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Thornburg-Suresh EJC, Summers DW. Microtubules, Membranes, and Movement: New Roles for Stathmin-2 in Axon Integrity. J Neurosci Res 2024; 102:e25382. [PMID: 39253877 DOI: 10.1002/jnr.25382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 08/06/2024] [Accepted: 08/27/2024] [Indexed: 09/11/2024]
Abstract
Neurons establish functional connections responsible for how we perceive and react to the world around us. Communication from a neuron to its target cell occurs through a long projection called an axon. Axon distances can exceed 1 m in length in humans and require a dynamic microtubule cytoskeleton for growth during development and maintenance in adulthood. Stathmins are microtubule-associated proteins that function as relays between kinase signaling and microtubule polymerization. In this review, we describe the prolific role of Stathmins in microtubule homeostasis with an emphasis on emerging roles for Stathmin-2 (Stmn2) in axon integrity and neurodegeneration. Stmn2 levels are altered in Amyotrophic Lateral Sclerosis and loss of Stmn2 provokes motor and sensory neuropathies. There is growing potential for employing Stmn2 as a disease biomarker or even a therapeutic target. Meeting this potential requires a mechanistic understanding of emerging complexity in Stmn2 function. In particular, Stmn2 palmitoylation has a surprising contribution to axon maintenance through undefined mechanisms linking membrane association, tubulin interaction, and axon transport. Exploring these connections will reveal new insight on neuronal cell biology and novel opportunities for disease intervention.
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Affiliation(s)
| | - Daniel W Summers
- Department of Biology, University of Iowa, Iowa City, Iowa, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
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2
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Campanacci V, Gigant B. The C-terminus of stathmin-like proteins governs the stability of their complexes with tubulin. Biochem Biophys Res Commun 2023; 682:244-249. [PMID: 37826947 DOI: 10.1016/j.bbrc.2023.10.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/14/2023]
Abstract
Microtubule dynamics is modulated by many cellular factors including stathmin family proteins. Vertebrate stathmins sequester two αβ-tubulin heterodimers into a tight complex that cannot be incorporated in microtubules. Stathmins are regulated at the expression level during development and among tissues; they are also regulated by phosphorylation. Here, we study the dissociation kinetics of tubulin:stathmin assemblies in presence of different tubulin-binding proteins and identify a critical role of the C-terminus of the stathmin partner. Destabilizing this C-terminal region may represent an additional regulatory mechanism of the interaction with tubulin of stathmin proteins.
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Affiliation(s)
- Valérie Campanacci
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Benoît Gigant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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Thornburg-Suresh EJC, Richardson JE, Summers DW. The Stathmin-2 membrane-targeting domain is required for axon protection and regulated degradation by DLK signaling. J Biol Chem 2023; 299:104861. [PMID: 37236359 PMCID: PMC10404615 DOI: 10.1016/j.jbc.2023.104861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/16/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023] Open
Abstract
Axon integrity is essential for functional connectivity in the nervous system. The degeneration of stressed or damaged axons is a common and sometimes initiating event in neurodegenerative disorders. Stathmin-2 (Stmn2) is an axon maintenance factor that is depleted in amyotrophic lateral sclerosis, and replenishment of Stmn2 can restore neurite outgrowth in diseased neurons. However, mechanisms responsible for Stmn2-mediated axon maintenance in injured neurons are not known. We used primary sensory neurons to interrogate the role of Stmn2 in the degeneration of severed axons. We discover that membrane association of Stmn2 is critical for its axon-protective activity. Structure-function studies revealed that axonal enrichment of Stmn2 is driven by palmitoylation as well as tubulin interaction. Using live imaging, we discover that another Stmn, Stmn3, comigrates with Stmn2-containing vesicles. We also demonstrate that Stmn3 undergoes regulated degradation through dual leucine zipper kinase (DLK)-c-Jun N-terminal kinase signaling. The Stmn2 membrane-targeting domain is both necessary and sufficient for localization to a specific vesicle population and confers sensitivity to DLK-dependent degradation. Our findings reveal a broader role for DLK in tuning the local abundance of palmitoylated Stmns in axon segments. Moreover, palmitoylation is a critical component of Stmn-mediated axon protection, and defining the Stmn2-containing vesicle population will provide important clues toward mechanisms of axon maintenance.
