scholarly journals Synthesis of myo-inositol 1,3,4,5,6-pentakisphosphate from inositol phosphates generated by receptor activation

1988 ◽  
Vol 253 (3) ◽  
pp. 721-733 ◽  
Author(s):  
L R Stephens ◽  
P T Hawkins ◽  
C J Barker ◽  
C P Downes
Keyword(s):  
Rat Brain ◽  
Inositol Phosphates ◽  
Platelet Activating Factor ◽  
Chemical Properties ◽  
Brain Homogenate ◽  
Receptor Activation ◽  
Murine Bone Marrow ◽  
Astrocytoma Cells ◽  
Inositol 1,4,5 Trisphosphate ◽  
Stimulation Of

myo-[3H]Inositol 1,3,4,5,6-pentakisphosphate can be made from myo-[3H]inositol 1,4,5-trisphosphate in a rat brain homogenate or soluble fraction. Although D-myo-inositol 3,4,5,6-tetrakisphosphate can be phosphorylated by a soluble rat brain enzyme to give myo-inositol 1,3,4,5,6-pentakisphosphate, it is not an intermediate in the pathway from myo-inositol 1,4,5-trisphosphate. The intermediates in the above pathway are myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4-trisphosphate and myo-inositol 1,3,4,6-tetrakisphosphate [Shears, Parry, Tang, Irvine, Michell & Kirk (1987) Biochem. J. 246, 139-147; Balla, Guillemette, Baukal & Catt (1987) J. Biol. Chem. 262, 9952-9955], and it is catalysed by soluble kinase activities of similar anion-exchange mobility and Mr value. Compounds with chromatographic and chemical properties consistent with the structures myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,6-tetrakisphosphate and myo-inositol 3,4,5,6-tetrakisphosphate are present in avian erythrocytes, human 1321 N1 astrocytoma cells and primary-cultured murine bone-marrow-derived macrophages. The amounts of these inositol tetrakisphosphates rise upon muscarinic cholinergic stimulation of the astrocytoma cells or stimulation of macrophages with platelet-activating factor.

Modulation of phospholipase C pathway and level of Gq alpha/G11 alpha in rat myometrium during gestation

1996 ◽  
Vol 271 (3) ◽  
pp. C895-C904 ◽  
Author(s):  
S. Lajat ◽  
Z. Tanfin ◽  
G. Guillon ◽  
S. Harbon
Keyword(s):  
Phospholipase C ◽  
G Proteins ◽  
Pertussis Toxin ◽  
Inositol Phosphates ◽  
Receptor Activation ◽  
Similar Increase ◽  
Inositol 1,4,5 Trisphosphate ◽  
M3 Subtype ◽  
Subtype A ◽  
Stimulation Of

The regulation of the receptor-G protein-phospholipase C (PLC) cascade was investigated in rat myometrium at midgestation (day 12) and at term (day 21) comparatively to the estrogen-treated tissue (day 0). Carbachol-mediated generation of [3H]inositol phosphates was insensitive to pertussis toxin and was enhanced at days 12 and 21 two- and threefold, respectively, with no alteration of muscarinic sites (M3 subtype). A similar increase could be detected in the production of inositol 1,4,5-trisphosphate, indicating the stimulation of a PLC degrading phosphatidylinositol 4,5-bisphosphate. AlF4- also enhanced PLC activation during gestation, suggesting pregnancy-related regulations that bypass receptor activation. Immunoreactive G proteins, Gq alpha and G11 alpha, and PLC-beta 3 were detected in all myometrial preparations. The amount of PLC-beta 3 was similar in day 0 and day 21 myometrium, although decreasing by 75% at midgestation. Of significance was the increased amount of Gq alpha in day 12 and day 21 myometrium (3- and 2-fold, respectively) which coincided with the enhanced phosphoinositide breakdown. The upregulation of Gq alpha may contribute to the enhanced PLC activity during pregnancy and at term.

