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Sakagami T, Watanabe K, Hamada M, Sakamoto T, Hatabu T, Ando M. Structure of putative epidermal sensory receptors in an acoel flatworm, Praesagittifera naikaiensis. Cell Tissue Res 2024; 395:299-311. [PMID: 38305882 PMCID: PMC10904500 DOI: 10.1007/s00441-024-03865-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 01/08/2024] [Indexed: 02/03/2024]
Abstract
Acoel flatworms possess epidermal sensory-receptor cells on their body surfaces and exhibit behavioral repertoires such as geotaxis and phototaxis. Acoel epidermal sensory receptors should be mechanical and/or chemical receptors; however, the mechanisms of their sensory reception have not been elucidated. We examined the three-dimensional relationship between epidermal sensory receptors and their innervation in an acoel flatworm, Praesagittifera naikaiensis. The distribution of the sensory receptors was different between the ventral and dorsal sides of worms. The nervous system was mainly composed of a peripheral nerve net, an anterior brain, and three pairs of longitudinal nerve cords. The nerve net was located closer to the body surface than the brain and the nerve cords. The sensory receptors have neural connections with the nerve net in the entire body of worms. We identified five homologs of polycystic kidney disease (PKD): PKD1-1, PKD1-2, PKD1-3, PKD1-4, and, PKD2, from the P. naikaiensis genome. All of these PKD genes were implied to be expressed in the epidermal sensory receptors of P. naikaiensis. PKD1-1 and PKD2 were dispersed across the entire body of worms. PKD1-2, PKD1-3, and PKD1-4 were expressed in the anterior region of worms. PKD1-4 was also expressed around the mouth opening. Our results indicated that P. naikaiensis possessed several types of epidermal sensory receptors to convert various environmental stimuli into electrical signals via the PKD channels and transmit the signals to afferent nerve and/or effector cells.
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Affiliation(s)
- Tosuke Sakagami
- Laboratory of Animal Physiology and Pharmacology, Department of Animal Science, Graduate School of Environmental and Life Science, Okayama University, Okayama, 700-8530, Japan
| | - Kaho Watanabe
- Laboratory of Cell Physiology, Department of Science Education, Graduate School of Education, Okayama University, Okayama, 700-8530, Japan
| | - Mayuko Hamada
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Okayama, 701-4303, Japan
| | - Tatsuya Sakamoto
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Okayama, 701-4303, Japan
| | - Toshimitsu Hatabu
- Laboratory of Animal Physiology and Pharmacology, Department of Animal Science, Graduate School of Environmental and Life Science, Okayama University, Okayama, 700-8530, Japan
| | - Motonori Ando
- Laboratory of Animal Physiology and Pharmacology, Department of Animal Science, Graduate School of Environmental and Life Science, Okayama University, Okayama, 700-8530, Japan.
- Laboratory of Cell Physiology, Department of Science Education, Graduate School of Education, Okayama University, Okayama, 700-8530, Japan.
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Tantry MSA, Santhakumar K. Insights on the Role of α- and β-Tubulin Isotypes in Early Brain Development. Mol Neurobiol 2023; 60:3803-3823. [PMID: 36943622 DOI: 10.1007/s12035-023-03302-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/05/2023] [Indexed: 03/23/2023]
Abstract
Tubulins are the highly conserved subunit of microtubules which involve in various fundamental functions including brain development. Microtubules help in neuronal proliferation, migration, differentiation, cargo transport along the axons, synapse formation, and many more. Tubulin gene family consisting of multiple isotypes, their differential expression and varied post translational modifications create a whole new level of complexity and diversity in accomplishing manifold neuronal functions. The studies on the relation between tubulin genes and brain development opened a new avenue to understand the role of each tubulin isotype in neurodevelopment. Mutations in tubulin genes are reported to cause brain development defects especially cortical malformations, referred as tubulinopathies. There is an increased need to understand the molecular correlation between various tubulin mutations and the associated brain pathology. Recently, mutations in tubulin isotypes (TUBA1A, TUBB, TUBB1, TUBB2A, TUBB2B, TUBB3, and TUBG1) have been linked to cause various neurodevelopmental defects like lissencephaly, microcephaly, cortical dysplasia, polymicrogyria, schizencephaly, subcortical band heterotopia, periventricular heterotopia, corpus callosum agenesis, and cerebellar hypoplasia. This review summarizes on the microtubule dynamics, their role in neurodevelopment, tubulin isotypes, post translational modifications, and the role of tubulin mutations in causing specific neurodevelopmental defects. A comprehensive list containing all the reported tubulin pathogenic variants associated with brain developmental defects has been prepared to give a bird's eye view on the broad range of tubulin functions.
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Affiliation(s)
- M S Ananthakrishna Tantry
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, 603203, India
| | - Kirankumar Santhakumar
- Department of Genetic Engineering, SRM Institute of Science and Technology, Kattankulathur, 603203, India.
