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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)
Specification of the R7 cell fate in the developing Drosophila eye requires activation of the Sevenless (Sev) receptor tyrosine kinase, located on the surface of the R7 precursor cell, by its interaction with the Boss protein, expressed on the surface of the neighbouring R8 cell. Four genes that participate in the intracellular transmission of this signal have so far been identified and molecularly characterized: Ras1, Sos, Gap1 and sina (refs 4-8). The Drosophila homologue of the mammalian
Raf-1
serine/threonine kinase, which has been implicated in signal transduction pathways activated by many receptor
tyrosine
kinases (reviewed in refs 9 and 10), is encoded by the raf locus (also known as l(1)polehole, Draf-1 or Draf). Here we show that the Drosophila Raf serine/threonine kinase also plays a crucial role in the R7 pathway: the response to Sev activity is dependent on raf function, and a constitutively activated Raf protein can induce R7 cell development in the absence of sev function. We also present genetic evidence suggesting that Raf acts downstream of Ras1 and upstream of Sina in this signal transduction cascade.
...
PMID:Raf functions downstream of Ras1 in the Sevenless signal transduction pathway. 133 31
As detected by coimmunoprecipitation from PC12 cells, NGF induces rapid association between ERK1 (a growth factor-activated
serine/threonine protein kinase
) and gp140prototrk NGF receptors. In contrast, no such association is found with the closely related ERK2. Anti-trk immunocomplexes generated from NGF-treated cells also contain
protein kinase
activity that shares many properties with soluble ERK1. The association of both ERK1 protein and ERK-like kinase activity with gp140prototrk is maximal by 5 min of NGF treatment, persists for approximately 1 hr, and subsequently declines by 18 hr. Treatment with either basic fibroblast growth factor, epidermal growth factor, or orthovanadate also leads to association of ERK1 with gp140prototrk without
tyrosine
phosphorylation of the latter. The interaction between ERK1 and gp140prototrk may prove relevant to the NGF mechanism.
...
PMID:NGF and other growth factors induce an association between ERK1 and the NGF receptor, gp140prototrk. 146 7
The phytochrome gene (phyCer) of the moss Ceratodon purpureus was isolated and characterized. phyCer is composed of three coding exons: exon I of 2035 bp, exon II of 300 bp and exon III of 1574 bp. The deduced polypeptide encoded by exon I and II exhibits substantial sequence homology to the conserved NH2-terminal chromophore domain of known phytochromes. In contrast, the COOH-terminal polypeptide encoded by exon III shows no sequence homology to any phytochrome molecule. phyCer most likely represents a single-copy gene and is expressed in a light-independent manner. From the DNA sequence analysis it can be deduced that the PhyCer polypeptide is composed of 1303 amino acids (including the starting Met) which predicts a molecular mass for PhyCer of 145 kDa. The polypeptide encoded in exon III exhibits striking homology within the 300 carboxy-terminal amino acids to the catalytic domain of protein kinases. The carboxy terminus of PhyCer was found to be most homologous to protein-
tyrosine
kinases of Dictyostelium discoideum and to the products of retroviral oncogenes which belong to the Raf-Mos serine/threonine kinase family. From the hydropathy profile PhyCer appears to be a soluble protein. The predicted structure suggests that PhyCer represents a soluble light-sensor
protein kinase
which is linked with a cellular phosphorylating cascade.
...
PMID:Molecular cloning of a novel phytochrome gene of the moss Ceratodon purpureus which encodes a putative light-regulated protein kinase. 146 36
Exposure of mammalian cells to DNA-damaging agents induces the ultraviolet (UV) response, involving transcription factor AP-1, composed of Jun and Fos proteins. We investigated the mechanism by which UV irradiation induces the c-jun gene. The earliest detectable step was activation of Src
tyrosine
kinases, followed by activation of Ha-Ras and
Raf-1
. The response to UV was blocked by tyrosine kinase inhibitors and dominant negative mutants of v-src, Ha-ras, and raf-1. This signaling cascade leads to increased phosphorylation of c-Jun on two serine residues that potentiate its activity. These results strongly suggest that the UV response is initiated at or near the plasma membrane rather than the nucleus. The response may be elicited by oxidative stress, because it is inhibited by elevation of intracellular glutathione. Using tyrosine kinase inhibitors, we demonstrate that the UV response has a protective function.
