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:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasminogen activator inhibitor-1 (PAI-1) inhibits the tissue plasminogen activator (tPA) and urokinase activation of plasminogen to plasmin, a protease of trypsin-like specificity which is involved in a number of processes, including fibrinolysis, matrix degradation and angiogenesis. Both phorbol esters and cAMP elevating compounds have been shown to modulate PAI-1 and tPA expression in endothelial cell culture. HBGF-1 (previously designated endothelial cell growth factor) stimulates endothelial cell growth in vitro and is angiogenic in vivo. We have reported that removal of HBGF-1 from human umbilical vein endothelial cell (HUVEC) media results in an approximately 5-fold increase in PAI-1 mRNA levels and in PAI-1 protein secreted into the media by 20 h. Here we report the effects of HBGF-1 on the phorbol ester and cAMP modulation of HUVEC PAI-1 expression. The phorbol ester PMA induced an approximate 5-fold increase in PAI-1 mRNA levels at 4 h, which returned to base line by 20 h, with or without HBGF-1 present in the media. This increase in PAI-1 mRNA levels was mediated by an increase in PAI-1 gene transcription and was abated in the presence of cycloheximide. Treatment of cells with the adenylate cyclase activator forskolin or the phosphodiesterase inhibitor HL 725, in the presence of HBGF-1 or immediately after its withdrawal, decreased PAI-1 mRNA levels and protein secreted into the conditioned media by 20 h. However, forskolin or HL 725 addition had little or no effect on PAI-1 mRNA when added 20 h after HBGF-1 withdrawal. Both the PMA and HBGF-1 modulation of PAI-1 were abolished by treatment with the protein kinase inhibitor H-7. Treatment of HUVEC with HBGF-1 had no acute effect on intracellular inositol phosphate hydrolysis or cAMP levels. Further studies on intracellular pathways involved in HBGF-1 modulation of PAI-1 will enhance our understanding of the role these factors play in cellular proliferation and angiogenesis.
...
PMID:Heparin-binding growth factor-1 modulation of plasminogen activator inhibitor-1 expression. Interaction with cAMP and protein kinase C-mediated pathways. 170 36

Resonance energy-transfer approaches have been used to directly monitor the interactions of the GTP gamma S-bound alpha subunit of transducin (alpha T GTP gamma S) with the retinal cyclic GMP phosphodiesterase (PDE). The PDE was labeled with 5-(iodoacetamido) fluorescein (IAF-PDE) and served as the fluorescence donor in these experiments while the alpha T GTP gamma S was labeled with eosin-5-isothiocyanate (EITC-alpha T GTP gamma S) and served as the energy acceptor. The EITC-alpha T GTP gamma S species was able to quench a significant percentage of the IAF-PDE fluorescence (typically greater than or equal to 30%) due to resonance energy transfer between the IAF and EITC moieties. The quenching by the EITC-alpha T GTP gamma S species was dose-dependent, saturable (Kd = 21 nM), and specific for the GTP gamma S-bound form of the alpha T subunit. Limited trypsin treatment of the IAF-PDE, which selectively removes a fluorescein-labeled gamma subunit (gamma PDE), completely eliminates the quenching of the IAF fluorescence by the EITC-alpha T GTP gamma S complex. Although the EITC-alpha T GTP gamma S complex competes with the unlabeled alpha T GTP gamma S for a binding site on the IAF-PDE, as well as for a site on the native PDE, it is not able to stimulate PDE activity. Thus, the modification of a single EITC-reactive residue on the alpha T GTP gamma S complex prevents this subunit from eliciting a key activation event within the retinal effector enzyme.
...
PMID:Resonance energy transfer as a direct monitor of GTP-binding protein-effector interactions: activated alpha-transducin binding to the cGMP phosphodiesterase in the bovine phototransduction cascade. 171 60

