Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vascular endothelial growth factor (VEGF) is a dimeric protein which induces formation of new blood vessels (angiogenesis) through binding to VEGF-receptor-2 tyrosine kinase (VEGFR2 TK) or KDR (kinase insert domain-containing receptor) on the surface of endothelial cells. Angiogenesis has been shown to be essential for malignancy of tumors; therefore, VEGFR2 TK is a potential therapeutic target for the treatment of cancer. Sequence homology studies indicate that VEGFR2 TK contains three domains: extracellular (ligand-binding domain), transmembrane, and intracellular (catalytic domain). In this work, the catalytic domain of VEGFR2 TK was cloned and expressed in a soluble active form using a baculovirus expression system. In the absence of ligand, the enzyme is shown to catalyze its autophosphorylation in a time-dependent and enzyme-concentration-dependent manner, consistent with a trans mechanism for this reaction. Mass spectrometry analysis revealed incorporation of 5.5 +/- 0.5 mol of phosphate/mole of enzyme (monomer). In addition, the enzyme was shown to catalyze phosphorylation of a synthetic peptide, poly(E4Y). Using poly(E4Y) as substrate, the kinetic constants of both native and phosphorylated enzyme were determined. Enzyme phosphorylation increased catalytic efficiency of the enzyme by at least an order of magnitude. Furthermore, the enzyme was shown to catalyze the reverse reaction using phospho-poly(E4Y) as substrate. Cd2+ was found to be an inhibitor of the enzyme. Kinetic studies revealed that inhibition by Cd2+ was competitive with respect to Mg2+ and noncompetitive with respect to MgATP. These results indicate that Cd2+ competes for a second metal-binding site. Therefore, the reaction catalyzed by this enzyme was treated as a terreactant system. The kinetic mechanism of VEGFR2 TK was elucidated through the use of steady-state kinetic studies. According to these studies, the enzyme binds Mg2+ and MgATP in a random fashion followed by ordered addition of the peptide substrate. The release of product is also ordered, with MgADP being released last. The order of substrate binding was confirmed by using AMP-PCP, a dead-end inhibitor.
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PMID:Characterization and kinetic mechanism of catalytic domain of human vascular endothelial growth factor receptor-2 tyrosine kinase (VEGFR2 TK), a key enzyme in angiogenesis. 984 50

Phosphodiesterase 10A (PDE10A) is a recently identified cyclic nucleotide phosphodiesterase expressed primarily in dopaminoreceptive medium spiny neurons of the striatum. We report that papaverine is a potent, specific inhibitor of PDE10A and use this compound to explore the role of PDE10A in regulating striatal function. Papaverine administration produces an increase in striatal tissue levels of cGMP and an increase in extracellular cAMP measured by microdialysis. These cyclic nucleotide changes are accompanied by increases in the phosphorylation of CREB and ERK, downstream markers of neuronal activation. In rats, papaverine potentiates haloperidol-induced catalepsy, consistent with the hypothesis that inhibition of PDE10A can increase striatal output and prompting a further evaluation of papaverine in models predictive of antipsychotic activity. Papaverine is found to inhibit conditioned avoidance responding in rats and mice and to inhibit PCP- and amphetamine-stimulated locomotor activity in rats. The effects of papaverine on striatal cGMP and CREB and ERK phosphorylation, as well as on conditioned avoidance responding, were absent in PDE10A knockout mice, indicating that the effects of the compound are the result of PDE10A inhibition. These results indicate that PDE10A regulates the activation of striatal medium spiny neurons through effects on cAMP- and cGMP-dependent signaling cascades. Furthermore, the present results demonstrate that papaverine has efficacy in behavioral models predictive of antipsychotic activity. Thus, inhibition of PDE10A may represent a novel approach to the treatment of psychosis.
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PMID:Inhibition of the striatum-enriched phosphodiesterase PDE10A: a novel approach to the treatment of psychosis. 1678 Aug 99

