Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of the Raf-1 protein to morphologically transform murine fibroblasts can be activated by amino-terminal deletions or substitutions. We have compared the phosphorylation states of full-length and representative transforming and non-transforming amino-terminal deletion mutants of the Raf-1 protein using phosphoamino acid analysis and tryptic phosphopeptide mapping. Several [32P]orthophosphate-labeled tryptic phosphopeptides that were present in the full-length Raf-1 protein were absent from the highly transforming 22W Raf-1 mutant (lacking 305 amino-terminal residues). Peptide-specific antisera localized Raf-1 phosphorylation sites to several amino-terminal cyanogen bromide and tryptic peptides that are deleted from the 22W protein. A major phosphorylated tryptic peptide of the Raf-1 protein was immunoprecipitated by antiserum directed against amino acid residues 257-275, a highly conserved region of the raf family. This tryptic peptide is entirely deleted from the highly transforming 22W protein. Subtractive Edman degradation and electrophoretic analysis of the immunoprecipitated tryptic peptide indicated that phosphorylation of the Raf-1 protein occurs at serine 259. Multiple phosphorylated tryptic peptide forms were immunoprecipitated by antiserum directed against Raf-1 residues 283-309. The majority of this tryptic peptide is also deleted from the highly transforming Raf-1 mutant 22W.
...
PMID:Phosphorylation occurs in the amino terminus of the Raf-1 protein. 174 Nov 64

Transformation by activated pp60c-src has been correlated by genetic analysis with the tyrosine phosphorylation of a 120 kilodalton (kDa) protein, p120. We now demonstrate tyrosine phosphorylation of p120 following stimulation of cells by growth factors whose receptors have intrinsic tyrosine-specific protein kinase activity. Stimulation of quiescent NIH3T3 cells with platelet-derived growth factor (PDGF) resulted in the tyrosine phosphorylation of p120 that was maximal by 5 min and returned to background levels by 30 min. p120 was also phosphorylated on tyrosine after addition of colony-stimulating factor 1 (CSF-1) or epidermal growth factor (EGF) to NIH3T3 cells engineered to express high levels of their respective receptors. Two additional src substrates, p110 and p85, were analysed under identical assay conditions. PDGF, CSF-1, and EGF induced only a minimal increase in the tyrosine phosphorylation of p85 and no change in the phosphorylation of p110. Thus, the marked ligand-induced tyrosine phosphorylation of p120 was a property not shared by the other src substrates examined. Immunoblotting with antibodies to p120 and the ras GTPase activating protein, GAP, suggests that p120 and GAP are unrelated. In addition, the amino acid sequences of four cyanogen bromide peptides derived from p120 showed no homology to GAP or to sequences in either the PIR or Swiss-Prot databases. These data suggest that tyrosine phosphorylation of p120 may contribute to both signal transduction through growth factor receptors and pp60src induced transformation.
...
PMID:PDGF, CSF-1, and EGF induce tyrosine phosphorylation of p120, a pp60src transformation-associated substrate. 185 49

In the present study we have examined the ability of 8-bromoadenosine cyclic 3',5'-phosphate (8-bromo-cAMP; the membrane permeant analog of cAMP which can activate protein kinase A) to mimic hormone action and stimulate glucose transport and glucose transporter (GLUT-1) gene expression as well as the expression of several growth-related protooncogenes in quiescent 3T3-L1 fibroblasts. 8-Bromo-cAMP induced a rapid and prolonged increase in the rate of hexose transport. Early activation of hexose transport (within 30 min) was associated with increased plasma membrane immunoreactive glucose transporters, which corresponded to a doubling in the number of D-glucose-displaceable, plasma membrane cytochalasin B binding sites. The time course for 8-bromo-cAMP-induced hexose transport preceded the accumulation of GLUT-1 mRNA, which peaked between 4 and 8 h after exposure to the agent, and subsequently declined to approach basal (control) levels. Expression of the immediate-early genes c-fos and jun-B was induced by 8-bromo-cAMP on a rapid, but sustained time course, whereas induction of c-jun expression was delayed. Alterations in specific mRNAs following exposure to 8-bromo-cAMP were due to increased gene transcription (as judged by nuclear transcription run-on assays), although with respect to GLUT-1, an increase in mRNA stability was also observed. Treatment of the cells with forskolin resulted in the induction of GLUT-1 expression as well as expression of the immediate early genes. Exposure of quiescent 3T3-L1 fibroblasts to 8-bromo-cAMP resulted in a substantial increase in rates of total protein and RNA synthesis, but had little effect on DNA synthesis. The results demonstrate that 8-bromo-cAMP initiated a G0/G1 transition, but did not permit progression into S-phase. The results further suggest that increased cytosolic cAMP results in the stimulation of glucose transport by three distinct mechanisms to include translocation of pre-existing transporters, increased transcription of the GLUT-1 gene and increased stability of GLUT-1 mRNA.
...
PMID:Regulation of glucose transport as well as glucose transporter and immediate early gene expression in 3T3-L1 preadipocytes by 8-bromo-cAMP. 199 78