Inhibition of TASK-1 potassium channel by phospholipase C

2001 ◽  
Vol 281 (2) ◽  
pp. C700-C708 ◽  
Author(s):  
Gábor Czirják ◽  
Gábor L. Petheő ◽  
András Spät ◽  
Péter Enyedi
Keyword(s):  
Phospholipase C ◽  
Lysophosphatidic Acid ◽  
Protein S ◽  
Receptor Activation ◽  
Xenopus Laevis Oocytes ◽  
Ang Ii ◽  
Inositol 1,4,5 Trisphosphate ◽  
Glomerulosa Cells ◽  
Pore Domain ◽  
Stimulation Of

The two-pore-domain K+ channel, TASK-1, was recently shown to be a target of receptor-mediated regulation in neurons and in adrenal glomerulosa cells. Here, we demonstrate that TASK-1 expressed in Xenopus laevis oocytes is inhibited by different Ca2+-mobilizing agonists. Lysophosphatidic acid, via its endogenous receptor, and ANG II and carbachol, via their heterologously expressed ANG II type 1a and M1 muscarinic receptors, respectively, inhibit TASK-1. This effect can be mimicked by guanosine 5′- O-(3-thiotriphosphate), indicating the involvement of GTP-binding protein(s). The phospholipase C inhibitor U-73122 reduced the receptor-mediated inhibition of TASK-1. Downstream signals of phospholipase C action (inositol 1,4,5-trisphosphate, cytoplasmic Ca2+ concentration, and diacylglycerol) do not mediate the inhibition. Unlike the Gq-coupled receptors, stimulation of the Gi-activating M2 muscarinic receptor coexpressed with TASK-1 results in an only minimal decrease of the TASK-1 current. However, additional coexpression of phospholipase C-β2 (which is responsive also to Giβγ-subunits) renders M2 receptor activation effective. This indicates the significance of phospholipase C activity in the receptor-mediated inhibition of TASK-1.

Adrenergic stimulation of inositol phosphate accumulation in tracheal epithelium

1989 ◽  
Vol 66 (1) ◽  
pp. 504-508 ◽  
Author(s):  
T. Bainbridge ◽  
R. D. Feldman ◽  
M. J. Welsh
Keyword(s):  
Adrenergic Receptor ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Second Messengers ◽  
Receptor Activation ◽  
Adrenergic Stimulation ◽  
Cl Secretion ◽  
Phosphate Accumulation ◽  
Inositol Phosphate Accumulation ◽  
Stimulation Of

To determine whether inositol phosphates are important second messengers in the regulation of Cl- secretion by airway epithelia, we examined the relationship between inositol phosphate accumulation and Cl- secretion in response to adrenergic agonists. We found that epinephrine stimulated Cl- secretion and inositol phosphate accumulation with similar concentration dependence. Although isoproterenol stimulated Cl- secretion, there was no effect of beta-adrenergic receptor activation on inositol phosphate accumulation. In contrast, alpha 1-adrenergic receptor activation stimulated inositol phosphate accumulation but failed to induce Cl- secretion. Another Cl- secretagogue, prostaglandin E1, also failed to stimulate inositol phosphate accumulation. These data suggest that inositol phosphate accumulation is neither sufficient nor required for stimulation of Cl- secretion in cultured canine tracheal epithelial cells.

Mobilization of Intracellular Calcium by Methacholine and Inositol 1,4,5-Trisphosphate in Rat Parotid Acinar Cells

1987 ◽  
Vol 66 (2) ◽  
pp. 547-551 ◽  
Author(s):  
D.L. Aub ◽  
J.W. Putney
Keyword(s):  
Receptor Activation ◽  
Transient Phase ◽  
Cell Preparation ◽  
Similar Concentration ◽  
Parotid Acinar Cells ◽  
Parotid Acinar Cell ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Rat Parotid ◽  
Stimulation Of

In the rat parotid acinar cell, methacholine caused an increase in [Ca2+]i as determined by quin-2 fluorescence. The increase in [Ca2+] i was initially independent of, and subsequently dependent on, the presence of extracellular Ca2+, indicating mobilization of intracellular Ca2+, as well as activation of Ca2+ entry. Methacholine mobilization of the internal Ca2+ pool and stimulation of the initial transient phase of K+ efflux have similar concentration dependencies; the EC50 value for Ca2+ mobilization is 80 nmollL, the EC50 value for K+ efflux is 200 nmol/L. In a permeable parotid cell preparation, inositol 1,4,5-trisphosphate, inositol 2,4,5-trisphosphate, and inositol 4,5-bisphosphate were able to release Ca2+ from an ATP-dependent, oligomycininsensitive pool. These observations, when taken with the previous finding that methacholine stimulates Ca-independent inositol trisphosphate formation, support the view that inositol 1,4,5-trisphosphate acts as a second messenger mediating the release of an intracellular Ca 2+ pool following muscarinic receptor activation in the parotid gland.