New amine-groups containing tri-block copolymers and micelles that consisting of poly(epsilon-caprolactone)-b-chitooligosaccharide-b-poly(ethylene glycol) (PCL-b-COS-b-PEG, PCP), were synthesized, characterized, and evaluated for delivering doxorubicin (DOX) with or without crosslinked amine groups by genipin. The characteristics of the PCP copolymers of Fourier-transform infrared spectrometry (FT-IR) verify the amine and ester groups of the COS and the PCL of the copolymers, respectively. 1H nuclear magnetic resonance (1H NMR) spectra verify the structures of the PCP copolymers consisting two PCL and PEG polymers reacted onto the COS block. In addition, gel permeation chromatography (GPC) determines the number average molecular weight of the tri-block copolymers (Mn) of approximately 11340 Da/mole. The PCP copolymers can self-assemble to form polymeric micelles at the critical micelle concentration (CMC) of 1.0 microM as determined by the UV-VIS absorption spectra. The mean diameter of the PCP micelles is 90 nm, as determined using a dynamic light-scattering (DLS) analyzer. Moreover, the zeta potentials of PCP micelles change from neutral to cationic state when pH of suspension mediums varied from 7.4 to 3.0. For evaluating delivery characteristics of hydrophobic DOX, it was loaded into PCP micelles with or without crosslinked by genipin. The burst release and release period of DOX for the crosslinked micelles are significantly reduced (P < 0.003, n = 3, for pH = 7.4) and sustained (e.g., 8 days), respectively, than those non-crosslinked ones (e.g., 4 days). In conclusion, new tri-block amine groups containing PCP copolymers are synthesized that can self-assemble as PCP micelles. After post-crosslinked amine groups of DOX loaded the micelles, they can effectively reduce the burst release and sustain the release of DOX at different pH dissolution mediums. Further applications of PCP copolymers and micelles for drug delivery can be explored in future.
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PMID:Characterizing poly(epsilon-caprolactone)-b-chitooligosaccharide-b-poly(ethylene glycol) (PCP) copolymer micelles for doxorubicin (DOX) delivery: effects of crosslinked of amine groups. 1704 97

The p90 ribosomal S6 kinases (RSKs) also known as MAPKAP-Ks are serine/threonine protein kinases that are activated by ERK or PDK1 and act as downstream effectors of mitogen-activated protein kinase (MAPK). RSK1, a member of the RSK family, contains two distinct kinase domains in a single polypeptide chain, the regulatory C-terminal kinase domain (CTKD) and the catalytic N-terminal kinase domain (NTKD). Autophosphorylation of the CTKD leads to activation of the NTKD that subsequently phosphorylates downstream substrates. Here we report the crystal structures of the unactivated RSK1 NTKD bound to different ligands at 2.0 A resolution. The activation loop and helix alphaC, key regulatory elements of kinase function, are disordered. The DFG motif of the inactive RSK1 adopts an "active-like" conformation. The beta-PO(4) group in the AMP-PCP complex adopts a unique conformation that may contribute to inactivity of the enzyme. Structures of RSK1 ligand complexes offer insights into the design of novel anticancer agents and into the regulation of the catalytic activity of RSKs.
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PMID:Crystal structures of the N-terminal kinase domain of human RSK1 bound to three different ligands: Implications for the design of RSK1 specific inhibitors. 1796 87

The neuronal cell adhesion molecule (CAM) L1 promotes axonal outgrowth, presumably through an interaction with the fibroblast growth factor receptor (FGFR). The present study demonstrates a direct interaction between L1 fibronectin type III (FN3) modules I-V and FGFR1 immunoglobulin (Ig) modules II and III by surface plasmon resonance analysis. Binding of L1 to FGFR1 was enhanced by adenosine 5'-triphosphate (ATP), adenylylmethylenediphosphonate (AMP-PCP), and guanosine-5'-triphosphate (GTP), but not adenosine monophosphate (AMP). The L1-FN3 modules were capable of activating FGFR1, reflected by receptor phosphorylation, and this resulted in the induction of differentiation of primary neurons, reflected by neurite outgrowth. Furthermore, ATP modulated L1-induced neuronal differentiation and FGFR1 phosphorylation through regulation of the L1-FGFR1 interaction.
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PMID:Fibronectin type III (FN3) modules of the neuronal cell adhesion molecule L1 interact directly with the fibroblast growth factor (FGF) receptor. 1822 3

Phencyclidine (PCP) and other N-methyl-D-aspartate (NMDA) receptor antagonists have been shown to be neurotoxic to developing brains and to result in schizophrenia-like behaviors later in development. Prevention of both effects by antischizophrenic drugs suggests the validity of PCP neurodevelopmental toxicity as a heuristic model of schizophrenia. Lithium is used for the treatment of bipolar and schizoaffective disorders and has recently been shown to have neuroprotective properties. The present study used organotypic corticostriatal slices taken from postnatal day 2 rat pups to investigate the protective effect of lithium and the role of the phosphatidylinositol-3 kinase (PI-3K)/Akt and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) pathways in PCP-induced cell death. Lithium pretreatment dose-dependently reduced PCP-induced caspase-3 activation and DNA fragmentation in layers II to IV of the cortex. PCP elicited time-dependent inhibition of the MEK/ERK and PI-3K/Akt pathways, as indicated by dephosphorylation of ERK1/2 and Akt. The proapoptotic factor glycogen synthase kinase (GSK)-3beta was also dephosphorylated at serine 9 and thus activated. Lithium prevented PCP-induced inhibition of the two pathways and activation of GSK-3beta. Furthermore, blocking either PI-3K/Akt or MEK/ERK pathway abolished the protective effect of lithium, whereas inhibiting GSK-3beta activity mimicked the protective effect of lithium. However, no cross-talk between the two pathways was found. Finally, specific GSK-3beta inhibition did not prevent PCP-induced dephosphorylation of Akt and ERK. These data strongly suggest that the protective effect of lithium against PCP-induced neuroapoptosis is mediated through independent stimulation of the PI-3K/Akt and ERK pathways and suppression of GSK-3beta activity.
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PMID:Lithium protection of phencyclidine-induced neurotoxicity in developing brain: the role of phosphatidylinositol-3 kinase/Akt and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling pathways. 1854 76

