Identification of a Proline-rich Inositol Polyphosphate 5-Phosphatase (PIPP)center dot Collapsin Response Mediator Protein 2 (CRMP2) Complex That Regulates Neurite Elongation

Megan V. Astle, Lisa M. Ooms, Adam R. Cole, Lauren C. Binge, Jennifer M. Dyson, Meredith J. Layton, Steven Petratos, Calum Sutherland, Christina A. Mitchell

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    Abstract

    Neuron polarization is essential for the formation of one axon and multiple dendrites, establishing the neuronal circuitry. Phosphoinositide 3-kinase (PI3K) signaling promotes axon selection and elongation. Here we report in hippocampal neurons siRNA knockdown of the proline-rich inositol polyphosphate 5-phosphatase (PIPP), which degrades PI3K-generated PtdIns(3,4,5)P-3, results in multiple hyperelongated axons consistent with a polarization defect. We identify collapsin response mediator protein 2 (CRMP2), which regulates axon selection by promoting WAVE1 delivery via Kinesin-1 motors to the axon growth cone, as a PIPP-interacting protein by Y2H screening, direct binding studies, and coimmunoprecipitation of an endogenous PIPP, CRMP2, and Kinesin-1 complex from brain lysates. The C-terminal growth cone-targeting domain of PIPP facilitates its interaction with CRMP2. PIPP growth cone localization is CRMP2-dependent. PIPP knockdown in PC12 cells promotes neurite elongation, WAVE1 and Kinesin-1 growth cone localization, whereas knockdown of CRMP2 exhibits the opposite phenotype, with shorter neurites and decreased WAVE1/Kinesin-1 at the growth cone. In contrast, CRMP2 overexpression promotes neurite elongation, a phenotype rescued by full-length PIPP, or expression of the CRMP2-binding PIPP domain. Therefore this study identifies PIPP and CRMP2 exert opposing roles in promoting axon selection and neurite elongation and the complex between these proteins serves to regulate the localization of effectors that promote neurite extension.

    Original languageEnglish
    Pages (from-to)23407-23418
    Number of pages12
    JournalJournal of Biological Chemistry
    Volume286
    Issue number26
    DOIs
    Publication statusPublished - 1 Jul 2011

    Keywords

    • GLYCOGEN-SYNTHASE KINASE-3-BETA
    • NEURONAL POLARITY
    • ALZHEIMERS-DISEASE
    • GSK-3 PHOSPHORYLATION
    • HIPPOCAMPAL-NEURONS
    • MEMBRANE RUFFLES
    • AXON FORMATION
    • FEEDBACK LOOP
    • GROWTH CONES
    • RHO-KINASE

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