Type II topoisomerase has been purified from mouse FM3A cells by using P4 phage knotted DNA as a substrate. Analysis of the purified enzyme by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two bands of apparent molecular masses of 167 and 151 kDa. Partial digestion of the two bands with Staphylococcus aureus V8 protease indicated that the two polypeptides were structurally related. The enzyme required ATP and Mg2+ for activity. dATP could substitute for ATP, and ITP was slightly effective at 5-10 mM. The activity was sensitive to 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA), coumermycin, and ethidium bromide. A protein kinase activity was detected in the partially purified topoisomerase II fraction, and this protein kinase was further purified. The protein kinase phosphorylated the purified topoisomerase II, and the phosphorylation of topoisomerase II by the kinase increased the activity by 8.6-fold over that of the unmodified enzyme. The treatment of the purified topoisomerase II with alkaline phosphatase abolished the enzyme activity almost completely, and the treatment of the dephosphorylated topoisomerase II with the protein kinase restored the enzyme activity. The protein kinase activity was not stimulated by Ca2+ or cyclic nucleotides, and the aminoacyl residue phosphorylated by the kinase was serine. Enzymatic properties of the kinase were very similar to those of the kinase reported to be tightly associated with the Drosophila topoisomerase II [Sander, M., Nolan, J. M., & Hsieh, T.-S. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 6938-6942]. The immunoprecipitation of nuclear extracts prepared from 32P-labeled cells with anti-mouse topoisomerase II antiserum indicated that DNA topoisomerase II existed in mouse cells as a phosphoprotein.
...
PMID:Purification and characterization of type II DNA topoisomerase from mouse FM3A cells: phosphorylation of topoisomerase II and modification of its activity. 215 52

Several lines of evidence have demonstrated conclusively the presence of cAMP-dependent protein kinase (ecto-RC) activity on the external surface of goat cauda-epididymal intact spermatozoa. The intact-cell ecto-kinase that caused transfer of the terminal phosphate of exogenous ATP to the serine and threonine residues of exogenous histone was specifically activated by cAMP. As well, the ecto-kinase caused phosphorylation of the synthetic peptide Kemptide. The isolated spermatozoa, before or after incubation with reaction mixture for ecto-kinase assays, were approximately 99.5% viable, as shown by the analyses of ethidium bromide fluorescence and the cytosolic marker enzymes lactic dehydrogenase and 3-phosphoglycerate kinase. The ecto-kinase activity was not due to contamination of epididymal plasma and damaged cells or to protein kinase that may have leaked from the cells. There was little uptake of ATP and histone by the cells. The intact-cell kinase activity was strongly (80-90%) inhibited by treatment with membrane nonpenetrating surface probes: p-chloromercuriphenylsulfonic acid (2 microM), diazonium salt of sulfanilic acid (DSS, 0.5 mM), and proteases such as trypsin, chymotrypsin, and pronase (each 125 micrograms/mL). Disruption of sperm plasma membrane by sonication or Triton X-100 (0.2%) caused about a fivefold increase of the intact sperm kinase activity. Highly purified sperm plasma membrane (PM) possessed ecto-kinase activity that was resolved into type I and II kinases by DEAE-cellulose chromatography, the type I isoenzyme being the major (approximately 70%) enzymic species. Treatment of the intact spermatozoa with DSS prior to isolation of PM caused a marked loss of the activities of both the isoenzymes, indicating thereby the "ecto" nature of the PM-bound type I and II kinases. Preparations of vigorously forward-motile spermatozoa with 100% intactness had approximately fourfold higher specific activity of the ecto-kinase than the "composite" cells from which the former cells were isolated. However, the profiles of the type I and II ecto-kinases of the composite, as well as forward-motile spermatozoa, were nearly identical. The data are consistent with the view that ecto-kinases may have role in the regulation of flagellar motility.
...
PMID:Type I and II cAMP-dependent ecto-protein kinases in goat epididymal spermatozoa and their enriched activities in forward-motile spermatozoa. 216 Aug 33

