiology and therapy of glioblastoma multiforme. II. γ-tubulin. J Cell Physiol 2009; 221:514-20. [DOI: 10.1002/jcp.21884] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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29
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Identifying concerted evolution and gene conversion in mammalian gene pairs lasting over 100 million years. BMC Evol Biol 2009; 9:156. [PMID: 19583854 PMCID: PMC2720389 DOI: 10.1186/1471-2148-9-156] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 07/07/2009] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Concerted evolution occurs in multigene families and is characterized by stretches of homogeneity and higher sequence similarity between paralogues than between orthologues. Here we identify human gene pairs that have undergone concerted evolution, caused by ongoing gene conversion, since at least the human-mouse divergence. Our strategy involved the identification of duplicated genes with greater similarity within a species than between species. These genes were required to be present in multiple mammalian genomes, suggesting duplication early in mammalian divergence. To eliminate genes that have been conserved due to strong purifying selection, our analysis also required at least one intron to have retained high sequence similarity between paralogues. RESULTS We identified three human gene pairs undergoing concerted evolution (BMP8A/B, DDX19A/B, and TUBG1/2). Phylogenetic investigations reveal that in each case the duplication appears to have occurred prior to eutherian mammalian radiation, with exactly two paralogues present in all examined species. This indicates that all three gene duplication events were established over 100 million years ago. CONCLUSION The extended duration of concerted evolution in multiple distant lineages suggests that there has been prolonged homogenization of specific segments within these gene pairs. Although we speculate that selection for homogenization could have been utilized in order to maintain crucial homo- or hetero- binding domains, it remains unclear why gene conversion has persisted for such extended periods of time. Through these analyses, our results demonstrate additional examples of a process that plays a definite, although unspecified, role in molecular evolution.
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Regulation of microtubule nucleation from membranes by complexes of membrane-bound γ-tubulin with Fyn kinase and phosphoinositide 3-kinase. Biochem J 2008; 416:421-30. [DOI: 10.1042/bj20080909] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The molecular mechanisms controlling microtubule formation in cells with non-centrosomal microtubular arrays are not yet fully understood. The key component of microtubule nucleation is γ-tubulin. Although previous results suggested that tyrosine kinases might serve as regulators of γ-tubulin function, their exact roles remain enigmatic. In the present study, we show that a pool of γ-tubulin associates with detergent-resistant membranes in differentiating P19 embryonal carcinoma cells, which exhibit elevated expression of the Src family kinase Fyn (protein tyrosine kinase p59Fyn). Microtubule-assembly assays demonstrated that membrane-associated γ-tubulin complexes are capable of initiating the formation of microtubules. Pretreatment of the cells with Src family kinase inhibitors or wortmannin blocked the nucleation activity of the γ-tubulin complexes. Immunoprecipitation experiments revealed that membrane-associated γ-tubulin forms complexes with Fyn and PI3K (phosphoinositide 3-kinase). Furthermore, in vitro kinase assays showed that p85α (regulatory p85α subunit of PI3K) serves as a Fyn substrate. Direct interaction of γ-tubulin with the C-terminal Src homology 2 domain of p85α was determined by pull-down experiments and immunoprecipitation experiments with cells expressing truncated forms of p85α. The combined results suggest that Fyn and PI3K might take part in the modulation of membrane-associated γ-tubulin activities.