...
PMID:The mammalian ultraviolet response is triggered by activation of Src tyrosine kinases. 147 46
Like many other cell surface receptors for nutrients and polypeptide hormones, the insulin receptor undergoes a complex endocytotic itinerary. Upon insulin binding, the receptor is activated as a
tyrosine
-specific
protein kinase
and autophosphorylates. This autophosphorylation is necessary for the receptor to internalize. After endocytosis, the ligand (insulin) and its receptor are dissociated. Most of the insulin is degraded, whereas the receptors are largely recycled to the cell surface. The signals in the receptor that control and specify its endocytotic pathway are beginning to be understood. Through the techniques of in vitro mutagenesis, noninternalizing receptors have been engineered and their structural and functional properties have been analyzed. For example, the immediate submembranous domain of the insulin receptor has been found to contain sequences (Gly-Pro-Leu-
Tyr
and, to a lesser extent, Asn-Pro-Gln-
Tyr
) that are necessary for normal endocytosis. Receptors deleted or mutated in these sequences retain tyrosine kinase activity but fail to undergo endocytosis. Unlike the better understood low density lipoprotein and transferrin receptors, however, these sequences are not sufficient for endocytosis. An insulin receptor with only these sequences exposed in the cytoplasm does not internalize. Tyrosine kinase activity is thought to be needed to lead to autophosphorylation and a conformational change that exposes the otherwise buried endocytosis sequences in the normally dimerized insulin receptor. Non-internalizing mutants of the insulin receptor have been used to examine the role of endocytosis in insulin action. It was found that an endocytosis-defective receptor could induce a short-term metabolic action of insulin (glycogen synthetase stimulation) as well as longer-term mitogenic effects of insulin. Furthermore, insulin action deactivated after the hormone was removed from the noninternalizing receptors. Apparently, endocytosis is not necessary for insulin action, but probably is important for removing the insulin from the cell so the target cell for insulin responds in a time-limited fashion to the hormone.
...
PMID:Mechanism and role of insulin receptor endocytosis. 147 59
Activation of the
protein kinase
p34cdc2 is required for entry into meiotic or mitotic M phase in all eukaryotic cells. One important mechanism regulating the activity of p34cdc2 during the cell cycle is based on phosphorylation/dephosphorylation. Avian p34cdc2 is phosphorylated on threonine 14 (Thr14),
tyrosine
15 (Tyr15), threonine 161 (Thr161) and serine 277 (Ser277). Dephosphorylation of both Thr14 and Tyr15 is required for activation of p34cdc2 at the G2/M transition, indicating that phosphorylation of these residues negatively regulates p34cdc2 activity. Conversely, phosphorylation of Thr161 is required for kinase activity. Whether modification of this residue is due to intramolecular autophosphorylation or to the action of an as yet unidentified kinase remains unresolved. Likewise, the role of phosphorylation of p34cdc2 on Ser277 during G1 phase of the cell cycle remains to be determined. The function of p34cdc2 is regulated also by cell cycle-dependent complex formation with cyclin proteins. We found that chicken cyclin B2 undergoes a striking redistribution from the cytoplasm to the nucleus just prior to the onset of mitosis. Expression of a non-destructible cyclin B2 mutant causes HeLa cells to arrest in mitosis. Frequently, arrested cells displayed multiple mitotic spindles.
...
PMID:Regulation of p34cdc2 protein kinase activity by phosphorylation and cyclin binding. 148 52
The small GTP-binding protein Ras appears to be required for transformation and differentiation induced by
tyrosine
kinases. The Ras requirement may be limited to a few tyrosine kinase-regulated signaling pathways or may be universal for all tyrosine kinase actions. Because both Ras and the microtubule-associated protein 2 kinases ERK1 and ERK2 have been implicated in events that lead to neurite outgrowth, we explored the possibility that Ras and ERKs may lie on the same signaling pathway. Utilizing PC-12 rat adrenal pheochromocytoma cell lines that contain a dominant inhibitory Ras mutant (S17N-Ras(H)), we found that Ras was required for stimulation of the ERK cascade by nerve growth factor but apparently not by the heterotrimeric G protein activator AlF4-. Within this cascade, Ras appears to be upstream of an ERK activator, raising the intriguing possibility that Ras may directly regulate a
serine/threonine protein kinase
.
