scholarly journals Decreased Catalytic Activity and Expression of Protein Kinase C Isozymesin Teenage Suicide Victims

2004 ◽  
Vol 61 (7) ◽  
pp. 685 ◽  
Author(s):  
Ghanshyam N. Pandey ◽  
Yogesh Dwivedi ◽  
Hooriyah S. Rizavi ◽  
Xinguo Ren ◽  
Robert R. Conley
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Kinase C ◽  
Teenage Suicide

scholarly journals Protein kinase C in rod outer segments: effects of phosphorylation of the phosphodiesterase inhibitory subunit

1996 ◽  
Vol 317 (1) ◽  
pp. 291-295 ◽  
Author(s):  
Igor P. UDOVICHENKO ◽  
Jess CUNNICK ◽  
Karen GONZALEZ ◽  
Alexander YAKHNIN ◽  
Dolores J. TAKEMOTO
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Direct Interaction ◽  
Inhibitory Effect ◽  
Rod Outer Segments ◽  
Visual Transduction ◽  
Gtp Hydrolysis ◽  
Outer Segments ◽  
Kinase C

The inhibitory subunit (PDEγ) of the cGMP phosphodiesterase (PDEαβγ2) in rod outer segments (ROS) realizes its regulatory role in phototransduction by inhibition of PDEαβ catalytic activity. The photoreceptor G-protein, transducin, serves as a transducer from the receptor (rhodopsin) to the effector (PDE) and eliminates the inhibitory effect of PDEγ by direct interaction with PDEγ. Our previous study [Udovichenko, Cunnick, Gonzalez and Takemoto (1994) J. Biol. Chem. 269, 9850–9856] has shown that PDEγ is a substrate for protein kinase C (PKC) from ROS and that phosphorylation by PKC increases the ability of PDEγ to inhibit PDEαβ catalytic activity. Here we report that transducin is less effective in activation of PDEαβ(γp)2 (a complex of PDEαβ with phosphorylated PDEγ, PDEγp) than PDEαβγ2. PDEγp also increases the rate constant of GTP hydrolysis of transducin (from 0.16 s-1 for non-phosphorylated PDEγ to 0.21 s-1 for PDEγp). These data suggest that phosphorylation of the inhibitory subunit of PDE by PKC may regulate the visual transduction cascade by decreasing the photoresponse.

Regulation of Jak2 tyrosine kinase by protein kinase C during macrophage differentiation of IL-3–dependent myeloid progenitor cells

Blood ◽  
2000 ◽  
Vol 95 (5) ◽  
pp. 1626-1632 ◽  
Author(s):  
Panu E. Kovanen ◽  
Ilkka Junttila ◽  
Kati Takaluoma ◽  
Pipsa Saharinen ◽  
Leena Valmu ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Progenitor Cells ◽  
Growth Arrest ◽  
Macrophage Differentiation ◽  
Myeloid Progenitor ◽  
Kinase C ◽  
Myeloid Progenitor Cells

Differentiation of macrophages from myeloid progenitor cells depends on a discrete balance between cell growth, survival, and differentiation signals. Interleukin-3 (IL-3) supports the growth and survival of myeloid progenitor cells through the activation of Jak2 tyrosine kinase, and macrophage differentiation has been shown to be regulated by protein kinase C (PKC). During terminal differentiation of macrophages, the cells lose their mitogenic response to IL-3 and undergo growth arrest, but the underlying signaling mechanisms have remained elusive. Here we show that in IL-3–dependent 32D myeloid progenitor cells, the differentiation-inducing PKC isoforms PKC- and PKC-δ specifically caused rapid inhibition of IL-3–induced tyrosine phosphorylation. The target for this inhibition was Jak2, and the activation of PKC by 12-O-tetradecanoyl-phorbol-13-acetate treatment also abrogated IL-3–induced tyrosine phosphorylation of Jak2 in Ba/F3 cells. The mechanism of this regulation was investigated in 32D and COS7 cells, and the inhibition of Jak2 required catalytic activity of PKC-δ and involved the phosphorylation of Jak2 on serine and threonine residues by the associated PKC-δ. Furthermore, PKC-δ inhibited the in vitro catalytic activity of Jak2, indicating that Jak2 was a direct target for PKC-δ. In 32D cells, the inhibition of Jak2 either by PKC-δ, tyrosine kinase inhibitor AG490, or IL-3 deprivation caused a similar growth arrest. Reversal of PKC-δ–mediated inhibition by the overexpression of Jak2 promoted apoptosis in differentiating 32D cells. These results demonstrate a PKC-mediated negative regulatory mechanism of cytokine signaling and Jak2, and they suggest that it serves to integrate growth-promoting and differentiation signals during macrophage differentiation.

scholarly journals Yeast phenotype classifies mammalian protein kinase C cDNA mutants.

