GSK-3[beta] Regulates Phosphorylation of CRMP-2 and Neuronal Polarity

Department of Cell Pharmacology, Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa-ku, Nagoya, Aichi 466-8550, Japan.
Cell (Impact Factor: 32.24). 02/2005; 120(1):137-49. DOI: 10.1016/j.cell.2004.11.012
Source: PubMed

ABSTRACT Neurons are highly polarized and comprised of two structurally and functionally distinct parts, an axon and dendrites. We previously showed that collapsin response mediator protein-2 (CRMP-2) is critical for specifying axon/dendrite fate, possibly by promoting neurite elongation via microtubule assembly. Here, we showed that glycogen synthase kinase-3beta (GSK-3beta) phosphorylated CRMP-2 at Thr-514 and inactivated it. The expression of the nonphosphorylated form of CRMP-2 or inhibition of GSK-3beta induced the formation of multiple axon-like neurites in hippocampal neurons. The expression of constitutively active GSK-3beta impaired neuronal polarization, whereas the nonphosphorylated form of CRMP-2 counteracted the inhibitory effects of GSK-3beta, indicating that GSK-3beta regulates neuronal polarity through the phosphorylation of CRMP-2. Treatment of hippocampal neurons with neurotrophin-3 (NT-3) induced inactivation of GSK-3beta and dephosphorylation of CRMP-2. Knockdown of CRMP-2 inhibited NT-3-induced axon outgrowth. These results suggest that NT-3 decreases phosphorylated CRMP-2 and increases nonphosphorylated active CRMP-2, thereby promoting axon outgrowth.

Download full-text


Available from: Kozo Kaibuchi, Sep 27, 2015
67 Reads
  • Source
    • "It is found mainly in the hippocampus, olfactory bulb and cerebellum of the adult human brain [4]. In neurons, the protein is concentrated in the distal segments of neurites, ingrowth cones and synapses [3] [21]. Multiple isoforms of CRMP2 exist due to alternative splicing of the Nterminus , although two of these are predominantly expressed. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Collapsin response mediator protein-2 (CRMP2) is a central nervous system protein involved in neuronal development, axonal and neuronal growth, cell migration, and protein trafficking. Recent studies have linked perturbations in CRMP2 function to neurodegenerative disorders such as Alzheimer's disease, neuropathic pain and Batten disease, and to psychiatric disorders such as schizophrenia. Like most proteins, CRMP2 functions though interactions with a molecular network of proteins and other molecules. Here, we have attempted to identify additional proteins of the CRMP2 interactome to provide further leads about its roles in neurological functions. We used a combined co-immunoprecipitation and shotgun proteomic approach in order to identify CRMP2 protein partners. We identified 78 CRMP2 protein partners not previously reported in public protein interaction databases. These were involved in 7 biological processes, which included cell signaling, growth, metabolism, trafficking and immune function, according to Gene Ontology classifications. Furthermore, 32 different molecular functions were found to be associated with these proteins, such as RNA binding, ribosomal functions, transporter activity, receptor activity, serine/threonine phosphatase activity, cell adhesion, cytoskeletal protein binding and catalytic activity. In silico pathway interactome construction revealed a highly connected network with the most overrepresented functions corresponding to semaphorin interactions, along with axon guidance and WNT5A-signalling. Taken together, these findings suggest that the CRMP2 pathway is critical for regulating neuronal and synaptic architecture. Further studies along these lines might uncover novel biomarkers and drug targets for use in drug discovery. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    PROTEOMICS - CLINICAL APPLICATIONS 04/2015; DOI:10.1002/prca.201500004 · 2.96 Impact Factor
  • Source
    • "The aforementioned data suggest that chronic depolarization via KCl leads to a prolonged loss of both GSK3β-and Cdk5- phosphorylated CRMP2. As phosphorylation at these sites is canonically known to inactivate the outgrowth-promoting function of CRMP2 (Brown et al., 2004; Cole et al., 2004, 2006; Uchida et al., 2005; Yoshimura et al., 2005), the KCl-induced loss of phosphorylation should translate to an overall increase in CRMP2 activity. However, to determine how the increase in the proportion of active CRMP2 relates to KCl-facilitated neurite outgrowth, it is necessary to preferentially target CRMP2 function. "
    [Show abstract] [Hide abstract]
    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
    Frontiers in Cellular Neuroscience 07/2014; 8:196. DOI:10.3389/fncel.2014.00196 · 4.29 Impact Factor
  • Source
    • "Bajor et al. (2012) isolated two synaptic proteins that are cleaved in vivo by MMP-9: synaptic cell adhesion molecule-2 (synCAM-2) and collapsin response mediator protein-2 (CRMP-2). CRMP-2 is involved in axon guidance, neurite outgrowth, and the regulation of neuronal differentiation (Inagaki et al., 2001; Fukata et al., 2002; Yoshimura et al., 2005). It was suggested to play a role in numerous neurological diseases, such as Alzheimer’s disease, epilepsy, and ischemia (Gu and Ihara, 2000; Czech et al., 2004; Uchida and Goshima, 2005). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Dendritic spines are the locus for excitatory synaptic transmission in the brain and thus play a major role in neuronal plasticity. The ability to alter synaptic connections includes volumetric changes in dendritic spines that are driven by scaffolds created by the extracellular matrix (ECM). Here, we review the effects of the proteolytic activity of ECM proteases in physiological and pathological structural plasticity. We use matrix metalloproteinase-9 (MMP-9) as an example of an ECM modifier that has recently emerged as a key molecule in regulating the morphology and dysmorphology of dendritic spines that underlie synaptic plasticity and neurological disorders, respectively. We summarize the influence of MMP-9 on the dynamic remodeling of the ECM via the cleavage of extracellular substrates. We discuss its role in the formation, modification, and maintenance of dendritic spines in learning and memory. Finally, we review research that implicates MMP-9 in aberrant synaptic plasticity and spine dysmorphology in neurological disorders, with a focus on morphological abnormalities of dendritic protrusions that are associated with epilepsy.
    Frontiers in Neuroanatomy 07/2014; 8:68. DOI:10.3389/fnana.2014.00068 · 3.54 Impact Factor
Show more