Calcium uptake into acini from rat pancreas: Evidence for intracellular ATP-dependent calcium sequestration

Wakasugi, Hideyuki; Kimura, Toshinari; Haase, Winfried; Kribben, Andreas; Kaufmann, R.; Schulz, Irene

doi:10.1007/bf01869964

Cited by 99 publications

(36 citation statements)

References 60 publications

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“…Since the plasma membrane of the cells was permeabilized by exposure to the ergosterol-binding antifungal drug, nystatin, the non-vacuolar Ca2 + uptake activity does not originate from the plasma membrane. Neither does the Ca2+ uptake activity originate from the mitochondria, since it was measured in the presence of CCCP, an uncoupler of oxidative phosphorylation and a strong inhibitor of mitochondrial Ca2+ uptake [27]. In addition, it has been found that in yeast, Ca2+ is not taken up into the mitochondria [26].…”

Section: Discussionmentioning

confidence: 99%

An intracellular ATP‐dependent calcium pump within the yeast Schizosaccharomyces pombe, encoded by the gene cta3

Halachmi

Ghislain

Eilam

1992

European Journal of Biochemistry

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We have permeabilized the plasma membranes of Schizosaccharomyces pombe cell with nystatin and measured ATP-dependent Ca2+ uptake in the presence of K N 0 3 and a protonophore in order to inhibit Ca2 + uptake into the vacuole. ATP-dependent Ca2 + accumulation into non-vacuolar Ca2 . However, the K , value for Ca2+ uptake by the vacuolar exchanger, 0.1 mM, seems to be too high to control Ca2+ concentration at submicromolar levels.Recently two genes for P-types ATPase, PMRl and PMR2, were identified in S. cerevisiae [15]. The deduced amino acid sequence of PMRl and PMR2 proteins was similar to that of animal Ca2+-ATPases. It was suggested that PMRl encodes a Ca2 + -ATPase that controls the secretory pathways. Our group has recently identified a novel P-type ATPase gene, eta3 in S. pombe [l 11. The deduced amino acid sequence shows that cta3 gene encodes a P-type ATPase. A null mutation in eta3 leads to higher levels of free cytosolic Ca2+, and lower amounts of sequestered and bound Ca2' . When the permeability of the plasma membrane was loosened by DEAE-dextran treatment, uptake of Ca2 + in the null mutant was lower than in the wild type. These physiological results supported the conclusion that eta3 protein is involved in Ca2 + transport and homeostasis and suggested localization of eta3 protein in intracellular membranes.In the present work, we investigated Ca2+ accumulation into intracellular compartments in nystatin-permeabilized cells, which are freely permeable to ATP. In the presence of inhibitors of Ca2+ uptake into the vacuole, an ATP-dependent Ca2+ uptake, which could be inhibited by vanadate was detected. These results are the first biochemical evidence of Ca2+-ATPase in yeast. ATP-dependent Ca2+-uptake is reduced in the yeast strain MG4 harboring a null allele of cta3.

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Section: Discussionmentioning

confidence: 99%

An intracellular ATP‐dependent calcium pump within the yeast Schizosaccharomyces pombe, encoded by the gene cta3

Halachmi

Ghislain

Eilam

1992

European Journal of Biochemistry

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“…Platelets were suspended in a Krebs-Ringer's-HEPES buffer (120 mM NaC1, 4.7 mM KCl, 1.2 mM KH2P04, 1.2 mM MgC12, 10 mM HEPES, 15 mM dextrose, 0.2% albumin) pH 7.4 (13), for the study of all agonists except IP3. For agonists other than IP3, 1 mM CaC12 was added to each sample 2 min before the addition of agonist.…”

