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

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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)

Previously, we have shown that nuclear envelope assembly in cell-free extracts of Xenopus eggs requires two distinct vesicle-containing fractions, called Nuclear Envelope Precursor Fractions A and B (NEP-A and NEP-B). These fractions are characterized further in this paper and the manner in which they are regulated during metaphase is examined. Antisera against the NEP-B fraction recognized several proteins common to NEP-B and Xenopus oocyte or liver nuclei, but not to NEP-A or cytosol. A known glycoprotein component of the nuclear pore complex, p62, also co-fractionated with NEP-B, whereas the Xenopus egg lamin LIII did not. Together, these results provide further evidence that the NEP-B fraction contains precursors of the nuclear envelope. The regulation of NEP-A and -B function during metaphase, when the nuclear envelope is disassembled, was examined by treating each fraction with metaphase cytosol or purified protein kinase preparations isolated from metaphase-arrested eggs. Treatment of NEP-B with metaphase cytosol, under conditions where proteins are irreversibly phosphorylated, inhibited the subsequent assembly of the nuclear envelope by preventing the binding of NEP-B to chromatin. In contrast, similar treatment of NEP-A did not affect its ability to form nuclear envelopes. The changes in NEP-B during metaphase did not appear to be regulated directly by either p34cdc2/cyclin B, S6 kinase II or MAP kinase.
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PMID:Regulation of nuclear envelope precursor functions during cell division. 140 Jun 33

A facile method for isolating genes that encode interacting proteins has been developed with a polypeptide probe that contains an amino-terminal extension with recognition sites for a monoclonal antibody, a specific endopeptidase, and a site-specific protein kinase. This probe, containing the basic region-leucine zipper dimerization motif of c-Fos, was used to screen a complementary DNA library. A complementary DNA that encoded a member of the basic-helix-loop-helix-zipper (bHLH-Zip) family of proteins was isolated. The complementary DNA-encoded polypeptide FIP (Fos interacting protein) bound to oligonucleotide probes that contained DNA binding motifs for other HLH proteins. When cotransfected with c-Fos, FIP stimulated transcription of an AP-1-responsive promoter.
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PMID:Interaction cloning: identification of a helix-loop-helix zipper protein that interacts with c-Fos. 158 69

Two-dimensional tryptic peptide analysis showed that pp60c-src from the human retinoblastoma cell line Y79 gave a unique phosphopeptide, which was not found in human fibroblast RT59. There was no significant difference in the extent of phosphorylation of other peptides between the two cell lines. Only phosphoserine was detected in this phosphopeptide. Both the fibroblast form and the neuronal form of pp60c-src from Y79 cells had this unique peptide phosphorylated to the same extent. The phosphorylation site was inferred to be serine 97 by comparing the tryptic map and the arginyl-endopeptidase map. The specific protein kinase activity of pp60c-src from Y79 cells was nearly equal to that of RT59 pp60c-src. This unique serine phosphorylation in the fibroblast form was discussed in relation to the oncogenic change of Y79 cells.
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PMID:Novel serine phosphorylation occurs in the fibroblast form of pp60c-src from Y79 retinoblastoma cells. 171 55

The present work describes the detection, purification, and characterization of a serine endopeptidase with preference for a phosphoserine in the P1' position of the substrate. During probing for the enzyme in crude extracts, as well as during its 64,000-fold purification, 32P-labeled guanidovaleryl-Arg-Ala-Ser(P)-isobutyl amide (I) was used to measure the cleavage of the Ala-Ser(P) bond. With this substrate, kcat was 1.7 s-1 and Km was 30 microM at the pH optimum, 7.5. The enzyme was classified as a serine peptidase from its reaction with a set of inhibitors, among which diisopropyl fluorophosphate was effective at low (20 microM) concentration. The endopeptidase showed an Mr of 74,000 under native as well as denaturing and reducing conditions, indicating that the native enzyme consists of only one major polypeptide chain. The molecular size and inhibition profile suggested identity of this enzyme with prolyl endopeptidase (EC 3.4.21.26). This was supported by its activity against specific substrates, such as succinyl-Gly-Pro-Leu-Pro-7-amido-4-methylcoumarin (kcat = 7.2 s-1 and Km = 290 microM), and by the inhibition of the latter activity by I. Compared with the cleavage of 100 microM I, Gly-Val-Leu-Arg-Arg-Ala-Ser-Val-Ala-Gln-Leu, after phosphorylation by cAMP-dependent protein kinase, was cleaved at the Ala-Ser(P) bond at a relative rate of 0.43, while cleavage of the Ala-Ser bond of the unphosphorylated undecapeptide was undetectable, i.e. less than 0.03. The pentapeptide Arg-Arg-Pro-Ser-Val was rapidly cleaved at the Pro-Ser bond (relative rate, 2.2). Still, the cleavage of the Pro-Ser(P) bond of the corresponding phosphorylated pentapeptide was even higher (relative rate, 4.0). These data suggest that phosphorylation of a serine residue in the P1' position of at least a few substrates of prolyl endopeptidase will increase the rate of their cleavage.
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PMID:A human serine endopeptidase, purified with respect to activity against a peptide with phosphoserine in the P1' position, is apparently identical with prolyl endopeptidase. 199 35