Vertebrate photoreceptor cells contain a soluble phosphoprotein, phosducin, which complexes with the beta, gamma subunits of the GTP-binding protein, transducin. Light-induced changes in cyclic nucleotide levels modulate the phosphorylation of phosducin by protein kinase A. The complete amino acid sequence of purified phosducin from bovine retinas was determined by Edman degradation from overlapping polypeptides derived from enzymatic digestion by trypsin and Staphylococcus aureus V8 protease or from chemical degradation by cyanogen bromide. Excluding the unidentified group which blocks the NH2 terminus, phosducin contains 245 amino acids with a calculated molecular weight of 28,185 and isoelectric point of pH 4.5. Phosducin is enriched with acidic and sulfur-containing amino acids, having 32 glutamic acid, 16 aspartic acid, 9 methionine, and 5 cysteine residues. It also contains 24 serine and 8 threonine residues, of which only serine 73 is located within a consensus phosphorylation sequence (-RKMS(P)QV-) for cyclic nucleotide-dependent protein kinase. Secondary structure analysis predicts the presence of 62% alpha-helix, 22% beta-sheet, and 16% random coil, with eight turns. Computer-aided searches of protein data banks revealed no apparent homology to any sequenced protein except that coded by a MEKA cDNA clone (Kuo, C-H., Akiyama, M., and Miki, N. (1989) Mol. Brain Res. 6, 1-10) which deviates from the confirmed phosducin sequence in the last 15 amino acids. Sequence analysis of a cDNA clone for bovine retinal phosducin confirmed that the MEKA clone deviation resulted from an unidentified cDNA guanosine nucleotide, a shifted reading frame and a premature stop codon.
...
PMID:Amino acid and cDNA sequence of bovine phosducin, a soluble phosphoprotein from photoreceptor cells. 220 90

Reabsorptive cells of the human sweat gland normally exhibit a high basal Cl- permeability but are markedly impermeable to Cl- in cystic fibrosis (CF). We examined the possibility that the reduced basal Cl- permeability of CF sweat duct cells in primary culture is due to a defective regulation of plasma membrane Cl- permeability by prostaglandin E2 (PGE2), which is endogenously produced by cultured sweat duct cells. The macroscopic Cl- permeabilities of normal and CF sweat duct cells were assessed using a halide-specific fluorescent dye, 6-methoxy-N-(3-sulfopropyl)quinolinium, in combination with fluorescence digital-imaging microscopy. The Cl- and Br- permeabilities of normal sweat duct cells were markedly reduced by inhibiting endogenous PGE2 production with indomethacin. This inhibition of Cl- permeability by indomethacin was largely reversed by the addition of PGE2 (10 nM to 1 microM), but not forskolin. Conversely, PGE2 failed to stimulate the low Cl- permeabilities of sweat duct cells cultured from CF subjects. Our results support the following conclusions: 1) a defective regulation of Cl- permeability in CF is a feature of reabsorptive as well as secretory epithelial cells, and 2) the nature of this regulatory defect extends beyond altered Cl- permeability regulation by adenosine 3',5'-cyclic monophosphate-dependent protein kinase.
...
PMID:Regulation of Cl- permeability in normal and cystic fibrosis sweat duct cells. 224 Jan 98