The use of cells doubly labelled with [14C]inositol and [3H]inositol to search for a hormone-sensitive inositol lipid pool with atypically rapid metabolic turnover

1989 ◽  
Vol 122 (1) ◽  
pp. 379-389 ◽  
Author(s):  
S. H. Maccallum ◽  
C. J. Barker ◽  
P. A. Hunt ◽  
N. S. Wong ◽  
C. J. Kirk ◽  
...  
Keyword(s):  
Cell Lines ◽  
Inositol Phosphates ◽  
Phosphatidyl Inositol ◽  
Receptor Activation ◽  
Inositol Monophosphatase ◽  
Lipid Pool ◽  
Inositol Lipids ◽  
Prostaglandin F ◽  
Hormone Sensitive ◽  
Stimulation Of

ABSTRACT Some, though not all, previous studies have suggested that the inositol lipid which is hydrolysed during transmembrane signalling in response to receptor activation might be drawn from a metabolically discrete and relatively small hormone-sensitive lipid pool that turns over more rapidly than the bulk of membrane inositol lipid. In order to seek evidence for the existence of this putative hormone-sensitive lipid pool, we have double-labelled cells by growing them for 3 days in a medium containing [14C]inositol and then supplying them with [3H]inositol for the final 2 h before stimulation. We anticipated that stimulation of these doubly labelled cells might provoke the formation, from the postulated hormone-sensitive pool, of small quantities of relatively 3H-enriched inositol phosphates, and that these could be harvested from cells (provided that the cytosolic inositol monophosphatase and inositol 1,4-bisphosphate/inositol 1,3,4-trisphosphate 1-phosphatase activities are first inhibited by Li+). Experiments of this type, using both vasopressin-stimulated WRK1 rat mammary tumour cells and 3T3 mouse fibroblasts stimulated by prostaglandin F2α, have largely failed to demonstrate the formation of relatively 3H-enriched inositol phosphates. There was a tendency for phosphatidyl-inositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate to have slightly higher 3H: 14C ratios than phosphatidylinositol, but the 3H: 14C ratios of the inositol phosphates formed in stimulated cells were not substantially greater than the 3H: 14C ratios of the inositol lipids. We therefore conclude, at least for the two cell lines that we studied, that hormone-stimulated inositol lipid hydrolysis can call, either directly or indirectly, upon the majority of the inositol lipid complement of the stimulated cell. Journal of Endocrinology (1989) 122, 379–389

scholarly journals l-myo-inositol 1,4,5,6-tetrakisphosphate is present in both mammalian and avian cells

1988 ◽  
Vol 249 (1) ◽  
pp. 271-282 ◽  
Author(s):  
L Stephens ◽  
P T Hawkins ◽  
N Carter ◽  
S B Chahwala ◽  
A J Morris ◽  
...  
Keyword(s):  
High Performance ◽  
Periodic Acid ◽  
Platelet Activating Factor ◽  
Anion Exchange Chromatography ◽  
Total Radioactivity ◽  
Exchange Chromatography ◽  
Murine Bone Marrow ◽  
Cell Extracts ◽  
Inositol 1,4,5 Trisphosphate ◽  
Inositol Tetrakisphosphate

When myo-[3H]inositol-prelabelled primary-cultured murine bone-marrow-derived macrophages were challenged with platelet-activating factor (PAF; 200 ng/ml), there was a rapid (2.5-fold at 10 s) rise in the intracellular concentration of D-myo-[3H]inositol 1,4,5-trisphosphate, followed by a rise in myo-[3H]inositol tetrakisphosphate. myo-[3H]Inositol tetrakisphosphate fractions were isolated by high-performance anion-exchange chromatography from myo-[3H]inositol-prelabelled chick erythrocytes and primary-cultured macrophages. In both cases [3H]iditol and [3H]inositol were the only significant products (greater than 90% of recovered radioactivity) after oxidation to completion with periodic acid, reduction with NaBH4 and dephosphorylation with alkaline phosphatase. The presence of [3H]inositol after this procedure is consistent with the occurrence of [3H]inositol 1,3,4,5-tetrakisphosphate in the cell extracts, whereas [3H]iditol could only be derived from D- or L-inositol 1,4,5,6-tetrakisphosphate. When [3H]inositol tetrakisphosphate fractions obtained from (A) unstimulated macrophages, (B) macrophages that had been stimulated with PAF for 40s or (C) chick erythrocytes were subjected to the above procedure, radioactivity was recovered in these polyols in the following proportions: A, 60-90% in iditol, with 10-40% in inositol; B, total radioactivity increased by a factor of 9.8, 94% being recovered in inositol and 8% in iditol; C, 70-80% in iditol and 20-30% in inositol. [3H]Iditol derived from myo-[3H]inositol tetrakisphosphate fractions from macrophages and chick erythrocytes was oxidized to sorbose by L-iditol dehydrogenase (L-iditol:NAD+2-oxidoreductase, 1.1.1.14) at the same rate as authentic L-iditol. D-[14C]Iditol, derived from D-myo-inositol 1,4,5-trisphosphate, was not oxidized by L-iditol dehydrogenase. This result indicates that the [3H]iditol was derived from L-myo-inositol inositol 1,4,5,6-tetrakisphosphate. The data are consistent with rapid PAF-sensitive synthesis of D-myo-[3H]inositol 1,3,4,5-tetrakisphosphate in macrophages, and demonstrate that L-myo-inositol 1,4,5,6-tetrakisphosphate is synthesized in both mammalian and avian cells. The levels of L-myo-[3H]inositol 1,4,5,6-tetrakisphosphate in primary-cultured macrophages are not acutely sensitive to PAF.

