共查询到20条相似文献,搜索用时 31 毫秒
1.
Abstract: Recently, two of the 10 vertebrate protein kinase C (PKC) isoforms, PKCβII and PKCε, have been shown to bind specifically to actin filaments, suggesting that these kinases may regulate cytoskeletal dynamics. Here, we present evidence that two PKCs from the marine mollusk Aplysia californica , PKC Apl I, a Ca2+ -activated PKC, and PKC Apl II, a Ca2+ -independent PKC most similar to PKCε and η, also bind F-actin. First, they both cosedimented with purified actin filaments in a phorbol ester-dependent manner. Second, they both translocated to the Triton-insoluble fraction of the nervous system after phorbol ester treatment. PKC Apl II could also partially translocate to actin filaments and associate with the Triton-insoluble fraction in the absence of phorbol esters. Translocation to purified actin filaments was increased in the presence of a PKC inhibitor, suggesting that PKC phosphorylation reduces PKC bound to actin. Although both kinases bound F-actin, actin was not sufficient to activate the kinases. In support of a physiological role for actin-PKC interactions, immunochemical localization of PKC Apl II in neuronal growth cones revealed a striking colocalization with F-actin. Our results are consistent with a role for actin-PKC interactions in regulating cytoskeletal dynamics in Aplysia . 相似文献
2.
Hideyuki Matsushima Shun Shimohama Motohiko Chachin Takashi Taniguchi Jun Kimura 《Journal of neurochemistry》1996,67(1):317-323
Abstract: We examined protein kinase C (PKC) activity in Ca2+ -dependent PKC (Ca2+ -dependent PKC activities) and Ca2+ -independent PKC (Ca2+ -independent PKC activities) assay conditions in brains from Alzheimer's disease (AD) patients and age-matched controls. In cytosolic and membranous fractions, Ca2+ -dependent and Ca2+ -independent PKC activities were significantly lower in AD brain than in control brain. In particular, reduction of Ca2+ -independent PKC activity in the membranous fraction of AD brain was most enhanced when cardiolipin, the optimal stimulator of PKC-ε, was used in the assay; whereas Ca2+ -independent PKC activity stimulated by phosphatidylinositol, the optimal stimulator of PKC-δ, was not significantly reduced in AD. Further studies on the protein levels of Ca2+ -independent PKC-δ, PKC-ε, and PKC-ζ in AD brain revealed reduction of the PKC-ε level in both cytosolic and membranous fractions, although PKC-δ and PKC-ζ levels were not changed. These findings indicated that Ca2+ -dependent and Ca2+ -independent PKC are changed in AD, and that among Ca2+ -independent PKC isozymes, the alteration of PKC-ε is a specific event in AD brain, suggesting its crucial role in AD pathophysiology. 相似文献
3.
Activation of Mitogen-Activated Protein Kinase in Cultured Rat Hippocampal Neurons by Stimulation of Glutamate Receptors 总被引:8,自引:4,他引:4
†Masahito Kurino Kohji Fukunaga †Yukitaka Ushio Eishichi Miyamoto 《Journal of neurochemistry》1995,65(3):1282-1289
Abstract: Mitogen-activated protein kinase (MAP kinase) was activated by stimulation of glutamate receptors in cultured rat hippocampal neurons. Ten micromolar glutamate maximally stimulated MAP kinase activity, which peaked during 10 min and decreased to the basal level within 30 min. Experiments using glutamate receptor agonists and antagonists revealed that glutamate stimulated MAP kinase through NMDA and metabotropic glutamate receptors but not through non-NMDA receptors. Glutamate and its receptor agonists had no apparent effect on MAP kinase activation in cultured cortical astrocytes. Addition of calphostin C, a protein kinase C (PKC) inhibitor, or down-regulation of PKC activity partly abolished the stimulatory effect by glutamate, but the MAP kinase activation by treatment with ionomycin, a Ca2+ ionophore, remained intact. Lavendustin A, a tyrosine kinase inhibitor, was without effect. In experiments with 32 P-labeled hippocampal neurons, MAP kinase activation by glutamate was associated with phosphorylation of the tyrosine residue located on MAP kinase. However, phosphorylation of Raf-1, the c- raf protooncogene product, was not stimulated by treatment with glutamate. Our observations suggest that MAP kinase activation through glutamate receptors in hippocampal neurons is mediated by both the PKC-dependent and the Ca2+ -dependent pathways and that the activation of Raf-1 is not involved. 相似文献
4.