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Li X, Lin G, Liu T, Zhao N, Xu H, Wang H, Zheng W. Postnatal development of BAG3 expression in mouse cerebral cortex and hippocampus. Brain Struct Funct 2021; 226:2629-2650. [PMID: 34357438 DOI: 10.1007/s00429-021-02356-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
The decreased efficiency of autophagic processing in the central nervous system during aging may be a contributing factor in neurodegenerative diseases. BAG3 (Bcl2 associated athanogene 3) is a major member of the BAG family of co-molecular chaperones that mediate selective macroautophagy. Therefore, we analyzed the expression and distribution of BAG3 in the brain at postnatal 0 day (P0), P15, 1-, 2-, 9-, 12-, and 18 month-old C57BL/6 mice, thus covering almost all ages. Except for a significant steep drop in mRNA and protein levels in the cortex and hippocampus soon after birth, there were minimal differences in the expression and distribution of BAG3 among P15, M1, M2, M9, and M12 mice; however, at 18 months, BAG3 expression was significantly higher. Immunohistochemical analyses showed that BAG3 is mainly located in the neuronal cytoplasm and processes in C57BL/6 the cerebral cortex and hippocampus from P0 to M18 postnatal development. These findings indicate that BAG3 might be stable in young and middle-aged mice, but unstable in aged mice.
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Affiliation(s)
- Xinlu Li
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China
| | - Geng Lin
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China
| | - Tongtong Liu
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China.,Department of Neurology, The People's Hospital of Liaoning Province, Shenyang, 110016, China
| | - Ning Zhao
- Department of Infectious Diseases, Shengjing Hospital, Affiliated Hospital of China Medical University, Shenyang, 110022, China
| | - He Xu
- Department of Histology and Embryology, School of Medicine, Shenzhen University, Shenzhen, 518052, China
| | - Huaqin Wang
- Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122, China
| | - Wei Zheng
- Department of Histology and Embryology, China Medical University, Shenyang, 110122, China.
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Abstract
Imaging and postmortem studies indicate that schizophrenia subjects exhibit abnormal connectivity in several white matter tracts, including the cingulum bundle. Copper chelators given to experimental animals damage myelin and myelin-producing oligodendrocytes, and the substantia nigra of schizophrenia subjects shows lower levels of copper, copper transporters, and copper-utilizing enzymes. This study aimed to elucidate the potential role of copper homeostasis in white matter pathology in schizophrenia. Protein levels of the copper transporters ATP7A and CTR1, and dysbindin-1, an upstream modulator of copper metabolism and schizophrenia susceptibility factor, were measured using Western blot analyses of the postmortem cingulum bundle of schizophrenia subjects (n=16) and matched controls (n=13). Additionally, the patient group was subdivided by treatment status: off- (n=8) or on-medication (n=8). Relationships between proteins from the current study were correlated among themselves and markers of axonal integrity previously measured in the same cohort. Schizophrenia subjects exhibited similar protein levels to controls, with no effect of antipsychotic treatment. The dysbindin-1A/1BC relationship was positive in controls and schizophrenia subjects; however, antipsychotic treatment appeared to reverse this relationship in a statistically different manner from that of controls and unmedicated subjects. The relationships between dysbindin-1A/neurofilament heavy and ATP7A/α-tubulin were positively correlated in the schizophrenia group that was significantly different from the lack of correlation in controls. Copper transporters and dysbindin-1 appear to be more significantly affected in the grey matter of schizophrenia subjects. However, the relationships among proteins in white matter may be more substantial and dependent on treatment status.
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Affiliation(s)
- Kirsten E Schoonover
- Department of Psychology and Behavioral Neuroscience, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America.
| | - Rosalinda C Roberts
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America.
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Siegel D, Bersie S, Harris P, Di Francesco A, Armstrong M, Reisdorph N, Bernier M, de Cabo R, Fritz K, Ross D. A redox-mediated conformational change in NQO1 controls binding to microtubules and α-tubulin acetylation. Redox Biol 2020; 39:101840. [PMID: 33360352 PMCID: PMC7772575 DOI: 10.1016/j.redox.2020.101840] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/18/2022] Open
Abstract
The localization of NQO1 near acetylated microtubules has led to the hypothesis that NQO1 may work in concert with the NAD+-dependent deacetylase SIRT2 to regulate acetyl α-tubulin (K40) levels on microtubules. NQO1 catalyzes the oxidation of NADH to NAD+ and may supplement levels of NAD+ near microtubules to aid SIRT2 deacetylase activity. While HDAC6 has been shown to regulate the majority of microtubule acetylation at K40, SIRT2 is also known to modulate microtubule acetylation (K40) in the perinuclear region. In this study we examined the potential roles NQO1 may play in modulating acetyl α-tubulin levels. Knock-out or knock-down of NQO1 or SIRT2 did not change the levels of acetyl α-tubulin in 16HBE human bronchial epithelial cells and 3T3-L1 fibroblasts; however, treatment with a mechanism-based inhibitor of NQO1 (MI2321) led to a short-lived temporal increase in acetyl α-tubulin levels in both cell lines without impacting the intracellular pools of NADH or NAD+. Inactivation of NQO1 by MI2321 resulted in lower levels of NQO1 immunostaining on microtubules, consistent with redox-dependent changes in NQO1 conformation as evidenced by the use of redox-specific, anti-NQO1 antibodies in immunoprecipitation studies. Given the highly dynamic nature of acetylation-deacetylation reactions at α-tubulin K40 and the crowded protein environment surrounding this site, disruption in the binding of NQO1 to microtubules may temporally disturb the physical interactions of enzymes responsible for maintaining the microtubule acetylome. NQO1which produces NAD and Sirt2 which uses NAD are located in the perinuclear region. Depleting cellular NAD+ led to increased levels of acetyl α-tubulin. Knockout or knockdown of NQO1 did not change perinuclear acetyl α-tubulin levels. Pharmacological inhibition of NQO1 by MI2321 increased α-tubulin acetylation. Redox changes in NQO1 conformation and binding modulate microtubule acetyltubulin.