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31
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Genomic deletions correlate with underexpression of novel candidate genes at six loci in pediatric pilocytic astrocytoma. Neoplasia 2008; 10:757-72. [PMID: 18670637 DOI: 10.1593/neo.07914] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 05/09/2008] [Accepted: 05/11/2008] [Indexed: 01/24/2023] Open
Abstract
The molecular pathogenesis of pediatric pilocytic astrocytoma (PA) is not well defined. Previous cytogenetic and molecular studies have not identified nonrandom genetic aberrations. To correlate differential gene expression and genomic copy number aberrations (CNAs) in PA, we have used Affymetrix GeneChip HG_U133A to generate gene expression profiles of 19 pediatric patients and the SpectralChip 2600 to investigate CNAs in 11 of these tumors. Hierarchical clustering according to expression profile similarity grouped tumors and controls separately. We identified 1844 genes that showed significant differential expression between tumor and normal controls, with a large number clearly influencing phosphatidylinositol and mitogen-activated protein kinase signaling in PA. Most CNAs identified in this study were single-clone alterations. However, a small region of loss involving up to seven adjacent clones at 7q11.23 was observed in seven tumors and correlated with the underexpression of BCL7B. Loss of four individual clones was also associated with reduced gene expression including SH3GL2 at 9p21.2-p23, BCL7A (which shares 90% sequence homology with BCL7B) at 12q24.33, DRD1IP at 10q26.3, and TUBG2 and CNTNAP1 at 17q21.31. Moreover, the down-regulation of FOXG1B at 14q12 correlated with loss within the gene promoter region in most tumors. This is the first study to correlate differential gene expression with CNAs in PA.
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Changes of γ-tubulin expression and distribution in the zebrafish (Danio rerio) ovary, oocyte and embryo. Gene Expr Patterns 2008; 8:237-47. [DOI: 10.1016/j.gep.2007.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 12/18/2007] [Accepted: 12/20/2007] [Indexed: 11/22/2022]
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Wiese C. Distinct Dgrip84 isoforms correlate with distinct gamma-tubulins in Drosophila. Mol Biol Cell 2007; 19:368-77. [PMID: 18003974 DOI: 10.1091/mbc.e07-08-0801] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Gamma-tubulin is an indispensable component of the animal centrosome and is required for proper microtubule organization. Within the cell, gamma-tubulin exists in a multiprotein complex containing between two (some yeasts) and six or more (metazoa) additional highly conserved proteins named gamma ring proteins (Grips) or gamma complex proteins (GCPs). gamma-Tubulin containing complexes isolated from Xenopus eggs or Drosophila embryos appear ring-shaped and have therefore been named the gamma-tubulin ring complex (gammaTuRC). Curiously, many organisms (including humans) have two distinct gamma-tubulin genes. In Drosophila, where the two gamma-tubulin isotypes have been studied most extensively, the gamma-tubulin genes are developmentally regulated: the "maternal" gamma-tubulin isotype (named gammaTub37CD according to its location on the genetic map) is expressed in the ovary and is deposited in the egg, where it is thought to orchestrate the meiotic and early embryonic cleavages. The second gamma-tubulin isotype (gammaTub23C) is ubiquitously expressed and persists in most of the cells of the adult fly. In those rare cases where both gamma-tubulins coexist in the same cell, they show distinct subcellular distributions and cell-cycle-dependent changes: gammaTub37CD mainly localizes to the centrosome, where its levels vary only slightly with the cell cycle. In contrast, the level of gammaTub23C at the centrosome increases at the beginning of mitosis, and gammaTub23C also associates with spindle pole microtubules. Here, we show that gammaTub23C forms discrete complexes that closely resemble the complexes formed by gammaTub37CD. Surprisingly, however, gammaTub23C associates with a distinct, longer splice variant of Dgrip84. This may reflect a role for Dgrip84 in regulating the activity and/or the location of the gamma-tubulin complexes formed with gammaTub37CD and gammaTub23C.
