Regulation of protein kinase C activity in neuronal differentiation induced by the N-ras oncogene in PC-12 cells.

Expression of the N-ras oncogene under the control of the glucocorticoid-responsive promoter in the pheochromocytoma cell line UR61, a subline of PC-12 cells, has been used to investigate the differentiation process to neuronal cells triggered by ras oncogenes (I. Guerrero, A. Pellicer, and D. E. Burstein, Biochem. Biophys. Res. Commun. 150:1185-1192, 1988). Using ras-inducible cell lines, we observed that expression of the oncogenic N-ras p21 protein interferes with the ability of phorbol esters to induce downregulation of protein kinase C. This effect was associated with the appearance of immunologically detectable protein kinase C as well as the activity of the enzyme as analyzed either by binding of [3H]phorbol-12,13-dibutyrate in intact cells or by in vitro kinase activity. These results indicate a relationship between ras p21 and protein kinase C in neuronal differentiation in this model system. Comparison to the murine fibroblast system suggests that this relationship may be functional.

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Regulation of protein kinase C activity in neuronal differentiation induced by the N-ras oncogene in PC-12 cells

Molecular and Cellular Biology ◽

10.1128/mcb.10.6.2983-2990.1990 ◽

1990 ◽

Vol 10 (6) ◽

pp. 2983-2990

Author(s):

J C Lacal ◽

A Cuadrado ◽

J E Jones ◽

R Trotta ◽

D E Burstein ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Neuronal Differentiation ◽

Phorbol Esters ◽

Ras Oncogene ◽

Intact Cells ◽

Pc 12 Cells ◽

Kinase C ◽

Ras P21

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Isolation and characterization of protein kinase C from Y-1 adrenal cell cytoskeleton.

The Journal of Cell Biology ◽

10.1083/jcb.108.2.553 ◽

1989 ◽

Vol 108 (2) ◽

pp. 553-567 ◽

Cited By ~ 39

Author(s):

V Papadopoulos ◽

P F Hall

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Light Chain ◽

Myosin Light Chain ◽

Phorbol Esters ◽

Intact Cells ◽

Adrenal Cells ◽

Isolation And Characterization ◽

Kinase C

The cytoskeletons of Y-1 mouse adrenal tumor cells contain a calcium and phospholipid-dependent protein kinase (protein kinase C) that is bound sufficiently tight to resist extraction by 0.5% Triton but not by 1.0% Triton. The enzyme has been purified to near homogeneity from cytoskeleton and cytosol. It shows features typical of this type of kinase, namely a requirement for Ca2+ and phospholipid, stimulation by tumor promoters but not by nontumor-promoting phorbol esters, and inhibition by trifluoperazine. The enzyme shows specificity for four substrates found in the cytoskeleton, namely 80, 33, 20, and 18 kD. The first three substrates are phosphorylated by the enzyme; the fourth is dephosphorylated and is therefore affected by the kinase indirectly. The 80-kD protein is the kinase enzyme itself which is autophosphorylated in vitro and in the cytoskeleton. The 20-kD protein is myosin light chain. The 33- and 18-kD proteins are unidentified. The same substrates were phosphorylated when Y-1 cells were permeabilized with digitonin and incubated with [gamma-32P]ATP and phorbol-12-myristate-13-acetate. Partly purified protein kinase C changes the extent of phosphorylation of the same substrates when added to cytoskeletons previously extracted to remove endogenous protein kinase C. Addition of Ca2+, phosphatidylserine, and phorbol-12-myristate-13-acetate to cytoskeletons, and addition of these three agents plus protein kinase C to extracted cytoskeletons, causes these structures to undergo a rapid and extensive rounding. A similar change is induced in intact cells by addition of phorbol ester. It is concluded that protein kinase C is capable of changing the shape of adrenal cells by an action that involves autophosphorylation and phosphorylation of myosin light chain. This response may in turn be related to the steroidogenic responses to ACTH and cyclic AMP.