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Affiliation(s)
- David Siegel
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - Stephanie Bersie
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Peter Harris
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Andrea Di Francesco
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, 21224, USA
| | - Michael Armstrong
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Nichole Reisdorph
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Michel Bernier
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, 21224, USA
| | - Rafael de Cabo
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, Baltimore, MD, 21224, USA
| | - Kristofer Fritz
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - David Ross
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
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Fouani L, Huang MLH, Cole L, Jansson PJ, Kovacevic Z, Richardson DR. During mitosis ZEB1 "switches" from being a chromatin-bound epithelial gene repressor, to become a microtubule-associated protein. Biochim Biophys Acta Mol Cell Res 2020; 1867:118673. [PMID: 32057919 DOI: 10.1016/j.bbamcr.2020.118673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/30/2020] [Accepted: 02/02/2020] [Indexed: 12/23/2022]
Abstract
Microtubules are polymers of α/β-tubulin, with microtubule organization being regulated by microtubule-associated proteins (MAPs). Herein, we describe a novel role for the epithelial gene repressor, zinc finger E-box-binding homeobox 1 (ZEB1), that "switches" from a chromatin-associated protein during interphase, to a MAP that associates with α-, β- and γ-tubulin during mitosis. Additionally, ZEB1 was also demonstrated to associate with γ-tubulin at the microtubule organizing center (MTOC). Using confocal microscopy, ZEB1 localization was predominantly nuclear during interphase, with α/β-tubulin being primarily cytoplasmic and the association between these proteins being minimal. However, during the stages of mitosis, ZEB1 co-localization with α-, β-, and γ-tubulin was significantly increased, with the association commonly peaking during metaphase in multiple tumor cell-types. ZEB1 was also observed to accumulate in the cleavage furrow during cytokinesis. The increased interaction between ZEB1 and α-tubulin during mitosis was also confirmed using the proximity ligation assay. In contrast to ZEB1, its paralog ZEB2, was mainly perinuclear and cytoplasmic during interphase, showing some co-localization with α-tubulin during mitosis. Considering the association between ZEB1 with α/β/γ-tubulin during mitosis, studies investigated ZEB1's role in the cell cycle. Silencing ZEB1 resulted in a G2-M arrest, which could be mediated by the up-regulation of p21Waf1/Cip1 and p27Kip1 that are known downstream targets repressed by ZEB1. However, it cannot be excluded the G2/M arrest observed after ZEB1 silencing is not due to its roles as a MAP. Collectively, ZEB1 plays a role as a MAP during mitosis and could be functionally involved in this process.
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Kováčiková M, Paskerova GG, Diakin A, Simdyanov TG, Vaškovicová N, Valigurová A. Motility and cytoskeletal organisation in the archigregarine Selenidium pygospionis (Apicomplexa): observations on native and experimentally affected parasites. Parasitol Res 2019; 118:2651-67. [PMID: 31270680 DOI: 10.1007/s00436-019-06381-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 06/19/2019] [Indexed: 10/26/2022]
Abstract
Representatives of Apicomplexa perform various kinds of movements that are linked to the different stages of their life cycle. Ancestral apicomplexan lineages, including gregarines, represent organisms suitable for research into the evolution and diversification of motility within the group. The vermiform trophozoites and gamonts of the archigregarine Selenidium pygospionis perform a very active type of bending motility. Experimental assays and subsequent light, electron, and confocal microscopic analyses demonstrated the fundamental role of the cytoskeletal proteins actin and tubulin in S. pygospionis motility and allowed us to compare the mechanism of its movement to the gliding machinery (the so-called glideosome concept) described in apicomplexan zoites. Actin-modifying drugs caused a reduction in the movement speed (cytochalasin D) or stopped the motility of archigregarines completely (jasplakinolide). Microtubule-disrupting drugs (oryzalin and colchicine) had an even more noticeable effect on archigregarine motility. The fading and disappearance of microtubules were documented in ultrathin sections, along with the formation of α-tubulin clusters visible after the immunofluorescent labelling of drug-treated archigregarines. The obtained data indicate that subpellicular microtubules most likely constitute the main motor structure involved in S. pygospionis bending motility, while actin has rather a supportive function.
