Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.5.1.18 (glutathione S-transferase)
 22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

JNK3 alpha 1 is predominantly a neuronal specific MAP kinase that is believed to require, like all MAP kinases, both threonine and tyrosine phosphorylation for maximal enzyme activity. In this study we investigated the in vitro activation of JNK3 alpha 1 by MAP kinase kinase 4 (MKK4), MAP kinase kinase 7 (MKK7), and the combination of MKK4 + MKK7. Mass spectral analysis showed that MKK7 was capable of monophosphorylating JNK3 alpha 1 in vitro, whereas both MKK4 and MKK7 were required for bisphosphorylation and maximal enzyme activity. Measuring catalysis under Vmax conditions showed MKK4 + MKK7-activated JNK3 alpha 1 had Vmax 715-fold greater than nonactivated JNK3 alpha 1 and MKK7-activated JNK3 alpha 1 had Vmax 250-fold greater than nonactivated JNK3 alpha 1. In contrast, MKK4-activated JNK3 alpha 1 had no increase in Vmax compared to nonactivated levels and had no phosphorylation on the basis of mass spectrometry. These data suggest that MKK7 was largely responsible for JNK3 alpha 1 activation and that a single threonine phosphorylation may be all that is needed for JNK3 alpha 1 to be active. The steady-state rate constants kcat, Km(GST-ATF2++), and Km(ATP) for both monophosphorylated and bisphosphorylated JNK3 alpha 1 were within 2-fold between the two enzyme forms, suggesting the addition of tyrosine phosphorylation does not affect the binding of ATF2, ATP, or maximal turnover. Finally, the MAP kinase inhibitor, SB203580, had an IC50 value approximately 4-fold more potent on the monophosphorylated JNK3 alpha 1 compared to the bisphosphorylated JNK3 alpha 1, suggesting only a modest effect of tyrosine phosphorylation on inhibitor binding.
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PMID:Activation of JNK3 alpha 1 requires both MKK4 and MKK7: kinetic characterization of in vitro phosphorylated JNK3 alpha 1. 1071 36

Gadd45 family genes encode nuclear acidic proteins composed of Gadd45, MyD118, and CR6. Sequence analysis showed that Gadd45 family proteins (Gadd45, MyD118, and CR6) contain LXXLL signature motifs considered necessary and sufficient for the binding of several coactivators to nuclear receptors. Interaction between Gadd45 or CR6 and RXR alpha was confirmed by a two-hybrid test in yeast. Results from a series of GST pulldown assays showed that these Gadd45 family proteins interact with several nuclear hormone receptors including RXR alpha, RAR alpha, ER alpha, PPAR alpha, PPAR beta, and PPAR gamma2 in vitro. Interaction between Gadd45 family proteins and nuclear hormone receptors resulted in modest activation of transactivating function of nuclear hormone receptors in reporter systems. When fused to DNA binding domain of GAL4, Gadd45 and CR6 activated the UAS-mediated transcription in mammalian cells. These results suggest that Gadd45 family proteins bind to nuclear hormone receptors and act as nuclear coactivators.
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PMID:Gadd45 family proteins are coactivators of nuclear hormone receptors. 1087 26

To elucidate mechanisms underlying glutathione S-transferase p (GSTp)-mediated cellular protection against oxidative stress-induced cell death, the effect of GSTp on stress signaling pathways was investigated before and after H2O2 treatment. Under nonstressed conditions, increased expression of GSTp via a tet-off-inducible GSTp in NIH 3T3 cells increased the phosphorylation of mitogen-activated protein (MAP) kinase kinase 4, p38, extracellular receptor kinase (ERK), and inhibitor of kappa-kinase (IKK), and reduced phosphorylation of MAP kinase kinase 7 and Jun NH2-terminal kinase (JNK). Whereas H2O2 treatment of cells induced JNK, p38, and IKK activities, in the presence of H2O2 and elevated GSTp expression there was an additional increase in ERK, p38, and IKK activities and a decrease in JNK activity. GSTp-mediated protection from H2O2-induced death was attenuated upon inhibition of p38, nuclear factor KB, or MAP kinase by dominant negative or pharmacological inhibitors. Conversely, expression of a dominant negative JNK protected cells from H2O2-mediated death. These data suggest that the coordinated regulation of stress kinases by GSTp, as reflected by increased p38, ERK, and nuclear factor kappaB activities together with suppression of JNK signaling, contributes to protection of cells against reactive oxygen species-mediated death.
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PMID:Glutathione S-transferase p elicits protection against H2O2-induced cell death via coordinated regulation of stress kinases. 1094 8

The Gadd45 family of proteins includes Gadd45alpha, MyD118/Gadd45beta, and CR6/OIG37/Gadd45gamma. These proteins play important roles in maintaining genomic stability and in regulating the cell cycle. This study reports the cloning of a novel protein called CR6-interacting factor 1 (CRIF1) which interacts with Gadd45alpha, MyD118/Gadd45beta, and CR6/OIG37/Gadd45gamma. CRIF1 binds specifically to the Gadd45 family proteins, as determined by an in vitro glutathione S-transferase pull-down assay and an in vivo mammalian cell two-hybrid assay along with coimmunoprecipitation assays. CRIF1 mRNA is highly expressed in the thyroid gland, heart, lymph nodes, trachea, and adrenal tissues. CRIF1 localizes exclusively to the nucleus and colocalizes with Gadd45gamma. Recombinant CRIF1 inhibits the histone H1 kinase activity of immunoprecipitated Cdc2-cyclin B1 and Cdk2-cyclin E, and the inhibitory effects were additive with Gadd45 proteins. Overexpression of CRIF1 increases the percentage of cells in G1, decreases the percentage of cells in S phase, and suppresses growth in NIH3T3 cells. The down-regulation of endogenous CRIF1 by the transfection of the small interfering RNA duplexes resulted in the inactivation of Rb by phosphorylation and decreased the G1 phase cell populations. Expression of CRIF1 is barely detectable in adrenal adenoma and papillary thyroid cancer and much lower than in adjacent normal tissue. The results presented here suggest that CRIF1 is a novel nuclear protein that interacts with Gadd45 and may play a role in negative regulation of cell cycle progression and cell growth.
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PMID:CR6-interacting factor 1 interacts with Gadd45 family proteins and modulates the cell cycle. 1271 9