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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The 105-kDa
heat shock protein
alpha (HSP105alpha) and HSP105beta are mammalian heat shock proteins that belong to the HSP105/HSP110 family. Both HSP105alpha and HSP105beta consist of acidic and basic isoforms. Here we report that the acidic isoforms are serine phosphorylated HSP105alpha or HSP105beta. Furthermore, using an in-gel kinase assay with HSP105alpha or HSP105beta as the substrate, the
protein kinase
that phosphorylates HSP105alpha and HSP105beta was identified as
casein kinase II
. Since phosphorylated HSP105alpha is especially prominent in the brain compared to other tissues of mice and rats, the phosphorylation of HSP105alpha by
casein kinase II
may be biologically significant.
...
PMID:Phosphorylation of the 105-kDa heat shock proteins, HSP105alpha and HSP105beta, by casein kinase II. 1077 27
Stress activation of heat shock factor (HSF1) involves the conversion of repressed monomers to DNA-binding homotrimers with increased transcriptional capacity and results in transcriptional up-regulation of the
heat shock protein
(hsp) gene family. Cells tightly control the activity of HSF1 through interactions with hsp90 chaperone complexes and through integration into a number of different signaling cascades. A number of studies have shown that HSF1 transcriptional activity is negatively regulated by constitutive phosphorylation in the regulatory domain by
glycogen synthase kinase
(GSK3) isoforms alpha/beta. However, previous studies have not examined the ability of GSK3 to regulate the DNA-binding activity of native HSF1 in vivo under heat shock conditions. Here we show that GSK3beta inhibits both DNA-binding and transcriptional activities of HSF1 in heat-shocked cells. Specific inhibition of GSK3 increased the levels of DNA binding and transcription after heat shock and delayed the attenuation of HSF1 during recovery. In contrast, the overexpression of GSK3beta resulted in significant reduction in heat-induced HSF1 activities. These results confirm the role of GSK3beta as a negative regulator of HSF1 transcription in cells during heat shock and demonstrate for the first time that GSK3beta functions to repress DNA binding.
...
PMID:Glycogen synthase kinase 3beta negatively regulates both DNA-binding and transcriptional activities of heat shock factor 1. 1085 93
Cyclic nucleotide-dependent vascular relaxation is associated with increases in the phosphorylation of a small
heat shock protein
(
HSP
), HSP20. An increase in phosphorylation of another small
HSP
, HSP27, is associated with impaired cyclic nucleotide-dependent vascular relaxation. Expression of HSPs is altered by exposure to several types of cellular stress in vitro. To determine if behavioral stress in vivo alters vascular expression and phosphorylation of the small HSPs and cyclic nucleotide-dependent vascular relaxation, borderline hypertensive rats were stressed by restraint and exposure to air-jet stress 2 h/day for 10 days or remained in their home cage. Stress impaired relaxation of aorta to forskolin, which activates adenylyl cyclase, and sodium nitroprusside, which activates guanylyl cyclase. This was associated with an increase in the aortic expression and phosphorylation of HSP27, which was localized to the vascular smooth muscle, but a decrease in the amount of phosphorylated (P)-HSP20. To determine if P-HSP27 inhibits phosphorylation of HSP20, P-HSP27 was added to a reaction mixture containing recombinant HSP20 and the catalytic subunit of
cAMP-dependent protein kinase
. P-HSP27 inhibited phosphorylation of HSP20 in a concentration-dependent manner. These data demonstrate that P-HSP27 can inhibit phosphorylation of HSP20. The increase in P-HSP27 and decrease in P-HSP20 were associated with reduced cyclic nucleotide-dependent vascular smooth muscle relaxation in response to behavioral stress in vivo, an effect similar to that observed previously in response to cellular stress in vitro.
...
