phosphorus-radioisotopes and calmidazolium
phosphorus-radioisotopes has been researched along with calmidazolium* in 4 studies
Other Studies
4 other study(ies) available for phosphorus-radioisotopes and calmidazolium
Article | Year |
---|---|
Protein kinase C--catalyzed calponin phosphorylation in swine carotid arterial homogenate.
Calponin, a thin filament-associated protein, inhibits actin-activated myosin ATPase activity, and this inhibition is reversed by phosphorylation. Calponin phosphorylation by protein kinase C and Ca2+/calmodulin-dependent protein kinase II has been shown in purified protein systems but has been difficult to demonstrate in more physiological preparations. We have previously shown that calponin is phosphorylated in a cell-free homogenate of swine carotid artery. The goal of this study was to determine whether protein kinase C and/or Ca2+/calmodulin-dependent protein kinase II catalyzes calponin phosphorylation. Ca2+-dependent calponin phosphorylation was not inhibited by calmodulin antagonists. In contrast, both Ca2+- and phorbol dibutyrate/1-oleoyl-2-acetyl-sn-glycerol dependent calponin phosphorylation were inhibited by the pseudosubstrate inhibitor of protein kinase C and staurosporine. Our results also demonstrate that stimulation with either Ca2+, phorbol dibutyrate, or 1-oleoyl-2-acetyl-sn-glycerol activates endogenous protein kinase C. We interpret our results as clearly demonstrating that the physiological kinase for calponin phosphorylation is protein kinase C and not Ca2+/calmodulin-dependent protein kinase II. We also present data showing that the direct measurement of 32P incorporation into calponin and the indirect measurement of calponin phosphorylation using nonequilibrium pH gradient gel electrophoresis provide similar quantitative values of calponin phosphorylation. Topics: Animals; Antiemetics; Calcium; Calcium-Binding Proteins; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases; Calmodulin; Calmodulin-Binding Proteins; Calponins; Carcinogens; Carotid Arteries; Chelating Agents; Diglycerides; Egtazic Acid; Electrophoresis; Enzyme Inhibitors; Imidazoles; Microfilament Proteins; Okadaic Acid; Organ Culture Techniques; Peptide Fragments; Phorbol 12,13-Dibutyrate; Phosphorus Radioisotopes; Phosphorylation; Protein Kinase C; Staurosporine; Sulfonamides; Swine; Trifluoperazine; Vasodilator Agents | 1998 |
PKC phosphorylation disrupts gap junctional communication at G0/S phase in clone 9 cells.
Gap junctional communication during the progression of cell cycle from quiescent G0 to S phase was examined in cultured clone 9 rat liver cells. The transfer of scrape-loaded fluorescent dye was suppressed immediately after the stimulation of cell cycle progression in a synchronized cell population. Northern blot analysis showed that the temporal disturbance of gap junctional communication in cells passing from G0 to S phase did not result from transcriptional down-regulation of connexin 43. It was also found that the PKC inhibitor, calphostin C, was able to restore intercellular communication in serum stimulated cells. Data suggest a control mechanism by PKC mediated phosphorylation in the regulation of gap junction function which is vulnerable to cell cycling. The loss of gap junctional communication correlated with the increased phosphorylation of connexin 43 on serine residues in clone 9 cells. Topics: Animals; Calcium-Calmodulin-Dependent Protein Kinases; Carbazoles; Cell Communication; Cells, Cultured; Clone Cells; Connexin 43; Enzyme Inhibitors; Fluorescent Dyes; Gap Junctions; Imidazoles; Indoles; Liver; Naphthalenes; Phosphorus Radioisotopes; Phosphorylation; Protein Kinase C; Pyrroles; Rats; Resting Phase, Cell Cycle; S Phase; Transcription, Genetic | 1997 |
Increased phosphorylation of Ca2+/calmodulin-dependent protein kinase II and its endogenous substrates in the induction of long-term potentiation.
Induction of long-term potentiation in the CA1 region of hippocampal slices is associated with increased activity of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) (Fukunaga, K., Stoppini, L., Miyamoto, E., and Muller, D. (1993) J. Biol. Chem. 268, 7863-7867). Here we report that application of high but not low frequency stimulation to two groups of afferents in the CA1 region of 32P-labeled slices resulted in the phosphorylation of two major substrates of this enzyme, synapsin I and microtubule-associated protein 2, as well as in the autophosphorylation of CaM kinase II. Furthermore, immunoblotting analysis revealed that long term potentiation induction was associated with an increase in the amount of CaM kinase II in the same region. All these changes were prevented when high frequency stimulation was applied in the presence of the N-methyl-D-aspartate receptor antagonist, D-2-amino-5-phosphonopentanoate. These results indicate that activation of CaM kinase II is involved in the induction of synaptic potentiation in both the postsynaptic and presynaptic regions. Topics: Animals; Calcium-Calmodulin-Dependent Protein Kinases; Calmodulin; Electric Stimulation; Hippocampus; Imidazoles; In Vitro Techniques; Kinetics; Long-Term Potentiation; Macromolecular Substances; Male; Microtubule-Associated Proteins; Phosphoproteins; Phosphorus Radioisotopes; Phosphorylation; Pyramidal Cells; Rats; Rats, Sprague-Dawley; Synapses; Synapsins | 1995 |
Cytoplasmic dynein undergoes intracellular redistribution concomitant with phosphorylation of the heavy chain in response to serum starvation and okadaic acid.
Cytoplasmic dynein is a microtubule-binding protein which is considered to serve as a motor for retrograde organelle movement. In cultured fibroblasts, cytoplasmic dynein localizes primarily to lysosomes, membranous organelles whose movement and distribution in the cytoplasm have been shown to be dependent on the integrity of the microtubule cytoskeleton. We have recently identified conditions which lead to an apparent dissociation of dynein from lysosomes in vivo, indicating that alterations in membrane binding may be involved in the regulation of retrograde organelle movement (Lin, S. X. H., and C. A. Collins. 1993. J. Cell Sci. 105:579-588). Both brief serum withdrawal and low extracellular calcium levels induced this alteration, and the effect was reversed upon addition of serum or additional calcium. Here we demonstrate that the phosphorylation state of the dynein molecule is correlated with changes in its intracellular distribution in normal rat kidney fibroblasts. Dynein heavy chain phosphorylation level increased during serum starvation, and decreased back to control levels upon subsequent addition of serum. We found that okadaic acid, a phosphoprotein phosphatase inhibitor, mimicked the effects of serum starvation on both phosphorylation and the intracellular redistribution of dynein from a membrane-associated pool to one that was more soluble, with similar dose dependence for both phenomena. Cell fractionation by differential detergent extraction revealed that a higher proportion of dynein was present in a soluble pool after serum starvation than was found in comparable fractions from control cells. Our data indicate that cytoplasmic dynein is phosphorylated in vivo, and changes in phosphorylation state may be involved in a regulatory mechanism affecting the distribution of this protein among intracellular compartments. Topics: 8-Bromo Cyclic Adenosine Monophosphate; Adenosine Triphosphate; Alkaloids; Animals; Bucladesine; Calcimycin; Calmodulin; Cell Line; Colforsin; Culture Media; Cytoplasm; Dyneins; Edetic Acid; Ethers, Cyclic; Imidazoles; Kidney; Kinetics; Macromolecular Substances; Okadaic Acid; Phosphates; Phosphoprotein Phosphatases; Phosphorus Radioisotopes; Phosphorylation; Rats; Staurosporine; Sulfonamides; Tetradecanoylphorbol Acetate | 1994 |