scholarly journals Carbachol and histamine stimulation of guanine-nucleotide-dependent phosphoinositide hydrolysis in rat brain cortical membranes

1989 ◽  
Vol 261 (1) ◽  
pp. 29-35 ◽  
Author(s):  
E Claro ◽  
A Garcia ◽  
F Picatoste
Keyword(s):  
Rat Brain ◽  
Inositol Phosphates ◽  
Phosphoinositide Hydrolysis ◽  
Maximal Effect ◽  
Guanine Nucleotide ◽  
Effect Curve ◽  
Guanine Nucleotide Binding ◽  
Cortical Membranes ◽  
Nucleotide Binding Proteins ◽  
Stimulation Of

Guanine nucleotides have been shown to stimulate phosphoinositide breakdown in brain membranes, but no potentiation of such an effect by agonist was demonstrated. We have studied the effect of carbachol and histamine on guanosine 5′-[gamma-thio]triphosphate (GTP[S]) stimulation of inositol phosphates formation in [3H]inositol-labelled rat brain cortical membranes. In this preparation, GTP[S] enhancement of phosphoinositide hydrolysis required the presence of MgATP and low Ca2+ concentration (100 nM). Carbachol potentiation of the GTP[S] effect was only observed when 1 mM-deoxycholate was also added. Under these conditions, stimulated production of [3H]inositol phosphates was linear for at least 15 min, and [3H]inositol bisphosphate [(3H]IP2) accounted for approx. 80%, whereas the amount of [3H]inositol trisphosphate [(3H]IP3) was very low. Stimulation by GTP[S] was concentration-dependent (half-maximal effect at 0.86 microM), and its maximal effect (815% over basal) was increased by 1 mM-carbachol (1.9-fold) and -histamine (1.7-fold). Both agonists decreased the slope index of the GTP[S] concentration/effect curve to values lower than unity, suggesting the appearance of some heterogeneity in the population of guanine-nucleotide-binding proteins (G-proteins) involved. The carbachol and histamine effects were also concentration-dependent, and were inhibited by atropine and mepyramine respectively. Fluoroaluminate stimulated phosphoinositide hydrolysis to a higher extent than GTP[S] plus carbachol, and these stimulations were not additive, indicating that the same polyphosphoinositide phospholipase C-coupled G-protein mediates both effects.

Regulation of plasma membrane-bound Ca(2+)-ATPase pump by inositol phosphates in rat brain

1992 ◽  
Vol 262 (3) ◽  
pp. F411-F416
Author(s):  
C. L. Fraser ◽  
P. Sarnacki
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Rat Brain ◽  
Inositol Phosphates ◽  
Stimulatory Action ◽  
Inositol 1,4,5 Trisphosphate ◽  
Membrane Bound

We have previously shown that inositol 1,4,5-trisphosphate (1,4,5-IP3) may participate in signal transduction in brain by inhibiting plasma membrane-bound Na(+)-Ca2+ exchanger. This study was therefore designed to determine whether 1,4,5-IP3 and/or inositol 1,3,4,5-tetrakisphosphate (1,3,4,5-IP4) might also affect Ca2+ transport by the plasma membrane Ca(2+)-ATPase pump. Our data show that 1,4,5-IP3 significantly (P less than 0.005) stimulates Ca2+ transport, whereas 1,3,4,5-IP4 significantly (P less than 0.006) inhibits transport by the pump. However, in the presence of both 1,4,5-IP3 and 1,3,4,5-IP4, the stimulatory effect of 1,4,5-IP3 is dominant. Thus Ca2+ transport was significantly stimulated as though 1,4,5-IP3 alone was present. We also observed that 1,3,4-IP3, which had no effect on Ca2+ transport by itself, antagonizes the stimulatory action of 1,4,5-IP3 and potentiates the inhibition of Ca2+ transport by 1,3,4,5-IP4. Half-maximal activities were observed at 10(-8) M. Our data suggest that 1,3,4,5-IP4, 1,4,5-IP3, and 1,3,4-IP3 may participate in signal transduction in brain by regulating the plasma membrane-bound Ca(2+)-ATPase pump.