PMID:Stress causes decrease in vascular relaxation linked with altered phosphorylation of heat shock proteins. 1093 37
Since protection of cells from stress-induced apoptosis by the
heat shock protein
Hsp72 involves suppression of stress kinase JNK, we suggested that Hsp72-mediated JNK inhibition might also be critical for myocardial protection from ischemia/reperfusion. Transient energy deprivation of H9c2 myogenic cells, used as an in vitro model of myocardial ischemia, led to cell death that had morphological features of apoptosis and necrosis and was independent of caspases. Surprisingly, this unusual type of cell death was regulated by JNK and ERK kinases. In fact, specific inhibition of JNK increased cell survival; specific inhibition of ERKs enhanced deleterious consequences of energy deprivation, whereas inhibition of p38 kinase had no effect. Hsp72 suppressed activation of JNK and did not increase ERK activity, suggesting that inhibition of JNK is the important component of Hsp72-mediated protection. Upon transient energy deprivation, activation of JNK proceeds via two distinct pathways, stimulation of JNK phosphorylation by a
protein kinase
SEK1 and inhibition of JNK dephosphorylation. Remarkably, in cells exposed to transient energy deprivation, Hsp72 enhanced the rate of JNK dephosphorylation but did not affect SEK1 activity. Therefore, it appears that Hsp72 specifically down-regulates JNK by accelerating its dephosphorylation, which reduces the susceptibility of cardiac cells to simulated ischemia/reperfusion.
...
PMID:Suppression of stress kinase JNK is involved in HSP72-mediated protection of myogenic cells from transient energy deprivation. HSP72 alleviates the stewss-induced inhibition of JNK dephosphorylation. 1097 40
Nitric oxide (NO) exerts contrasting effects on apoptosis, depending on its concentration, flux and cell type. In some situations, NO activates the transduction pathways leading to apoptosis, whereas in other cases NO protects cells against spontaneous or induced apoptosis. The redox state of the cells appears to be a crucial parameter for the determination of the ultimate action of NO on cell multiplication and survival. Apoptosis is mostly associated with the delivery of NO by chemical donors and with myelomonocytic cells, whereas antiapoptotic effects seem to be related to the endogenous production of NO by NO synthases and is observed more frequently in cells of the B lymphocyte lineage. Pro-apoptotic effects are often observed when NO reacts with superoxide to produce the highly toxic peroxynitrite. Through the induction of damages to DNA, NO stimulates the expression of enzymes and transcription factors involved in DNA repair and modulation of apoptosis, such as the tumor suppressor p53. The latter molecule transactivates the expression of pro-apoptotic genes, such as bax, and that of the cyclin-dependent kinase inhibitor p21, whereas it down-regulates the expression of the anti-apoptotic protein bcl-2. On the other hand, NO inactivates caspases through oxidation and S-nitrosylation of the active cystein, providing an efficient means to block apoptosis. Other protective effects of NO on apoptosis rely on the stimulation of
cGMP-dependent protein kinase
(PKG), modulation of the members of the bcl-2/bax family that control the mitochondrial pore transition permeability, induction of the
heat shock protein
HSP 70 and interaction with the ceramide pathway. A defect in the apoptotic process contributes to the accumulation of tumoral cells in leukemia, notably in B-CLL. A better knowledge of the targets of NO would provide efficient means to control cell apoptosis, and hence would possibly lead to the development of new therapeutic approaches for diseases where an alteration of apoptosis is involved.
...
PMID:Mechanisms involved in the pro- and anti-apoptotic role of NO in human leukemia. 1099 17
The current study investigates the activation in vivo and regulation of the expression of components of the p38 mitogen-activated protein kinase (MAPK) pathway during gonadotropin-induced formation and development of the rat corpus luteum, employing a sequential PMSG/human CG (hCG) treatment paradigm. We postulated that the p38 MAPK pathway could serve to promote phosphorylation of key substrates during luteal maturation, since maturing luteal cells, thought to be cAMP-nonresponsive, nevertheless maintain critical phosphoproteins. Both p38 MAPK and its upstream activator MAPK kinase-6 (MKK6) were found to be chronically activated during the luteal maturation phase, with activation detected by 24 h post hCG and maintained through 4 days post hCG. The p38 MAPK downstream
protein kinase
target termed MAPK-activated protein kinase-3 (MAPKAPK-3) was newly induced at both mRNA and protein levels during luteal formation and maturation, while mRNA and protein expression of the closely related MAPKAPK-2 diminished. Two potential substrates for MAPKAPKs, the small
heat shock protein
HSP-27 and the cAMP regulatory element binding protein CREB, were monitored in vivo for phosphorylation. HSP-27 phosphorylation was not modulated during luteal maturation. In contrast, we observed sustained luteal-phase CREB phosphorylation in vivo, consistent with upstream MKK6/p38 MAPK activation and MAPKAPK-3 induction. MAPKAPK-3-specific immune complex kinase assays provided direct evidence that MAPKAPK-3 was in an activated state during luteal maturation in vivo. Cellular inhibitor studies indicated that an intact p38 MAPK path was required for CREB phosphorylation in a cellular model of luteinization, as treatment of luteinized granulosa cells with the p38 MAPK inhibitor SB 203580 strongly inhibited CREB phosphorylation. Transient transfection studies provided direct evidence that MAPKAPK-3 was capable of signaling to activate CREB transcriptional activity, as assessed by means of GAL4-CREB fusion protein construct coexpressed with GAL4-luciferase reporter construct. Introduction of wild-type, but not kinase-dead mutant, MAPKAPK-3 cDNA, into a mouse ovarian cell line stimulated GAL4-CREB- dependent transcriptional activity approximately 3-fold. Thus MAPKAPK-3 is indeed uniquely poised to support luteal maturation through the phosphorylation and activation of the nuclear transcription factor CREB.