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Affiliation(s)
- Christiane Wiese
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Divinski I, Holtser-Cochav M, Vulih-Schultzman I, Steingart RA, Gozes I. Peptide neuroprotection through specific interaction with brain tubulin. J Neurochem 2006; 98:973-84. [PMID: 16893427 DOI: 10.1111/j.1471-4159.2006.03936.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study aimed to identify the neuronal target for the potent neuroprotective peptide NAP. When added to pheochromocytoma cells (neuronal model), NAP was found in the intracellular milieu and was co-localized with microtubules. NAP induced neurite outgrowth and protected primary neurons against microtubule-associated ZnCl2 toxicity. Rapid microtubule reorganization into distinct microtubules ensued after NAP addition to both pheochromocytoma cells and primary cerebral cortical neurons, but not to fibrobalsts. While binding neuronal tubulin and protecting pheochromocytoma cells against oxidative stress, NAP did not bind tubulin extracted from fibroblasts, nor did it protect those cells against oxidative stress. Affinity chromatography identified the brain-specific betaIII-tubulin as a major NAP binding protein. Paclitaxel (a microtubule aggregating agent that interacts with beta-tubulin) reduced NAP tubulin binding. Thus, the underlying mechanism for the neuroprotection offered by NAP is targeting neuronal microtubules that are essential for neuronal survival and function.
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Affiliation(s)
- Inna Divinski
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Yuba-Kubo A, Kubo A, Hata M, Tsukita S. Gene knockout analysis of two gamma-tubulin isoforms in mice. Dev Biol 2005; 282:361-73. [PMID: 15893303 DOI: 10.1016/j.ydbio.2005.03.031] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Revised: 03/14/2005] [Accepted: 03/16/2005] [Indexed: 11/19/2022]
Abstract
Gamma-tubulin regulates the nucleation of microtubules, but knowledge of its functions in vivo is still fragmentary. Here, we report the identification of two closely related gamma-tubulin isoforms, TUBG1 and TUBG2, in mice, and the generation of TUBG1- and TUBG2-deficient mice. TUBG1 was expressed ubiquitously, whereas TUBG2 was primarily detected in the brain. The development of TUBG1-deficient (Tubg1-/-) embryos stopped at the morula/blastocyst stages due to a characteristic mitotic arrest: the mitotic spindle was highly disorganized, and disorganized spindles showed one or two pole-like foci of bundled MTs that were surrounded by condensed chromosomes. TUBG2 was expressed in blastocysts, but could not rescue the TUBG1 deficiency. By contrast, TUBG2-deficient (Tubg2-/-) mice were born, grew, and intercrossed normally. In the brain of wild-type mice, TUBG2 was expressed in approximately the same amount as TUBG1, but no histological abnormalities were found in the Tubg2-/- brain. These findings indicated that TUBG1 and TUBG2 are not functionally equivalent in vivo, that TUBG1 corresponds to conventional gamma-tubulin, and that TUBG2 may have some unidentified function in the brain.
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Affiliation(s)
- Akiko Yuba-Kubo
- Solution Oriented Research for Science and Technology, Japan Science and Technology Corporation, Sakyo-ku, Kyoto 606-8501, Japan
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Kukharskyy V, Sulimenko V, Macůrek L, Sulimenko T, Dráberová E, Dráber P. Complexes of gamma-tubulin with nonreceptor protein tyrosine kinases Src and Fyn in differentiating P19 embryonal carcinoma cells. Exp Cell Res 2004; 298:218-28. [PMID: 15242776 DOI: 10.1016/j.yexcr.2004.04.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2003] [Revised: 04/08/2004] [Indexed: 11/19/2022]
Abstract
Nonreceptor protein tyrosine kinases of the Src family have been shown to play an important role in signal transduction as well as in regulation of microtubule protein interactions. Here we show that gamma-tubulin (gamma-Tb) in P19 embryonal carcinoma cells undergoing neuronal differentiation is phosphorylated and forms complexes with protein tyrosine kinases of the Src family, Src and Fyn. Elevated expression of both kinases during differentiation corresponded with increased level of proteins phosphorylated on tyrosine. Immunoprecipitation experiments with antibodies against Src, Fyn, gamma-tubulin, and with anti-phosphotyrosine antibody revealed that gamma-tubulin appeared in complexes with these kinases. In vitro kinase assays showed tyrosine phosphorylation of proteins in gamma-tubulin complexes isolated from differentiated cells. Pretreatment of cells with Src family selective tyrosine kinase inhibitor PP2 reduced the amount of phosphorylated gamma-tubulin in the complexes. Binding experiments with recombinant SH2 and SH3 domains of Src and Fyn kinases revealed that protein complexes containing gamma-tubulin bound to SH2 domains and that these interactions were of SH2-phosphotyrosine type. The combined data suggest that Src family kinases might have an important role in the regulation of gamma-tubulin interaction with tubulin dimers or other proteins during neurogenesis.