K-259-2 and KS-619-1, novel anionic anthraquinone metabolites isolated from culture broth of microorganisms, inhibited activation of bovine brain phosphodiesterase induced by calmodulin (CaM), sodium oleate, or limited proteolysis with almost equal potency. The inhibition of calmodulin-activated phosphodiesterase (CaM-PDE) by K-259-2 or KS-619-1 was overcome by a higher concentration of CaM. Direct interaction of K-259-2 and KS-619-1 with CaM was confirmed through use of hydrophobic fluorescent probes. Kinetic analysis revealed that the inhibition of the trypsin-activated phosphodiesterase was competitively inhibited by K-259-2 or KS-619-1 with respect to cAMP. Addition of a lower amount of either phosphatidylserine or sodium oleate to the reaction mixture was efficacious in attenuating the inhibition of the CaM-PDE by W-7, chlorpromazine, trifluoperazine, compound 48/80, or R-24571 but, in contrast, had little or no effect on the inhibition by K-259-2 or KS-619-1. In conclusion, K-259-2 and KS-619-1, unlike so-called CaM antagonists, do not interact with phosphatidylserine or sodium oleate and it appears that these novel anthraquinone compounds inhibit the enzyme not only via CaM antagonism but possibly also by interacting directly with the enzyme.
...
PMID:Inhibition by new anthraquinone compounds, K-259-2 and KS-619-1, of calmodulin-dependent cyclic nucleotide phosphodiesterase. 215 16

The cyclic GMP phosphodiesterase (PDE) of vertebrate retinal rod outer segments (ROS) is kept inactive in the dark by its gamma subunits and is activated following illumination by the GTP form of the alpha subunit of transducin (T alpha-GTP). Recent studies have shown that the stoichiometry of the inhibited holoenzyme is alpha beta gamma 2. T alpha-GTP and gamma act reciprocally. We have investigated the activation mechanism using fluorescein-labeled gamma subunit (gamma F) as a probe. gamma F containing a single covalently attached fluorescein was prepared by reaction of PDE with 5-(iodoacetamido)fluorescein and purification by reversed-phase high-pressure liquid chromatography (HPLC). gamma F, like native gamma, inhibits the catalytic activity of trypsin-activated PDE and transducin-activated PDE. Inhibition by gamma F was overcome by further addition of T alpha-GTP. gamma F binds very weakly to ROS membranes stripped of PDE and other peripheral membrane proteins. gamma F added to ROS membranes became incorporated into a component that could be extracted with a low ionic strength buffer. HPLC gel filtration showed that gamma F became part of the PDE holoenzyme. Incorporation occurred in less than 1 min in the presence of light and GTP, but much more slowly (t1/2 approximately 500 s) in the absence of GTP. This result indicates that transducin activates PDE by binding to the holoenzyme and accelerating the dissociation of gamma from the inhibitory sites. The binding of gamma F to trypsin-activated PDE alpha beta was monitored by steady-state emission anisotropy measurements and compared with PDE activity.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Activation mechanism of retinal rod cyclic GMP phosphodiesterase probed by fluorescein-labeled inhibitory subunit. 215 46

The cyclic GMP phosphodiesterase of the retinal rod is composed of three distinct types of polypeptides: alpha (90 kDa), beta (86 kDa), and gamma (10 kDa). The gamma subunit has been shown to inhibit phosphodiesterase activity associated with alpha and beta. To investigate the subunit stoichiometry of the retinal phosphodiesterase, we have developed a panel of monoclonal and peptide antibodies that recognize individual phosphodiesterase subunits. By quantitative and immunochemical analysis of the purified subunits, we have shown that each phosphodiesterase molecule contains one copy each of alpha and beta subunit and two copies of gamma subunit. Moreover, gamma can be chemically cross-linked to both alpha and beta, but not to itself, suggesting that alpha and beta may each bind one gamma. The phosphodiesterase is fully activated when both copies of gamma were removed by proteolysis with trypsin. Upon recombination of the purified gamma subunit with the trypsin-activated phosphodiesterase containing alpha beta, the alpha beta gamma 2 stoichiometry is once again restored, with concomitant total inhibition of activity. Our results suggest that at least two activated transducin molecules are required to fully activate one molecule of phosphodiesterase in retinal rods.
...
PMID:Subunit stoichiometry of retinal rod cGMP phosphodiesterase. 216 Dec 52

