• Title/Summary/Keyword: calcium-dependent activity

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Cell Cycle-Dependent Activity Change of Calcium/Calmodulin-Dependent Protein Kinase II (칼슘/calmodulin-의존적 단백질 인산화 효소 II의 동물세포 주기에 따른 활성도 변화에 관한 연구)

  • Koung, Hoon-Suh
    • The Journal of Natural Sciences
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    • v.9 no.1
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    • pp.1-7
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    • 1997
  • Calcium/calmodulin-dependent protein kinase II (CaMK-II) is responsible for the phosphorylation of proteins involved in various cellular functions. Since the level of intracellular calcium ($Ca_2+$) oscillate during the cell cycle, it is expected that the activity of CaMK-II is also dependent on the cell cycle. The kinase activity in NIH3T3 cells which were arrested at or released from certain phase of the cell cycle was measured and compared to that in the normally growing asynchronous control cells to investigate whether the activity of this kinase is cell cycle-dependent. Cells were arrested at G0, G1, G1/S, G2/M and M phase, respectively by use of various drugs which do not have any effect on the kinase activity of CaMK-II at G0, G1, G1/s and G2/M phase was similar to that of the control cells, whereas lower at M. Calcium-independent activity of CaMK_II by autophosphorylation was higher at M and, thus, higher autonomy at M, which represented the physiologically relevant activity of CaMK-II. A similar pattern of activity change of the kinase was demonstrated during the cell cycle of synchronized cells which were released from G1 arrest. These results indicate that the activity of CaMK-11 is cell cycle-dependent and is activity during the mitosis.

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Activation of Phospholipase D in Rat Thymocytes by Sphingosine

  • Lee, Young-kyun;Choi, Myung-Un
    • Bulletin of the Korean Chemical Society
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    • v.23 no.10
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    • pp.1451-1489
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    • 2002
  • Sphingosine is known to regulate a wide range of cell physiology including growth, differentiation, and apoptosis. In this study, we examined the effect of sphingosine on the phospholipase D (PLD) activity in rat thymocytes. Sphingosine potently stimulated PLD in the absence of extracellular calcium, while depletion of intracellular calcium by BAPTA/AM treatment completely blocked activation of PLD by sphingosine. Sphingosine-induced increase of the intracellular calcium concentration was confirmed using a fluorescent calcium indicator Fluo-3/AM. A phosphoinositide-specific phospholipase C inhibitor U73122 partially inhibited the stimulation of PLD by sphingosine. When mouse PLD2 gene was transfected into mouse thymoma EL4 cells, which lack intrinsic PLD activity, sphingosine could stimulate PLD2 significantly while overexpression of human PLD1 had no effect. Taken together, the sphingosine-stimulated PLD activity in rat thymocytes is dependent on the mobilization of intracellular calcium and appears to be due to the PLD2 isoform.

Physiological Changes in the Cichlid Fish Maylandia lombardoi according to Various Calcium Concentrations in Rearing Water (환경수 내의 다양한 Ca2+ 농도에 따른 시클리드(Maylandia lombardoi)의 생리적 변화)

  • Moon, Hye-Na;Yeo, In-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.2
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    • pp.184-189
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    • 2016
  • We investigated physiological changes in the freshwater cichlid, fish Maylandia lombardoi in response to different calcium concentrations in rearing water. Four different calcium concentrations (0, 2, 4 and 8 mM) were prepared in rearing water by the addition of ionized calcium (CaO) to examine the effect of various calcium concentrations in rearing water on physiological changes in the cichlid fish, M. lombardoi. Total calcium concentrations in plasma and body increased in a calcium concentration-dependent manner and reached the maximum at 8-mM calcium concentration. Stress-related cortisol was significantly decreased in the 8-mM group compared to the control group (0 mM). Lysozyme activity also significantly decreased in the 8-mM group. These results suggest that CaO in rearing water increases calcium uptake in fish and affects the body by decreasing stress and improving immunity in fish.

