An Atypical Role for Collapsin Response Mediator Protein 2 (CRMP-2) in Neurotransmitter Release via Interaction with Presynaptic Voltage-gated Calcium Channels

作者：Brittain Joel M; Piekarz Andrew D; Wang Yuying; Kondo Takako; Cummins Theodore R; Khanna Rajesh^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2009, 284(45): 31375-31390.

DOI：10.1074/jbc.M109.009951

Collapsin response mediator proteins (CRMPs) specify axon/dendrite fate and axonal growth of neurons through protein-protein interactions. Their functions in presynaptic biology remain unknown. Here, we identify the presynaptic N-type Ca(2 ) channel (CaV2.2) as a CRMP-2-interacting protein. CRMP-2 binds directly to CaV2.2 in two regions: the channel domain I-II intracellular loop and the distal C terminus. Both proteins co-localize within presynaptic sites in hippocampal neurons. Overexpression in hippocampal neurons of a CRMP-2 protein fused to enhanced green fluorescent protein caused a significant increase in Ca(2 ) channel current density, whereas lentivirus-mediated CRMP-2 knockdown abolished this effect. Interestingly, the increase in Ca(2 ) current density was not due to a change in channel gating. Rather, cell surface biotinylation studies showed an increased number of CaV2.2 at the cell surface in CRMP-2-overexpressing neurons. These neurons also exhibited a significant increase in vesicular release in response to a depolarizing stimulus. Depolarization of CRMP-2-enhanced green fluorescent protein-overexpressing neurons elicited a significant increase in release of glutamate compared with control neurons. Toxin block of Ca(2 ) entry via CaV2.2 abolished this stimulated release. Thus, the CRMP-2-Ca(2 ) channel interaction represents a novel mechanism for modulation of Ca(2 ) influx into nerve terminals and, hence, of synaptic strength.

• 出版日期2009-11-6