Calmodulin‐sensitive ATP‐dependent calcium transport by the rat parotid endoplasmic reticulum

Kanagasuntheram, P; Teo, Tian Seng

doi:10.1016/0014-5793(82)80055-0

Cited by 15 publications

(10 citation statements)

References 17 publications

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“…The CaM role could be that of stimulating the phosphorylation of endogenous protein(s) that will then interact with the Ca2 + pumping ATPase. CaM, however, could also activate the ATPase directly as is the case for the Ca2+ ATPase of erythrocytes and heart plasma membranes, or of parathyroid microsomes [33]. The latter possibility is supported by the finding that one of the CaM-binding proteins of microsomes has the same apparent M, of the component which forms a Ca2 +-dependent, hydroxylamine-sensitive phosphopeptide [lo].…”

Section: Cum Dependency Of the Cu2+ Uptakesupporting

confidence: 50%

Calmodulin‐dependent protein phosphorylation and calcium uptake in rat‐liver microsomes

Famulski

Carafoli

1984

European Journal of Biochemistry

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A 20-kDa protein becomes phosphorylated in a process stimulated by Ca2+ and calmodulin in the light microsomal fraction of rat liver homogenate. The uptake of Ca2+ in light microsomal fraction is also calmodulinstimulated. The stimulation of Ca2 + transport is associated with the operation of a protein phosphorylation system dependent on Ca2+ and calmodulin. Transport is inhibited by a protein phosphatase which is stimulated by Ca2+ and calmodulin. It is proposed that the phosphorylation of the 20-kDa protein, which is stimulated by Ca2+ and calmodulin, plays a role in the regulation of the microsomal Ca2+, Mg2+-ATPase. [6]). The third is the mitochondrial transport system, which consists of the electrophoretic uptake pathway and of a Na+/Ca2+ (or H+/CaZ+) exchange system which mediates Ca2 + release (for a recent review see [7]). It is generally assumed that microsomes play an important role in the regulation of the Ca2 + level in liver, and may be involved in some types of toxininduced liver injury [S], as well as in some hormonal signalresponse cascade [9].In a previous paper from this laboratory it has been demonstrated [lo] that the postmitochondrial supernatant of rat liver contains two vesicular fractions which transport Ca2+ actively. The heavier fraction is enriched in plasma membrane markers, and contains a Ca2+-pumping ATPase and a Na+/Ca2 + exchanger. The light microsomal fraction does not possess Na+/CaZ+ exchange activity, and its ATP-driven Ca2 + uptake is relatively insensitive to vanadate. The Ca2 + uptake in this fraction is activated by a cytosolic fraction and by CAMP, and inhibited by the CAMP-dependent protein kinase inhibitor. The anticalmodulin drug trifluoperazine inhibits Ca2 + uptake and Ca2 +-dependent protein phosphorylation in liver microsomes [lo]. This finding has focused our attention on the possible involvement of calmodulin and a protein kinase in the regulation of the Ca2+, Mg2+-ATPase in these membranes.The results presented here show that indeed protein phosphorylation and Ca2+ uptake in rat liver microsomes are regulated by calmodulin. They also show that the latter process is regulated by a Ca2 +-dependent protein phosphorylationdephosphorylation cycle.While the manuscript was in preparation, a report by Moore and Kraus-Friedman has appeared [IOa] on the purification of the liver microsomal Ca2+, Mg2+-ATPase by calmodulin affi ni t y chromatography . ~~Abbreviations. CaM, calmodulin; N,-['251]CaM, azidoiodocalmodulin ; PAGE, polyacrylamide gel electrophoresis ; SDS, sodium dodecyl sulphate. MATERIALS AND METHODS Membrane preparationAlbino male Wistar-strain rats weighing 120 -150 g were killed by decapitation and the livers immediately removed and cut into small pieces in 0.25 M sucrose buffered with 5 mM Tris/Cl pH 7.4, and containing 1 mM mercaptoethanol and 0.5 mM phenylmethylsulfonyl fluoride (buffer A). One liver was homogenized in 70 ml of this medium using a glass Potter homogenizer with two passages of a loosely fitting teflon pestle. The homogenate was filtered t...

