Wyniki wyszukiwania

1

Mitochondrial uncoupling does not influence the stability of the intracellular signal activating plasma membrane calcium channels

100%

Zablocki K., Makowska A., Duszynski J.

Acta Biochimica Polonica

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2001

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tom 48

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nr 1

The effects of various concentrations of thapsigargin, a specific inhibitor of Ca2+ -ATPase in the endoplasmic reticulum (ER) membrane, on calcium homeostasis in lymphoidal T cells (Jurkat) were investigated. Preincubation of these cells suspended in nominally calcium-free medium with 0.1 UM thapsigargin resulted in a complete release of Ca2+ from intracellular calcium stores. When the medium was supplemented with 3 mM CaCl2 the cells maintained constantly elevated level of cytosolic Ca2+ . However, thapsigargin applied at lower concentration produced only a partial depletion of the stores. For example, in the cells pretreated with 1 nM thapsigargin and suspended in calcium-free medium approximately 75% of the calcium content was released from the intracellular stores. The addition of 3 mM CaCl2 to such cell suspension led to a transient increase in cytosolic calcium concentration, followed by a return to a lower steady-state. This phenomenon, related to the refilling of the ER by Ca2+ , allowed to estimate the half-time for the process of cell recovery after activation of store-operated calcium channels. By this approach we have found that carbonyl cyanide m-chlorophenylhydrazone, which has been documented to inhibit calcium entry into Jurkat cells, does not influence the stability of the intracellular signal involved in the activation of store-operated calcium channels.

2

Signal transducer and activator of transcription STAT3 plays a major role in gp130-mediated acute phase protein gene activation

100%

May P., Schniertshauer U., Gerhartz C., Horn F., Heinrich P. C.

Acta Biochimica Polonica

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2003

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tom 50

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nr 3

Interleukin-6 is a potent inducer of acute-phase response gene transcription. The intracellular signal transduction mechanisms by which this and other biological effects of the cytokine are achieved include activation of the JAK-STAT signaling pathway. More specifically, activation of the signal transducers and activators of transcription STAT1, 3, and 5 in response to IL-6 has been described. We examined the relative potency of these three STAT factors for the activation of acute-phase gene promoters in HepG2 cells in a reporter gene-based assay, where specific STAT factors could be activated via recombinant receptor constructs bearing different STAT-recruiting modules. These experiments indicate that amongst the STAT factors known to be activated by IL-6 STAT3 is the most potent activator of acute-phase gene transcription.

3

Lipoxins and aspirin-triggered 15-epi-lipoxins are endogenous components of antiinflammation: Emergence of the counterregulatory side

84%

Serhan C. N.

Archivum Immunologiae et Therapiae Experimentalis

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2001

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tom 49

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nr 3

177-188

4

Participation of phospholipase A2 isoforms in the control of calcium influx into electrically non-excitable cells

67%

Zablocki K., Wasniewska M., Duszynski J.

Acta Biochimica Polonica

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2000

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tom 47

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nr 3

The participation of phospholipase A2 isoforms in capacitative store-operated Ca2+ influx into Jurkat leukemic T and MDCK cells was investigated. Preincubation of Jurkat cells with either bromophenacyl bromide (an inhibitor of secreted phospholipase A2, sPLA2) or Helss (an inhibitor of calcium independent phospholipase A2 iPLA2) resulted in a significant inhibition of the calcium influx. The extent of this inhibition depended on the pH of the extracellular millieu; it increased with alkalisation. The rate of Ca2+ influx into MDCK cells was reduced by bromophenacyl bromide. Preincubation of these cells with Helss resulted in the stimulation of the influx. These observations suggest the participation of different PLA2 isoforms in the regulation of Ca2+ influx. They also show that the extent that PLA2 isoforms control the influx depends on the pH of the medium. Finally, these data indicate that various phospholipase A2 isoforms may play a role in the control of Ca2+ influx in different cell lines.

Ograniczanie wyników

3 Acta Biochimica Polonica

1 Archivum Immunologiae et Therapiae Experimentalis

2 Duszynski J.

2 Zablocki K.

1 Gerhartz C.

1 Heinrich P. C.

1 Horn F.

1 Makowska A.

1 May P.

1 Schniertshauer U.

1 Serhan C. N.

1 Wasniewska M.

1 2003

2 2001

1 2000

Mitochondrial uncoupling does not influence the stability of the intracellular signal activating plasma membrane calcium channels

Signal transducer and activator of transcription STAT3 plays a major role in gp130-mediated acute phase protein gene activation

Lipoxins and aspirin-triggered 15-epi-lipoxins are endogenous components of antiinflammation: Emergence of the counterregulatory side

Participation of phospholipase A2 isoforms in the control of calcium influx into electrically non-excitable cells