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Coulup SK, Georg GI. Revisiting microtubule targeting agents: α-Tubulin and the pironetin binding site as unexplored targets for cancer therapeutics. Bioorg Med Chem Lett 2019; 29:1865-73. [PMID: 31130264 DOI: 10.1016/j.bmcl.2019.05.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/17/2019] [Accepted: 05/19/2019] [Indexed: 01/21/2023]
Abstract
Molecules that bind to tubulin and disrupt tubulin dynamics are known as microtubule targeting agents. Treatment with a microtubule targeting agent leads to cell cycle arrest followed by apoptosis. Tubulin inhibitors have been highly effective in the clinical treatment of a variety of tumors and are being investigated for treatment of several other diseases. Currently, all FDA approved microtubule inhibitors bind to β-tubulin. Given the overall success of tubulin-binding agents in anticancer chemotherapy, α-tubulin is an attractive and unexplored target. Herein, we will discuss pironetin, the only compound known to bind α-tubulin, with particular focus on the known biological properties, the total syntheses, exploration of its structure-activity relationship, and future directions.
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Borisanova AO, Malakhov VV, Temereva EN. The neuroanatomy of Barentsia discreta (Entoprocta, Coloniales) reveals significant differences between bryozoan and entoproct nervous systems. Front Zool 2019; 16:9. [PMID: 30962810 PMCID: PMC6437902 DOI: 10.1186/s12983-019-0307-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 03/12/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Entoprocta affinities within Lophotrochozoa remain unclear. In different studies, entoprocts are considered to be related to different groups, including Cycliophora, Bryozoa, Annelida, and Mollusca. The use of modern methods to study the neuroanatomy of Entoprocta should provide new information that may be useful for phylogenetic analysis. RESULTS The anatomy of the nervous system in the colonial Barentsia discreta was studied using immunocytochemistry and transmission electron microscopy. The ganglion gives rise to several main nerves: paired lateral, aboral, and arcuate nerves, and three pairs of tentacular cords that branch out into tentacular nerves. The serotonergic nervous system includes paired esophageal perikarya and two large peripheral perikarya, each with a complex net of neurites. Each tentacle is innervated by one abfrontal and two laterofrontal neurite bundles. Sensory cells occur regularly along the abfrontal side of each tentacle. Star-like nerve cells are scattered in the epidermis of the calyx. The stalk is innervated by paired stalk nerves. CONCLUSIONS The neuroanatomy of the colonial Barentsia discreta is generally similar to that of solitary entoprocts but differs in the anatomy and ultrastructure of the ganglion, the number of neurite bundles in the calyx, and the distribution of serotonin in the nerve elements. A comparison of the organization of the nervous system in the Entoprocta and Bryozoa reveals many differences in tentacle innervations, which may indicate that these groups may not be closely related. Our results can not support with any certainty the homology of nervous system elements in adult entoprocts and adult "basal mollusks".
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Affiliation(s)
- Anastasia O. Borisanova
- Biological Faculty, Dept. Invertebrate Zoology, Moscow State University, Leninskie Gory, 1-12, 119991 Moscow, Russia
| | - Vladimir V. Malakhov
- Biological Faculty, Dept. Invertebrate Zoology, Moscow State University, Leninskie Gory, 1-12, 119991 Moscow, Russia
- Far Eastern Federal University, 690600 Vladivostok, Russia
| | - Elena N. Temereva
- Biological Faculty, Dept. Invertebrate Zoology, Moscow State University, Leninskie Gory, 1-12, 119991 Moscow, Russia
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Ma J, Huo X, Jarpe MB, Kavelaars A, Heijnen CJ. Pharmacological inhibition of HDAC6 reverses cognitive impairment and tau pathology as a result of cisplatin treatment. Acta Neuropathol Commun 2018; 6:103. [PMID: 30270813 PMCID: PMC6166273 DOI: 10.1186/s40478-018-0604-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 09/21/2018] [Indexed: 12/22/2022] Open
Abstract
Chemotherapy-induced cognitive impairment (CICI) is a commonly reported neurotoxic side effect of chemotherapy, occurring in up to 75% cancer patients. CICI manifests as decrements in working memory, executive functioning, attention, and processing speed, and greatly interferes with patients’ daily performance and quality of life. Currently no treatment for CICI has been approved by the US Food and Drug Administration. We show here that treatment with a brain-penetrating histone deacetylase 6 (HDAC6) inhibitor for two weeks was sufficient to fully reverse cisplatin-induced cognitive impairments in male mice, as demonstrated in the Y-maze test of spontaneous alternation, the novel object/place recognition test, and the puzzle box test. Normalization of cognitive impairment was associated with reversal of cisplatin-induced synaptosomal mitochondrial deficits and restoration of synaptic integrity. Mechanistically, cisplatin induced deacetylation of the microtubule protein α-tubulin and hyperphosphorylation of the microtubule-associated protein tau. These cisplatin-induced changes were reversed by HDAC6 inhibition. Our data suggest that inhibition of HDAC6 restores microtubule stability and reverses tau phosphorylation, leading to normalization of synaptosomal mitochondrial function and synaptic integrity and thereby to reversal of CICI. Remarkably, our results indicate that short-term daily treatment with the HDAC6 inhibitor was sufficient to achieve prolonged reversal of established behavioral, structural and functional deficits induced by cisplatin. Because the beneficial effects of HDAC6 inhibitors as add-ons to cancer treatment have been demonstrated in clinical trials, selective targeting of HDAC6 with brain-penetrating inhibitors appears a promising therapeutic approach for reversing chemotherapy-induced neurotoxicity while enhancing tumor control.