Jun-Ping Liu Qun-Xing Zhang †Graham Baldwin Phillip J. Robinson 《Journal of neurochemistry》1996,66(5):2074-2081
Abstract: Synaptic vesicle recycling is a neuronal specialization of endocytosis that requires the GTPase activity of dynamin I and is triggered by membrane depolarization and Ca2+ entry. To establish the relationship between dynamin I GTPase activity and Ca2+ , we used purified dynamin I and analyzed its interaction with Ca2+ in vitro. We report that Ca2+ bound to dynamin I and this was abolished by deletion of dynamin's C-terminal tail. Phosphorylation of dynamin I by protein kinase C promoted formation of a dynamin I tetramer and increased Ca2+ binding to the protein. Moreover, Ca2+ inhibited dynamin I GTPase activity after stimulation by phosphorylation or by phospholipids but not after stimulation with a GST-SH3 fusion protein containing the SH3 domain of phosphoinositide 3-kinase. These results suggest that in resting nerve terminals, phosphorylation of dynamin I by protein kinase C converts it to a tetramer that functions as a Ca2+ -sensing protein. By binding to Ca2+ , dynamin I GTPase activity is specifically decreased, possibly to regulate synaptic vesicle recycling. 相似文献
5.
Motohiro Morioka † Kohji Fukunaga Shinji Nagahiro †Masahito Kurino Yukitaka Ushio †Eishichi Miyamoto 《Journal of neurochemistry》1995,64(5):2132-2139
Abstract: The exposure of cultured rat hippocampal neurons to 500 µ M glutamate for 20 min induced a 55% decrease in the total Ca2+ /calmodulin-dependent protein kinase II (CaM kinase II) activity. The Ca2+ -independent activity and autophosphorylation of CaM kinase II decreased to the same extent as the changes observed in total CaM kinase II activity, and these decreases in activities were prevented by pretreatment with MK-801, an N -methyl- d -aspartate (NMDA)-type receptor antagonist, and the removal of extracellular calcium but not by antagonists against other types of glutamate receptors and protease inhibitors. Similarly, the decrease in the CaM kinase II activity was induced by a Ca2+ ionophore, ionomycin. Immunoblot analysis with the anti-CaM kinase II antibody revealed a significant decrease in the amount of the enzyme in the soluble fraction, in contrast with the inverse increase in the insoluble fraction; thus, the translocation was probably induced during treatment of the cells with glutamate. These results suggest that glutamate released during brain ischemia induces a loss of CaM kinase II activity in hippocampal neurons, by stimulation of the NMDA receptor, and that inactivation of the enzyme may possibly be involved in the cascade of the glutamate neurotoxicity following brain ischemia. 相似文献
6.
Abstract: Light activation of rhodopsin in the Drosophila photoreceptor induces a G protein-coupled signaling cascade that results in the influx of Ca2+ into the photoreceptor cells. Immediately following light activation, phosphorylation of a photoreceptor-specific protein, phosrestin I, is detected. Strong sequence similarity to mammalian arrestin and electroretinograms of phosrestin mutants suggest that phosrestin I is involved in light inactivation. We are interested in identifying the protein kinase responsible for the phosphorylation of phosrestin I to link the transmembrane signaling to the light-adaptive response. Type II Ca2+ /calmodulin-dependent kinase is one of the major classes of protein kinases that regulate cellular responses to transmembrane signals. We show here that partially purified phosrestin I kinase activity can be immunodepleted and immunodetected with antibodies to Ca2+ /calmodulin-dependent kinase II and that the kinase activity exhibits regulatory properties that are unique to Ca2+ /calmodulin-dependent kinase II such as Ca2+ independence after autophosphorylation and inhibition by synthetic peptides containing the Ca2+ /calmodulin-dependent kinase II autoinhibitory domain. We also show that Ca2+ /calmodulin-dependent kinase II activity is present in Drosophila eye preparations. These results are consistent with our hypothesis that Ca2+ /calmodulin-dependent kinase II phosphorylates phosrestin I. We suggest that Ca2+ /calmodulin-dependent kinase II plays a regulatory role in Drosophila photoreceptor light adaptation. 相似文献
7.
