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Wilson SM, Moutal A, Melemedjian OK, Wang Y, Ju W, François-Moutal L, Khanna M, Khanna R. The functionalized amino acid (S)-Lacosamide subverts CRMP2-mediated tubulin polymerization to prevent constitutive and activity-dependent increase in neurite outgrowth. Front Cell Neurosci 2014; 8:196. [PMID: 25104922 PMCID: PMC4109617 DOI: 10.3389/fncel.2014.00196] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 06/26/2014] [Indexed: 01/18/2023] Open
Abstract
Activity-dependent neurite outgrowth is a highly complex, regulated process with important implications for neuronal circuit remodeling in development as well as in seizure-induced sprouting in epilepsy. Recent work has linked outgrowth to collapsin response mediator protein 2 (CRMP2), an intracellular phosphoprotein originally identified as axon guidance and growth cone collapse protein. The neurite outgrowth promoting function of CRMP2 is regulated by its phosphorylation state. In this study, depolarization (potassium chloride)-driven activity increased the level of active CRMP2 by decreasing its phosphorylation by GSK3β via a reduction in priming by Cdk5. To determine the contribution of CRMP2 in activity-driven neurite outgrowth, we screened a limited set of compounds for their ability to reduce neurite outgrowth but not modify voltage-gated sodium channel (VGSC) biophysical properties. This led to the identification of (S)-lacosamide ((S)-LCM), a stereoisomer of the clinically used antiepileptic drug (R)-LCM (Vimpat®), as a novel tool for preferentially targeting CRMP2-mediated neurite outgrowth. Whereas (S)-LCM was ineffective in targeting VGSCs, the presumptive pharmacological targets of (R)-LCM, (S)-LCM was more efficient than (R)-LCM in subverting neurite outgrowth. Biomolecular interaction analyses revealed that (S)-LCM bound to wildtype CRMP2 with low micromolar affinity, similar to (R)-LCM. Through the use of this novel tool, the activity-dependent increase in neurite outgrowth observed following depolarization was characterized to be reliant on CRMP2 function. Knockdown of CRMP2 by siRNA in cortical neurons resulted in reduced CRMP2-dependent neurite outgrowth; incubation with (S)-LCM phenocopied this effect. Other CRMP2-mediated processes were unaffected. (S)-LCM subverted neurite outgrowth not by affecting the canonical CRMP2-tubulin association but rather by impairing the ability of CRMP2 to promote tubulin polymerization, events that are perfunctory for neurite outgrowth. Taken together, these results suggest that changes in the phosphorylation state of CRMP2 are a major contributing factor in activity-dependent regulation of neurite outgrowth.
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Affiliation(s)
- Sarah M Wilson
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA
| | - Ohannes K Melemedjian
- Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA
| | - Yuying Wang
- Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA
| | - Weina Ju
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA ; Department of Neurology, The First Hospital of Jilin University, and Jilin University Jilin, China
| | | | - May Khanna
- Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA
| | - Rajesh Khanna
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA ; Department of Pharmacology, College of Medicine, University of Arizona Tucson, AZ, USA ; Neuroscience Graduate Interdisciplinary Program, College of Medicine, University of Arizona Tucson, AZ, USA
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de Thonel A, Ferraris SE, Pallari HM, Imanishi SY, Kochin V, Hosokawa T, Hisanaga SI, Sahlgren C, Eriksson JE. Protein kinase Czeta regulates Cdk5/p25 signaling during myogenesis. Mol Biol Cell 2010; 21:1423-34. [PMID: 20200223 PMCID: PMC2854099 DOI: 10.1091/mbc.e09-10-0847] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Atypical protein kinase Cζ (PKCζ) is emerging as a mediator of differentiation. Here, we describe a critical role for PKCζ during myogenic differentiation. Our results identify PKCζ as a controller of myogenic differentiation by its regulation of Cdk5. Atypical protein kinase Cζ (PKCζ) is emerging as a mediator of differentiation. Here, we describe a novel role for PKCζ in myogenic differentiation, demonstrating that PKCζ activity is indispensable for differentiation of both C2C12 and mouse primary myoblasts. PKCζ was found to be associated with and to regulate the Cdk5/p35 signaling complex, an essential factor for both neuronal and myogenic differentiation. Inhibition of PKCζ activity prevented both myotube formation and simultaneous reorganization of the nestin intermediate filament cytoskeleton, which is known to be regulated by Cdk5 during myogenesis. p35, the Cdk5 activator, was shown to be a specific phosphorylation target of PKCζ. PKCζ-mediated phosphorylation of Ser-33 on p35 promoted calpain-mediated cleavage of p35 to its more active and stable fragment, p25. Strikingly, both calpain activation and the calpain-mediated cleavage of p35 were shown to be PKCζ-dependent in differentiating myoblasts. Overall, our results identify PKCζ as a controller of myogenic differentiation by its regulation of the phosphorylation-dependent and calpain-mediated p35 cleavage, which is crucial for the amplification of the Cdk5 activity that is required during differentiation.
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Affiliation(s)
- Aurélie de Thonel
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, 20521 Turku, Finland
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Striatal dysregulation of Cdk5 alters locomotor responses to cocaine, motor learning, and dendritic morphology. Proc Natl Acad Sci U S A 2008; 105:18561-6. [PMID: 19017804 PMCID: PMC2587606 DOI: 10.1073/pnas.0806078105] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Motor learning and neuro-adaptations to drugs of abuse rely upon neuronal signaling in the striatum. Cyclin-dependent kinase 5 (Cdk5) regulates striatal dopamine neurotransmission and behavioral responses to cocaine. Although the role for Cdk5 in neurodegeneration in the cortex and hippocampus and in hippocampal-dependent learning has been demonstrated, its dysregulation in the striatum has not been examined. Here we show that strong activation of striatal NMDA receptors produced p25, the truncated form of the Cdk5 co-activator p35. Furthermore, inducible overexpression of p25 in the striatum prevented locomotor sensitization to cocaine and attenuated motor coordination and learning. This corresponded with reduced dendritic spine density, increased neuro-inflammation, altered dopamine signaling, and shifted Cdk5 specificity with regard to physiological and aberrant substrates, but no apparent loss of striatal neurons. Thus, dysregulation of Cdk5 dramatically affects striatal-dependent brain function and may be relevant to non-neurodegenerative disorders involving dopamine neurotransmission.
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