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Kallergi G, Aggouraki D, Zacharopoulou N, Stournaras C, Georgoulias V, Martin SS. Evaluation of α-tubulin, detyrosinated α-tubulin, and vimentin in CTCs: identification of the interaction between CTCs and blood cells through cytoskeletal elements. Breast Cancer Res 2018; 20:67. [PMID: 29976237 PMCID: PMC6034292 DOI: 10.1186/s13058-018-0993-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 05/25/2018] [Indexed: 01/16/2023] Open
Abstract
Background Circulating tumor cells (CTCs) are the major players in the metastatic process. A potential mechanism of cell migration and invasion is the formation of microtentacles in tumor cells. These structures are supported by α-tubulin (TUB), detyrosinated α-tubulin (GLU), and vimentin (VIM). In the current study, we evaluated the expression of those cytoskeletal proteins in CTCs. Methods Forty patients with breast cancer (BC) (16 early and 24 metastatic) were enrolled in the study. CTCs were isolated using the ISET platform and stained with the following combinations of antibodies: pancytokeratin (CK)/VIM/TUB and CK/VIM/GLU. Samples were analyzed with the ARIOL platform and confocal laser scanning microscopy. Results Fluorescence quantification revealed that the ratios CK/TUB, CK/VIM, and CK/GLU were statistically increased in MCF7 compared with more aggressive cell lines (SKBR3 and MDA-MB-231). In addition, all of these ratios were statistically increased in MCF7 cells compared with metastatic BC patients’ CTCs (p = 0.0001, p = 0.0001, and p = 0.003, respectively). Interestingly, intercellular connections among CTCs and between CTCs and blood cells through cytoskeleton bridges were revealed, whereas microtentacles were increased in patients with CTC clusters. These intercellular connections were supported by TUB, VIM, and GLU. Quantification of the examined molecules revealed that the median intensity of TUB, GLU, and VIM was significantly increased in patients with metastatic BC compared with those with early disease (TUB, 62.27 vs 11.5, p = 0.0001; GLU, 6.99 vs 5.29, p = 0.029; and VIM, 8.24 vs 5.38, p = 0.0001, respectively). Conclusions CTCs from patients with BC aggregate to each other and to blood cells through cytoskeletal protrusions, supported by VIM, TUB, and GLU. Quantification of these molecules could potentially identify CTCs related to more aggressive disease. Electronic supplementary material The online version of this article (10.1186/s13058-018-0993-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- G Kallergi
- Laboratory of Τumor Cell Biology, School of Medicine, University of Crete, Heraklion, Greece. .,Department of Biochemistry, University of Crete, Greece Medical School, Heraklion, Greece.
| | - D Aggouraki
- Laboratory of Τumor Cell Biology, School of Medicine, University of Crete, Heraklion, Greece
| | - N Zacharopoulou
- Department of Biochemistry, University of Crete, Greece Medical School, Heraklion, Greece
| | - C Stournaras
- Department of Biochemistry, University of Crete, Greece Medical School, Heraklion, Greece
| | - V Georgoulias
- Laboratory of Τumor Cell Biology, School of Medicine, University of Crete, Heraklion, Greece
| | - S S Martin
- Department of Physiology, Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD, USA
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Nekooki-Machida Y, Nakakura T, Nishijima Y, Tanaka H, Arisawa K, Kiuchi Y, Miyashita T, Hagiwara H. Dynamic localization of α-tubulin acetyltransferase ATAT1 through the cell cycle in human fibroblastic KD cells. Med Mol Morphol 2018; 51:217-26. [PMID: 29869029 DOI: 10.1007/s00795-018-0195-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/01/2018] [Indexed: 12/22/2022]
Abstract
Acetylation of α-tubulin is a well-studied posttranscriptional modification, which is mostly catalyzed by α-tubulin N-acetyltransferase (ATAT1). ATAT1 possibly affects various cellular functions related with microtubules, such as intracellular transport, cell motility, cilia formation, and neuronal signaling. Here, we analyzed the subcellular localization of immunolabeled ATAT1 in human fibroblast KD cells through the cell cycle using confocal laser scanning microscopy. ATAT1 dramatically changed its localization through the cell cycle, depending on the mitotic phase. In interphase, immunolabeled ATAT1 was observed in centrioles, nuclei, and basal bodies if the cells projected primary cilia. ATAT1 was intensely detected as clusters in the nuclei in the G1-G2 phase. In telophase, ATAT1 colocalized with chromatids and spindle poles, and ultimately migrated to the daughter nucleus, newly synthesized centrioles, and midbody. The nucleolus is a core region of ribosomal RNA transcription, and the midbody is associated with severing and depolymerizing of microtubules in the stembody. The specific distributions of ATAT1 through the cell cycle suggest multiple functions of ATAT1, which could include acetylation of microtubules, RNA transcription activity, severing microtubules, and completion of cytokinesis.