Depolarization and Neurotransmitters Increase Neuronal Protein Tyrosine Phosphorylation 总被引:5,自引:2,他引:3
Julio C. Siciliano Michèle Gelman Jean-Antoine Girault 《Journal of neurochemistry》1994,62(3):950-959
Abstract: In rat hippocampal slices and in neurons in primary culture, K+ -induced depolarization increased markedly and rapidly tyrosine phosphorylation of a 110-kDa protein (pp110) and, to a lesser degree, of a 120-kDa protein (pp120), in a calcium-dependent fashion. Qlutamate, 1-aminocyclopentane- trans -1,3-dicarboxylic acid (an agonist of metabotropic glutamate receptors), and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (an agonist of ionotropic glutamate receptors) stimulated also tyrosine phosphorylation of pp110 and pp120. These effects were not observed in astrocytes in primary culture. In hippocampal slices tyrosine phosphorylation of pp110 and pp120 was stimulated by Ca2+ -ionophores and by phorbol esters and antagonized by a chelator of intracellular Ca2+ and by drugs that inhibit protein kinase C. Stimulation of muscarinic and α1 ,-adrenergic receptors increased also tyrosine phosphorylation of pp110 and pp120. These results demonstrate that membrane depolarization and stimulation of neurotransmitter receptors activate a tyrosine phosphorylation pathway in neurons. This pathway involves an increase in intracellular Ca2+ concentrations and the activation of protein kinase C. It may provide a biochemical basis for some neurotrophic effects of electrical activity and neurotransmitters and may contribute to the role of tyrosine phosphorylation in long-term potentiation. 相似文献
8.
Abstract: Purified rat brain Ca2+ /calmodulin-dependent protein kinase II (CaM-kinase II) is stimulated by brain gangliosides to a level of about 30% the activity obtained in the presence of Ca2+ /calmodulin (CaM). Of the various gangliosides tested, GT1b was the most potent, giving half-maximal activation at 25 μ M . Gangliosides GD1a and GM1 also gave activation, but asialo-GM1 was without effect. Activation was rapid and did not require calcium. The same gangliosides also stimulated the autophosphorylation of CaM-kinase II on serine residues, but did not produce the Ca2+ -independent form of the kinase. Ganglioside stimulation of CaM-kinase II was also present in rat brain synaptic membrane fractions. Higher concentrations (125-250 μ M ) of GT1b, GD1a, and GM1 also inhibited CaM-kinase II activity. This inhibition appears to be substrate-directed, as the extent of inhibition is very dependent on the substrate used. The molecular mechanism of the stimulatory effect of gangliosides was further investigated using a synthetic peptide (CaMK 281-309), which contains the CaM-binding, inhibitory, and autophosphorylation domains of CaM-kinase II. Using purified brain CaM-kinase II in which these regulatory domains were removed by limited proteolysis, CaMK 281-309 strongly inhibited kinase activity (IC50 =0.2 μ M ). GT1b completely reversed this inhibition, but did not stimulate phosphorylation of the peptide on threonine-286. These results demonstrate that GT1b can partially mimic the effects of Ca2+ /CaM on native CaM-kinase II and on peptide CaMK 281-309. 相似文献
9.
Michael K. McMillian Pearlie M. Hudson Harold H. Suh Hong Ye Raimo K. Tuominen John S. Hong 《Journal of neurochemistry》1993,61(1):93-99
Abstract: The relative contributions of Ca2+ influx and intracellular Ca2+ mobilization were examined for angiotensin II-stimulated [3 H]phorbol 12, 13-dibutyrate binding, which reflects the level of activated protein kinase C in bovine chromaffin cells. Angiotensin II receptors activate phospholipase C in chromaffin cells, leading to a shortlived mobilization of intracellular Ca2+ . Angiotensin II-stimulated [3 H]phorbol 12, 13-dibutyrate binding was largely blocked in Ca2+ -free buffer and by pretreatment with the Ca2+ -channel blocker ω-conotoxin GVIA. The [3 H]phorbol 12, 13-dibutyrate binding response to [Sar1 ]angiotensin II also appeared to be voltage sensitive, as no additivity was observed with the response to the depolarizing agent 4-aminopyridine (3 m M ). Threshold sensitivities of the extra-and intracellular Ca2+ -mobilizing pathways to angiotensin II were similar, and all examined effects of angiotensin II in these cells were apparently mediated by losartan-sensitive (AT1 -Iike) receptors. The dependence of angiotensin II-stimulated [3 H]phorbol 12, 13-dibutyrate binding on extracellular Ca2+ entry, in contrast to stimulation by other phospholipase C-linked receptor agonists (bradykinin and methacholine), suggests that angiotensin II preferentially stimulates protein kinase C translocation to the plasma membrane, rather than to internal membranes, in bovine adrenal medullary cells. 相似文献
10.