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Affiliation(s)
- Vitaliy Kukharskyy
- Institute of Molecular Genetics, Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, Prague 4
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Leong T, Chao M, Bassal S, McKay M. Radiation-hypersensitive cancer patients do not manifest protein expression abnormalities in components of the nonhomologous end-joining (NHEJ) pathway. Br J Cancer 2003; 88:1251-5. [PMID: 12698192 PMCID: PMC2747564 DOI: 10.1038/sj.bjc.6600897] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Radiation therapy (RT) is utilised for the treatment of around half of all oncology patients during the course of their illness. Despite great clinical progress in the rational deployment of RT, the underlying molecular basis for its efficacy and toxicity are currently imperfectly understood. In this study, we took a biochemical approach to evaluate the potential role of key ionising radiation repair proteins in the treatment outcomes of patients with severe acute or late RT side effects. Lymphoblastoid cell lines were established from blood samples from 36 radiosensitive cases and a number of controls (the latter had had RT but did not develop significant toxicity). The expression level and migration of key proteins from the nonhomologous end-joining (NHEJ) pathway was evaluated by Western blot analysis on cases and controls. We did not observe any abnormalities in expression level or migration pattern of the following NHEJ proteins in radiosensitive cancer cases: Ku70, Ku80, XRCC4, DNA Ligase IV. These important negative results provide evidence that mutations that affect protein expression of these NHEJ components are unlikely to underlie clinical radiation sensitivity.
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Affiliation(s)
- T Leong
- Peter MacCallum Cancer Institute, Smorgon Family Building, St Andrews Place, East Melbourne, Victoria 3002, Australia
| | - M Chao
- Peter MacCallum Cancer Institute, Smorgon Family Building, St Andrews Place, East Melbourne, Victoria 3002, Australia
| | - S Bassal
- Peter MacCallum Cancer Institute, Smorgon Family Building, St Andrews Place, East Melbourne, Victoria 3002, Australia
| | - M McKay
- Peter MacCallum Cancer Institute, Smorgon Family Building, St Andrews Place, East Melbourne, Victoria 3002, Australia
- Division of Radiation Oncology, Peter MacCallum Cancer Institute, Locked Bag 1, A'Beckett Street, Melbourne, Victoria 8006, Australia. E-mail:
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Sulimenko V, Sulimenko T, Poznanovic S, Nechiporuk-Zloy V, Böhm KJ, Macurek L, Unger E, Dráber P. Association of brain gamma-tubulins with alpha beta-tubulin dimers. Biochem J 2002; 365:889-95. [PMID: 11939909 PMCID: PMC1222706 DOI: 10.1042/bj20020175] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2002] [Revised: 04/04/2002] [Accepted: 04/08/2002] [Indexed: 11/17/2022]
Abstract
gamma-Tubulin is necessary for nucleation and polar orientation of microtubules in vivo. The molecular mechanism of microtubule nucleation by gamma-tubulin and the regulation of this process are not fully understood. Here we show that there are two gamma-tubulin forms in the brain that are present in complexes of various sizes. Large complexes tend to dissociate in the presence of a high salt concentration. Both gamma-tubulins co-polymerized with tubulin dimers, and multiple gamma-tubulin bands were identified in microtubule protein preparations under conditions of non-denaturing electrophoresis. Immunoprecipitation experiments with monoclonal antibodies against gamma-tubulin and alpha-tubulin revealed interactions of both gamma-tubulin forms with tubulin dimers, irrespective of the size of complexes. We suggest that, besides small and large gamma-tubulin complexes, other molecular gamma-tubulin form(s) exist in brain extracts. Two-dimensional electrophoresis revealed multiple charge variants of gamma-tubulin in both brain extracts and microtubule protein preparations. Post-translational modification(s) of gamma-tubulins might therefore have an important role in the regulation of microtubule nucleation in neuronal cells.