...
PMID:Evidence for a Ras-dependent extracellular signal-regulated protein kinase (ERK) cascade. 149 81
The IL-2 receptor complex is minimally composed of two genetically unrelated subunits of relative molecular masses 55 and 75 kDa respectively. Structural information deduced from the cDNA sequences of either subunit have not revealed significant information as to the basis of the mechanisms of IL-2 receptor signal transduction. Nevertheless, IL-2 stimulates the activation of one or more
tyrosine
kinases requiring the functional participation of the p75 member of the receptor complex. Here we have developed the methods to isolate the receptor complex with an associated tyrosine protein kinase. Extracts of membrane glycoproteins from activated normal human T lymphocytes and cell lines demonstrated catalytic activation of tyrosine kinase activity when stimulated with IL-2. Purification of the receptor complex with biotinylated IL-2 revealed the presence of two dominant phosphotyrosyl-proteins of approximate molecular masses 58 and 97 kDa. Denaturation gel electrophoresis followed by renaturation of proteins associated with the IL-2 receptor complex demonstrated that the 97 kDa protein had catalytic autophosphorylation activity. The results indicate that the 58 and 97 kDa phosphotyrosyl-proteins can be found to co-precipitate with the IL-2 receptor complex and that the 97 kDa protein was demonstrated to have
protein kinase
activity. The association of such kinases with receptors devoid of catalytic structure may represent a unique paradigm of growth-factor receptor mechanisms.
...
PMID:Characterization of a tyrosine kinase activity associated with the high-affinity interleukin 2 receptor complex. 149 23
The 14-3-3 proteins are a family of acidic proteins found mainly in the brain and are suggested to have a role in monoamine synthesis based on their ability to activate
tyrosine
and tryptophan hydroxylases in the presence of type II Ca2+/calmodulin-dependent protein kinase. Recently, however, it has been demonstrated that a member of the 14-3-3 family, termed Exo1, stimulates Ca(2+)-dependent exocytosis in permeabilized adrenal chromaffin cells, suggesting that this protein family may influence the protein kinase C-mediated control of Ca(2+)-dependent exocytosis. Here we show that the 14-3-3 proteins activate protein kinase C at about 2-fold more than the known level of the activated
protein kinase
, i.e. the activity of protein kinase C in the presence of Ca2+ and phospholipids. This raises the possibility that the cellular activity of protein kinase C is regulated by diverse members of the 14-3-3 family and that the reported ability of Exo1 to reactivate Ca(2+)-dependent exocytosis is based on its stimulatory effect on protein kinase C activity. The 14-3-3 family, therefore, appears to be a multifunctional regulator of cell signalling processes mediated by two types of Ca(2+)-dependent
protein kinase
, protein kinase C and type II calmodulin-dependent
protein kinase
.
...
PMID:Activation of protein kinase C by the 14-3-3 proteins homologous with Exo1 protein that stimulates calcium-dependent exocytosis. 149 18
MAP kinase kinase (MAPKK) was purified 30,000-fold to homogeneity from extracts of rabbit skeletal muscle and shown to be a monomeric protein of apparent molecular mass 44 kDa. MAPKK activated the 42 kDa isoform of MAP kinase by phosphorylation of Thr-183 and
Tyr
-185, and phosphorylated itself slowly on
tyrosine
, threonine and serine residues, establishing that it is a 'dual specificity'
protein kinase
. Peptide sequences from MAPKK were homologous to other protein serine/threonine kinases, especially to the subfamily that includes yeast protein kinases that lie upstream of yeast MAP kinase homologues in the pheromone-dependent mating pathways.
...
PMID:MAP kinase kinase from rabbit skeletal muscle. A novel dual specificity enzyme showing homology to yeast protein kinases involved in pheromone-dependent signal transduction. 149 29
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