Phosphorylated CRMP2 Regulates Spinal Nociceptive Neurotransmission

Abstract

The collapsin response mediator protein 2 (CRMP2) has emerged as a central node in assembling nociceptive signaling complexes involving voltage-gated ion channels. Concerted actions of posttranslational modifications, phosphorylation and SUMOylation, of CRMP2 contribute to regulation of pathological pain states. In the present study, we demonstrate a novel role for CRMP2 in spinal nociceptive transmission. We found that, of six possible post-translational modifications, three phosphorylation sites on CRMP2 were critical for regulating calcium influx in dorsal root ganglion sensory neurons. Of these, only CRMP2 phosphorylated at serine 522 by cyclin dependent kinase 5 (Cdk5) contributed to spinal neurotransmission in a bidirectional manner. Accordingly, expression of a non-phosphorylatable CRMP2 (S522A) decreased the frequency of spontaneous excitatory postsynaptic currents (sEPSCs), whereas expression of a constitutively phosphorylated CRMP2 (S522D) increased the frequency of sEPSCs. The presynaptic nature of CRMP2's actions were further confirmed by pharmacological antagonism of Cdk5-mediated CRMP2 phosphorylation with S-N-benzy-2-acetamido3-methoxypropionamide ((S)-Lacosamide; (S)-LCM) which (i) decreased sEPSC frequency, (ii) increased paired pulse ratio, and (iii) reduced the presynaptic distribution of CaV2.2 and NaV1.7, two voltage-gated ion

Evaluation of edonerpic maleate as a CRMP2 inhibitor for pain relief

“…We tested three different ratios of CRMP2/edonerpic maleate: no binding was detected between CRMP2 and edonerpic maleate (Figure 1(a)). (S)-lacosamide, an inhibitor of CRMP2 phosphorylation [3,5,7], was used as a positive control at the same concentrations and showed binding to CRMP2 (not shown), consistent with our previously published finding [7]. Next, we used microscale thermophoresis (MST), a method for the biophysical analysis of biomolecular interactions, but were unable to detect any interaction between edonerpic maleate and CRMP2 with this method either (not shown).…”

“…Edonerpic maleate was found to disrupt CRMP2 tetramers [10]. Our previous body of work has established a role for phosphorylated and non-phosphorylated CRMP2 in control of voltage-gated calcium and sodium channels [1,[3][4][5][6][7][8][13][14][15][16][17][18][19][20][21][22]. Therefore, we tested the effect of edonerpic maleate on these channels.…”

“…When searching for novel non-opioid therapeutic targets for chronic pain treatment, we identified the collapsin response mediator protein 2 (CRMP2) as necessary for mechanical allodynia [1]. CRMP2 is localized pre-synaptically in the dorsal horn of the spinal cord where dorsal root ganglia (DRG) sensory neurons synapse onto second-order neurons [2,3]. At this location, CRMP2 controls the presynaptic levels of both CaV2.2 and NaV1.7, two voltage gated ion channels essential for nociceptive signal transmission [3].…”

“…CRMP2 is localized pre-synaptically in the dorsal horn of the spinal cord where dorsal root ganglia (DRG) sensory neurons synapse onto second-order neurons [2,3]. At this location, CRMP2 controls the presynaptic levels of both CaV2.2 and NaV1.7, two voltage gated ion channels essential for nociceptive signal transmission [3]. Actions of CRMP2 are tightly regulated by post-translational modifications [1].…”

Studies on CRMP2 SUMOylation-deficient transgenic mice identify sex-specific NaV1.7 regulation in the pathogenesis of chronic neuropathic pain

“…We previously reported that CRMP2 phosphorylation by cyclin dependent kinase 5 (Cdk5) affected the frequency of sEPSCs in the spinal dorsal horn [73]. This function was hypothesized to be linked to CRMP2's regulation of both the N-type voltage-gated calcium channel (CaV2.2) as well as NaV1.7.…”