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Kupferschmid M, Aquino-Gil MO, Shams-Eldin H, Schmidt J, Yamakawa N, Krzewinski F, Schwarz RT, Lefebvre T. Identification of O-GlcNAcylated proteins in Plasmodium falciparum. Malar J 2017; 16:485. [PMID: 29187233 PMCID: PMC5707832 DOI: 10.1186/s12936-017-2131-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/23/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Post-translational modifications (PTMs) constitute a huge group of chemical modifications increasing the complexity of the proteomes of living beings. PTMs have been discussed as potential anti-malarial drug targets due to their involvement in many cell processes. O-GlcNAcylation is a widespread PTM found in different organisms including Plasmodium falciparum. The aim of this study was to identify O-GlcNAcylated proteins of P. falciparum, to learn more about the modification process and to understand its eventual functions in the Apicomplexans. METHODS The P. falciparum strain 3D7 was amplified in erythrocytes and purified. The proteome was checked for O-GlcNAcylation using different methods. The level of UDP-GlcNAc, the donor of the sugar moiety for O-GlcNAcylation processes, was measured using high-pH anion exchange chromatography. O-GlcNAcylated proteins were enriched and purified utilizing either click chemistry labelling or adsorption on succinyl-wheat germ agglutinin beads. Proteins were then identified by mass-spectrometry (nano-LC MS/MS). RESULTS While low when compared to MRC5 control cells, P. falciparum disposes of its own pool of UDP-GlcNAc. By using proteomics methods, 13 O-GlcNAcylated proteins were unambiguously identified (11 by click-chemistry and 6 by sWGA-beads enrichment; 4 being identified by the 2 approaches) in late trophozoites. These proteins are all part of pathways, functions and structures important for the parasite survival. By probing clicked-proteins with specific antibodies, Hsp70 and α-tubulin were identified as P. falciparum O-GlcNAc-bearing proteins. CONCLUSIONS This study is the first report on the identity of P. falciparum O-GlcNAcylated proteins. While the parasite O-GlcNAcome seems close to those of other species, the structural differences exhibited by the proteomes provides a glimpse of innovative therapeutic paths to fight malaria. Blocking biosynthesis of UDP-GlcNAc in the parasites is another promising option to reduce Plasmodium life cycle.
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Affiliation(s)
- Mattis Kupferschmid
- Institute for Virology, Laboratory of Parasitology, Philipps-University, Marburg, Germany
| | - Moyira Osny Aquino-Gil
- Univ. Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, 59000, Lille, France.,Instituto Tecnológico de Oaxaca, Tecnológico Nacional de México, Oaxaca, Mexico.,Centro de Investigación UNAM-UABJO, Universidad Autónoma Benito Juárez de Oaxaca, Oaxaca, Mexico
| | - Hosam Shams-Eldin
- Institute for Virology, Laboratory of Parasitology, Philipps-University, Marburg, Germany
| | - Jörg Schmidt
- Institute for Virology, Laboratory of Parasitology, Philipps-University, Marburg, Germany
| | - Nao Yamakawa
- Univ. Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, 59000, Lille, France
| | - Frédéric Krzewinski
- Univ. Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, 59000, Lille, France
| | - Ralph T Schwarz
- Institute for Virology, Laboratory of Parasitology, Philipps-University, Marburg, Germany.,Univ. Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, 59000, Lille, France
| | - Tony Lefebvre
- Univ. Lille, CNRS, UMR 8576, UGSF, Unité de Glycobiologie Structurale et Fonctionnelle, 59000, Lille, France.
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Kováčiková M, Simdyanov TG, Diakin A, Valigurová A. Structures related to attachment and motility in the marine eugregarine Cephaloidophora cf. communis (Apicomplexa). Eur J Protistol 2017; 59:1-13. [PMID: 28363137 DOI: 10.1016/j.ejop.2017.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/07/2017] [Accepted: 02/28/2017] [Indexed: 11/26/2022]
Abstract
Gregarines represent a highly diversified group of ancestral apicomplexans, with various modes of locomotion and host-parasite interactions. The eugregarine parasite of the barnacle Balanus balanus, Cephaloidophora cf. communis, exhibits interesting organisation of its attachment apparatus along with unique motility modes. The pellicle covered gregarine is arranged into longitudinal epicytic folds. The epimerite is separated from the protomerite by a septum consisting of tubulin-rich filamentous structures and both are packed with microneme-like structures suggestive of their function in the production of adhesives important for attachment and secreted through the abundant epimerite pores. Detached trophozoites and gamonts are capable of gliding motility, enriched by jumping and rotational movements with rapid changes in gliding direction and cell flexions. Actin in its polymerised form (F-actin) is distributed throughout the entire gregarine, while myosin, detected in the cortical region of the cell, follows the pattern of the epicytic folds. Various motility modes exhibited by individuals of C. cf. communis, together with significant changes in their cell shape during locomotion, are not concordant with the gliding mechanisms generally described in apicomplexan zoites and indicate that additional structures must be involved (e.g. two 12-nm filaments; the specific dentate appearance of internal lamina inside the epicytic folds).