2',3' cyclic nucleotide-3'-phosphodiesterase (CNP) is phosphorylated in the peripheral nervous system after immunoprecipitation of myelin proteins radiolabeled in vivo, in nerve slices and in a cell-free system. Only radiolabeled phosphoserine was detected after partial acid hydrolysis of immunoprecipitated CNP. Two major phosphopeptides were resolved by two dimensional electrophoresis-chromatography after digestion with trypsin of CNP phosphorylated in the nerve slices. Phosphorylation of CNP was not stimulated a) by forskolin in the nerve slices and b) after incubation of purified nerve myelin with cAMP. However, CNP phosphorylation was increased after incubation of PNS myelin with catalytic unit of protein kinase A. Phosphorylation of the central nervous system myelin CNP was dramatically stimulated by cAMP. These results suggest that PKA may be absent from peripheral nerve myelin or CNP may not be accessible to this enzyme in the PNS. Incubation of nerve slices with phorbol 12 myristate-13-acetate caused a marked increase in the phosphorylation of CNP. These results provide strong evidence that CNP is phosphorylated in the PNS and its phosphorylation in vivo is in all probability regulated by protein kinase C.
...
PMID:2',3'cyclic nucleotide-3'-phosphodiesterase in peripheral nerve myelin is phosphorylated by a phorbol ester-sensitive protein kinase. 216 8

The gamma-subunit of retinal rod-outer-segment phosphodiesterase (PDE-gamma) is a multifunctional protein which interacts directly with both of the catalytic subunits of PDE (PDE alpha/beta) and the alpha-subunit of the retinal G (guanine-nucleotide-binding)-protein transducin alpha (T alpha). We have previously reported that the PDE gamma binds to T alpha at residue nos. 24-45 [Morrison. Rider & Takemoto (1987) FEBS Lett. 222, 266-270]. In vitro this results in inhibition of T alpha GTP/GDP exchange [Morrison, Cunnick, Oppert & Takemoto (1989) J. Biol. Chem. 264, 11671-11681]. We now report that the inhibitory region of PDE gamma for PDE alpha/beta occurs at PDE gamma residues 54-87. This binding results in inhibition of either trypsin-solubilized or membrane-bound PDE alpha/beta. PDE gamma which has been treated with carboxypeptidase Y, removing the C-terminus, does not inhibit PDE alpha/beta, but does inhibit T alpha GTP/GDP exchange. Inhibition by PDE gamma can be removed by T alpha-guanosine 5'-[gamma-thio]triphosphate (GTP[S]) addition to membranes. This results in a displacement of PDE gamma, but not in removal of this subunit from the membrane [Whalen, Bitensky & Takemoto (1990) Biochem. J. 265, 655-658]. These results suggest that low levels of T alpha-GTP[S] can result in displacement of PDE gamma from the membrane in vitro as a GTP[S]-T alpha-PDE gamma complex. Further activation by high levels of T alpha-GTP[S] occurs by displacement of PDE gamma from its inhibitory site on PDE alpha/beta, but not in removal from the membrane.
...
PMID:Binding of the gamma-subunit of retinal rod-outer-segment phosphodiesterase with both transducin and the catalytic subunits of phosphodiesterase. 217 4

Animals with impaired immune function show numerous reproductive disorders. To determine whether immune factors might play a direct role in the regulation of ovarian function, we examined the effects of Concanavalin-A-stimulated lymphocyte supernates (CAS) on steroidogenesis by cultured rat granulosa cells. Granulosa cells from immature estrogen-primed rats were incubated for 48 h with increasing doses of CAS in the presence or absence of FSH. In the absence of FSH, CAS produced a dose-dependent increase in progestin (progesterone and 20 alpha-hydroxyprogesterone) production to a maximum of 190-fold greater than untreated controls, but did not stimulate estrogen production. In the presence of FSH, the stimulatory effect of CAS on progestin production was additive with that of FSH. In contrast, CAS inhibited FSH-stimulated estrogen production in a dose-dependent manner. The maximum inhibition was greater than 90%. Addition of the phosphodiesterase inhibitor isobutylmethylxanthine to CAS-containing cultures significantly enhanced the stimulatory effect of CAS on progesterone production, suggesting that this action may be exerted through a cAMP-mediated pathway. The stimulatory component of CAS was heat labile, acid stable, and required a trypsin-sensitive cell surface recognition site, whereas the inhibitory component was both heat and acid stable. Neither the stimulatory nor the inhibitory actions of CAS were mimicked by treating granulosa cells with supernates from Concanavalin-A-stimulated neonatal cardiac or hepatic cell cultures. Thus, the present studies demonstrate that secretory products of lymphocytes (collectively termed lymphokines) can affect steroidogenesis in cultured rat granulosa cells. These data imply that immune cell factors may play a significant role in the differentiation and maturation of granulosa cells.
...
PMID:Lymphokines from concanavalin-A-stimulated lymphocytes regulate rat granulosa cell steroidogenesis in vitro. 245 14