Kristina Kosenburger Klaus W. Schicker Helmut Drobny Stefan Boehm 《Journal of neurochemistry》2009,110(6):1977-1988
Through inhibitory and excitatory effects on sympathetic neurons, B2 bradykinin receptors contribute to protective and noxious cardiovascular mechanisms. Presynaptic inhibition of sympathetic transmitter release involves an inhibition of CaV 2 channels, neuronal excitation an inhibition of KV 7 channels. To investigate which of these mechanisms prevail over time, the respective currents were determined. The inhibition of Ca2+ currents by bradykinin reached a maximum of 50%, started to fade within the first minute, and became attenuated significantly after ≥ 4 min. The inhibition of K+ currents reached a maximum of 85%, started to fade after > 3 min, and became attenuated significantly after ≥ 7 min. Blocking Ca2+ -independent protein kinase C (PKC) enhanced the inhibition of Ca2+ currents by bradykinin and delayed its fading, left the inhibition of K+ currents and its fading unaltered, and enhanced the reduction of noradrenaline release and slowed its fading. Conversely, direct activation of PKC abolished the inhibition of noradrenaline release and largely attenuated the inhibition of Ca2+ currents. These results show that the inhibitory effects of bradykinin in sympathetic neurons are outweighed over time by its excitatory actions because of more rapid, PKC-dependent fading of the inhibitory response. 相似文献
11.
Stefan Strack Mary Ann Barban Brian E. Wadzinski Roger J. Colbran 《Journal of neurochemistry》1997,68(5):2119-2128
Abstract: Autophosphorylation of Ca2+ /calmodulin-dependent protein kinase II (CaMKII) at Thr286 generates Ca2+ -independent activity. As an initial step toward understanding CaMKII inactivation, protein phosphatase classes (PP1, PP2A, PP2B, or PP2C) responsible for dephosphorylation of Thr286 in rat forebrain subcellular fractions were identified using phosphatase inhibitors/activators, by fractionation using ion exchange chromatography and by immunoblotting. PP2A-like enzymes account for >70% of activity toward exogenous soluble Thr286 -autophosphorylated CaMKII in crude cytosol, membrane, and cytoskeletal extracts; PP1 and PP2C account for the remaining activity. CaMKII is present in particulate fractions, specifically associated with postsynaptic densities (PSDs); each protein phosphatase is also present in isolated PSDs, but only PP1 is enriched during PSD isolation. When isolated PSDs dephosphorylated exogenous soluble Thr286 -autophosphorylated CaMKII, PP2A again made the major contribution. However, CaMKII endogenous to PSDs (32 P autophosphorylated in the presence of Ca2+ /calmodulin) was predominantly dephosphorylated by PP1. In addition, dephosphorylation of soluble and PSD-associated CaMKII in whole forebrain extracts was catalyzed predominantly by PP2A and PP1, respectively. Thus, soluble and PSD-associated forms of CaMKII appear to be dephosphorylated by distinct enzymes, suggesting that Ca2+ -independent activity of CaMKII is differentially regulated by protein phosphatases in distinct subcellular compartments. 相似文献
12.
Marten H Hyun T Gomi K Seo S Hedrich R Roelfsema MR 《The Plant journal : for cell and molecular biology》2008,55(4):698-708
Light-induced stomatal opening in C3 and C4 plants is mediated by two signalling pathways. One pathway is specific for blue light and involves phototropins, while the second pathway depends on photosyntheticaly active radiation (PAR). Here, the role of Nt MPK4 in light-induced stomatal opening was studied, as silencing of this MAP kinase stimulates stomatal opening. Stomata of Nt MPK4-silenced plants do not close in elevated atmospheric CO2 , and show a reduced response to PAR. However, stomatal closure can still be induced by abscisic acid. Measurements using multi-barrelled intracellular micro-electrodes showed that CO2 activates plasma membrane anion channels in wild-type Nicotiana tabacum guard cells, but not in Nt MPK4-silenced cells. Anion channels were also activated in wild-type guard cells after switching off PAR. In approximately half of these cells, activation of anion channels was accompanied by an increase in the cytosolic free Ca2+ concentration. The activity of anion channels was higher in cells showing a parallel increase in cytosolic Ca2+ than in those with steady Ca2+ levels. Both the darkness-induced anion channel activation and Ca2+ signals were repressed in Nt MPK4-silenced guard cells. These data show that CO2 and darkness can activate anion channels in a Ca2+ -independent manner, but the anion channel activity is enhanced by parallel increases in the cytosolic Ca2+ concentration. Nt MPK4 plays an essential role in CO2 - and darkness-induced activation of guard-cell anion channels, through Ca2+ -independent as well as Ca2+ -dependent signalling pathways. 相似文献
13.