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Mitogen stimulation of Na+-H+ exchange: differential involvement of protein kinase C

AJP Cell Physiology ◽

10.1152/ajpcell.1987.253.2.c219 ◽

1987 ◽

Vol 253 (2) ◽

pp. C219-C229 ◽

Cited By ~ 19

Author(s):

L. L. Muldoon ◽

G. A. Jamieson ◽

A. C. Kao ◽

H. C. Palfrey ◽

M. L. Villereal

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Cell Types ◽

Intact Cells ◽

Kinase C ◽

Protein Kinase C Activity ◽

Human Fibroblast Strains ◽

Stimulation Of

The mitogen-induced activation of Na+-H+ exchange was investigated in two cultured human fibroblast strains (HSWP and WI-38 cells) that, based on previous studies, differed in their response to the tumor-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) (L. M. Vincentini and M. L. Villereal, Proc. Natl. Acad. Sci. USA 82: 8053-8056, 1985). The role of protein kinase C in the activation of Na+-H+ exchange was investigated by comparing the effects of TPA on Na+ influx, in vitro phosphorylation, and in vivo phosphorylation in both cell types. Although both cell types have significant quantities of protein kinase C activity that can be activated by TPA in intact cells, the addition of TPA to intact cells stimulates Na+ influx in WI-38 cells but not in HSWP cells, indicating that in HSWP cells the stimulation of protein kinase C is not sufficient to activate the Na+-H+ exchanger. Cells were then depleted of protein kinase C activity by chronic treatment with high doses of TPA. Both HSWP and WI-38 cells were rendered protein kinase C deficient by this treatment as determined by in vitro and in vivo phosphorylation studies. Protein kinase C-deficient HSWP cells lose the ability for TPA to inhibit the serum-induced activation of Na+-H+ exchange, but there is no reduction in the stimulation of Na+ influx by serum, bradykinin, vasopressin, melittin, or vanadate, indicating that protein kinase C activity is not necessary for the mitogen-induced activation of Na+-H+ exchange in HSWP cells by agents known to stimulate phosphatidylinositol turnover (G. A. Jamieson and M. Villereal. Arch. Biochem. Biophys. 252: 478-486, 1987). In contrast, depletion of protein kinase C activity in WI-38 cells significantly reduces both the TPA- and the serum-induced activation of the Na+-H+ exchange system, suggesting that protein kinase C activity is necessary for at least a portion of the mitogen-induced activation of the Na+-H+ exchanger in WI-38 cells. These results indicate that the mechanisms for regulating Na+-H+ exchange can differ dramatically between different types of fibroblasts.

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Characterization of the Rac-GAP (Rac-GTPase-activating protein) activity of β2-chimaerin, a ‘non-protein kinase C’ phorbol ester receptor

Biochemical Journal ◽

10.1042/bj20030727 ◽

2003 ◽

Vol 375 (2) ◽

pp. 313-321 ◽

Cited By ~ 71

Author(s):

Maria Jose CALOCA ◽

HongBin WANG ◽

Marcelo G. KAZANIETZ

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Phorbol Ester ◽

Phorbol Esters ◽

Gtpase Activating Protein ◽

Protein Activity ◽

Rac Gtpase ◽

Kinase C ◽

Phorbol Ester Receptor

The regulation and function of β2-chimaerin, a novel receptor for the phorbol ester tumour promoters and the second messenger DAG (diacylglycerol), is largely unknown. As with PKC (protein kinase C) isoenzymes, phorbol esters bind to β2-chimaerin with high affinity and promote its subcellular distribution. β2-Chimaerin has GAP (GTPase-activating protein) activity for the small GTP-binding protein Rac1, but for not Cdc42 or RhoA. We show that acidic phospholipids enhanced its catalytic activity markedly in vitro, but the phorbol ester PMA had no effect. β2-Chimaerin and other chimaerin isoforms decreased cellular levels of Rac-GTP markedly in COS-1 cells and impaired GTP loading on to Rac upon EGF (epidermal growth factor) receptor stimulation. Deletional and mutagenesis analysis determined that the β2-chimaerin GAP domain is essential for this effect. Interestingly, PMA has a dual effect on Rac-GTP levels in COS-1 cells. PMA increased Rac-GTP levels in the absence of a PKC inhibitor, whereas under conditions in which PKC activity is inhibited, PMA markedly decreased Rac-GTP levels and potentiated the effect of β2-chimaerin. Chimaerin isoforms co-localize at the plasma membrane with active Rac, and these results were substantiated by co-immunoprecipitation assays. In summary, the novel phorbol ester receptor β2-chimaerin regulates the activity of the Rac GTPase through its GAP domain, leading to Rac inactivation. These results strongly emphasize the high complexity of DAG signalling due to the activation of PKC-independent pathways, and cast doubts regarding the selectivity of phorbol esters and DAG analogues as selective PKC activators.