1993 ◽  
Vol 13 (8) ◽  
pp. 4728-4735 ◽  
Author(s):  
H Riedel ◽  
L Su ◽  
H Hansen
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Phorbol Ester ◽  
Colony Size ◽  
Receptor Protein ◽  
Amino Terminal ◽  
Kinase C ◽  
Carboxyl Terminal ◽  
Pkc Alpha

The phorbol ester receptor protein kinase C (PKC) gene family encodes essential mediators of eukaryotic cellular signals. Molecular dissection of their mechanisms of action has been limited in part by the lack of random mutagenesis approaches and by the complexity of signaling pathways in mammalian cells which involve multiple PKC isoforms. Here we present a rapid screen which permits the quantification of mammalian PKC activity phenotypically in the yeast Saccharomyces cerevisiae. Bovine PKC alpha cDNA is functionally expressed in S. cerevisiae. This results in a phorbol ester response: a fourfold increase in the cell doubling time and a substantial decrease in yeast colony size on agar plates. We have expressed pools of bovine PKC alpha cDNAs mutagenized by Bal 31 deletion of internal, amino-terminal, or carboxyl-terminal sequences and have identified three classes of mutants on the basis of their distinct yeast phenotypes. Representatives of each class were analyzed. An internal deletion of amino acids (aa) 172 to 225 displayed ligand-dependent but reduced catalytic activity, an amino-terminal truncation of aa 1 to 153 displayed elevated and ligand-independent activity, and a carboxyl-terminal 26-aa truncation (aa 647 to 672) lacked activity under any conditions. Additional mutations confirmed the distinct functional characteristics of these classes. Our data show that deletion of the V1 and C1 regions results in elevated basal catalytic activity which is still Ca2+ responsive. Internal deletions in the V2 and C2 regions do not abolish phorbol ester or Ca2+ regulation of PKC activity, suggesting that most of the C2 domain is not essential for phorbol ester stimulation and most of the regulatory domain is dispensable for Ca2+ regulation of PKC activity. These distinct activities od the PKC mutants correlate with a specific and proportional yeast phenotype and are quantified on agar plates by yeast colony size. This provides a phenotypic screen which is suitable to identity rare, randomly altered but active mammalian PKC mutants. It quantifies their catalytic and biological activities in response to PKC activators or inhibitors for a systematic mapping of PKC structure and function or PKC-drug interaction.

Effects of withdrawal of dopamine on translocation of protein kinase C isozymes and prolactin secretion in rat lactotroph-enriched pituitary cells. Modulation of substance P-mediated responses

1997 ◽  
Vol 18 (3) ◽  
pp. 181-191 ◽  
Author(s):  
S E Mau
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Substance P ◽  
Prolactin Secretion ◽  
Particulate Fraction ◽  
Pituitary Cells ◽  
Resting Cells ◽  
Kinase C ◽  
Pkc Isozymes

ABSTRACT The present study deals with the effects of withdrawal of dopamine (DA) on the translocation of protein kinase C (PKC) isozymes and release of prolactin (Prl) in resting- and substance P (SP)-stimulated cultures of enriched rat pituitary lactotrophs. Following a brief tonic input (10 min), DA withdrawal induced a redistribution of PKC α- and β-immunoreactivity (IR) to the particulate fraction with maximal levels, attained after 5 min, remaining translocated for 20 min. DA withdrawal prolonged the effect of SP-induced translocation of PKC α-and β-IR. Similar effects were detected when the catalytic activity of PKC in response to DA withdrawal was evaluated. Thus, DA washout redistributed PKC catalytic activity and prolonged the effect of SP on catalytical PKC translocation to the particulate fraction. Pretreatment of cells with the protein kinase A inhibitor, rp-adenosine-3′,5′-cyclic monophosphothionate (rp-cAMP), reduced the amount of PKC α- and β-IR redistributed after DA withdrawal. Furthermore, this treatment also reduced the DA withdrawal effect on SP-mediated translocation of PKC α- and β-IR. Methoxyverapamil, a blocker of voltage-gated Ca2+ channels, completely inhibited the redistribution of PKC isozymes after DA withdrawal, but also reduced the potentiating effect of DA withdrawal on SP-induced redistribution of PKC isozyme-IR. In perifused enriched lactotrophs, DA withdrawal induced a release of Prl that lasted 45-55 min and prolonged the effect of SP on Prl secretion. rp-cAMP did not significantly affect Prl release due to DA removal, but the prolonging effect of DA withdrawal on SP-induced Prl secretion was abolished. Methoxyverapamil completely abolished the rebound release of Prl after DA withdrawal, and the potentiating effect of DA removal on SP-mediated Prl release was also diminished. Readdition of DA after DA withdrawal was able to suppress the translocation of PKC isozyme-IR and catalytic activity and to reduce the release of Prl to baseline levels. Moreover, readdition of DA reduced the potentiating effects of DA withdrawal on the same parameters after SP-stimulation of cells. On the basis of these results it is concluded that in resting cells following DA withdrawal prolactin is released and specific PKC isozymes and concomitant catalytic activity are translocated to the particulate fraction in enriched lactotrophs. While cAMP/PKA and influx of Ca2+ seem to work in concert in translocating PKC, influx of Ca2+ is the primary mechanism responsible for the rebound release of Prl after DA withdrawal. DA withdrawal exerts a potentiating effect on SP-induced PKC translocation and Prl release. It is suggested that the biochemical events involved in these processes are cAMP/PKA and Ca2+ influx.