LIGHT DEPENDENT CHANNELS AND EXCHANGER IN THE INTERNAL LIMITING MEMBRANE OF VERTEBRATE EYE

  • Hyuk Jung;Kim, You-Young
    • Journal of Photoscience
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    • v.6 no.2
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    • pp.77-83
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    • 1999
  • Calcium has a variety of functions in neuron and muscle cells and blood clotting, especially in the visual system where dark adapted rods cotransport with Na$\^$+/ into the cell. An influx of Ca$\^$++/ flows out of the cell through the Na$\^$+/-Ca$\^$++/ exchanger. By using a modified Using chamber in order to bring in vivo environment close, we have known that Ca$\^$++/ blocks the activity of guanylate cyclase, in consequence, having an effect on the amplitude of electroretinogram (ERG). We have measured the Ca$\^$++/, K$\^$+/, and Na$\^$+/ concentration in dark and light adapted bullfrog's (Rana catesbeiana) vitreous humor. The calcium concentration of the light adapted bullfrog's vitreous humor was higher than that of the dark adapted bullfrog's vitreous humor This means that ion activity between the photoreceptor and vitreous humor side is light dependent and we have found that a Ca$\^$++/ channel and Ca$\^$++/K$\^$+/ exchanger exist in the vitreous humor side. Taken together permeability of Ca$\^$++/, K$\^$+/ and K$\^$+/ ion internal limiting membrane faced in the vitreous humor side has light-dependent activity during the illumination.

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THE NEW FINDING OF A LIGHT DEPENDENT $Ca^{2+}$ CHANNEL AND $Na^+-Ca^{2+}$ EXCHANGER IN THE VERTEBRATE RETINA (II)

  • Kim, Yun-Sook;Jung, Hyuk;Park, Chang-Suck;Woo, Suk-Hyang;Kim, Hyun-Jung;Kim, You-Young
    • Journal of Photoscience
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    • v.3 no.3
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    • pp.133-136
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    • 1996
  • Calcium modulates the activity of guanylate cyclase and plays a key role in dark and light adaptation in the visual system. We have measured the Ca$^{2+}$, K$^+$ and Na$^+$ concentration in dark and light adapted bullfrog's (Rana catesbeiana) vitreous humor by using the atomic absorption spectrophotometer. The calcium concentration of the light adapted bullfrog's vitreous humor was higher than that of the dark adapted bullfrog's vitreous humor. This means that ion activity between the photoreceptor and vitreous humor side is light dependent and we have found that a Ca$^{2+}$ channel and Na$^+$ - Ca$^{2+}$ exchanger exist in the vitreous humor.

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Study on the Action by PAF on IL-1 Modulation in Alveolar Macrophages: Involvement of Endogenous Arachidonate Metabolites and Intracellular $Ca^{++}$ Mobilization

  • Lee, Ji-Hee;Kim, Won-Ki;Hah, Jong-Sik
    • The Korean Journal of Physiology and Pharmacology
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    • v.2 no.2
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    • pp.241-249
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    • 1998
  • Platelet-activating factor(PAF) enhanced interleukin-1(IL-1) activity by the interaction with a specific receptor in rat alveolar macrophages. In this study, we investigated the role of endogenous arachidonate metabolites and intracellular calcium mobilization in the PAF-induced IL-1 activity. Alveolar macrophages were preincubated with 5-lipoxygenase and cyclooxygenase inhibitors 30 min before the addition of PAF and lipopolysaccharide(LPS). After 24h culture, IL-1 activity was measured in the supernate of sample using the thymocyte proliferation assay. Inhibition of 5-lipoxygenase by nordihydroguaiaretic acid and AA-861 completely blocked the PAF-induced enhancement of IL-1 activity with $IC_{50}\;of\;2\;{\mu}M\;and\;5\;{\mu}M$, respectively. In contrast, the inhibition of cyclooxygenase pathway by indomethacin and ibuprofen resulted in the potentiation in PAF-induced IL-1 activity with maximal effect at $1\;{\mu}M\;and\;5\;{\mu}M$, respectively. In addition, leukotriene $B_4$ and prostaglandin $E_2$ production were observed in PAF-stimulated alveolar macrophage culture. As could be expected, 5-lipoxygenase and cyclooxygenase inhibitors abolished PAF- stimulated leukotriene $B_4$ and prostaglandin $E_2$ production, respectively. The effects of PAF on intracellular calcium mobilization in alveolar macrophages were evaluated using the calcium-sensitive dye fura-2 at the single cell level. PAF at any dose between $10^{-16}\;and\;10^{-8}$ M did not increase intracellular calcium. Furthermore, there was no effective change of intracellular calcium level when PAF was added to alveolar macrophages in the presence of LPS or LPS+LTB4, and 4, 24 and 48h after treatment of these stimulants. Together, the results indicate that IL-1 activity induced by PAF is differently regulated through subsequent induction of endogenous 5-lipoxygenase and cyclooxygenase pathways, but not dependent on calcium signalling pathway.