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Affiliation(s)
- Emma J C Thornburg-Suresh
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA; Department of Biology, University of Iowa, Iowa City, Iowa, USA
| | | | - Daniel W Summers
- Department of Biology, University of Iowa, Iowa City, Iowa, USA; Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA.
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Benoit B, Baillet A, Poüs C. Cytoskeleton and Associated Proteins: Pleiotropic JNK Substrates and Regulators. Int J Mol Sci 2021; 22:8375. [PMID: 34445080 PMCID: PMC8395060 DOI: 10.3390/ijms22168375] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
This review extensively reports data from the literature concerning the complex relationships between the stress-induced c-Jun N-terminal kinases (JNKs) and the four main cytoskeleton elements, which are actin filaments, microtubules, intermediate filaments, and septins. To a lesser extent, we also focused on the two membrane-associated cytoskeletons spectrin and ESCRT-III. We gather the mechanisms controlling cytoskeleton-associated JNK activation and the known cytoskeleton-related substrates directly phosphorylated by JNK. We also point out specific locations of the JNK upstream regulators at cytoskeletal components. We finally compile available techniques and tools that could allow a better characterization of the interplay between the different types of cytoskeleton filaments upon JNK-mediated stress and during development. This overview may bring new important information for applied medical research.
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Affiliation(s)
- Béatrice Benoit
- Université Paris-Saclay, INSERM UMR-S-1193, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; (A.B.); (C.P.)
| | - Anita Baillet
- Université Paris-Saclay, INSERM UMR-S-1193, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; (A.B.); (C.P.)
| | - Christian Poüs
- Université Paris-Saclay, INSERM UMR-S-1193, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; (A.B.); (C.P.)
- Biochimie-Hormonologie, AP-HP Université Paris-Saclay, Site Antoine Béclère, 157 Rue de la Porte de Trivaux, 92141 Clamart, France
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Carretero-Rodriguez L, Guðjónsdóttir R, Poparic I, Reilly ML, Chol M, Bianco IH, Chiapello M, Feret R, Deery MJ, Guthrie S. The Rac-GAP alpha2-Chimaerin Signals via CRMP2 and Stathmins in the Development of the Ocular Motor System. J Neurosci 2021; 41:6652-6672. [PMID: 34168008 PMCID: PMC8336708 DOI: 10.1523/jneurosci.0983-19.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
A precise sequence of axon guidance events is required for the development of the ocular motor system. Three cranial nerves grow toward, and connect with, six extraocular muscles in a stereotyped pattern, to control eye movements. The signaling protein alpha2-chimaerin (α2-CHN) plays a pivotal role in the formation of the ocular motor system; mutations in CHN1, encoding α2-CHN, cause the human eye movement disorder Duane Retraction Syndrome (DRS). Our research has demonstrated that the manipulation of α2-chn signaling in the zebrafish embryo leads to ocular motor axon wiring defects, although the signaling cascades regulated by α2-chn remain poorly understood. Here, we demonstrate that several cytoskeletal regulatory proteins-collapsin response mediator protein 2 (CRMP2; encoded by the gene dpysl2), stathmin1, and stathmin 2-bind to α2-CHN. dpysl2, stathmin1, and especially stathmin2 are expressed by ocular motor neurons. We find that the manipulation of dpysl2 and of stathmins in zebrafish larvae leads to defects in both the axon wiring of the ocular motor system and the optokinetic reflex, impairing horizontal eye movements. Knockdowns of these molecules in zebrafish larvae of either sex caused axon guidance phenotypes that included defasciculation and ectopic branching; in some cases, these phenotypes were reminiscent of DRS. chn1 knock-down phenotypes were rescued by the overexpression of CRMP2 and STMN1, suggesting that these proteins act in the same signaling pathway. These findings suggest that CRMP2 and stathmins signal downstream of α2-CHN to orchestrate ocular motor axon guidance and to control eye movements.SIGNIFICANCE STATEMENT The precise control of eye movements is crucial for the life of vertebrate animals, including humans. In humans, this control depends on the arrangement of nerve wiring of the ocular motor system, composed of three nerves and six muscles, a system that is conserved across vertebrate phyla. Mutations in the protein alpha2-chimaerin have previously been shown to cause eye movement disorders (squint) and axon wiring defects in humans. Our recent work has unraveled how alpha2-chimaerin coordinates axon guidance of the ocular motor system in animal models. In this article, we demonstrate key roles for the proteins CRMP2 and stathmin 1/2 in the signaling pathway orchestrated by alpha2-chimaerin, potentially giving insight into the etiology of eye movement disorders in humans.