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The role of protein kinase C in LHRH-induced LH and FSH release and LHRH self-priming in rat anterior pituitary glands in vitro

Journal of Endocrinology ◽

10.1677/joe.0.1160231 ◽

1988 ◽

Vol 116 (2) ◽

pp. 231-239 ◽

Cited By ~ 24

Author(s):

M. S. Johnson ◽

R. Mitchell ◽

G. Fink

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Phorbol Esters ◽

Polymyxin B ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Kinase C ◽

Pituitary Glands

ABSTRACT We have investigated the role of protein kinase C (PKC) in LHRH-induced LH and FSH secretion and LHRH priming. Hemipituitary glands from pro-oestrous rats were incubated with agents known to affect PKC and with or without LHRH, during which time the secretion of gonadotrophins was measured. Phorbol esters and phospholipase C, activators of PKC, released LH and FSH in a concentration-dependent manner and potentiated the LHRH-induced secretion of gonadotrophins in parallel with their ability to release these hormones alone. Inhibitors of PKC had either no effect on LH release (1-(5-isoquinolinesulphonyl)-2-methylpiperazine hydrochloride) or they augmented LHRH-induced gonadotrophin release (polymyxin B and 8-(N,N-diethylamino) octyl-3,4,5-trimethoxybenzoate). Neither the activators nor the inhibitors of PKC, when present with LHRH, caused any change in LHRH priming, even though the activators alone produced a release of gonadotrophins that showed a temporal pattern similar to that produced by LHRH priming. The profiles of effects on LH and FSH secretion were always qualitatively similar. These results show that PKC may be involved in general regulation of gonadotrophin release but that it is not important in acute responses to LHRH nor in LHRH self-priming. J. Endocr. (1988) 116, 231–239

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Evidence that interleukin-1 and phorbol esters activate NF-kappa B by different pathways: role of protein kinase C.

Cell Regulation ◽

10.1091/mbc.2.4.329 ◽

1991 ◽

Vol 2 (4) ◽

pp. 329-335 ◽

Cited By ~ 46

Author(s):

K Bomsztyk ◽

J W Rooney ◽

T Iwasaki ◽

N A Rachie ◽

S K Dower ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Cell Line ◽

Phorbol Esters ◽

Interleukin 1 ◽

Interleukin 2 ◽

Nf Kappa B ◽

Kinase C ◽

Protein Kinase C Inhibitor

Nuclear factor kappa B (NF-kappa B) is a ubiquitous transcription factor that affects expression of many genes, including immunoglobulin kappa (kappa), the interleukin-2 receptor alpha chain, and two genes in HIV-1. NF-kappa B can be activated by a number of stimuli, including pharmacological stimulation of protein kinase C by phorbol 12-myristate 13-acetate (PMA) and treatment in vitro with either protein kinase C or protein kinase A. This has lead to the proposal that these kinases are key enzymes in the physiological activation of NF-kappa B as well. We have used a murine B cell line, 70Z/3, and T cell line, EL-4 6.1 C10, to study the activation of NF-kappa B by two physiological activators, interleukin-1 alpha (IL-1) and lipopolysaccharide (LPS). There are four reasons to propose that these agents activate pathways that do not include protein kinase C as a major component in these cell lines. First, the protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) strongly inhibited PMA-induced activation of NF-kappa B in 70Z/3 cells but had no effect on NF-kappa B activated by IL-1 or LPS. Second, depletion of protein kinase C by prolonged growth of 70Z/3 in PMA abrogated the capacity of the cells to activate NF-kappa B in response to further PMA treatment. However, these same cells activated NF-kappa B normally after either IL-1 or LPS treatment. Third, IL-1 effectively activated NF-kappa B in EL-4 6.1 C10 cells, but PMA did not. Fourth, interferon-gamma is a potent activator of protein kinase C in 70Z/3 cells, but is completely inactive in the mobilization of NF-kappa B. These results suggest that the physiological inducers IL-1 and LPS activate NF-kappa B by pathways independent of protein kinase C in both 70Z/3 and EL-4 6.1 C10 cells.