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Antiplatelet Activity of 2-(4-Cyanophenyl) amino-1,4-naphthalenedione-3-pyridinium perchlorate (PQ5) (2-(4-시아노페닐) 아미노 -1,4-나프탈렌디온-3-피리디니움 퍼클로레이트 (PQ5)의 항혈소판작용)

  • 김도희;이수환;최소연;문창현;문창현;김대경;유충규
    • YAKHAK HOEJI
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    • v.43 no.6
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    • pp.809-817
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    • 1999
  • The effect of 2-(4-cyanophenyl)amino-1,4-naphthalenedione-3-pyridinium perchlorate (PQ5) on pla-telet aggregation and its action mechanisms were investigated with rat platelet. PQ5 inhibited the platelet aggregation induced by collagen ($6{\;}{\mu\textrm{g}}/ml$), thrombin (0.4 U/ml) and A23187 ($3{\mu}M$) in concentration-dependent manner with $IC_{50}$ values of 5.50, 25.89 and $37.12{\;}{\mu}M$, respectively. PQ5 also significantly reduced the thromboxane $A_2$ (TXA2) formation in a concentration dependent manner. The collagen-induced arachidonic acid (AA) release in [-3H]-AA incorporated platelet, an indication of the phospholipase $A_2$ activity, was decreased by PQ5 pretreatment PQ5 significantly inhibited the activity of thormboxane synthase only at high concentration ($100{\mu}M$), but did not affect the cyclooxygenase activity at all. Collagen-induced ATP release was significantly reduced by PQ5. Calcium-induced platelet aggregation experiment suggests that the elevation of intracellular free $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) by collagen stimulation is decreased by the pretreatment of PQ5, which is due to the inhibition of calcium release from intracellular store and influx from outside of the cell. PQ5 did not showed the effect of anticoagulation as prothrombin time (PT) or activated partial thromboplastin time (APTT). Form these results, it is suggested that PQ5 exerts its antiplatelet activity through the inhibition of the intracellular $Ca^{2+}$ mobilization and the decrease of the $TXA_2$ synthesis.

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Effects of Calcium Antagonists on Superoxide Generation, NADPH Oxidase Activity and Phagocytic Activity in Activated Neutrophils (칼슘 길항제가 활성화된 호중구에서의 $O_{\overline{2}}$의 생성, NADPH oxidase활성도 및 탐식작용에 미치는 영향)

  • Lee, Chung-Soo;Han, Eun-Sook;Lee, Kwang-Soo
    • The Korean Journal of Pharmacology
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    • v.23 no.1
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    • pp.33-44
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    • 1987
  • NADPH oxidase dependent superoxide generation and phagocytosis in neutrophils stimulated with opsonized zymosan or heat aggregated IgG were coincided with the process of calcium uptake. The responses in activated neutrophils were enhanced with increasing concentrations of extracellular calcium and these effects were significantly inhibited by calcium chelators, EGTA and EDTA. The superoxide generation in activated neutrophils was reduced by dantrolene and chlorpromazine. Calcium antagonists, bepredil, diltiazem, verapamil, nifedipine and nimodipine effectively inhibited the calcium uptake, superoxide generation and phagocytosis in activated neutrophils, and NADPH oxidase activity was also inhibited. The results suggest that calcium antagonists may inhibit the superoxide generation and phagocytosis in activted neurtophils by the inhibition of calcium influx and by the action on intracellular redistribution of calcium and NADPH oxidase system.