scholarly journals Phosphorylation by protein kinase C decreases catalytic activity of avian phospholipase C-β

1999 ◽  
Vol 338 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Theresa M. FILTZ ◽  
Michelle L. CUNNINGHAM ◽  
Kara J. STANIG ◽  
Andrew PATERSON ◽  
T. Kendall HARDEN
Keyword(s):  
Enzyme Activity ◽  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Phospholipase C ◽  
G Protein ◽  
Erythrocyte Membranes ◽  
Basal Activity ◽  
Kinase C

The potential role of protein kinase C (PKC)-promoted phosphorylation has been examined in the G-protein-regulated inositol lipid signalling pathway. Incubation of [32P]Pi-labelled turkey erythrocytes with either the P2Y1 receptor agonist 2-methylthioadenosine triphosphate (2MeSATP) or with PMA resulted in a marked increase in incorporation of 32P into the G-protein-activated phospholipase C PLC-βT. Purified PLC-βT also was phosphorylated by PKC in vitro to a stoichiometry (mean±S.E.M.) of 1.06±0.2 mol of phosphate/mol of PLC-βT. Phosphorylation by PKC was isoenzyme-specific because, under identical conditions, mammalian PLC-β2 also was phosphorylated to a stoichiometry near unity, whereas mammalian PLC-β1 was not phosphorylated by PKC. The effects of PKC-promoted phosphorylation on enzyme activity were assessed by reconstituting purified PLC-βT with turkey erythrocyte membranes devoid of endogenous PLC activity. Phosphorylation resulted in a decrease in basal activity, AlF4--stimulated activity, and activity stimulated by 2MeSATP plus guanosine 5´-[γ-thio]triphosphate in the reconstituted membranes. The decreases in enzyme activities were proportional to the extent of PKC-promoted phosphorylation. Catalytic activity assessed by using mixed detergent/phospholipid micelles also was decreased by up to 60% by phosphorylation. The effect of phosphorylation on Gqα-stimulated PLC-βT in reconstitution experiments with purified proteins was not greater than that observed on basal activity alone. Taken together, these results illustrate that PKC phosphorylates PLC-βT in vivo and to a physiologically relevant stoichiometry in vitro. Phosphorylation is accompanied by a concomitant loss of enzyme activity, reflected as a decrease in overall catalytic activity rather than as a specific modification of G-protein-regulated activity.

Protein kinase C in mouse kidney: subcellular distribution and endogenous substrates

1988 ◽  
Vol 66 (4) ◽  
pp. 262-272 ◽  
Author(s):  
Avihu Boneh ◽  
Harriet S. Tenenhouse
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Brush Border ◽  
Subcellular Distribution ◽  
Brush Border Membrane ◽  
Mouse Kidney ◽  
Kidney Cortex ◽  
Kinase C ◽  
Endogenous Substrates

The subcellular distribution, kinetic properties, and endogenous substrates of calcium-activated, phospholipid-dependent protein kinase (protein kinase C) were examined in mouse kidney cortex. Protein kinase C associated with the particulate, mitochondrial, and brush border membrane fractions was assayed after solubilization in 0.2% Triton X-100 under conditions shown to be noninhibitory to catalytic activity. Of recovered activity, 52% was associated with the cytosolic fraction; mitochondrial and brush border membrane associated protein kinase C constituted 12 and 3%, respectively, of the activity recovered in the particulate fraction. Protein kinase C associated with brush border membranes exhibited a high affinity for ATP (apparent Km = 62 ± 10 μM) and the highest apparent maximal velocity (1146 ± 116 pmol P/(mg protein∙min)) of the renal fractions examined. Maximal stimulation of protein kinase C by diacylglycerol (in the presence of phosphatidylserine) was achieved at both 25 and 300 μM calcium in all renal fractions. These results are consistent with previous reports demonstrating that diacylglycerol increases the apparent affinity of protein kinase C for calcium. Phorbol 12-myristate 13-acetate, but not 4α-phorbol, was able to substitute for diacylglycerol and stimulate cytosolic and particulate renal protein kinase C. 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride, a specific inhibitor of protein kinase C, led to significant inhibition of catalytic activity in all renal subcellular fractions. Endogenous substrates for protein kinase C were demonstrated in renal cytosolic (26, 45, 63, and 105 kilodaltons (kDa)), particulate (26, 33, 68, and 105 kDa), mitochondrial (43 kDa), and brush border membrane (26, 41, 52, 88, and 105 kDa) fractions. The possible physiological significance of protein kinase C in mammalian kidney is discussed.

scholarly journals Phosphorylation by protein kinase C decreases catalytic activity of avian phospholipase C-β

1999 ◽  
Vol 338 (2) ◽  
pp. 257 ◽  
Author(s):  
Theresa M. FILTZ ◽  
Michelle L. CUNNINGHAM ◽  
Kara J. STANIG ◽  
Andrew PATERSON ◽  
T.Kendall HARDEN
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Kinase C
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