Stimulation of acid secretion and phosphoinositol production by rat parietal cell muscarinic M2 receptors

1988 ◽  
Vol 254 (4) ◽  
pp. G622-G629
Author(s):  
A. Pfeiffer ◽  
H. Rochlitz ◽  
A. Herz ◽  
G. Paumgartner
Keyword(s):  
Acid Secretion ◽  
Muscarinic Receptor ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Receptor Activation ◽  
Receptor Subtype ◽  
Muscarinic Agonists ◽  
Receptor System ◽  
Drug Concentrations ◽  
Stimulation Of

The muscarinic receptor system involved in hydrogen ion production by enriched rat gastric parietal cells was investigated. Muscarinic receptor density determined by [N-methyl-3H]scopolamine binding was 8,100/cell. The receptor appeared to be of the M2 muscarinic receptor subtype, since it had a low affinity (Kd, 189 nM) for the M1 receptor antagonist pirenzepine compared with atropine (Kd, 0.74 nM). Receptor activation by carbachol rapidly augmented levels of polyphosphoinositides, indicating an activation of a phospholipase C. The dose-response relations for the increase in inositol phosphates closely paralleled the binding of carbachol to muscarinic receptors with a Km of 17 microM. The inositol phosphate response was antagonized by pirenzepine with a Ki of 177 nM. The stimulation of inositol phosphate levels by carbachol correlated well with the stimulation of [14C]aminopyrine uptake, determined as an index of acid secretion. The muscarinic agonists oxotremorine, pilocarpine, and bethanechol elicited partial increases in inositol phosphates at maximal drug concentrations, and these partial increases correlated with their ability to stimulate [14C]aminopyrine uptake. These data indicate that inositol polyphosphates may be a second messenger of M2 receptors stimulating acid secretion.

scholarly journals Partial purification and some properties of rat brain inositol 1,4,5-trisphosphate 3-kinase

1988 ◽  
Vol 251 (1) ◽  
pp. 157-163 ◽  
Author(s):  
A J Morris ◽  
K J Murray ◽  
P J England ◽  
C P Downes ◽  
R H Michell
Keyword(s):  
Rat Brain ◽  
Inositol Phosphates ◽  
Gel Filtration ◽  
Partial Purification ◽  
First Order Kinetics ◽  
Inositol 1,4,5 Trisphosphate ◽  
Inositol Tetrakisphosphate ◽  
Dependent Protein ◽  
Metabolic Properties ◽  
Sepharose 4B

An enzyme which catalyses the ATP-dependent phosphorylation of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] was purified approx. 180-fold from rat brain cytosol by (NH4)2SO4 precipitation, chromatography through hydroxyapatite, anion-exchange fast protein liquid chromatography and gel-filtration chromatography. Gel filtration on Sepharose 4B CL gives an Mr of 200 × 10(3) for the native enzyme. The inositol tetrakisphosphate (InsP4) produced by the enzyme has the chromatographic, chemical and metabolic properties of Ins(1,3,4,5)P4. Ins(1,4,5)P3 3-kinase displays simple Michaelis-Menten kinetics for both its substrates, having Km values of 460 microM and 0.44 microM for ATP and Ins(1,4,5)P3 respectively. When many of the inositol phosphates known to occur in cells were tested, only Ins(1,4,5)P3 was a substrate for the enzyme; the 2,4,5-trisphosphate was not phosphorylated. Inositol 4,5-bisphosphate and glycerophosphoinositol 4,5-bisphosphate were phosphorylated much more slowly than Ins(1,4,5)P3. CTP, GTP and adenosine 5′-[gamma−thio]triphosphate were unable to substitute for ATP. When assayed under conditions of first-order kinetics, Ins(1,4,5)P3 kinase activity decreased by about 40% as the [Ca2+] was increased over the physiologically relevant range. This effect was insensitive to the presence of calmodulin and appeared to be the result of an increase in the Km of the enzyme for Ins(1,4,5)P3. Preincubation with ATP and the purified catalytic subunit of cyclic AMP-dependent protein kinase did not affect the rate of phosphorylation of Ins(1,4,5)P3 when the enzyme was assayed at saturating concentrations of Ins(1,4,5)P3 or at concentrations close to its Km for this substrate.

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