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Effects of insulin and phorbol esters on MARCKS (myristoylated alanine-rich C-kinase substrate) phosphorylation (and other parameters of protein kinase C activation) in rat adipocytes, rat soleus muscle and BC3H-1 myocytes

Biochemical Journal ◽

10.1042/bj2950155 ◽

1993 ◽

Vol 295 (1) ◽

pp. 155-164 ◽

Cited By ~ 20

Author(s):

T P Arnold ◽

M L Standaert ◽

H Hernandez ◽

J Watson ◽

H Mischak ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Soleus Muscle ◽

Plasma Membranes ◽

Phorbol Esters ◽

Kinase Substrate ◽

Rat Adipocytes ◽

Kinase C ◽

Rat Soleus Muscle

To evaluate the question of whether or not insulin activates protein kinase C (PKC), we compared the effects of insulin and phorbol esters on the phosphorylation of the PKC substrate, i.e. myristoylated alanine-rich C-kinase substrate (MARCKS). In rat adipocytes, rat soleus muscle and BC3H-1 myocytes, maximally effective concentrations of insulin and phorbol esters provoked comparable, rapid, 2-fold (on average), non-additive increases in the phosphorylation of immunoprecipitable MARCKS. These effects of insulin and phorbol esters on MARCKS phosphorylation in intact adipocytes and soleus muscles were paralleled by similar increases in the phosphorylation of an exogenous, soluble, 85 kDa PKC substrate (apparently a MARCKS protein) during incubation of post-nuclear membrane fractions in vitro. Increases in the phosphorylation of this 85 kDa PKC substrate in vitro were also observed in assays of both plasma membranes and microsomes obtained from rat adipocytes that had been treated with insulin or phorbol esters. These insulin-induced increases in PKC-dependent phosphorylating activities of adipocyte plasma membrane and microsomes were associated with increases in membrane contents of diacylglycerol, PKC-beta 1 and PKC-beta 2. Our findings suggest that insulin both translocates and activates PKC in rat adipocytes, rat soleus muscles and BC3H-1 myocytes.

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The diacylglycerol analogue, 1,2-sn-dioctanoylglycerol, induces an increase in cytosolic free Ca2+ and cytosolic acidification of T lymphocytes through a protein kinase C-independent process

Biochemical Journal ◽

10.1042/bj2580689 ◽

1989 ◽

Vol 258 (3) ◽

pp. 689-698 ◽

Cited By ~ 12

Author(s):

R Ebanks ◽

C Roifman ◽

A Mellors ◽

G B Mills

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

T Lymphocytes ◽

Cell Activation ◽

Phorbol Esters ◽

Inositol Phosphates ◽

Free Calcium ◽

Intact Cells ◽

Kinase C ◽

Cytosolic Acidification

In this paper, we demonstrate that low concentrations (0.5-2.5 microM) of 1,2-sn-dioctanoylglycerol (DiC8), a potent diacylglycerol used in many previous studies to probe the role of protein kinase C (PKC) in cell activation, cause cytosolic alkalinization of human, mouse and pig T lymphocytes through PKC-mediated activation of the Na+/H+ antiport. However, at higher concentrations (greater than or equal to 12.5 microM), the effect on cytosolic pH (pHi) is reversed, resulting in a marked cytosolic acidification, followed by a gradual return of pHi to baseline values. DiC8 also induces marked changes in cytosolic free calcium concentrations ([Ca2+]i), initially by releasing calcium from intracellular stores, followed by a net transmembrane influx of calcium. The DiC8-induced cytosolic acidification, the resultant return to baseline pH and the increase in [Ca2+]i are independent of activation of PKC. Unlike many other agents which increase [Ca2+]i, DiC8 does not induce phosphatidylinositol hydrolysis with the resultant production of inositol phosphates. Other compounds known to activate PKC, including the closely related diacylglycerol analogues, 1,2-sn-dihexanoylglycerol and 1,2-sn-didecanoylglycerol, phorbol esters and mezerein, did not induce changes in [Ca2+]i or cytosolic acidification in T lymphocytes. Thus the action of DiC8 on intact lymphocytes is different from that of phorbol esters and other diacylglycerols, and is specific to the length of the acyl chains. Because changes in [Ca2+]i are often associated with cell proliferation and cell differentiation, some effects of DiC8 on intact cells may be a consequence of changes in [Ca2+]i.

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