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Affiliation(s)
| | | | - Ivana Poparic
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, United Kingdom
| | | | - Mary Chol
- Department of Developmental Neurobiology, King's College London, London SE1 1UL, United Kingdom
| | - Isaac H Bianco
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Marco Chiapello
- Cambridge Centre for Proteomics, Cambridge Systems Biology Centre, Department of Biochemistry, University of Cambridge, Cambridge CB2 1QR, United Kingdom
| | - Renata Feret
- Institute for Sustainable Plant Protection, National Research Council, 10135 Torino, Italy
| | - Michael J Deery
- Institute for Sustainable Plant Protection, National Research Council, 10135 Torino, Italy
| | - Sarah Guthrie
- School of Life Sciences, University of Sussex, Brighton BN7 9QG, United Kingdom
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Systematic Elucidation of the Mechanism of Sappan Lignum in the Treatment of Diabetic Peripheral Neuropathy Based on Network Pharmacology. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:5528018. [PMID: 34306139 PMCID: PMC8263209 DOI: 10.1155/2021/5528018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/06/2021] [Accepted: 06/21/2021] [Indexed: 11/17/2022]
Abstract
Background Diabetic peripheral neuropathy (DPN) is one of the most common chronic complications of diabetes, which seriously affects the physical and mental health of patients. Sappan Lignum (SL) is effective in treating DPN. Previous reports have shown that SL has a clear hypoglycemic and anti-inflammatory effect. However, the study of SL in the treatment of DPN is still limited and rare. Objective To investigate the mechanism of SL in the treatment of DPN based on network pharmacology. Methods The active ingredients of SL were screened by related databases. The compound targets were collected by the target prediction platforms. The DPN-related targets were gathered through disease databases. The intersection targets were obtained by uploading the compound targets and disease targets to Venny 2.1.0, and a compound-target network was constructed by Cytoscape3.7.2. The protein-protein interaction (PPI) relationships were obtained by the STRING11.0 database. Genome Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the DAVID6.8 database. Molecular docking of key compounds and core targets was performed by DockThor. Results A total of 29 compounds and 51 intersection targets with potential therapeutic effects on DPN were obtained. The compound-target network construction resulted in four key compounds: protostemonine, 3-deoxysappanchalcone, 7,3′,4′-trihydroxy-3-benzyl-2H-chromene, and o-12′-methylergocornine. PPI network analysis yielded 10 core targets: AKT1, MAPK3, CXCL8, TNF, OPRM1, MTOR, STAT3, MAPK8, SIRT1, and HSP90AA1. KEGG analysis resulted in 82 signaling pathways (P < 0.05), including insulin resistance, HIF-1 signaling pathway, and type II diabetes. The docking results indicated that the main active compounds could stably bind to core targets. Conclusion SL had the mechanism of multiple ingredients, multiple targets, and multiple pathways in the treatment of DPN. This study provided a scientific basis for further research on the treatment of DPN with SL and its extracts.