Retention of the vital dyes rhodamine 123 (R-123) and hydroethidine (HET) correlates inversely with the multidrug resistant phenotypes of the adriamycin (ADM)-selected variants of a uv-induced murine fibrosarcoma cell line (UV-2237M). The differential affinity of these dyes for specific cellular organelles makes them unique compounds for studies of cellular transport. HET enters viable cells freely, is dehydrogenated to ethidium bromide (EtBr), and is subsequently accumulated in the nucleus. Viable cells are impermeable to extracellular EtBr, facilitating kinetic analysis of the efflux of intracellular EtBr. We found that the metabolite EtBr was rapidly cleared by ADM-resistant but not by ADM-sensitive cells. R-123 has a high affinity to mitochondria. Our results show that ADM-sensitive cells retain R-123 whereas the ADM-resistant cells do not. The clearance of both R-123 and EtBr from these cells was inhibited by verapamil. Therefore, R-123 and HET may be considered MDR-associated compounds useful in studying the MDR phenotype of cancer cells. Previously we reported a direct correlation between the level of activity of the calcium- and phospholipid-dependent protein kinase (protein kinases C) and ADM resistance in UV-2237M variant lines. In this report, we demonstrate a direct correlation between cellular calcium and MDR in these cells. Although chelation of extracellular calcium by EDTA did not alter the fluorescence profile of R-123 of the various cell lines, treating the ADM-resistant variants with verapamil restored cellular calcium to the same level as that of the parental cells and, at the same time, retarded the facilitated efflux of R-123 and EtBr and partially reversed cancer cell resistance to ADM.
...
PMID:Retention of vital dyes correlates inversely with the multidrug-resistant phenotype of adriamycin-selected murine fibrosarcoma variants. 238 29

Calmodulin-dependent multiprotein kinase and protein kinase C phosphorylate and inactivate both intact, microsomal HMG-CoA reductase, and the purified 53 kDa catalytic fragment. Isolation of the single phosphopeptide produced by combined cleavage with cyanogen bromide and Lys-C proteinase reveals that this is due to phosphorylation of a single serine residue near the C-terminus, corresponding to serine-872 in the human enzyme. This is identical with the single serine phosphorylated by the AMP-activated protein kinase. The nature of the protein kinase responsible for phosphorylation of this site in vivo is discussed.
...
PMID:Calmodulin-dependent multiprotein kinase and protein kinase C phosphorylate the same site on HMG-CoA reductase as the AMP-activated protein kinase. 238 4

The effect of 8-bromo-cAMP and forskolin on the phosphorylation state and protein kinase activity of the insulin receptor was evaluated in cultured IM-9 lymphoblasts. 8-Bromo-cAMP (1 mM) or forskolin (10 microM) enhanced the phosphorylation of the insulin receptor purified from 32P-labeled cells by affinity chromatography on wheat germ agglutinin-agarose and immunoprecipitation with monoclonal antibody. In the absence of insulin, phosphorylation of the beta subunit of the receptor was increased approximately 2-fold by raising intracellular cAMP. Phosphoamino acid analysis of the beta subunit following treatment of cells with forskolin revealed an increase in phosphoserine and phosphothreonine residues. In contrast, the insulin-stimulated phosphorylation of the receptor occurred on serine, threonine, and tyrosine residues and was diminished by prior exposure of cells to forskolin. Pulse-chase experiments indicated that forskolin did not enhance the turnover of phosphate on the receptor of cells previously exposed to insulin. Furthermore, extracts from forskolin-treated cells did not differ from control extracts in their capacity to dephosphorylate 32P-labeled receptor isolated from cells treated with insulin. The insulin-dependent tyrosine protein kinase activity of the receptor isolated from forskolin-treated cells was approximately 50% as active as the receptor isolated from either control or insulin-treated cells. This was assessed using both histone and a peptide synthesized in accordance with the deduced amino acid sequence of a potential autophosphorylation site of the human receptor (Thr-Arg-Asp-Ile-Tyr-Glu-Thr-Asp-Tyr-Tyr-Arg-Lys) as substrates for the protein kinase reaction. These results suggest that agents that raise intracellular cAMP increase phosphorylation of the insulin receptor on serine and threonine residues, reduce insulin-mediated receptor phosphorylation on tyrosine, serine, and threonine residues, and inhibit the insulin-dependent tyrosine protein kinase activity of the receptor. Thus cAMP may attenuate insulin action by altering the state of phosphorylation of the insulin receptor.
...
PMID:Increasing the cAMP content of IM-9 cells alters the phosphorylation state and protein kinase activity of the insulin receptor. 241 31


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---