...
PMID:Developmental regulation of mitogen-activated protein kinase-activated kinases-2 and -3 (MAPKAPK-2/-3) in vivo during corpus luteum formation in the rat. 1132 54
As a result of substantial advances in recent cancer biology, cell cycle regulation in the G1 phase has attracted a great deal of attention as a promising target for the research and treatment of cancer. Many of the important genes associated with G1 regulation have been shown to play a key role in proliferation, differentiation and oncogenic transformation and programmed cell death (apoptosis). Currently, a variety of "cytostatic" agents that affects G1 progression and/or G1/S transition are being evaluated in clinical trials. Flavopiridol is a potent inhibitor of cyclin-dependent kinases (CDKs). UCN-01 was originally found to be a PKC-selective
protein kinase
antagonist. More recent studies have revealed that this agent can also inhibit several CDKs and the checkpoint kinase CHK1. FR901228, MS-27-275 and SAHA are histone deacetylase inhibitors that induce changes in the transcription of specific genes via the hyperacetylation of histones. The proteasome inhibitor PS-341 disrupts the degradation process of intracellular proteins, including cell cycle regulatory proteins such as cyclins. R115777, SCH66336 and BMS-214662 are non-peptidic farnesyl transferase inhibitors that prevent p21 ras oncogene activation. Rapamycin derivative CCI-779 downregulates signals through S6 kinase and FRAP (FKBP-rapamycin associating protein), affecting the expression levels of mRNAs important for progression from G1 to S phase. 17-Allylaminogeldanamycin targets the Hsp-90 (
heat shock protein
-90) family of cellular chaperones regulating the function of signaling proteins. TNP-470 (AGM-1470), a fumagillin derivative shows antiangiogenic action through binding to MetAP-2 (methionine aminopeptidase-2). The antitumor sulfonamide E7070, causing a cellular accumulation in the G1 phase, has been shown to suppress the activation of CDK2 and cyclin E expression in HCT116 colorectal cancer cell line highly sensitive to the drug. With respect to several growth factor receptors such as EGFR, PDGFR, bFGFR and VEGFR, potent and specific inhibitors of receptor tyrosine kinases have been also examined as hopeful drug candidates. In this report, we review the current status of extensive efforts directed towards the discovery and development of new chemotherapeutic anticancer agents targeting cell cycle regulation in the G1 phase, with particular focus on the compounds undergoing clinical investigations.
...
PMID:Cell cycle regulation in the G1 phase: a promising target for the development of new chemotherapeutic anticancer agents. 1156 78
Phosphatidylinositol 3-kinase (PI3-kinase) activates protein kinase B (also known as Akt), which phosphorylates and activates a cyclic nucleotide phosphodiesterase 3B. Increases in cyclic nucleotide concentrations inhibit agonist-induced contraction of vascular smooth muscle. Thus we hypothesized that the PI3-kinase/Akt pathway may regulate vascular smooth muscle tone. In unstimulated, intact bovine carotid artery smooth muscle, the basal phosphorylation of Akt was higher than that in cultured smooth muscle cells. The phosphorylation of Akt decreases in a time-dependent manner when incubated with the PI3-kinase inhibitor, LY-294002. Agonist (serotonin)-, phorbol ester (phorbol 12,13-dibutyrate; PDBu)-, and depolarization (KCl)-induced contractions of vascular smooth muscles were all inhibited in a dose-dependent fashion by LY-294002. However, LY-294002 did not inhibit serotonin- or PDBu-induced increases in myosin light chain phosphorylation or total O(2) consumption, suggesting that inhibition of contraction was not mediated by reversal or inhibition of the pathways that lead to smooth muscle activation and contraction. Treatment of vascular smooth muscle with LY-294002 increased the activity of
cAMP-dependent protein kinase
and increased the phosphorylation of the
cAMP-dependent protein kinase
substrate
heat shock protein
20 (HSP20). These data suggest that activation of the PI3-kinase/Akt pathway in unstimulated smooth muscle may modulate vascular smooth muscle tone (allow agonist-induced contraction) through inhibition of the cyclic nucleotide/HSP20 pathway and suggest that cyclic nucleotide-dependent inhibition of contraction is dissociated from the myosin light chain contractile regulatory pathways.