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Hoque A, Williamson NA, Ameen SS, Ciccotosto GD, Hossain MI, Oakhill JS, Ng DCH, Ang CS, Cheng HC. Quantitative proteomic analyses of dynamic signalling events in cortical neurons undergoing excitotoxic cell death. Cell Death Dis 2019; 10:213. [PMID: 30824683 PMCID: PMC6397184 DOI: 10.1038/s41419-019-1445-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 01/20/2019] [Accepted: 02/01/2019] [Indexed: 12/23/2022]
Abstract
Excitotoxicity, caused by overstimulation or dysregulation of ionotropic glutamate receptors (iGluRs), is a pathological process directing neuronal death in many neurological disorders. The aberrantly stimulated iGluRs direct massive influx of calcium ions into the affected neurons, leading to changes in expression and phosphorylation of specific proteins to modulate their functions and direct their participation in the signalling pathways that induce excitotoxic neuronal death. To define these pathways, we used quantitative proteomic approaches to identify these neuronal proteins (referred to as the changed proteins) and determine how their expression and/or phosphorylation dynamically changed in association with excitotoxic cell death. Our data, available in ProteomeXchange with identifier PXD008353, identified over 100 changed proteins exhibiting significant alterations in abundance and/or phosphorylation levels at different time points (5–240 min) in neurons after glutamate overstimulation. Bioinformatic analyses predicted that many of them are components of signalling networks directing defective neuronal morphology and functions. Among them, the well-known neuronal survival regulators including mitogen-activated protein kinases Erk1/2, glycogen synthase kinase 3 (GSK3) and microtubule-associated protein (Tau), were selected for validation by biochemical approaches, which confirmed the findings of the proteomic analysis. Bioinformatic analysis predicted Protein Kinase B (Akt), c-Jun kinase (JNK), cyclin-dependent protein kinase 5 (Cdk5), MAP kinase kinase (MEK), Casein kinase 2 (CK2), Rho-activated protein kinase (Rock) and Serum/glucocorticoid-regulated kinase 1 (SGK1) as the potential upstream kinases phosphorylating some of the changed proteins. Further biochemical investigation confirmed the predictions of sustained changes of the activation states of neuronal Akt and CK2 in excitotoxicity. Thus, future investigation to define the signalling pathways directing the dynamic alterations in abundance and phosphorylation of the identified changed neuronal proteins will help elucidate the molecular mechanism of neuronal death in excitotoxicity.
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Affiliation(s)
- Ashfaqul Hoque
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.,Metabolic Signalling Laboratory, St. Vincent's Institute for Medical Research, University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Nicholas A Williamson
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - S Sadia Ameen
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3010, Australia
| | - M Iqbal Hossain
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jonathan S Oakhill
- Metabolic Signalling Laboratory, St. Vincent's Institute for Medical Research, University of Melbourne, Fitzroy, VIC, 3065, Australia.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, 3000, Australia
| | - Dominic C H Ng
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Ching-Seng Ang
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia. .,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia. .,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
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You M, Dong J, Fu Y, Cong Z, Fu H, Wei L, Wang Y, Wang Y, Chen J. Exposure to Di-(2-ethylhexyl) Phthalate During Perinatal Period Gender-Specifically Impairs the Dendritic Growth of Pyramidal Neurons in Rat Offspring. Front Neurosci 2018; 12:444. [PMID: 30087586 PMCID: PMC6066609 DOI: 10.3389/fnins.2018.00444] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/12/2018] [Indexed: 01/09/2023] Open
Abstract
Di-(2-ethylhexyl) phthalate (DEHP), as a prevalent xenoestrogen endocrine disrupter, is omnipresent in the environment and commonly used in polyethylene plastic products. Although DEHP has potential adverse effects on multisystem organs, damage to the central nervous system is more significant. However, the consequences and mechanisms of DEHP exposure remain to be explored. The aim of this study was to investigate the effects and related mechanisms of maternal DEHP exposure on dendritic development of hippocampal pyramidal neurons in a rat model. Pregnant Wistar rats were intragastrically administrated either vehicle or DEHP (30, 300, and 750 mg/kg/d) from gestation day 0 to postnatal day (PN) 21. The dendritic length and complexity of dendritic arbors' pattern in pyramidal neurons of the hippocampus were measured using Golgi-Cox staining and Sholl analysis. The expression of dendritic development-related proteins was detected using western blot and immunofluorescence staining. DEHP-treated male but not female pups showed an obvious decrease in the total length and branching numbers of basal dendrites on PN7, PN14, and PN21. The phosphorylation of MAP2c, stathmin, and JNK1 in the male pup hippocampus was significantly decreased in DEHP treatment groups compared to controls. However, protein expression alteration in the hippocampus of female offspring was not observed. In summary, our study indicated that DEHP has a gender-specific negative impact on the dendritic growth of CA1 pyramidal neurons in male offspring of a rat model of DEHP exposure. The adverse impact may be related to the dysregulation of phosphorylated and total MAP2c and stathmin mediated by JNK1.
