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Liu Q, Yang H, Luo J, Peng C, Wang K, Zhang G, Lin H, Ji Z. 14-3-3 protein augments the protein stability of phosphorylated spastin and promotes the recovery of spinal cord injury through its agonist intervention. eLife 2024; 12:RP90184. [PMID: 38231910 PMCID: PMC10945579 DOI: 10.7554/elife.90184] [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] [Indexed: 01/19/2024] Open
Abstract
Axon regeneration is abortive in the central nervous system following injury. Orchestrating microtubule dynamics has emerged as a promising approach to improve axonal regeneration. The microtubule severing enzyme spastin is essential for axonal development and regeneration through remodeling of microtubule arrangement. To date, however, little is known regarding the mechanisms underlying spastin action in neural regeneration after spinal cord injury. Here, we use glutathione transferase pulldown and immunoprecipitation assays to demonstrate that 14-3-3 interacts with spastin, both in vivo and in vitro, via spastin Ser233 phosphorylation. Moreover, we show that 14-3-3 protects spastin from degradation by inhibiting the ubiquitination pathway and upregulates the spastin-dependent severing ability. Furthermore, the 14-3-3 agonist Fusicoccin (FC-A) promotes neurite outgrowth and regeneration in vitro which needs spastin activation. Western blot and immunofluorescence results revealed that 14-3-3 protein is upregulated in the neuronal compartment after spinal cord injury in vivo. In addition, administration of FC-A not only promotes locomotor recovery, but also nerve regeneration following spinal cord injury in both contusion and lateral hemisection models; however, the application of spastin inhibitor spastazoline successfully reverses these phenomena. Taken together, these results indicate that 14-3-3 is a molecular switch that regulates spastin protein levels, and the small molecule 14-3-3 agonist FC-A effectively mediates the recovery of spinal cord injury in mice which requires spastin participation.
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Affiliation(s)
- Qiuling Liu
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Hua Yang
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Jianxian Luo
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Cheng Peng
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Ke Wang
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Guowei Zhang
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Hongsheng Lin
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Zhisheng Ji
- Department of Orthopedics, The First Affiliated Hospital of Jinan UniversityGuangzhouChina
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p27 Kip1, an Intrinsically Unstructured Protein with Scaffold Properties. Cells 2021; 10:cells10092254. [PMID: 34571903 PMCID: PMC8465030 DOI: 10.3390/cells10092254] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/21/2021] [Accepted: 08/24/2021] [Indexed: 12/27/2022] Open
Abstract
The Cyclin-dependent kinase (CDK) regulator p27Kip1 is a gatekeeper of G1/S transition. It also regulates G2/M progression and cytokinesis completion, via CDK-dependent or -independent mechanisms. Recently, other important p27Kip1 functions have been described, including the regulation of cell motility and migration, the control of cell differentiation program and the activation of apoptosis/autophagy. Several factors modulate p27Kip1 activities, including its level, cellular localization and post-translational modifications. As a matter of fact, the protein is phosphorylated, ubiquitinated, SUMOylated, O-linked N-acetylglicosylated and acetylated on different residues. p27Kip1 belongs to the family of the intrinsically unstructured proteins and thus it is endowed with a large flexibility and numerous interactors, only partially identified. In this review, we look at p27Kip1 properties and ascribe part of its heterogeneous functions to the ability to act as an anchor or scaffold capable to participate in the construction of different platforms for modulating cell response to extracellular signals and allowing adaptation to environmental changes.
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Łysyganicz PK, Pooranachandran N, Liu X, Adamson KI, Zielonka K, Elworthy S, van Eeden FJ, Grierson AJ, Malicki JJ. Loss of Deacetylation Enzymes Hdac6 and Sirt2 Promotes Acetylation of Cytoplasmic Tubulin, but Suppresses Axonemal Acetylation in Zebrafish Cilia. Front Cell Dev Biol 2021; 9:676214. [PMID: 34268305 PMCID: PMC8276265 DOI: 10.3389/fcell.2021.676214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/13/2021] [Indexed: 01/26/2023] Open
Abstract
Cilia are evolutionarily highly conserved organelles with important functions in many organs. The extracellular component of the cilium protruding from the plasma membrane comprises an axoneme composed of microtubule doublets, arranged in a 9 + 0 conformation in primary cilia or 9 + 2 in motile cilia. These microtubules facilitate transport of intraflagellar cargoes along the axoneme. They also provide structural stability to the cilium, which may play an important role in sensory cilia, where signals are received from the movement of extracellular fluid. Post-translational modification of microtubules in cilia is a well-studied phenomenon, and acetylation on lysine 40 (K40) of alpha tubulin is prominent in cilia. It is believed that this modification contributes to the stabilization of cilia. Two classes of enzymes, histone acetyltransferases and histone deacetylases, mediate regulation of tubulin acetylation. Here we use a genetic approach, immunocytochemistry and behavioral tests to investigate the function of tubulin deacetylases in cilia in a zebrafish model. By mutating three histone deacetylase genes (Sirt2, Hdac6, and Hdac10), we identify an unforeseen role for Hdac6 and Sirt2 in cilia. As expected, mutation of these genes leads to increased acetylation of cytoplasmic tubulin, however, surprisingly it caused decreased tubulin acetylation in cilia in the developing eye, ear, brain and kidney. Cilia in the ear and eye showed elevated levels of mono-glycylated tubulin suggesting a compensatory mechanism. These changes did not affect the length or morphology of cilia, however, functional defects in balance was observed, suggesting that the level of tubulin acetylation may affect function of the cilium.