The interaction between neurokinin and excitatory amino acid receptors in the spinal cord have been characterised using the neonatal rat spinal cord in vitro preparation. Ventral root (VR) depolarization evoked by N-methyl-D-aspartate (NMDA) and quisqualate was reversibly enhanced in the presence of subthreshold concentrations of neurokinin A (NKA; 1.0-10 nM), but not by substance P (1.0-5.0 nM). When substance P (SP) was replaced by the metabolically stable substance P methyl ester (SPOMe), both NMDA and quisqualate responses were significantly enhanced. VR depolarization evoked by kainate was not altered by any of the neurokinin (NK) receptor agonists. In the presence of the endopeptidase inhibitors, bestatin, captopril and thiorphan (each 1.0 microM), SP significantly enhanced NMDA-evoked responses. The selective NK1 receptor antagonist (+/-) CP96 345 (100 nM) reversibly blocked the enhancement of NMDA-evoked depolarization by SPOMe. Furthermore, MEN10 376 (50 nM), a selective NK2 receptor antagonist blocked the enhancement of NMDA- and quisqualate-evoked depolarization by NKA. The protein kinase C and protein kinase A inhibitor staurosporine (1.0 microM) blocked the enhancement of excitatory amino acid-induced responses by NK-receptor activation. However, whilst NKA-evoked ventral root depolarization was completely abolished in the presence of staurosporine, SPOMe- and SP-induced depolarizations were unaffected. These data show that activation of NK1 or NK2 receptors enhances NMDA- and quisqualate-evoked ventral root depolarization in the neonatal rat spinal cord. The interaction between neurokinin and excitatory amino acid receptors involves protein kinase C activation.
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PMID:Tachykinin induced regulation of excitatory amino acid responses in the rat spinal cord in vitro. 751 61

The leucocyte surface glycosylphosphatidylinositol (GPI)-anchored membrane proteins are localized within specific membrane microdomains which also contain specific (glyco)lipids and intracellular proteins including protein kinases. These "GPI-domains" are devoid of most abundant transmembrane proteins, but in T-cells they appear to contain small amounts of CD4 and CD8 and in B-cell lines, small amounts of CD10. The existence of these relatively detergent-resistant membrane microdomains explains the signal-transducing ability of GPI-anchored receptors. In addition to the "GPI-microdomains", several other types of analogous very large detergent-resistant complexes/domains appear to exist, such as those containing T-cell receptor, others containing CD45R molecules associated with a protein kinase, and still others composed mainly of several proteins of the tetraspan family. Therefore, we suggest that the leucocyte surface is a mosaic of microdomains of unique composition associated with specific signal-transducing molecules.
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PMID:Association of GPI-anchored glycoproteins with other components of the leucocyte membrane. 808 Dec 39