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Affiliation(s)
- Mingdan You
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Jing Dong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Yuanyuan Fu
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Zhangzhao Cong
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Hui Fu
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Lingling Wei
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Yi Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Yuan Wang
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
| | - Jie Chen
- Department of Occupational and Environmental Health, School of Public Health, China Medical University, Shenyang, China
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RNAi targeting STMN alleviates the resistance to taxol and collectively contributes to down regulate the malignancy of NSCLC cells in vitro and in vivo. Cell Biol Toxicol 2017; 34:7-21. [DOI: 10.1007/s10565-017-9398-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/04/2017] [Indexed: 02/07/2023]
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The Cdc2/Cdk1 inhibitor, purvalanol A, enhances the cytotoxic effects of taxol through Op18/stathmin in non-small cell lung cancer cells in vitro. Int J Mol Med 2017; 40:235-242. [PMID: 28534969 DOI: 10.3892/ijmm.2017.2989] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 05/03/2017] [Indexed: 11/05/2022] Open
Abstract
Purvalanol A is a highly selective inhibitor of Cdc2 [also known as cyclin-dependent kinase 1 (CDK1)]. Taxol is an anti-tumor chemotherapeutic drug which is widely used clinically. In this study, the CDK1 inhibitor, purvalanol A was applied to explore the relevance of Cdc2 signaling and taxol sensitivity through analyses, such as cellular proliferation and apoptosis assays, ELISA, western blot analysis and immunoprecipitation. We demonstrated that purvalanol A effectively enhanced the taxol-induced apoptosis of NCI-H1299 cells, as well as its inhibitory effects on cellular proliferation and colony formation. In combination, purvalanol A and taxol mainly decreased the expression of oncoprotein 18 (Op18)/stathmin and phosphorylation at Ser16 and Ser38, while purvalanol A alone inhibited the phosphorylation of Op18/stathmin at all 4 serine sites. Co-treatment with purvalanol A and taxol weakened the expression of Bcl-2 and activated the extrinsic cell death pathway through the activation of caspase-3 and caspase-8. Further experiments indicated that Cdc2 kinase activities, including the expression of Cdc2 and the level of phospho-Cdc2 (Thr161) were significantly higher in taxol-resistant NCI-H1299 cells compared with the relatively sensitive CNE1 cells before and following treatment with taxol. These findings suggest that Cdc2 is positively associatd with the development of taxol resistance. The Cdc2 inhibitor, purvalanol A, enhanced the cytotoxic effects of taxol through Op18/stathmin. Our findings may prove to be useful in clinical practice, as they may provide a treatment strategy with which to to reduce the doses of taxol applied clinically, thus alleviating the side-effects.
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JNK Signaling: Regulation and Functions Based on Complex Protein-Protein Partnerships. Microbiol Mol Biol Rev 2016; 80:793-835. [PMID: 27466283 DOI: 10.1128/mmbr.00043-14] [Citation(s) in RCA: 321] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The c-Jun N-terminal kinases (JNKs), as members of the mitogen-activated protein kinase (MAPK) family, mediate eukaryotic cell responses to a wide range of abiotic and biotic stress insults. JNKs also regulate important physiological processes, including neuronal functions, immunological actions, and embryonic development, via their impact on gene expression, cytoskeletal protein dynamics, and cell death/survival pathways. Although the JNK pathway has been under study for >20 years, its complexity is still perplexing, with multiple protein partners of JNKs underlying the diversity of actions. Here we review the current knowledge of JNK structure and isoforms as well as the partnerships of JNKs with a range of intracellular proteins. Many of these proteins are direct substrates of the JNKs. We analyzed almost 100 of these target proteins in detail within a framework of their classification based on their regulation by JNKs. Examples of these JNK substrates include a diverse assortment of nuclear transcription factors (Jun, ATF2, Myc, Elk1), cytoplasmic proteins involved in cytoskeleton regulation (DCX, Tau, WDR62) or vesicular transport (JIP1, JIP3), cell membrane receptors (BMPR2), and mitochondrial proteins (Mcl1, Bim). In addition, because upstream signaling components impact JNK activity, we critically assessed the involvement of signaling scaffolds and the roles of feedback mechanisms in the JNK pathway. Despite a clarification of many regulatory events in JNK-dependent signaling during the past decade, many other structural and mechanistic insights are just beginning to be revealed. These advances open new opportunities to understand the role of JNK signaling in diverse physiological and pathophysiological states.
