Involvement of calmodulin in the activation of store‐operated Ca<sup>2+</sup> entry in rat hepatocytes

Cao, Yumei; Chatton, Jean–Yves

doi:10.1016/s0014-5793(98)00133-1

Cited by 13 publications

(7 citation statements)

References 24 publications

(24 reference statements)

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“…11,32,37,[41][42][43] However, the mechanism of this regulation is still unknown. Furthermore, the results of studies with rat hepatocytes led Cao and Chatton 46 to suggest that calmodulin is required for the activation of hepatocyte SOCs. Therefore, the role of calmodulin in the activation of SOCs in H4-IIE cells was investigated.…”

Section: Identification Of a Camentioning

confidence: 99%

Plasma Membrane Ca2+ Release-Activated Ca2+ Channels With A High Selectivity for Ca2+ Identified by Patch–Clamp Recording in Rat Liver Cells

et al. 2001

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Repetitive waves of increased cytoplasmic Ca 2؉ concentration play a central role in the process by which hormones regulate liver function. Maintenance of these Ca 2؉ waves requires Ca 2؉ inflow through store-operated Ca 2؉ channels. The properties and mechanism(s) of activation of these channels are not well understood. Store-operated Ca 2؉ channels (SOCs) in the H4-IIE rat liver cell line were studied by whole-cell patch clamping. Increases in the concentration of Ca 2ϩ in the cytoplasmic space ([Ca 2ϩ ] cyt ) of hepatocytes play a central role in the mechanisms by which hormones and growth factors regulate intermediary metabolism, drug metabolism, the transport of bile acids and inorganic ions, and cell growth and differentiation. [1][2][3][4] One of the main types of intracellular Ca 2ϩ signals in hepatocytes is composed of repetitive waves of increased [Ca 2ϩ ] cyt that move within the cytoplasmic space of individual hepatocytes and from one hepatocyte to another along liver cell cords. 1,3-6 Within individual hepatocytes, it is often observed that the wave of increased [Ca 2ϩ ] cyt moves from the canalicular side to the basal side of the cell. 5 These Ca 2ϩ waves are initiated by the release of Ca 2ϩ from the endoplasmic reticulum induced by inositol 1,4,5-trisphosphate (InsP 3 ), and are propagated by InsP 3 -and Ca 2ϩ -induced Ca 2ϩ release from the endoplasmic reticulum through InsP 3 and ryanodine receptors, respectively.

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Section: Identification Of a Camentioning

confidence: 99%

Plasma Membrane Ca2+ Release-Activated Ca2+ Channels With A High Selectivity for Ca2+ Identified by Patch–Clamp Recording in Rat Liver Cells

et al. 2001

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“…The Ca 2+ ‐binding protein CaM has an important regulatory effect on many Ca 2+ ‐permeable ion channels (Zhu, 2005) and therefore not surprisingly the role of CaM has been investigated on SOCs in many cell systems. However, these experiments have produced much conflicting data (Vaca, 1996; Cao & Chatton, 1998; Vazquez et al ., 2000; Machaca, 2003; Litjens et al ., 2004; Moreau et al ., 2005) and thus there is no consistent picture on the role for CaM on SOCs. These discrepancies may be accounted for by the use of cell lines and cultured cells that may contain a variety of different Ca 2+ entry pathways and underlying molecular entities (see Parekh & Putney (2005) for different types of SOCs).…”

Section: Introductionmentioning

confidence: 99%

Dual effect of calmodulin on store‐operated Ca²⁺‐permeable cation channels in rabbit portal vein myocytes