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Affiliation(s)
- Magdaléna Kováčiková
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
| | - Timur G Simdyanov
- Department of Invertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory 1-12, Moscow 119234, Russian Federation
| | - Andrei Diakin
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Andrea Valigurová
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
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Che JX, Shi JL, Lu Y, Liu YL. Validation of reference genes for normalization of gene expression by qRT-PCR in a resveratrol-producing entophytic fungus (Alternaria sp. MG1). AMB Express 2016; 6:106. [PMID: 27826948 PMCID: PMC5101243 DOI: 10.1186/s13568-016-0283-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 10/31/2016] [Indexed: 12/12/2022] Open
Abstract
Alternaria sp. MG1, an endophytic fungus isolated from Vitis vinifera, can independently produce resveratrol, indicating that this species contains the key genes for resveratrol biosynthesis. Identification of these key genes is essential to understand the resveratrol biosynthesis pathway in this strain, which is currently unknown in microorganisms. qRT-PCR is an efficient and widely used method to identify the key genes related to unknown pathways at the level of gene expression. Verification of stable reference genes in this strain is essential for qRT-PCR data normalization, although results have been reported for other Alternaria sp. strains. In this study, nine candidate reference genes including TUBA, EF1, EF2, UBC, UFD, RPS5, RPS24, ACTB and 18S were evaluated for expression stability in a diverse set of six samples representing different growth periods. We compared cell culture conditions and an optimized condition for resveratrol production. The comparison of the results was performed using four statistical softwares. A combination of TUBA and EF1 was found to be suitable for normalization of Alternaria sp. MG1 in different developmental stages, and 18S was found to be the least stable. The reference genes verified in this study will facilitate further research to explore gene expression and molecular mechanisms as well as the improvement of secondary metabolite yields in Alternaria sp. MG1. To our knowledge, this is the first validation of reference genes in Alternaria with the capability to produce resveratrol. Additionally, these results provide useful guidelines for the selection of reference genes in other Alternaria species.
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Fortes MAS, Marzuca-Nassr GN, Vitzel KF, da Justa Pinheiro CH, Newsholme P, Curi R. Housekeeping proteins: How useful are they in skeletal muscle diabetes studies and muscle hypertrophy models? Anal Biochem 2016; 504:38-40. [PMID: 27060530 DOI: 10.1016/j.ab.2016.03.023] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/28/2016] [Accepted: 03/29/2016] [Indexed: 12/15/2022]
Abstract
The use of Western blot analysis is of great importance in research, and the measurement of housekeeping proteins is commonly used for loading controls. However, Ponceau S staining has been shown to be an alternative to analysis of housekeeping protein levels as loading controls in some conditions. In the current study, housekeeping protein levels were measured in skeletal muscle hypertrophy and streptozotocin-induced diabetes experimental models. The following housekeeping proteins were investigated: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-actin, α-tubulin, γ-tubulin, and α-actinin. Evidence is presented that Ponceau S is more reliable than housekeeping protein levels for specific protein quantifications in Western blot analysis.
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Affiliation(s)
- Marco Aurélio Salomão Fortes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Butantã, São Paulo 05508-900, Brazil.
| | - Gabriel Nasri Marzuca-Nassr
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Butantã, São Paulo 05508-900, Brazil
| | - Kaio Fernando Vitzel
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Butantã, São Paulo 05508-900, Brazil
| | - Carlos Hermano da Justa Pinheiro
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Butantã, São Paulo 05508-900, Brazil
| | - Philip Newsholme
- School of Biomedical Sciences, Curtin Health Innovation Research Institute (CHIRI) Biosciences, Curtin University, Bentley, Perth, Western Australia 6102, Australia
| | - Rui Curi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Butantã, São Paulo 05508-900, Brazil
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Kozlov MV, Kleymenova AA, Romanova LI, Konduktorov KA, Kamarova KA, Smirnova OA, Prassolov VS, Kochetkov SN. Pyridine hydroxamic acids are specific anti-HCV agents affecting HDAC6. Bioorg Med Chem Lett 2015; 25:2382-5. [PMID: 25937017 DOI: 10.1016/j.bmcl.2015.04.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 04/02/2015] [Accepted: 04/04/2015] [Indexed: 11/30/2022]
Abstract
Recently we reported benzohydroxamic acids (BHAs) as potent and selective inhibitors of hepatitis C virus (HCV) replicon propagation. In this work 12 pyridine hydroxamic acids (PHAs) were synthesized and tested in full-genome replicon assay. It was found that PHAs possessed very similar anti-HCV properties compared to BHAs. Both classes of hydroxamic acids caused hyperacetylation of α-tubulin pointing to inhibition of histone deacetylase 6 (HDAC6) as part of their antiviral activity. The tested compounds did not inhibit the growth of poliovirus, displaying high selectivity against HCV.
