ERK5 Phosphorylates Kv4.2 and Inhibits Inactivation of the A-Type Current in PC12 Cells

Abstract

Extracellular signal-regulated kinase 5 (ERK5) regulates diverse physiological responses such as proliferation, differentiation, and gene expression. Previously, we demonstrated that ERK5 is essential for neurite outgrowth and catecholamine biosynthesis in PC12 cells and sympathetic neurons. However, it remains unclear how ERK5 regulates the activity of ion channels, which are important for membrane excitability. Thus, we examined the effect of ERK5 on the ion channel activity in the PC12 cells that overexpress both ERK5 and the constitutively active MEK5 mutant. The gene and protein expression levels of voltage-dependent Ca2+ and K+ channels were determined by RT-qPCR or Western blotting. The A-type K+ current was recorded using the whole-cell patch clamp method. In these ERK5-activated cells, the gene expression levels of voltage-dependent L- and P/Q-type Ca2+ channels did not alter, but the N-type Ca2+ channel was slightly reduced. In contrast, those of Kv4.2 and Kv4.3, which are components of the A-type current, were significantly enhanced. Unexpectedly, the protein levels of Kv4.2 were not elevated by ERK5 activation, but the phosphorylation levels were increased by ERK5 activation. By electrophysiological analysis, the inactivation time constant of the A-type current was prolonged by ERK5 activation, without changes in the peak current. Taken together, ERK5 inhibits an inactivation of the A-type current by phosphorylation of Kv4.2, which may contribute to the neuronal differentiation process.

Extracellular signal‐regulated kinases 2 (Erk2) and Erk5 in the central nervous system differentially contribute to central sensitization in male mice

“…Erk2 phosphorylates Thr602, Thr607, and Ser616 residues at the C‐terminal cytoplasmic domain of K V 4.2 (Adams et al., 2000). The minimum consensus sequence of Erk5 and Erk1/2 is similar, but a previous study suggest the difference in K V 4.2 phosphorylation component between them (Kashino et al., 2018). Although the roles of each phosphorylation residue of K V 4.2 are still controversial, it could be speculated that different preference of Erk2 and Erk5 for K V 4.2 phosphorylation residues is associated with the discrete but parallel mechanisms of Erk2 and Erk5 underlying additive effects on nociceptive behaviors in the second phase, part I of the formalin test.…”

“…Erk2 phosphorylates Thr602, Thr607, and Ser616 residues at the C-terminal cytoplasmic domain of K V 4.2 (Adams et al, 2000). The minimum consensus sequence of Erk5 and Erk1/2 is similar, but a previous study suggest the difference in K V 4.2 phosphorylation component between them (Kashino et al, 2018…”

Insulin Enhances Gene Expression of Midnolin, a Novel Genetic Risk Factor for Parkinson’s Disease, via Extracellular Signal-Regulated Kinase, Phosphoinositide 3-Kinase and Multiple Transcription Factors in SH-SY5Y Cells

“…Total RNA from SH-SY5Y cells was extracted using TriPure isolation reagent (Roche, Indianapolis, IN) according to the manufacturer's protocol. The RNA was then reverse transcribed using an RT-PCR kit (Toyobo, Osaka, Japan), and real-time PCR was performed using FastStart Essential DNA Green Master for real-time PCR and a LightCycler Nano thermal cycler (Roche), as described previously (Kashino et al, 2018). The PCR primers used were as follows: MIDN (5′-GAG CAG ATG GAC TGC TCC CC-3′ and 5′-ACA AAG CTC TCG ATG ACG GC-3′), c-FOS (5′-CAG ACT ACG AGG CGT CAT CC-3′ and 5′-AGT TGG TCT GTC TCC GCT TG-3′), and GAPDH (5′-ACC ACA GTC CAT GCC ATC AC-3′ and 5′-TCC ACC ACC CTG TTG CTG TA-3′).…”

SP600125 Enhances Temperature-Controlled Repeated Thermal Stimulation-Induced Neurite Outgrowth in PC12-P1F1 Cells

“…Furthermore, NGF signaling mediated by tropomyosin receptor kinase A induces neurite outgrowth by rapidly and sustainably activating ERK1/2 [ 16 ]. Besides ERK1/2, ERK5 is essential for neurite outgrowth [ 17 ] and may contribute to neuronal differentiation by phosphorylating a voltage-gated potassium channel, i.e., Kv4.2 in PC12 cells [ 18 ]. Furthermore, p38 MAPK is required for neuritogenesis induced by ligands, such as BMPs, in PC12 cells [ 19 ].…”