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Enhanced Calreticulin Expression Promotes Calcium-dependent Apoptosis in Postnatal Cardiomyocytes

  • Lim, Soyeon;Chang, Woochul;Lee, Byoung Kwon;Song, Heesang;Hong, Ja Hyun;Lee, Sunju;Song, Byeong-Wook;Kim, Hye-Jung;Cha, Min-Ji;Jang, Yangsoo;Chung, Namsik;Choi, Soon-Yong;Hwang, Ki-Chul
    • Molecules and Cells
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    • v.25 no.3
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    • pp.390-396
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    • 2008
  • Calreticulin (CRT) is one of the major $Ca^{2+}$ binding chaperone proteins of the endoplasmic reticulum (ER) and an unusual luminal ER protein. Postnatally elevated expression of CRT leads to impaired development of the cardiac conductive system and may be responsible for the pathology of complete heart block. In this study, the molecular mechanisms that affect $Ca^{2+}$-dependent signal cascades were investigated using CRT-overexpressing cardiomyocytes. In particular, we asked whether calreticulin plays a critical role in the activation of $Ca^{2+}$-dependent apoptosis. In the cells overexpressing CRT, the intracellular calcium concentration was significantly increased and the activity of PKC and level of SECAR2a mRNA were reduced. Phosphorylation of Akt and ERKs decreased compared to control. In addition the activity of the anti-apoptotic factor, Bcl-2, was decreased and the activities of pro-apoptotic factor, Bax, p53 and caspase 8 were increased, leading to a dramatic augmentation of caspase 3 activity. Our results suggest that enhanced CRT expression in mature cardiomyocytes disrupts intracellular calcium regulation, leading to calcium-dependent apoptosis.

CBP-Mediated Acetylation of Importin α Mediates Calcium-Dependent Nucleocytoplasmic Transport of Selective Proteins in Drosophila Neurons

  • Cho, Jae Ho;Jo, Min Gu;Kim, Eun Seon;Lee, Na Yoon;Kim, Soon Ha;Chung, Chang Geon;Park, Jeong Hyang;Lee, Sung Bae
    • Molecules and Cells
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    • v.45 no.11
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    • pp.855-867
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    • 2022
  • For proper function of proteins, their subcellular localization needs to be monitored and regulated in response to the changes in cellular demands. In this regard, dysregulation in the nucleocytoplasmic transport (NCT) of proteins is closely associated with the pathogenesis of various neurodegenerative diseases. However, it remains unclear whether there exists an intrinsic regulatory pathway(s) that controls NCT of proteins either in a commonly shared manner or in a target-selectively different manner. To dissect between these possibilities, in the current study, we investigated the molecular mechanism regulating NCT of truncated ataxin-3 (ATXN3) proteins of which genetic mutation leads to a type of polyglutamine (polyQ) diseases, in comparison with that of TDP-43. In Drosophila dendritic arborization (da) neurons, we observed dynamic changes in the subcellular localization of truncated ATXN3 proteins between the nucleus and the cytosol during development. Moreover, ectopic neuronal toxicity was induced by truncated ATXN3 proteins upon their nuclear accumulation. Consistent with a previous study showing intracellular calcium-dependent NCT of TDP-43, NCT of ATXN3 was also regulated by intracellular calcium level and involves Importin α3 (Imp α3). Interestingly, NCT of ATXN3, but not TDP-43, was primarily mediated by CBP. We further showed that acetyltransferase activity of CBP is important for NCT of ATXN3, which may acetylate Imp α3 to regulate NCT of ATXN3. These findings demonstrate that CBP-dependent acetylation of Imp α3 is crucial for intracellular calcium-dependent NCT of ATXN3 proteins, different from that of TDP-43, in Drosophila neurons.