Endothelial neutral endopeptidase (EC 3.4.24.11, NEP) contributes to the inactivation of vasoactive and inflammatory peptides such as f-Met-Leu-Phe, substance P, atrial natriuretic peptide, and bradykinin. The aim of the present study was to investigate the cellular regulation of NEP expression in human endothelial cells, focusing on the role of cyclic nucleotides and cellular phosphodiesterases (PDE). Activation of adenylate cyclase by forskolin or prostaglandin E1 (PGE1) induced an increase of NEP activity and NEP protein after 24 h of incubation. This effect was mimicked by two activators of protein kinase A, dibutyryl-cAMP and 8-bromo-cAMP. The nonspecific PDE inhibitor, 3-isobutyl-1-methylxanthine (200 microM), increased NEP activity up to 192%. The activator of guanylate cyclase, sodium nitroprusside (SNP), did not affect NEP activity but completely inhibited the 3-isobutyl-1-methylxanthine-mediated increase of NEP activity. The PDE-III inhibitors motapizone (100 microM) and enoximone (100 microM) enhanced NEP activity up to 188% and 213%, the PDE-IV inhibitor rolipram (3 microM) up to 162%, and the combined PDE-III/IV inhibitor zardaverine (1 microM) up to 176% of control values. The present data provide evidence for a cAMP-mediated increase of NEP activity in human endothelial cells.
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PMID:Activation of adenylate cyclase and phosphodiesterase inhibition enhance neutral endopeptidase activity in human endothelial cells. 854 50

1. The aim of this study was a pharmacological characterization of the multiple NANC inhibitory transmission systems producing relaxation of the circular muscle of guinea-pig proximal colon. In the presence of atropine (1 microM), guanethidine (3 microM) and of the tachykinin NK1 and NK2 receptor antagonists, SR 140333 (0.3 microM) and MEN 10627 (1 microM), respectively, electrical field stimulation (EFS) produced a frequency-dependent (0.1-3 Hz) relaxation. During a cumulative frequency-response curve, the maximal relaxant effect was produced at 3 Hz and approached the maximal relaxation to 1 microM isoprenaline. In the presence of both apamin (0.3 microM) and L-nitroarginine (L-NOARG, 100 microM), EFS failed to evoke relaxation up to 1 Hz; at 1-10 Hz, a slowly developing relaxation ensured which approached 50% of the Emax to isoprenaline. The EFS-evoked NANC relaxation, either in the presence or absence of apamin and L-NOARG, was unaffected by in vitro capsaicin pretreatment (10 microM for 15 min). 2. Three protocols of EFS were developed for further pharmacological analysis: (a) EFS at 1 Hz for 5 s in the presence of L-NOARG, producing a transient fast apamin-sensitive relaxation; (b) EFS at 1 Hz for 5 s in the presence of apamin, producing a transient fast L-NOARG-sensitive relaxation; and (c) EFS at 10 Hz for 5 s in the presence of both apamin and L-NOARG, producing a transient but slowly developing and more sustained relaxation. 3. The neutral endopeptidase inhibitor, thiorphan (1-10 microM), enhanced and prolonged the apamin- and L-NOARG-resistant NANC relaxation produced by EFS at 10 Hz, without affecting that evoked at 1 Hz in the presence of apamin or L-NOARG. The angiotensin converting enzyme inhibitor, captopril (1-10 microM) was without effect. 4. The cAMP analogue inhibitor of protein kinase A, Rp-cAMPs (100-300 microM) significantly reduced and shortened the NANC relaxation produced by 10 Hz EFS in the presence of L-NOARG without affecting that produced by 1 Hz EFS in the presence of apamin or L-NOARG. 5. The inhibitor of sarcoplasmic reticulum Ca-ATPase, cyclopiazonic acid (CPA, 3-10 microM for 60 min) abolished the 1 Hz EFS-induced relaxation in the presence of L-NOARG, and greatly inhibited that produced by 10 Hz EFS in the presence of both apamin and L-NOARG. The relaxation produced by 1 Hz EFS in the presence of apamin was inhibited by about 32% at 10 microM only. 6. Nifedipine (1 microM) did not affect the EFS-induced NANC relaxations. In the presence of nifedipine, tetraethylammonium (TEA, 1 mM) enhanced the 1 Hz EFS-induced relaxation in the presence of L-NOARG (158% of control) and that produced by 10 Hz EFS in the presence of apamin and L-NOARG (215% of control) while that evoked by 1 Hz EFS in the presence of apamin was slightly affected (109% of control). 7. In the presence of atropine, guanethidine, SR 140333 and MEN 10627, bath application of human vasoactive intestinal polypeptide (VIP, 0.1 nM-10 nM) produced a concentration-dependent, slowly developing relaxation of colonic strips. The relaxation to VIP was unaffected by apamin (0.3 microM), L-NOARG (100 microM), nifedipine (1 microM) or nifedipine plus TEA (1 mM); it was inhibited by CPA (10 microM) and Rp-cAMPs (100 microM) and was potentiated by thiorphan (10 microM). 8. The putative VIP receptor antagonist, VIP(10-28) (10 microM) did not affect the VIP-induced relaxation nor the NANC relaxation to 10 Hz EFS in the presence of apamin and L-NOARG. 9. The present findings provide evidence that three distinct NANC inhibitory mechanisms mediate relaxation of the circular muscle of the guinea-pig proximal colon. The first system provides a fast relaxation in response to low frequency of stimulation and may involve the action of a transmitter(s) (possibly ATP) which mobilizes intracellular Ca2+ from sarcoplasmic reticulum leading to the activation of apamin-sensitive K+ channels. The second system likewise provides a fast relaxation of the colon in
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PMID:Characterization of the apamin- and L-nitroarginine-resistant NANC inhibitory transmission to the circular muscle of guinea-pig colon. 888 60