Wnt signaling plays an important role in cancer. Signaling is initiated by binding of Wnt ligands to Frizzled cell surface receptors and results in signaling via one of three pathways, the canonical Wnt pathway, which is the best characterized in both normal tissues and in cancer, and two non-canonical Wnt pathways, the Ca(2+)-dependent and the PCP pathways. Canonical Wnt signaling results in beta-catenin accumulation in the cytoplasm, translocation into the nucleus and activation of transcription of Wnt target genes including the c-Myc oncogene. Some cancer types, including colorectal cancer, have mutations in APC and Axin, which are involved in beta-catenin phosphorylation, such that the canonical pathway is constitutively active. Few studies have investigated the role non-canonical Wnt signaling in cancer, or of Wnt signaling on tumor stromal cells. Wnt overexpression is observed in tumor stroma, as is overexpression of the Wnt pathway inhibitors, secreted Frizzled-related proteins and Dickkopf proteins. Interactions between epithelial cells and stromal cells have been observed to activate Wnt signaling in both cell types. Wnt signaling is also observed in tumor blood vessels and is likely to be activated by signals from tumor cells. Current cancer therapies focus on interfering with canonical Wnt signaling in the tumor cells. Future therapeutic targets for interfering with Wnt signaling include cell surface receptors such as the RYK and Ror2 receptors and secreted signaling molecules, which mediate signaling between cancer cells and the stromal environment.
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PMID:Importance of Wnt signaling in the tumor stroma microenvironment. 1878 92

The ACH Medical Home Program serves as a comprehensive, multi-discipline clinic and program designed to facilitate comprehensive, coordinated care to the most medically complex and fragile children in Arkansas. In partnership with the family, the PCP and the subspecialty physicians, the program strives to ensure that the ideals of providing the "medical home" are accomplished, both in the community and at Arkansas Children's Hospital. An ongoing evaluation process has been implemented and it is the hope and mission of this program to evolve to provide the highest quality of care and highest quality of life for these children with complex medical conditions and for their families. Referrals and inquiries are welcomed and encouraged and can be made at (501) 364-3030.
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PMID:CH medical home program for special needs children. A new medical era... 1917 Mar 34

Wnt signaling controls a variety of developmental and homeostatic events. As a key component of Wnt signaling, Dishevelled (Dvl/Dsh) protein relays Wnt signals from receptors to downstream effectors. In the canonical Wnt pathway that depends on the nuclear translocation of beta-catenin, Dvl is recruited by the receptor Frizzled and prevents the constitutive destruction of cytosolic beta-catenin. In the non-canonical Wnt pathways such as Wnt-Frizzled/PCP (planar cell polarity) signaling, Dvl signals via the Daam1-RhoA axis and the Rac1 axis. In addition, Dvl plays important roles in Wnt-GSK3beta-microtubule signaling, Wnt-calcium signaling, Wnt-RYK signaling, Wnt-atypical PKC signaling, etc. Dvl also functions to mediate receptor endocytosis. To fulfill its multifaceted functions, it is not surprising that Dvl associates with various kinds of proteins. Its activity is also modulated dynamically by phosphorylation, ubiquitination and degradation. In this review, we summarize the current understanding of Dvl functions in Wnt signal transduction and its biological functions in mouse development, and also discuss the molecular mechanisms of its actions.
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PMID:Dishevelled: The hub of Wnt signaling. 2000 83

The mammalian PCP pathway regulates diverse developmental processes requiring coordinated cellular movement, including neural tube closure and cochlear stereociliary orientation. Here, we show that epidermal wound repair is regulated by PCP signaling. Mice carrying mutant alleles of PCP genes Vangl2, Celsr1, PTK7, and Scrb1, and the transcription factor Grhl3, interact genetically, exhibiting failed wound healing, neural tube defects, and disordered cochlear polarity. Using phylogenetic analysis, ChIP, and gene expression in Grhl3(-)(/-) mice, we identified RhoGEF19, a homolog of a RhoA activator involved in PCP signaling in Xenopus, as a direct target of GRHL3. Knockdown of Grhl3 or RhoGEF19 in keratinocytes induced defects in actin polymerization, cellular polarity, and wound healing, and re-expression of RhoGEF19 rescued these defects in Grhl3-kd cells. These results define a role for Grhl3 in PCP signaling and broadly implicate this pathway in epidermal repair.
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PMID:Epidermal wound repair is regulated by the planar cell polarity signaling pathway. 2064 56


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