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Affiliation(s)
- Vadym Sulimenko
- Institute of Molecular Genetics, Department of Biology of Cytoskeleton, Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic
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Linhartová I, Novotná B, Sulimenko V, Dráberová E, Dráber P. Gamma-tubulin in chicken erythrocytes: changes in localization during cell differentiation and characterization of cytoplasmic complexes. Dev Dyn 2002; 223:229-40. [PMID: 11836787 DOI: 10.1002/dvdy.10047] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The mechanism of marginal band (MB) formation in differentiating erythroid cells is not fully understood, and the proteins involved in nucleation of MB microtubules are largely unknown. To gain insights into the function of gamma-tubulin in MB formation, we have followed its distribution in developing chicken erythrocytes and characterized soluble forms of the protein. In early stages of erythroid cells differentiation, gamma-tubulin was present in microtubule-organizing centers, mitotic spindles, as well as on MB. Its subcellular localization changed in the course of differentiation, and in postnatal peripheral erythrocytes gamma-tubulin was found only in soluble forms. After cold-induced depolymerization gamma-tubulin in erythroid cells formed large clusters that were not observed in matured cells, and re-growth experiments demonstrated that gamma-tubulin was not present in distinct nucleation structures at the cell periphery. Soluble gamma-tubulin formed complexes of various size and large complexes were prone to dissociation in the presence of high salt concentration. Interaction of gamma-tubulin with tubulin dimers was revealed by precipitation experiments. gamma-Tubulin occurred in multiple charge variants whose number increased in the course of erythrocyte differentiation and corresponded with decreased binding to MB. The presented data demonstrate for the first time that gamma-tubulin is a substrate for developmentally regulated posttranslational modifications and that the binding properties of gamma-tubulin or its complexes change during differentiation events.
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Affiliation(s)
- Irena Linhartová
- Department of Biology of the Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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40
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Affiliation(s)
- Y Ovechkina
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210, USA
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Raynaud-Messina B, Debec A, Tollon Y, Garès M, Wright M. Differential properties of the two Drosophila gamma-tubulin isotypes. Eur J Cell Biol 2001; 80:643-9. [PMID: 11713868 DOI: 10.1078/0171-9335-00195] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The functional significance of distinct gamma-tubulins in several unrelated eukaryotes remains an enigma due to the difficulties to investigate this question experimentally. Using specific nucleotidic and immunological probes, we have demonstrated that the two divergent Drosophila gamma-tubulins, gamma-tub23C and gamma-tub37CD, are expressed in cultured cells. Gamma-tub37CD is constantly detected at the centrosome and absent in the mitotic spindle, while gamma-tub23C is extensively recruited to the centrosome during mitosis and relocalizes in the mitotic spindle. The two gamma-tubulins exhibit distinct biochemical properties. Gamma-tub23C is present in the soluble gamma-tubulin small complexes (10S) and gamma-tubulin big complexes (35S) and is loosely associated to the cytoskeleton. In contrast, gamma-tub37CD is undetectable in the soluble fraction and exhibits a tight binding to the centrosome. Syncytial embryos also contain the two gamma-tubulin isotypes, which are differentially recruited at the centrosome. Gamma-tub23C is present in the 10S soluble complexes only, while y-tub37CD is contained in the two soluble complexes and is recruited at the centrosome where it exhibits an heterogeneous binding. These results demonstrated an heterogeneity of the two Drosophila gamma-tubulin isotypes both in the cytoskeletal and the soluble fractions. They suggest the direct implication of the 35S complex in the centrosomal recruitment of gamma-tubulin and a conditional functional redundancy between the two gamma-tubulins.
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Affiliation(s)
- B Raynaud-Messina
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, Toulouse/France
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