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Section: Cum Dependency Of the Cu2+ Uptakesupporting

confidence: 50%

Calmodulin‐dependent protein phosphorylation and calcium uptake in rat‐liver microsomes

Famulski

Carafoli

1984

European Journal of Biochemistry

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“…214 (Kirchberger & Antonetz, 1982). A Ca2+-ATPase present in the microsomal fraction of the rat parotid gland has also been recently described to be calmodulin-sensitive (Kanagasuntheram & Teo, 1982). In the liver, although addition of calmodulin to the microsomal fraction did not alter the activity of the Ca2+-ATPase, the enzyme activity was sensitive to trifluoperazine as demonstrated by inhibition of 45Ca2+ uptake.…”

mentioning

confidence: 97%

Hepatic microsomal Ca2+-dependent ATPase. Calmodulin-dependence and partial purification

Moore¹,

Kraus‐Friedmann²

1983

Biochemical Journal

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The hepatic microsomal fraction contains tightly bound calmodulin as demonstrated by affinity chromatography. When this calmodulin was partially removed by EGTA treatment (0.5 mM-EGTA), the uptake of 45Ca2+ by the microsomal vesicles was stimulated by added calmodulin and inhibited by trifluoperazine (TFP). The Ca2+-dependent ATPase was partially purified on a calmodulin column. This partial purification resulted in a 500-fold increase in the specific activity of the enzyme when measured in the presence of added calmodulin. Antibodies prepared against calmodulin prevented this stimulatory effect. The fraction eluted from the calmodulin column contained several protein bands indicating that the specific activity of the Ca2+-dependent ATPase is probably still underestimated. There are likely to be other calmodulin-sensitive processes present in the hepatic microsomal fraction.

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“…Attempts to elucidate the therapeutic mechanisms) of PTZ action have focused on two aspects of their functional properties: First, PTZ are known to interfere with a-adrenergic and cholinergic neurotransmitter receptorbinding events in the central nervous system (Yamamura et al, 1976;Gilman et al, 1980); and second, PTZ interfere with the intracellular calcium-binding protein, calmodulin (CaM), which is believed to play an important role in regulating numerous Ca2+-dependent physiologic processes in eukaryotic cells (Manalan and Klee, 1984). For the latter reason, in broken cell preparations, PTZ have been experimentally very useful in implicating physiologic roles for CaM (e.g., Dartt et al, 1982;Kanagasuntheram and Teo, 1982;Watkins and Cooperstein, 1983). However, because PTZ can interfere with neurotransmitter receptor-binding events, it is difficult to suggest CaM involvement based simply on intact cell experiments (e.g., Blackmore et al, 1981).…”

mentioning

confidence: 98%

“…It is known that rat parotid acinar cells contain CaM and Ca2+/CaM-sensitive enzymes (Ku and Butcher, 1980;Kanagasuntheram and Teo, 1982).…”

mentioning

confidence: 99%

Chlorpromazine Inhibition of Muscarinic-Cholinergic Responses in the Rat Parotid Gland

1986

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The ability of chlorpromazine (CPZ) to inhibit muscarinic-cholinergic secretory events was studied in vitro in rat parotid acinar cells. CPZ inhibited carbachol-induced amylase release in a dose-dependent fashion but had no effect on that elicited by isoproterenol. The inhibition of parotid protein synthesis induced by carbachol, but not that induced by A23187, was blocked by CPZ. CPZ exhibited a dose-dependent inhibition of [3H] quinuclidinyl benzilate (QNB) binding to muscarinic receptors, and altered the KD of the receptor for the ligand. These results are consistent with an ability of CPZ to inhibit muscarinic-cholinergic-induced salivary secretion by complex interference with receptor binding. In addition, CPZ may block parotid-muscarinic responses by impeding a post-receptor signaling step which is proximal to Ca2+ mobilization.

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Calmodulin‐sensitive ATP‐dependent calcium transport by the rat parotid endoplasmic reticulum

Cited by 15 publications

References 17 publications

Calmodulin‐dependent protein phosphorylation and calcium uptake in rat‐liver microsomes

Calmodulin‐dependent protein phosphorylation and calcium uptake in rat‐liver microsomes

Hepatic microsomal Ca2+-dependent ATPase. Calmodulin-dependence and partial purification

Chlorpromazine Inhibition of Muscarinic-Cholinergic Responses in the Rat Parotid Gland

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