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Affiliation(s)
- Maxim V Kozlov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia.
| | - Alla A Kleymenova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia
| | - Lyudmila I Romanova
- Chumakov Institute of Poliomyelitis, Russian Academy of Medical Sciences, 142782 Moscow Region, Russia
| | - Konstantin A Konduktorov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia
| | - Kamila A Kamarova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia
| | - Olga A Smirnova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia
| | - Vladimir S Prassolov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia
| | - Sergey N Kochetkov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia
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Fernandes S, Salta S, Summavielle T. Methamphetamine promotes α-tubulin deacetylation in endothelial cells: the protective role of acetyl-l-carnitine. Toxicol Lett 2015; 234:131-8. [PMID: 25703822 DOI: 10.1016/j.toxlet.2015.02.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 11/15/2022]
Abstract
Methamphetamine (METH) is a powerful psychostimulant drug used worldwide for its reinforcing properties. In addition to the classic long-lasting monoaminergic-disrupting effects extensively described in the literature, METH has been consistently reported to increase blood brain barrier (BBB) permeability, both in vivo and in vitro, as a result of tight junction and cytoskeleton disarrangement. Microtubules play a critical role in cell stability, which relies on post-translational modifications such as α-tubulin acetylation. As there is evidence that psychostimulants drugs modulate the expression of histone deacetylases (HDACs), we hypothesized that in endothelial cells METH-mediation of cytoplasmatic HDAC6 activity could affect tubulin acetylation and further contribute to BBB dysfunction. To validate our hypothesis, we exposed the bEnd.3 endothelial cells to increasing doses of METH and verified that it leads to an extensive α-tubulin deacetylation mediated by HDACs activation. Furthermore, since we recently reported that acetyl-l-carnitine (ALC), a natural occurring compound, prevents BBB structural loss in a context of METH exposure, we reasoned that ALC could also preserve the acetylation of microtubules under METH action. The present results confirm that ALC is able to prevent METH-induced deacetylation providing effective protection on microtubule acetylation. Although further investigation is still needed, HDACs regulation may become a new therapeutic target for ALC.
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Affiliation(s)
- S Fernandes
- Rua Alfredo Allen, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Rua do Campo Alegre, 823, Addiction Biology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4150-180 Porto, Portugal; Rua Valente Perfeito, 322, School of Allied Health Sciences - Polytechnic Institute of Porto (ESTSP-IPP), 4400-330 Vila Nova de Gaia, Portugal; Alameda Prof. Hernâni Monteiro, Faculdade de Medicina da Universidade do Porto (FMUP), 4200-319 Porto, Portugal.
| | - S Salta
- Rua Alfredo Allen, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Rua do Campo Alegre, 823, Addiction Biology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4150-180 Porto, Portugal; Rua Valente Perfeito, 322, School of Allied Health Sciences - Polytechnic Institute of Porto (ESTSP-IPP), 4400-330 Vila Nova de Gaia, Portugal.
| | - T Summavielle
- Rua Alfredo Allen, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; Rua do Campo Alegre, 823, Addiction Biology Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4150-180 Porto, Portugal; Rua Valente Perfeito, 322, School of Allied Health Sciences - Polytechnic Institute of Porto (ESTSP-IPP), 4400-330 Vila Nova de Gaia, Portugal.
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Liu X, Xiao W, Wang XD, Li YF, Han J, Li Y. The p38-interacting protein (p38IP) regulates G2/M progression by promoting α-tubulin acetylation via inhibiting ubiquitination-induced degradation of the acetyltransferase GCN5. J Biol Chem 2013; 288:36648-61. [PMID: 24220028 DOI: 10.1074/jbc.m113.486910] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
p38-interacting protein (p38IP) is a component of the GCN5 histone acetyltransferase-containing coactivator complex (GCN5-SAGA complex). It remains unclear whether p38IP or GCN5-SAGA is involved in cell cycle regulation. Using RNA interference to knock down p38IP, we observed that cells were arrested at the G2/M phase, exhibiting accumulation of cyclins, shrunken spindles, and hypoacetylation of α-tubulin. Further analysis revealed that knockdown of p38IP led to proteasome-dependent degradation of GCN5. GCN5 associated with and acetylated α-tubulin, and recovering GCN5 protein levels in p38IP knockdown cells by ectopic expression of GCN5 efficiently reversed α-tubulin hypoacetylation and G2/M arrest. During the G2/M transition, the association of α-tubulin with GCN5 increased, and the acetylation of α-tubulin reached a peak. Biochemical analyses demonstrated that the interaction between p38IP and GCN5 depended on the p38IP N terminus (1-381 amino acids) and GCN5 histone acetyltransferase domain and bromodomain. The p38IP N terminus could effectively reverse p38IP depletion-induced GCN5 degradation, thus recovering α-tubulin acetylation and G2/M progression. p38IP-mediated suppression of GCN5 ubiquitination most likely occurs via nuclear sequestration of GCN5. Our data indicate that the GCN5-SAGA complex is required for G2/M progression, mainly because p38IP promotes the acetylation of α-tubulin by preventing the degradation of GCN5, in turn facilitating the formation of the mitotic spindle.
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Affiliation(s)
- Xin Liu
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275 and
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