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Effects of Maternal Marginal Iodine Deficiency on Dendritic Morphology in the Hippocampal CA1 Pyramidal Neurons in Rat Offspring. Neuromolecular Med 2016; 18:203-15. [DOI: 10.1007/s12017-016-8391-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 03/19/2016] [Indexed: 01/05/2023]
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13
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Mahal K, Ahmad A, Sethi S, Resch M, Ficner R, Sarkar FH, Schobert R, Biersack B. Role of JNK and NF-κB in mediating the effect of combretastatin A-4 and brimamin on endothelial and carcinoma cells. Cell Oncol (Dordr) 2015; 38:463-78. [PMID: 26358135 DOI: 10.1007/s13402-015-0243-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2015] [Indexed: 10/23/2022] Open
Abstract
PURPOSE The 4,5-diarylimidazole brimamin is an analog of the natural vascular-disrupting agent combretastatin A-4 (CA-4) with improved water solubility, tolerance by animals and efficacy in multidrug-resistant tumors. Here, we aimed at identifying the major mechanisms underlying the in vitro and in vivo actions of brimamin on endothelial and carcinoma cells, including vascularization. METHODS The contribution of specific signaling kinases to the effects of brimamin on cytoskeleton organization and the viability and differentiation of endothelial cells was assessed by MTT and tube formation assays in the presence or absence of specific kinase inhibitors. Changes in DNA affinity and expression of NF-κB in endothelial and carcinoma-derived cells and their solid tumors (xenografts) treated with brimamin were ascertained by electrophoretic mobility shift assays and Western blotting. The anti-vascular effect of brimamin in solid tumors was verified by CD31 immunostaining. RESULTS We found that brimamin can inhibit tubulin polymerization and cause a reorganization of F-actin in Ea.hy926 endothelial cells. Its inhibitory effect on tube formation was found to depend on functional Rho kinase and JNK. JNK inhibition was found to suppress the induction of endothelial cell apoptosis by brimamin. In CA-4-refractory human BxPC-3 pancreas carcinoma-derived and triple-negative MDA-MB-231 breast carcinoma-derived cells brimamin was found to inhibit growth and to induce apoptosis at low nanomolar concentrations by blocking NF-κB activation in a dose-dependent manner. Brimamin was also found to reduce the in vivo growth rate and vascularization of MDA-MB-231 xenografts in mice. Residual tumor cells of these treated xenografts showed a relatively low expression of the p65 subunit of NF-κB. CONCLUSIONS Our data indicate that cellular JNK and Rho kinase activities are crucial for the cytotoxic and cytoskeleton reorganizing effects of brimamin on endothelial cells. In addition, we found that in resistant carcinoma cells and xenografts brimamin can induce down-regulation of anti-apoptotic NF-κB expression and signaling. Its chemical properties and efficacy against clinically relevant cancer entities make brimamin a promising candidate vascular-disrupting agent.
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Affiliation(s)
- Katharina Mahal
- Organic Chemistry Laboratory, University Bayreuth, Universitaetsstrasse 30, 95440, Bayreuth, Germany
| | - Aamir Ahmad
- Karmanos Cancer Institute, Department of Pathology, Wayne State University School of Medicine, 4100 John R. Street, Detroit, 48201, MI, USA
| | - Seema Sethi
- Karmanos Cancer Institute, Department of Pathology, Wayne State University School of Medicine, 4100 John R. Street, Detroit, 48201, MI, USA
| | - Marcus Resch
- Department of Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Fazlul H Sarkar
- Karmanos Cancer Institute, Department of Pathology, Wayne State University School of Medicine, 4100 John R. Street, Detroit, 48201, MI, USA
| | - Rainer Schobert
- Organic Chemistry Laboratory, University Bayreuth, Universitaetsstrasse 30, 95440, Bayreuth, Germany.
| | - Bernhard Biersack
- Organic Chemistry Laboratory, University Bayreuth, Universitaetsstrasse 30, 95440, Bayreuth, Germany
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Chauvin S, Sobel A. Neuronal stathmins: A family of phosphoproteins cooperating for neuronal development, plasticity and regeneration. Prog Neurobiol 2015; 126:1-18. [DOI: 10.1016/j.pneurobio.2014.09.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/23/2014] [Accepted: 09/29/2014] [Indexed: 02/06/2023]
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