Matías Calcerrada

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In this study we report that protein kinase C zeta (PKC zeta), one of the atypical isoforms of the PKC family located predominantly in cytosol, is redistributed by C2-ceramide treatment in isolated hepatocytes. PKC zeta increased in membrane and nuclear fractions after 30 min of treatment with C2-ceramide in a dose- and time-dependent manner. The action of(More)
In this study we have analyzed the distribution of protein kinase C isoforms in cytosol, membrane, and nucleus in HL60 cells. Furthermore, we have studied the redistribution of these isoforms after cyclic AMP treatment. Protein kinase C localization and cyclic AMP-induced translocation was demonstrated by Western blot analysis. Cytosol, membrane and nucleus(More)
The action of platelet activating factor (PAF) on subcellular distribution and activity of protein kinase C (PKC) isoforms in rabbit platelets was analyzed. The results showed an increase of PKC alpha in membrane fraction, concomitantly with a decrease in cytosolic fraction after 5 min PAF treatment, indicating that a translocation of PKC alpha occurred. In(More)
The effect of platelet-activating factor (PAF) on protein tyrosine phosphorylation was studied in rat brain slices. PAF induced a time- and concentration-dependent increase in tyrosine phosphorylation of a doublet of approximately 125 kDa. These proteins were identified by immunoprecipitation as p125(FAK) and p130(Cas), using monoclonal antibodies. This(More)
When isolated rat liver nuclei were treated with platelet-activating factor (PAF), a rapid increase in the mass of diacylglycerol (DAG) occurred. This effect was dose- and time-dependent. The maximum effect was observed after 1 min of 10(-7) M PAF treatment. A concomitant decrease of polyphosphoinositides and phosphatidic acid (PA) levels was observed.(More)
The effect of platelet-activating factor (PAF) on protein tyrosine phosphorylation was studied in rat hippocampal slices. PAF caused an increase in the tyrosine phosphorylation of two phosphoproteins, which we identified by immunoprecipitation assays as the focal adhesion kinase p125FAK and crk-associated substrate p130Ca. The PAF effect was time- and(More)
The sphingolipids, sphingosine (SPH), sphingosylphosphorylcholine (SPC) and psycosine induce a rapid and transient rise in nuclear free Ca2+ concentration in a dose dependent manner. To determine whether these sphingolipids act by a IP3-dependent pathway, we tested the increase of Ca2+ in the presence of heparin, an antagonist of IP3 receptor or U70122, an(More)
Sphingosylphosphorylcholine (SPC) caused a rapid increase of Ca2+ concentration in isolated brain nuclei. This effect was prevented by nimodipine, an inhibitor of L-type Ca2+ channels, and by thapsigargin, an inhibitor of Ca(2+)-ATPase. Neither heparin nor U73122 modified this effect, suggesting that phospholipase C activation and inositol(More)
In the present study, experiments were conducted to determine the effect of platelet-activating factor (PAF) on (Na+,K+)-ATPase in rat cerebral cortex. PAF, but not lysoPAF, inhibited (Na+,K+)ATPase activity, in a dose- and time-dependent manner, 10(-7) to 10(6) M being the most effective dose. These effects were abolished in the presence of PCA-4248, a PAF(More)
We examined the effect of ET-1 on cyclic AMP levels in rat cerebral cortex. The peptide caused a concentration-dependent increase of [(3)H]cyclic AMP accumulation after 10 min of treatment. This effect was due to adenosine accumulation since it was inhibited by the treatment with adenosine deaminase. ET-1, apart from being able to increase cyclic AMP, also(More)