The Ubiquitin Ligase MYCBP2 Regulates Transient Receptor Potential Vanilloid Receptor 1 (TRPV1) Internalization through Inhibition of p38 MAPK Signaling

Abstract

The E3 ubiquitin ligase MYCBP2 negatively regulates neuronal growth, synaptogenesis, and synaptic strength. More recently it was shown that MYCBP2 is also involved in receptor and ion channel internalization. We found that mice with a MYCBP2-deficiency in peripheral sensory neurons show prolonged thermal hyperalgesia. Loss of MYCBP2 constitutively activated p38 MAPK and increased expression of several proteins involved in receptor trafficking. Surprisingly, loss of MYCBP2 inhibited internalization of transient receptor potential vanilloid receptor 1 (TRPV1) and prevented desensitization of capsaicin-induced calcium increases. Lack of desensitization, TRPV internalization and prolonged hyperalgesia were reversed by inhibition of p38 MAPK. The effects were TRPVspecific, since neither mustard oil-induced desensitization nor behavioral responses to mechanical stimuli were affected. In summary, we show here for the first time that p38 MAPK activation can inhibit activity-induced ion channel internalization and that MYCBP2 regulates internalization of TRPV1 in peripheral sensory neurons as well as duration of thermal hyperalgesia through p38 MAPK.The E3-ubiquitin ligase MYCBP2 (Myc-binding protein 2; also known as protein associated with Myc (PAM)) 2 is an unusual large protein with a predicted size of 510 kDa. MYCBP2 orthologs have been described in mouse as Phr1, in zebrafish as Esrom, in drosophila as Highwire and in Caenorhabditis elegans as RPM-1. While MYCBP2 mRNA is found in nearly all human tissues, its expression is exceptionally high in peripheral and central neurons (1-3). MYCBP2 has been shown to act as negative regulators of synaptic growth, synaptogenesis, and neurite growth in C. elegans (4), Drosophila (5), zebrafish (6), and mice (7,8). In C. elegans and Drosophila MYCBP2-dependent growth inhibition is largely mediated by the p38 MAPK pathway (9, 10) whereas in mice the role of p38 MAPK in MYCBP2-regulated axonal growth is less clear.Whereas growth regulation of cortical axons by MYCBP2 does not involve p38 MAPK (8), MYCBP2-dependent axonal overgrowth of spinal cord motor neurons and sensory dorsal root ganglion (DRG) neurons was regulated by p38 MAPKmediated alterations in microtubule stability (11).Besides its role in the regulation of neuronal growth, also a function of MYCBP2 in neuronal transmission has been demonstrated. In C. elegans and drosophila loss-of-function mutations in the MYCBP2 orthologs decreased the number of synaptic vesicles at cholinergic and GABAergic synapses in a p38 MAPK-dependent manner (9) and reduced strength of synaptic transmission at neuromuscular junctions (5, 12, 13). More recently, it was shown that the MYCBP2 ortholog in C. elegans, RPM-1, prevents in central neurons activity-dependent internalization of AMPA receptors by inhibiting p38 MAPK signaling through ubiquitylation of MAPK kinase kinase 12 (MAPKKK12), (14). Loss of RPM-1 caused constitutive activation of p38MAPK leading to an increased internalization of the AMPA receptor ortholog GLR1.Interestingly, in ma...

TRIM45 negatively regulates NF-κB-mediated transcription and suppresses cell proliferation

“…Recent studies have revealed that numerous ubiquitin ligases are involved in regulation of transcriptional factors including the MAPK signaling pathway and NF-B signaling pathway [29,30]. Moreover, some members of the TRIM family of ubiquitin ligases have been shown to be involved in the regulation of these signaling pathways [23,28,31,32].…”

Metabolic Connection of Inflammatory Pain: Pivotal Role of a Pyruvate Dehydrogenase Kinase-Pyruvate Dehydrogenase-Lactic Acid Axis

“…RotaRod experiment was performed to confirm the data obtained from the open field test. A cutoff time of 90 s was used for RotaRod experiments as practiced previously (Holland et al, 2011;Möser et al, 2015). Moreover, Nicol et al (2015) have recently reported that WT and GPR84 KO mice were unable to remain on the RotaRod apparatus for Ͼ100 s at a similar rate of rotation, supporting that 90 s is long enough to determine a motor deficit.…”

MYCBP2 Is a Guanosine Exchange Factor for Ran Protein and Determines Its Localization in Neurons of Dorsal Root Ganglia

“…2A). MYCBP2 has been previously shown to mediate inflammatory hyperalgesia by altering neuronal functions in DRGs and spinal cords (12,20). Therefore, we determined RanGAP1 expression in DRGs from SNS Cre-negative MYCBP2 fl/fl mice during zymosan-induced hyperalgesia.…”

“…Determination of Protein Translocation and ExpressionThe cellular localization of MYCBP2, RanGAP1, or Ran was assessed as described previously (20). The experimenter was unaware of the treatment.…”

“…1A) on protein expression in DRG neurons using an antibody microarray covering 750 proteins (20). The array showed the up-regulation of SUMO1 and/or SUMOylated proteins in MYCBP2-deficient DRGs.…”