Internalization of Voltage-Dependent Sodium Channels in Fetal Rat Brain Neurons: A Study of the Regulation of Endocytosis 总被引:4,自引:0,他引:4
Abstract: In fetal rat brain neurons, activation of voltage-dependent Na+ channels induced their own internalization, probably triggered by an increase in intracellular Na+ level. To investigate the role of phosphorylation in internalization, neurons were exposed to either activators or inhibitors of cyclic AMP- and cyclic GMP-dependent protein kinases, protein kinase C, and tyrosine kinase. None of the tested compounds mimicked or inhibited the effect of Na+ channel activation. An increase in intracellular Ca2+ concentration induced either by thapsigargin, a Ca2+ -ATPase blocker, or by A23187, a Ca2+ ionophore, was unable to provoke Na+ channel internalization. However, Ca2+ seems to be necessary because both neurotoxin- and amphotericin B-induced Na+ channel internalizations were partially inhibited by BAPTA-AM. The selective inhibitor of Ca2+ /calmodulin-dependent protein kinase II, KN-62, caused a dose-dependent inhibition of neurotoxin-induced internalization due to a blockade of channel activity but did not prevent amphotericin B-induced internalization. The rate of increase in Na+ channel density at the neuronal cell surface was similar before and after channel internalization, suggesting that recycling of internalized Na+ channels back to the cell surface was almost negligible. Pretreatment of the cells with an acidotropic agent such as chloroquine prevented Na+ channel internalization, indicating that an acidic endosomal/lysosomal compartment is involved in Na+ channel internalization in neurons. 相似文献
14.
Gideon M. Polya Vito Micucci Anne L. Rae Philip J. Harris Adrienne E. Clarke 《Physiologia plantarum》1986,67(2):151-157
The 40 000 g supernatant and 40 000 g pellet from extracts of germinated pollen of Nicotiana alata Link et Otto contain protein kinase activity which catalyzes the phosphorylation of histones, casein and a range of endogenous polypeptides. Phosphorylation of certain low-molecular-weight, casein-derived polypeptides is activated at low (12–37 μ M ) and partially inhibited at higher (540 μ M ) concentrations of free Ca2+ . Histone phosphorylation is largely Ca2+ -dependent and is activated by 540 μM free Ca2+ . No activation of protein phosphorylation by micromolar concentrations of calmodulin is found, but phenothiazine-derived calmodulin antagonists markedly stimulate protein phosphorylation. 相似文献
15.
Abstract: The transduction pathways coupling muscarinic receptors to induction of fos and jun genes were investigated in neuroblastoma SH-SY5Y cells. Stimulation with carbachol induced expression of c- fos , fosB , c- jun , junB , and junD . This effect was abolished by pretreatment with atropine, indicating an involvement of muscarinic receptors. These genes were also induced by activation of protein kinase C with phorbol ester or by elevating the intracellular Ca2+ concentration with a Ca2+ ionophore. The Ca2+ effect was inhibited by KN-62, suggesting an induction through Ca2+ /calmodulin-dependent kinase II. Inhibition of protein kinase C with GF109203X suppressed the carbachol-stimulated increase in mRNA levels of c- fos , fosB , and junB by ∼70% but had only minor effects on the expression of c- jun and junD . On the other hand, preincubation with KN-62 attenuated the carbachol-induced increase in c- jun and junD expression by 70% but had no effect on c- fos , fosB , and junB mRNA levels. Simultaneous inhibition of both protein kinase C and Ca2+ /calmodulin-dependent kinase II completely abolished the carbachol-stimulated expression of c- jun and junD , but c- fos , fosB , and junB were still expressed to a certain extent under this condition. Comparison of the inhibitory effects of GF109203X and Gö 6976 suggests the involvement of classical protein kinase C isozymes in muscarinic receptor-stimulated expression of fos and jun genes. These results demonstrate that the muscarinic receptor-induced expression of individual fos and jun genes is regulated via different pathways, primarily protein kinase C or Ca2+ /calmodulin-dependent kinase II. 相似文献
16.
