TY - JOUR
T1 - An atypical role for collapsin response mediator protein 2 (CRMP-2) in neurotransmitter release via interaction with presynaptic voltage-gated calcium channels
AU - Brittain, Joel M.
AU - Piekarz, Andrew D.
AU - Wang, Yuying
AU - Kondo, Takako
AU - Cummins, Theodore R.
AU - Khanna, Rajesh
PY - 2009/11/6
Y1 - 2009/11/6
N2 - 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 Ca2+ 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 Ca2+ channel current density, whereas lentivirus-mediated CRMP-2 knockdown abolished this effect. Interestingly, the increase in Ca2+ 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 Ca2+ entry via CaV2.2 abolished this stimulated release. Thus, the CRMP-2-Ca2+ channel interaction represents a novel mechanism for modulation of Ca2+ influx into nerve terminals and, hence, of synaptic strength.
AB - 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 Ca2+ 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 Ca2+ channel current density, whereas lentivirus-mediated CRMP-2 knockdown abolished this effect. Interestingly, the increase in Ca2+ 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 Ca2+ entry via CaV2.2 abolished this stimulated release. Thus, the CRMP-2-Ca2+ channel interaction represents a novel mechanism for modulation of Ca2+ influx into nerve terminals and, hence, of synaptic strength.
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U2 - 10.1074/jbc.M109.009951
DO - 10.1074/jbc.M109.009951
M3 - Article
C2 - 19755421
AN - SCOPUS:70849088180
SN - 0021-9258
VL - 284
SP - 31375
EP - 31390
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 45
ER -