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Affiliation(s)
- Paweł K Łysyganicz
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | | | - Xinming Liu
- The School of Clinical Dentistry, The University of Sheffield, Sheffield, United Kingdom
| | - Kathryn I Adamson
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Katarzyna Zielonka
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Stone Elworthy
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Fredericus J van Eeden
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Andrew J Grierson
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Jarema J Malicki
- The Bateson Centre, The University of Sheffield, Sheffield, United Kingdom.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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Baker L, Tar M, Kramer AH, Villegas GA, Charafeddine RA, Vafaeva O, Nacharaju P, Friedman J, Davies KP, Sharp DJ. Fidgetin-like 2 negatively regulates axonal growth and can be targeted to promote functional nerve regeneration. JCI Insight 2021; 6:138484. [PMID: 33872220 PMCID: PMC8262307 DOI: 10.1172/jci.insight.138484] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 04/01/2021] [Indexed: 02/05/2023] Open
Abstract
The microtubule (MT) cytoskeleton plays a critical role in axon growth and guidance. Here, we identify the MT-severing enzyme fidgetin-like 2 (FL2) as a negative regulator of axon regeneration and a therapeutic target for promoting nerve regeneration after injury. Genetic knockout of FL2 in cultured adult dorsal root ganglion neurons resulted in longer axons and attenuated growth cone retraction in response to inhibitory molecules. Given the axonal growth-promoting effects of FL2 depletion in vitro, we tested whether FL2 could be targeted to promote regeneration in a rodent model of cavernous nerve (CN) injury. The CNs are parasympathetic nerves that regulate blood flow to the penis, which are commonly damaged during radical prostatectomy (RP), resulting in erectile dysfunction (ED). Application of FL2-siRNA after CN injury significantly enhanced functional nerve recovery. Remarkably, following bilateral nerve transection, visible and functional nerve regeneration was observed in 7 out of 8 animals treated with FL2-siRNA, while no control-treated animals exhibited regeneration. These studies identify FL2 as a promising therapeutic target for enhancing regeneration after peripheral nerve injury and for mitigating neurogenic ED after RP - a condition for which, at present, only poor treatment options exist.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - David J. Sharp
- Department of Physiology and Biophysics
- Dominick P. Purpura Department of Neuroscience, and
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
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Kormendi V, Szyk A, Piszczek G, Roll-Mecak A. Crystal structures of tubulin acetyltransferase reveal a conserved catalytic core and the plasticity of the essential N terminus. J Biol Chem 2012; 287:41569-75. [PMID: 23105108 DOI: 10.1074/jbc.c112.421222] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tubulin acetyltransferase (TAT) acetylates Lys-40 of α-tubulin in the microtubule lumen. TAT is inefficient, and its activity is enhanced when tubulin is incorporated in microtubules. Acetylation is associated with stable microtubules and regulates the binding of microtubule motors and associated proteins. TAT is important in neuronal polarity and mechanosensation, and decreased tubulin acetylation levels are associated with axonal transport defects and neurodegeneration. We present the first structure of TAT in complex with acetyl-CoA (Ac-CoA) at 2.7 Å resolution. The structure reveals a conserved stable catalytic core shared with other GCN5 superfamily acetyltransferases consisting of a central β-sheet flanked by α-helices and a C-terminal β-hairpin unique to TAT. Structure-guided mutagenesis establishes the molecular determinants for Ac-CoA and tubulin substrate recognition. The wild-type TAT construct is a monomer in solution. We identify a metastable interface between the conserved core and N-terminal domain that modulates the oligomerization of TAT in solution and is essential for activity. The 2.45 Å resolution structure of an inactive TAT construct with an active site point mutation near this interface reveals a domain-swapped dimer in which the functionally essential N terminus shows evidence of marked structural plasticity. The sequence segment corresponding to this structurally plastic region in TAT has been implicated in substrate recognition in other GCN5 superfamily acetyltransferases. Our structures provide a rational platform for the mechanistic dissection of TAT activity and the design of TAT inhibitors with therapeutic potential in neuronal regeneration.
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Affiliation(s)
- Vasilisa Kormendi
- Cell Biology and Biophysics Unit, NINDS, National Institutes of Health, Bethesda, Maryland 20892, USA
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