Abstract: A new protein kinase modulated by S-100 (tentatively referred to as protein kinase X) was partially purified from pig brain extracts. The activity of protein kinase X, which was independent of Ca2+ , was demonstrated when protamine (free base), but not protamine sulfate and other proteins (including histone), was used as substrate. The enzyme activity, found to distribute in both soluble and particulate fractions and to occur at the highest level in brain compared with other tissues (heart, kidney, liver, skeletal muscle, spleen, and testis) of rats, was also modulated by other acidic proteins (calmodulin, troponin C, and stimulatory modulator) in a Ca2+ -independent manner. S-100 and other acidic proteins appeared to function as "substrate modifiers" by interacting with protamine (a highly basic protein), but not with the enzyme, thus rendering protamine in the complex a superior phosphate acceptor. The two isoforms of S-100 (i.e., a and b) were equally effective. Although the enzyme was not inhibited by many agents (trifluoperazine, melittin, cytotoxin I, polymyxin B, and spermine) shown to inhibit markedly phospholipid/Ca2+ - or calmodulin/Ca2+ -stimulated protein kinase, gossypol was found to inhibit specifically protein kinase X. The present findings suggest that S-100, a major acidic protein specific to nervous system, may promote phosphorylation by protein kinase X of certain neural proteins resembling protamine or containing protamine-like domains, in addition to its presumed role of a low-affinity Ca2+ -binding protein. 相似文献
17.
Rajeevkumar Raveendran Sudarsana Devi Suma Priya Madhavan Mayadevi Mathew Steephan Thankayyan R. Santhoshkumar John Cheriyan Rajendran Sanalkumar Kurup K. Pradeep Jackson James Ramakrishnapillai V. Omkumar 《Journal of neurochemistry》2009,110(1):92-105
Ca2+ influx through NMDA-type glutamate receptor at excitatory synapses causes activation of post-synaptic Ca2+ /calmodulin-dependent protein kinase type II (CaMKII) and its translocation to the NR2B subunit of NMDA receptor. The major binding site for CaMKII on NR2B undergoes phosphorylation at Ser1303, in vivo . Even though some regulatory effects of this phosphorylation are known, the mode of dephosphorylation of NR2B-Ser1303 is still unclear. We show that phosphorylation status at Ser1303 enables NR2B to distinguish between the Ca2+ /calmodulin activated form and the autonomously active Thr286-autophosphorylated form of CaMKII. Green fluorescent protein–α-CaMKII co-expressed with NR2B sequence in human embryonic kidney 293 cells was used to study intracellular binding between the two proteins. Binding in vitro was studied by glutathione- S -transferase pull-down assay. Thr286-autophosphorylated α-CaMKII or the autophosphorylation mimicking mutant, T286D-α-CaMKII, binds NR2B sequence independent of Ca2+ /calmodulin unlike native wild-type α-CaMKII. We show enhancement of this binding by Ca2+ /calmodulin. Phosphorylation or a phosphorylation mimicking mutation on NR2B (NR2B-S1303D) abolishes the Ca2+ /calmodulin-independent binding whereas it allows the Ca2+ /calmodulin-dependent binding of α-CaMKII in vitro . Similarly, the autonomously active mutants, T286D-α-CaMKII and F293E/N294D-α-CaMKII, exhibited Ca2+ -independent binding to non-phosphorylatable mutant of NR2B under intracellular conditions. We also show for the first time that phosphatases in the brain such as protein phosphatase 1 and protein phosphatase 2A dephosphorylate phospho-Ser1303 on NR2B. 相似文献
18.
