Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• Journal of cell science, 2009-12, Vol.122 (23), p.4351-4362

Ort / Verlag

England: The Company of Biologists Limited

Erscheinungsjahr

2009

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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 synaptophysin-positive 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-2 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.