Plasma membrane has been prepared from pea seedlings in the presence of [ethylenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA). Calmodulin has been detected in these plasma membrane preparations using calcium overlay techniques, immunoblots, quantitation with antibodies raised against spinach calmodulin, phosphodiesterase activation, mobility shift, and heat stability. EGTA-stable calmodulin represents 0.5-1% of the total plasma membrane protein, and it is the only detectable calcium-binding protein in plasma membrane isolated under these conditions. The anti-spinach calmodulin reacts only with the N-terminal region of spinach calmodulin representing residues 1-106. The positioning of EGTA-stable calmodulin in the plasma membrane has been probed with trypsin and anti-spinach calmodulin. The data suggest that the calmodulin N-terminal region representing residues 1-106 projects from the membrane and could be available for binding other proteins. Calcium-dependent calmodulin binding to the plasma membrane has also been detected. Calcium-dependent calmodulin-binding proteins have been characterized using calmodulin overlay methods. The exposure of calmodulin-binding domains of most of these proteins from the plasma membrane is further suggested by their reaction with azidoiodinated calmodulin.
...
PMID:The location of calmodulin in the pea plasma membrane. 249 18

The functional interactions of the retinal G protein, transducin, with the cyclic GMP phosphodiesterase (PDE) have been examined using the different purified subunit components of transducin and the native and trypsin-treated forms of the effector enzyme. The limited trypsin treatment of the PDE removes the low molecular weight gamma subunit (Mr approximately 14,000) of the enzyme, yielding a catalytic moiety comprised of the two larger molecular subunits (alpha, Mr approximately 85,000-90,000; beta, Mr approximately 85,000-90,000), which is insensitive to the addition of either the pure alpha T.GTP gamma S species or the pure beta gamma T subunit complex. However, the addition of the pure alpha T.GDP species to the trypsin-treated PDE (tPDE) results in a significant (90-100%) inhibition of the enzyme activity. This inhibition can be reversed by excess beta gamma T, suggesting that the holotransducin molecule does not (functionally) interact with the tPDE. However, the inhibition by alpha T.GDP is not reversed by the alpha T.GTP gamma S complex, over a range of [alpha T.GTP gamma S] which elicits a marked stimulation of the native enzyme activity, suggesting that the activated alpha T species does not effectively bind to the tPDE. The alpha T.GDP complex also is capable of inhibiting the alpha T.GTP gamma S-stimulated cyclic GMP hydrolysis by the native PDE. This inhibition can be reversed by excess alpha T.GTP gamma S, as well as by beta gamma T, indicating that the binding site for the activated alpha T species is in close proximity and/or overlaps the binding site for the alpha T.GDP complex on the enzyme. Overall, these results are consistent with a scheme where (a) both the small and larger molecular weight subunits of PDE participate in alpha T-PDE interactions, (b) the activation of PDE by the alpha T.GTP gamma S (or alpha T.GTP) species does not result in the complete dissociation of the gamma subunit from the enzyme, and (c) the deactivation of this signal transduction system results from a direct interaction between the alpha T.GDP species and the catalytic moiety of the effector enzyme.
...
PMID:The regulation of the cyclic GMP phosphodiesterase by the GDP-bound form of the alpha subunit of transducin. 253 46


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

---