Regulation of N-type voltage-gated calcium channels (Cav2.2) and transmitter release by collapsin response mediator protein-2 (CRMP-2) in sensory neurons

Xian Xuan Chi, Brian S. Schmutzler, Joel M. Brittain, Yuying Wang, Cynthia M. Hingtgen, Grant D. Nicol, Rajesh Khanna

Research output: Contribution to journalArticle

92 Scopus citations

Abstract

Collapsin response mediator proteins (CRMPs) mediate signal transduction of neurite outgrowth and axonal guidance during neuronal development. Voltage-gated Ca2+ channels and interacting proteins are essential in neuronal signaling and synaptic transmission during this period. We recently identified the presynaptic N-type voltage-gated Ca2+ channel (Cav2.2) as a CRMP-2-interacting partner. Here, we investigated the effects of a functional association of CRMP-2 with Cav2.2 in sensory neurons. Cav2.2 colocalized with CRMP-2 at immature synapses and growth cones, in mature synapses and in cell bodies of dorsal root ganglion (DRG) neurons. Co-immunoprecipitation experiments showed that CRMP-2 associates with Cav2.2 from DRG lysates. Overexpression of CRMP-2 fused to enhanced green fluorescent protein (EGFP) in DRG neurons, via nucleofection, resulted in a significant increase in Cav2.2 current density compared with cells expressing EGFP. CRMP-2 manipulation changed the surface levels of Cav2.2. Because CRMP-2 is localized to synaptophysinpositive puncta in dense DRG cultures, we tested whether this CRMP-2-mediated alteration of Ca2+ currents culminated in changes in synaptic transmission. Following a brief high-K+-induced stimulation, these puncta became loaded with FM4-64 dye. In EGFP and neurons expressing CRMP-2-EGFP, similar densities of FM-loaded puncta were observed. Finally, CRMP-2 overexpression in DRG increased release of the immunoreactive neurotransmitter calcitonin gene-related peptide (iCGRP) by ∼70%, whereas siRNA targeting CRMP- significantly reduced release of iCGRP by ∼54% compared with control cultures. These findings support a novel role for CRMP-2 in the regulation of N-type Ca2+ channels and in transmitter release.

Original languageEnglish (US)
Pages (from-to)4351-4362
Number of pages12
JournalJournal of Cell Science
Volume122
Issue number23
DOIs
StatePublished - Dec 1 2009
Externally publishedYes

Keywords

  • CGRP
  • CRMP-2
  • DRG
  • Presynaptic Ca2 channels
  • Transmitter release
  • α1B/Cav2.2

ASJC Scopus subject areas

  • Cell Biology

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