CD10/neutral endopeptidase 24.11 (NEP) regulates peptidemediated proliferation of lymphoid progenitors and certain epithelial cells and is itself regulated by cellular proliferation. To further characterize mechanisms by which cell-surface signaling might regulate CD10/NEP expression, we determined whether CD10/NEP was phosphorylated and whether the enzyme co-associated with additional cellular phosphoproteins. The CD10/NEP cytoplasmic tall contains two consensus recognition sequences for casein kinase II (CKII), a serine and threonine kinase that increases in activity following peptide signaling. In standard in vitro kinase assays, CKII phosphorylated full-length recombinant CD10/NEP but did not phosphorylate a truncated CD10/NEP protein that lacked the transmembrane region and cytoplasmic tail. To determine whether CD10/NEP might interact with additional cellular phosphoproteins, in vitro kinase assays were performed on CD10/NEP immune complexes from Nalm-6 cells. Three additional tyrosine phosphoproteins of approximately 40 kD, approximately 58 kD, and approximately 75 kD were identified in the CD10/NEP immunoprecipitates. The approximately 56-kD CD10/NEP-associated phosphoprotein was immunoprecipitated with an anti-lyn antibody confirming its identity as the lyn src-related kinase. Taken together, these data indicate that CD10/NEP is itself phosphorylated by CKII and that CD10/NEP co-associates with additional tyrosine phosphoproteins including lyn.
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PMID:CD10/neutral endopeptidase 24.11 is phosphorylated by casein kinase II and coassociates with other phosphoproteins including the lyn src-related kinase. 894 50

During B- and T-cell ontogeny, extensive apoptosis occurs at distinct stages of development. Agents that increase intracellular levels of cAMP induce apoptosis in thymocytes and mature B cells, prompting us to investigate the role of cAMP signaling in human CD10+ B-precursor cells. We show for the first time that forskolin (which increases intracellular levels of cAMP) increases apoptosis in the CD10- cells in a dose-dependent manner (19%-94% with 0-1,000 microM forskolin after 48 hours incubation, IC50 = 150 microM). High levels of apoptosis were also obtained by exposing the cells to the cAMP analogue 8-chlorophenylthio-cAMP (8-CPT-cAMP). Specific involvement of cAMP-dependent protein kinase (PKA) was demonstrated by the ability of a cAMP antagonist, Rp-isomer of 8-bromo-adenosine- 3', 5'- monophosphorothioate (Rp-8-Br-cAMPS), to reverse the apoptosis increasing effect of the complementary cAMP agonist, Sp-8-Br-cAMPS. Furthermore, we investigated the expression of Bcl-2 family proteins. We found that treatment of the cells with forskolin or 8-CPT-cAMP for 48 hours resulted in a fourfold decline in the expression of Mcl-1 (n = 6, P = 0.002) compared to control cells. The expression of Bcl-2, Bcl-xL, or Bax was largely unaffected. Mature peripheral blood B cells showed a smaller increase in the percentage of apoptotic cells in response to 8-CPT-cAMP (1.3-fold, n = 6, P = 0.045) compared to B-precursor cells, and a smaller decrease in Mcl-1 levels (1.5-fold, n = 4, P = 0.014). Taken together, these findings show that cAMP is important in the regulation of apoptosis in B-progenitor and mature B cells and suggest that cAMP-increased apoptosis could be mediated, at least in part, by a decrease in Mcl-1 levels.
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PMID:Activation of the cAMP signaling pathway increases apoptosis in human B-precursor cells and is associated with downregulation of Mcl-1 expression. 1036 19


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