...
PMID:PI3-kinase/Akt modulates vascular smooth muscle tone via cAMP signaling pathways. 1156 68
Human skin is exposed to an environment that varies in humidity from 100 to 0%, leading to seasonal variations in the condition of the skin. Exposure to a low humidity environment creates an osmotic gradient across the stratum corneum, which is known to modulate cutaneous barrier function. Heat shock proteins protect against stress-induced destabilization of proteins. We investigated whether osmotic shock (sorbitol) induced a
heat shock protein
response in normal human keratinocytes, and used heat shock as a positive control. Both heat shock and osmotic stress (200 and 300 mM sorbitol) clearly induced heat shock proteins 70 and 27 mRNA levels. The induction of heat shock protein 70 mRNA levels by osmotic stress peaked at 16 h and persisted until 24 h, whereas upregulation of heat shock protein 70 mRNA levels by heat peaked at 2 h and returned to baseline levels by 6 h. Sorbitol also increased heat shock protein 70 levels in a concentration-dependent manner. The kinetics of heat shock protein 27 mRNA induction by osmotic stress and heat were similar with peak induction at 6 h. The mitogen activated
protein kinase
family of proteins plays an important part in the coordination of gene responses to various stress conditions. We have demonstrated that the p38 mitogen activated protein kinase was strongly activated by 200 mM and 300 mM sorbitol. The specific p38 mitogen activated protein kinase inhibitor PD169316 almost completely blocked heat shock protein 70 mRNA induction by 200 mM and 300 mM sorbitol and completely suppressed heat shock protein 27 mRNA induction with 200 mM sorbitol. PD169316 also counteracted upregulation of heat shock protein 70 levels by sorbitol. These data indicate that keratinocytes respond to osmotic stress by p38 mitogen activated protein kinase regulated induction of heat shock proteins. This molecular pathway may be relevant for the mechanisms regulating the response of human skin to variations in environmental humidity.
...
PMID:Human keratinocytes respond to osmotic stress by p38 map kinase regulated induction of HSP70 and HSP27. 1171 Sep 46
The interaction of caldesmon with different Ca2+-binding proteins has been analyzed, and it is supposed that one of the conformers of calmodulin might be an endogenous regulator of caldesmon. The arrangement of caldesmon and Ca2+-binding proteins within their complexes has been analyzed by different methods. The central helix of calmodulin is supposed to be located near the single Cys residue in the C-terminal domain of caldesmon. The N-terminal globular domain of calmodulin interacts with sites A and B' of caldesmon, whereas the C-terminal globular domain of calmodulin binds to site B of caldesmon. The complex of calmodulin and caldesmon is very flexible; therefore, both parallel and antiparallel orientation of polypeptide chains of the two proteins is possible in experiments with short fragments of caldesmon and calmodulin. The length, flexibility, and charge of the central helix of calmodulin play an important role in its interaction with caldesmon. Phosphorylation of caldesmon by different protein kinases in vitro has been analyzed. It was shown that phosphorylation catalyzed by
casein kinase II
of sites located in the N-terminal domain decreases the interaction of caldesmon with myosin and tropomyosin. Caldesmon and calponin may interact with phospholipids. The sites involved in the interaction of these actin-binding proteins with phospholipids have been mapped. It is supposed that the interaction of calponin and caldesmon with phospholipids may play a role in the formation of cytoskeleton. Calponin interacts with 90-kD
heat shock protein
(hsp90) that may be involved in transportation of calponin and its proper interaction with different elements of cytoskeleton. Calponin, filamin, and alpha-actinin can simultaneously interact with actin filaments. Simultaneous binding of two actin-binding proteins affects the structure of actin bundles and their mechanical properties and may be of great importance in formation of different elements of cytoskeleton.
...
PMID:Some properties of caldesmon and calponin and the participation of these proteins in regulation of smooth muscle contraction and cytoskeleton formation. 1173 32
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