Section: Methodsmentioning

confidence: 99%

Deficient Collagen-Induced Activation in the Newborn Platelet

1990

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ABSTRACT. We have investigated the impaired secretion response of neonatal platelets. We compared the response of washed neonatal and adult platelets to thrombin and collagen, and to specific activators of calcium flux (inositol trisphosphate) and protein kinase C activation (oleoylacetyl glycerol). Neonatal platelets show no impairment ofaggregation, secretion of ['4C]serotonin or phosphorylation of saecific intracellular rotei ins in resDonse to thrombin. inositol trisphosphate, o; oleoyl-acetyl glycerol. ow ever; neonatal platelets have a markedly decreased response to collagen. To further evaluate this deficient response, we examined specific aspects of the collagen activation pathway. Collagen-platelet interaction as measured by adhesion of platelets to collagen-coated dishes showed no difference in adhesion of neonatal platelets compared to adult controls (20.1 f 11.6 versus 18.6 2 9.3%). The presence of GPIa/ Ila, a Mgz+-dependent collagen receptor, was evaluated by flow cytometric analysis of binding of fluorescein-tagged monoclonal antibody, 6F1 (directed against GPIaJIIa). There was no difference either in the percent of platelets that bound antibody (80 versus 81%) or in the mean fluorescence intensity of the adult and neonatal samples. Phosphoinositide hydrolysis was decreased in neonatal platelets in response to collagen but normal in response to thrombin. Neonatal platelets released more arachidonic acid than adult platelets in response to thrombin (29.5 f 3.2 versus 19.6 + 1.8%) but less than adult platelets in response to 10 pg/mL collagen (3.2 2 1.1 versus 9.3 + 3.0%). Thromboxane B2 production was also decreased in response to collagen (52.7 f 12.6 versus 101.4 + 18.7 ng/mL). These results suggest that the deficient collagen response in neonatal platelets may lie in transduction of the collagen signal to phospholipases Az and C . (Pediatr Res 27: 337-343,1990) Abbreviations AA, arachidonic acid IP3, inositol-1,4,5-trisphosphate OAG, oleoyl-acetyl glycerol PIPZ, phosphatidylinositol-4,5-bisphosphate MLC, myosin light chain 47 K, 47000 dalton protein TxAZ, thromboxane A2 TxBz, thromboxane Bz HBSS, Hanks' balanced salt solution clinical importance to those caring for sick and premature infants. The differences in clotting factor activity and fibrinolytic enzymes between cord blood and that of adult controls are well established (1,2). The abnormalities of neonatal platelet function are less completely understood. In the mid-1970s, differences in the in vitro responses of cord and newborn platelets compared to those from older subjects were identified (3-6). These abnormalities include a decreased aggregation response to certain agonists including ADP, epinephrine and collagen (3, 4), and decreased secretion of dense granule contents (5, 6). Neonatal platelets were shown to have decreased endogenous stores of dense granule contents, ADP, and serotonin, although Whaun demonstrated that their uptake and storage of radiolabeled serotonin was as effective as that of adult platelets (6). In addition,...

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“…We investigated changes in Ca ionomycin, which dissipates the extra/intracellular calcium gradient (26,27). Under these conditions, increasing concentrations of Ca 2þ o still caused a concentration-dependent increment of PTHrP production (Fig.…”

Section: Ca 2þ I and Pthrp Productionmentioning

confidence: 99%

Calcium stimulates parathyroid hormone-related protein production in Leydig tumor cells through a putative cation-sensing mechanism

Buchs

Manen²,

Bonjour³

et al. 2000

European Journal of Endocrinology

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The production of parathyroid hormone-related protein (PTHrP) is regulated by a variety of hormones and growth factors. Previous research has shown that several PTHrP-producing cells are influenced by extracellular calcium (Ca 2þ o ) concentration, with elevated levels increasing PTH-like activity released by cultured H500 rat Leydig tumor cells through a post-transcriptional mechanism. We have investigated the hypothesis that calcium stimulates PTHrP production in H500 cells by interacting with a cell membrane-associated cation-sensing receptor. Besides increased Ca 2þ o concentration, magnesium and the polycationic antibiotic neomycin also increased PTHrP production in a concentration-dependent manner. In the presence of the calcium ionophore, ionomycin, which markedly elevated cytosolic free calcium, the stimulation by Ca 2þ o of PTHrP could still be detected. These results indicate that increasing Ca 2þ o stimulates PTHrP production, possibly through a putative cell membrane-associated calcium-sensing mechanism. RT-PCR revealed the presence of a very small amount of calcium-sensing receptor coding mRNA.

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Calcium uptake into acini from rat pancreas: Evidence for intracellular ATP-dependent calcium sequestration

Cited by 99 publications

References 60 publications

An intracellular ATP‐dependent calcium pump within the yeast Schizosaccharomyces pombe, encoded by the gene cta3

An intracellular ATP‐dependent calcium pump within the yeast Schizosaccharomyces pombe, encoded by the gene cta3

Deficient Collagen-Induced Activation in the Newborn Platelet

Calcium stimulates parathyroid hormone-related protein production in Leydig tumor cells through a putative cation-sensing mechanism

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