Search results for "protein kinase C"
showing 10 items of 180 documents
Polyunsaturated fatty acids in the modulation of T-cell signalling
2009
n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activati…
Regulatory activity of polyunsaturated fatty acids in T-cell signaling.
2009
n-3 Polyunsaturated fatty acids (PUFA) are considered to be authentic immunosuppressors and appear to exert beneficial effects with respect to certain immune-mediated diseases. In addition to promoting T-helper 1 (Th1) cell to T-helper 2 (Th2) cell effector T-cell differentiation, n-3 PUFA may also exert anti-inflammatory actions by inducing apoptosis in Th1 cells. With respect to mechanisms of action, effects range from the modulation of membrane receptors to gene transcription via perturbation of a number of second messenger cascades. In this review, the putative targets of anti-inflammatory n-3 PUFA, activated during early and late events of T-cell activation will be discussed. Studies h…
ChemInform Abstract: Advances in Indolo[2,3-a]carbazole Chemistry: Design and Synthesis of Protein Kinase C and Topoisomerase I Inhibitors
2010
Indolo[2,3-a]carbazoles, their pyrrolo[3,4-c]anellated variants and structurally closely related bisindolylmaleimides represent a biologically highly interesting class of natural compounds which are potential anticancer agents. According to the ongoing literature new and efficient synthetic methods yield a great variety of these compounds which have been reported in detail. The biological activities and the inhibitory activities against the target enzymes protein kinase C and topoisomerase I are also discussed including structure activity relationships. A molecular binding model of the protein kinase C inhibitors with the target enzyme at the atomic level is presented and supported by X-ray…
Electrophilic substitution and cyclization of 2,2′-bis(N-methylindolyl): A simple access to potential protein kinase C inhibitor
1994
A strategy is described for the synthesis of functionalized and cyclized 2,2′-bisindolyl derivatives related to several basic systems of natural products. The starting 2,2′-bis(N-methylindolyl) (8) reacts with a variety of electrophiles and electrophilic dienophiles to furnish the novel, functionalized and cyclized bisindolyl derivatives 9–16. In addition, some reactivity and structural aspects are discussed; an X-ray crystallographic analysis of the 2,2′-bisindolyl 8 provided valuable information for the conformational analyses.
Phorbol Esters and Muscarinic Receptor Agonists Activate Phospholipase D in Heart and Brain
1991
Phospholipase D (PLD) hydrolyzes phosphatidylcholine and thereby seems to play a key role in a novel pathway of signal transduction. PLD activity in rat hippocampal slices and atria of rat, guinea pig and chicken hearts was determined by measuring the catalytic products choline (Ch), phosphatidic acid (PA) and, in the presence of a primary alcohol, phosphatidylpropanol or phosphatidylethanol. It was found that the PLD activity was high, even under resting conditions, in both tissues, especially in the hippocampus, and that the enzyme activity could be enhanced by activation of protein kinase C and by muscarinic receptor stimulation.
Phosphorylation of mismatch repair proteins MSH2 and MSH6 affecting MutSα mismatch-binding activity
2002
Mismatch repair (MMR) is involved in the removal of mispaired bases from DNA and thus plays an important role in the maintenance of genomic stability and the prevention of mutations and cancer. Moreover, MMR triggers genotoxicity and apoptosis upon processing of DNA lesions such as O6-methylguanine. Whereas the enzymology of MMR has been elucidated in great detail, only limited data are available concerning its regulation. Here we show that the major mismatch-binding proteins MSH2 and MSH6, forming the MutSalpha complex, are phosphorylated in vitro by protein kinase C and casein kinase II, but not by protein kinase A. Phosphorylation of MSH2 and MSH6 was also found within the cell, with MSH…
Receptor for advanced glycation end products is subjected to protein ectodomain shedding by metalloproteinases.
2008
The receptor for advanced glycation end products (RAGE) is a 55-kDa type I membrane glycoprotein of the immunoglobulin superfamily. Ligand-induced up-regulation of RAGE is involved in various pathophysiological processes, including late diabetic complications and Alzheimer disease. Application of recombinant soluble RAGE has been shown to block RAGE-mediated pathophysiological conditions. After expression of full-length RAGE in HEK cells we identified a 48-kDa soluble RAGE form (sRAGE) in the culture medium. This variant of RAGE is smaller than a 51-kDa soluble version derived from alternative splicing. The release of sRAGE can be induced by the phorbol ester PMA and the calcium ionophore c…
The Myristoylated Alanine-Rich C-Kinase Substrate (MARCKS) is Sequentially Phosphorylated by Conventional, Novel and Atypical Isotypes of Protein Kin…
1995
The myristoylated alanine-rich C-kinase substrate (MARCKS) is the major protein kinase C (PKC) substrate in many cell types including fibroblasts and brain cells. Here we describe the phosphorylation of MARCKS and the site specificity for different PKC isotypes. Conventional (c)PKC beta 1, novel (n)PKC delta and nPKC epsilon efficiently phosphorylated the MARCKS protein in vitro. The Km values were extremely low, reflecting a high affinity between kinases and substrate. The apparent affinity of nPKC delta (Km = 0.06 microM) was higher than that of nPKC epsilon and cPKC beta 1 (Km = 0.32 microM). The rate of substrate phosphorylation was inversely correlated with affinity and decreased in th…
Adrenergic modulation of astroglial phospholipase D activity and cell proliferation.
1999
As phospholipase D (PLD) activation has been associated with mitogenic signalling in several cell types, we tested an association between adrenergic activation of PLD and cellular proliferation in primary cultures of rat cortical astrocytes. In 2-week old cultures, PLD activation by noradrenaline (EC50: 0.49 microM) was inhibited by prazosin, a specific antagonist at alpha1-adrenergic receptors (IC50: 0.23 microM). Adrenergic PLD activation was not affected by genistein, an inhibitor of tyrosine kinases, or by Ro 31-8220, an inhibitor of protein kinase C (PKC), but was dose-dependently depressed in the presence of brefeldin A (1-100 microg/ml), an inhibitor of ARF activation. In experiments…
Amphiregulin activates human hepatic stellate cells and is upregulated in non alcoholic steatohepatitis
2015
AbstractAmphiregulin (AR) involvement in liver fibrogenesis and hepatic stellate cells (HSC) regulation is under study. Non-alcoholic fatty liver disease (NAFLD) and its more severe form non-alcoholic steatohepatitis (NASH) may progress to cirrhosis and hepatocellular cancer (HCC). Our aim was to investigate ex vivo the effect of AR on human primary HSC (hHSC) and verify in vivo the relevance of AR in NAFLD fibrogenesis. hHSC isolated from healthy liver segments were analyzed for expression of AR and its activator, TNF-α converting enzyme (TACE). AR induction of hHSC proliferation and matrix production was estimated in the presence of antagonists. AR involvement in fibrogenesis was also ass…