Carlos-Alberto Gonçalves Amanda Hall Alistair T. R. Sim Stephen J. Bunn Philip D. Marley Tat B. Cheah Peter R. Dunkley 《Journal of neurochemistry》1997,69(6):2387-2396
Abstract: The protein kinases and protein phosphatases that act on tyrosine hydroxylase in vivo have not been established. Bovine adrenal chromaffin cells were permeabilized with digitonin and incubated with [γ-32 P]ATP, in the presence or absence of 10 µ M Ca2+ , 1 µ M cyclic AMP, 1 µ M phorbol dibutyrate, or various kinase or phosphatase inhibitors. Ca2+ increased the phosphorylation of Ser19 and Ser40 . Cyclic AMP, and phorbol dibutyrate in the presence of Ca2+ , increased the phosphorylation of only Ser40 . Ser31 and Ser8 were not phosphorylated. The Ca2+ -stimulated phosphorylation of Ser19 was incompletely reduced by inhibitors of calcium/calmodulin-stimulated protein kinase II (46% with KN93 and 68% with CaM-PKII 273–302), suggesting that another protein kinase(s) was contributing to the phosphorylation of this site. The Ca2+ -stimulated phosphorylation of Ser40 was reduced by specific inhibitors of protein kinase A (56% with H89 and 38% with PKAi 5–22 amide) and protein kinase C (70% with Ro 31-8220 and 54% with PKCi 19–31), suggesting that protein kinases A and C contributed to most of the phosphorylation of this site. Results with okadaic acid and microcystin suggested that Ser19 and Ser40 were dephosphorylated by PP2A. 相似文献
19.
Gabor Tigyi David J. Fischer Ágnes Sebök Charles Yang David L. Dyer Ricardo Miledi 《Journal of neurochemistry》1996,66(2):537-548
Abstract: The endogenous phospholipid mediator lysophosphatidic acid (LPA) caused growth cone collapse, neurite retraction, and cell flattening in differentiated PC12 cells. Neurite retraction was blocked by cytochalasin B and ADP-ribosylation of the small-molecular-weight G protein Rho by the Clostridium botulinum C-3 toxin. LPA induced a transient rise in the level of inositol 1,4,5-trisphosphate, and retraction was blocked by inhibitors of phospholipase β. Repeated application of LPA elicited homologous desensitization of the Ca2+ mobilization response. The activation of the phosphoinositide (PIP)-Ca2+ second messenger system played a permissive role in the morphoregulatory response. Blockers of protein kinase C—chelerythrine, a myristoylated pseudosubstrate peptide, staurosporine, and depletion of protein kinase C from the cells by long-term phorbol ester treatment—all diminished neurite retraction by interfering with LPA-induced Ca2+ mobilization, which was required for the withdrawal of neurites. A brief 15-min treatment with 4β-phorbol 12-myristate 13-acetate also blocked retraction and Ca2+ mobilization, by inactivating the LPA receptor. Inhibition of protein tyrosine phosphorylation by herbimycin diminished retraction. Although activation of the PIP-Ca2+ second messenger system appears necessary for the Rho-mediated rearrangements of the actin cytoskeleton, bradykinin, which activates similar signaling events, failed to cause retraction, indicating that a yet unidentified novel mechanism is also involved in the LPA-induced morphoregulatory response. 相似文献
20.
Goizane Marcaida Elena Kosenko María-Dolores Miñana Santiago Grisolía Vicente Felipo 《Journal of neurochemistry》1996,66(1):99-104
Abstract: In primary cultures of cerebellar neurons glutamate neurotoxicity is mainly mediated by activation of the NMDA receptor, which allows the entry of Ca2+ and Na+ into the neuron. To maintain Na+ homeostasis, the excess Na+ entering through the ion channel should be removed by Na+ ,K+ -ATPase. It is shown that incubation of primary cultured cerebellar neurons with glutamate resulted in activation of the Na+ ,K+ -ATPase. The effect was rapid, peaking between 5 and 15 min (85% activation), and was maintained for at least 2 h. Glutamate-induced activation of Na+ ,K+ -ATPase was dose dependent: It was appreciable (37%) at 0.1 µ M and peaked (85%) at 100 µ M . The increase in Na+ ,K+ -ATPase activity by glutamate was prevented by MK-801, indicating that it is mediated by activation of the NMDA receptor. Activation of the ATPase was reversed by phorbol 12-myristate 13-acetate, an activator of protein kinase C, indicating that activation of Na+ ,K+ -ATPase is due to decreased phosphorylation by protein kinase C. W-7 or cyclosporin, both inhibitors of calcineurin, prevented the activation of Na+ ,K+ -ATPase by glutamate. These results suggest that activation of NMDA receptors leads to activation of calcineurin, which dephosphorylates an amino acid residue of the Na+ ,K+ -ATPase that was previously phosphorylated by protein kinase C. This dephosphorylation leads to activation of Na+ ,K+ -ATPase. 相似文献