Distinct regulation of expressed calcium channels 2.3 in Xenopus oocytes by direct or indirect activation of protein kinase C

Kamatchi, Ganesan L.; Tiwari, Shveta N.; Chan, Carrie K.; Chen, Daguang; Hwan, Sang; Durieux, Marcel E.; Lynch, Carl

doi:10.1016/s0006-8993(03)02245-5

Cited by 21 publications

(39 citation statements)

References 34 publications

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“…In previous studies, use of PKC inhibitors/antagonists had suggested that cPKC isozymes are involved in the action of MCh and that nPKC isozymes are involved in the action of PMA (Kamatchi et al, 2003). In this study, Western blotting and densitometry analysis reveal that among the four cPKCs (α, βI, βII and γ), PKC α is translocated to the membrane in response to MCh (see Fig.…”

Section: Discussionsupporting

confidence: 53%

“…Several studies support a role for PKC in the enhancement (Swartz, 1993;Yang and Tsien, 1993;Kamatchi et al, 2003) or inhibition (Pemberton and Jones, 1997;Rane and Dunlap, 1986) of depolarization-evoked Ca v currents by DAG, PMA or MCh. Although the auxiliary β subunit is required for this action (Stea et al, 1995;Kamatchi et al, 2003) most evidence suggests that PKC targets the α 1 subunit.…”

Section: Discussionmentioning

confidence: 94%

“…Although the auxiliary β subunit is required for this action (Stea et al, 1995;Kamatchi et al, 2003) most evidence suggests that PKC targets the α 1 subunit. The contribution of α 1 subunits is evident because only selected Ca v currents are modulated.…”

Section: Discussionmentioning

confidence: 99%

“…PKC activation by phorbol-12-myristate, 13-acetate (PMA) enhanced Ca v 2.2 or 2.3 currents, whereas Ca v 1.2c or 2.1 currents were not affected. In contrast, acetyl-β-methylcholine (MCh), which also leads to PKC activation, potentiated Ca v 2.3 currents, decreased Ca v 1.2c currents, and failed to modulate Ca v 2.1 or 2.2 currents (Kamatchi et al, 2003). The differential response of the Ca v currents to PMA and MCh may be attributed to i) the kind of PKC isozyme(s) activated and ii) the presence of PKC isozyme-selective phosphorylation sites in the α 1 subunit of the Ca v channels.…”

Section: Introductionmentioning

confidence: 99%

“…The differential response of the Ca v currents to PMA and MCh may be attributed to i) the kind of PKC isozyme(s) activated and ii) the presence of PKC isozyme-selective phosphorylation sites in the α 1 subunit of the Ca v channels. It was suggested that while cPKC is involved in the action of MCh, both cPKC and nPKC are required for the action of PMA (Kamatchi et al, 2003). Mutation analysis revealed Ser-888, Ser-892, Ser-984 in the II-III linker and Ser-1987 in the C-terminus as MCh-selective potential PKC phosphorylation sites in the α 1 2.3 subunit.…”

Section: Introductionmentioning

confidence: 99%

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Protein kinase C isozyme-specific potentiation of expressed Cav 2.3 currents by acetyl-β-methylcholine and phorbol-12-myristate, 13-acetate

et al. 2008

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Protein kinase C (PKC) is implicated in the potentiation of Ca v 2.3 currents by acetyl-β-methylcholine (MCh), a muscarinic M 1 receptor agonist or phorbol-12-myristate, 13-acetate (PMA). The PKC isozymes responsible for the action of MCh and PMA were investigated using translocation as a measure of activation and with isozyme-selective antagonists and siRNA. Ca v channels were expressed with α 1 2.3, β 1 b and α 2 δ subunits and muscarinic M 1 receptors in the Xenopus oocytes and the expressed currents (I Ba ) were studied using Ba 2+ as the charge carrier. Translocation of PKC isozymes to the membrane studied by Western blot revealed that all eleven known PKC isozymes are present in the Xenopus oocytes. Exposure of the oocytes to MCh led to the translocation of PKC α whereas PMA activated PKC βII and ε isozymes. The action of MCh was inhibited by Go 6976, an inhibitor of cPKC isozymes or PKC α siRNA. PMA-induced potentiation of Ca v 2.3 currents was inhibited by CG533 53, a PKC βII antagonist, βIIV5.3, a peptide translocation inhibitor of PKC βII or PKC βII siRNA. Similarly, εV1.2, a peptide translocation inhibitor of PKC ε or PKC ε siRNA inhibited PMA action. The inhibitors of PKC increased the basal I Ba slightly. It is possible that some PKC isozymes have negative control over the I Ba . Our results implicate PKC α in the potentiation of Ca v 2.3 currents by MCh and PKC βII and ε in the potentiation of Ca v 2.3 currents by PMA. Classification of termsSection: 3. Neurophysiology, Neruopharmacology and other forms of Interceullular communication

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Protein kinase C isozyme-specific potentiation of expressed Cav 2.3 currents by acetyl-β-methylcholine and phorbol-12-myristate, 13-acetate

et al. 2008

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Protein Interaction Partners of Cav2.3 R-Type Voltage-Gated Calcium Channels

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Tevoufouet

Neumaier

et al. 2013

Modulation of Presynaptic Calcium Channels

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Contribution of protein kinase Cα in the stimulation of insulin by the down-regulation of Cavβ subunits

2014

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Voltage-gated calcium (Cav) channels and protein kinase C (PKC) isozymes are involved in insulin secretion. In addition, Cavβ, one of the auxiliary subunits of Cav channels, also regulate the secretion of insulin as knockout of Cavβ3 (β3−/−) subunits in mice led to efficient glucose homeostasis and increased insulin levels. We examined if other types of Cavβ subunits also have similar properties. In this regard, we used small interfering RNA (siRNA) of these subunits (20 μg each) to down regulate them and examined blood glucose, serum insulin and PKC translocation in isolated pancreatic β cells of mice. While the down regulation of Cavβ2 and β3 subunits increased serum insulin levels and caused efficient glucose homeostasis, the down regulation of Cavβ1 and β4 subunits failed to affect both these parameters. Examination of PKC isozymes in the pancreatic β-cells of Cavβ2 or β3 siRNA injected mice showed that three PKC isozymes, viz., PKCα, βII and θ translocated to the membrane. This suggests that when present, Cavβ2 and β3 subunits inhibited PKC activation. Among these three isozymes, only PKCα siRNA inhibited insulin and increased glucose concentrations. It is possible that the activation of PKCs βII and θ are not sufficient for the release of insulin and PKCα is the mediator of insulin secretion under the control of Cavβ subunits. Since Cavβ subunits are present intracellularly, it is possible that they i) inhibited the translocation of PKC isozymes to the membrane and ii) decreased the interaction between Cav channels and PKC isozymes and thus the secretion of insulin.

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Distinct regulation of expressed calcium channels 2.3 in Xenopus oocytes by direct or indirect activation of protein kinase C

Cited by 21 publications

References 34 publications

Protein kinase C isozyme-specific potentiation of expressed Cav 2.3 currents by acetyl-β-methylcholine and phorbol-12-myristate, 13-acetate

Protein kinase C isozyme-specific potentiation of expressed Cav 2.3 currents by acetyl-β-methylcholine and phorbol-12-myristate, 13-acetate

Protein Interaction Partners of Cav2.3 R-Type Voltage-Gated Calcium Channels

Contribution of protein kinase Cα in the stimulation of insulin by the down-regulation of Cavβ subunits

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