Albert

Liu

Large

2006

British J Pharmacology

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1 We have previously described a Ca 2 þ -permeable non-selective cation channel in freshly dispersed rabbit ear artery myocytes, which is activated by agents that deplete internal Ca 2 þ stores and also by protein kinase C (PKC). In the present study, we investigated the effect of calmodulin (CaM) on storeoperated channels (SOCs) with electrophysiological techniques. 2 Bath application of the CaM inhibitor calmidazolium (CMZ) to quiescent cells produced transient activation of SOC activity in cell-attached patches. CMZ produced a dual effect on cyclopiazonic acid (CPA)-evoked SOCs by initially inducing an increase in mean open probability (NP o ) and subsequently producing a marked inhibition of SOC activity. In contrast, SOCs activated by the cell-permeable Ca 2 þ chelator 1,2-bis (2-aminophenoxy)ethane-N-N,N 0 ,N 0 -tetraacetic acid (BAPTA-AM) were inhibited by CMZ. 3 In inside-out patches where SOCs were activated by CPA or the PKC activator phorbol-12,13-dibutyrate (PDBu), bath application of CaM induced an initial inhibition followed by an increase in SOC activity. In contrast, CaM only enhanced BAPTA-AM-evoked SOC activity in inside-out patches. 4 Bath application of CaM to the cytoplasmic surface of quiescent inside-out patches evoked single channel currents with biophysical properties similar to SOCs. 5 The inhibitory action of CaM on PDBu-induced SOC activity was inhibited by the calmodulindependent kinase II (CaM kinase II) inhibitor autocamtide-related inhibitory peptide (AIP) but not by inhibitors of calcineurin or myosin light chain kinase (MLCK). In addition, CaM-evoked channel currents were inhibited by coapplication of purified CaM kinase II but not by inhibitors of CaM kinase II, calcineurin or MLCK. 6 With whole-cell and cell-attached recording, bath application of the CaM kinase II inhibitors KN93 and AIP evoked SOCs in unstimulated myocytes. 7 These results indicate that CaM has pronounced dual inhibitory and excitatory actions on SOCs with the inhibitory effect of CaM mediated by CaM kinase II. Moreover, the present work provides strong evidence that CaM has an important role in activating SOCs, possibly through a direct action on channel/associated proteins.

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“…As we observed essentially the same effects with the CAM antagonists as with the CAMKII inhibitor, we cannot exclude a role of CAM itself in the regulatory process. Although it has been shown by others that some CAM antagonists could directly inhibit both VDCC and SOC channels (26,27), the experiments shown in Figs. 2 and 3 allow us to exclude a direct interaction of the CAM inhibitors with the channel itself, which would be observed regardless at which point of the assay the drug is added to the bath.…”

Section: Resultsmentioning

confidence: 85%

Involvement of Calmodulin in 1α,25-Dihydroxyvitamin D3 Stimulation of Store-operated Ca2+ Influx in Skeletal Muscle Cells

Vázquez

Boland

2000

Journal of Biological Chemistry

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Involvement of calmodulin in the activation of store‐operated Ca²⁺ entry in rat hepatocytes

Cited by 13 publications

References 24 publications

Plasma Membrane Ca2+ Release-Activated Ca2+ Channels With A High Selectivity for Ca2+ Identified by Patch–Clamp Recording in Rat Liver Cells

Plasma Membrane Ca2+ Release-Activated Ca2+ Channels With A High Selectivity for Ca2+ Identified by Patch–Clamp Recording in Rat Liver Cells

Dual effect of calmodulin on store‐operated Ca²⁺‐permeable cation channels in rabbit portal vein myocytes

Involvement of Calmodulin in 1α,25-Dihydroxyvitamin D3 Stimulation of Store-operated Ca2+ Influx in Skeletal Muscle Cells

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Involvement of calmodulin in the activation of store‐operated Ca2+ entry in rat hepatocytes

Cited by 13 publications

References 24 publications

Plasma Membrane Ca2+ Release-Activated Ca2+ Channels With A High Selectivity for Ca2+ Identified by Patch–Clamp Recording in Rat Liver Cells

Plasma Membrane Ca2+ Release-Activated Ca2+ Channels With A High Selectivity for Ca2+ Identified by Patch–Clamp Recording in Rat Liver Cells

Dual effect of calmodulin on store‐operated Ca2+‐permeable cation channels in rabbit portal vein myocytes

Involvement of Calmodulin in 1α,25-Dihydroxyvitamin D3 Stimulation of Store-operated Ca2+ Influx in Skeletal Muscle Cells

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Involvement of calmodulin in the activation of store‐operated Ca²⁺ entry in rat hepatocytes

Dual effect of calmodulin on store‐operated Ca²⁺‐permeable cation channels in rabbit portal vein myocytes