Influence of Ca2+ and Mg2+ on the turnover of the phosphomonoester group of phosphatidylinositol 4-phosphate in human erythrocyte membranes

Hegewald, H; Müller, Elke; Klinger, R; Wetzker, Reinhard; Frunder, Horst

doi:10.1042/bj2440183

Cited by 14 publications

(5 citation statements)

References 34 publications

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“…These data suggest that PLC and PLA2, at this concentration, attack the same pool of PIP2 molecules. The effect of PLA2 on PIP, in saponin membranes, cannot be determined because their incubation at 37 °C in the isotonic medium used in these experiments, with or without Ca2+, resulted in the activation of a PIP phosphatase, a membrane-bound enzyme (Hegewald et al, 1987), which reduced the PIP content by about 75% and interfered with the measurement of PIP hydrolysis by PLA2 (data not shown).…”

Section: Resultsmentioning

confidence: 97%

“…This indicated that PLC was entirely responsible for PIP2 hydrolysis at this concentration of PLA2. To determine the effect of PLA2 without interference with PLC, PPI hydrolysis was measured in saponin membranes which lack PLC activity (Hegewald et al, 1987). The electrophoretic protein pattern, the phospholipid composition, and the cholesterol/phospholipid ratio were similar in the saponin membranes and in the hypotonic membranes (data not shown).…”

Section: Resultsmentioning

confidence: 99%

“…Membranes were prepared either by hypotonic lysis in 5 mM sodium phosphate (pH 7.6), 1 mM EDTA (medium A), and 0.1 mM phenylmethanesulfonyl fluoride (PMSF) or by isotonic lysis in the presence of saponin [100 mM KC1, 50 mM Tris-HCl (pH 7.2), 0.5 mM EDTA, and 0.3 mg/mL saponin]. This second method allows inactivation of PLC (Hegewald et al, 1987).…”

Section: Methodsmentioning

confidence: 99%

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Characterization of structural and functional phosphoinositide domains in human erythrocyte membranes

Gascard

Sauvage²,

Sulpice³

et al. 1993

Biochemistry

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In the erythrocyte membrane, only a fraction (50-60%) of phosphatidylinositol 4,5-bisphosphate (PIP2) and of phosphatidylinositol 4-phosphate (PIP) is rapidly turned over by specific kinases and phosphatases and accessible to hydrolysis by the polyphosphoinositide (PPI)-specific phospholipase C (PLC). To investigate whether the metabolic segregation of PPI resulted from preferential interactions with proteins, we have measured the accessibility of PPI to bee venom phospholipase A2 (PLA2) in native erythrocyte membranes, or after treatments designed to remove peripheral proteins and cytoplasmic domains of integral proteins. In native membranes, PPI, as well as the other major phospholipids, behaved as two distinct fractions (R1 and R2) differing by their sensitivity to PLA2. Such a behavior was not observed in PIP and PIP2 containing artificial vesicles. Evidence was provided that the highly sensitive fraction of PIP and PIP2 (R1) may be identical to the PLC-sensitive and rapidly metabolized pool. Removal of peripheral proteins, followed by proteolysis of the cytoplasmic domain of integral proteins, mainly glycophorins and band 3, led to a reduction of the R1 fraction of PIP and of PIP2. It is proposed that the rapidly metabolized pool of PIP2 and PIP, involved in the regulation of major cellular functions, would be maintained in its functional state through interactions with integral proteins.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Characterization of structural and functional phosphoinositide domains in human erythrocyte membranes

Gascard

Sauvage²,

Sulpice³

et al. 1993

Biochemistry

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“…Incubation of rat liver plasma membranes with [32P]ATP resulted in the rapid incorporation of 32p into Ptdlns(4)P and PtdIns(4,5)P2 ( The stimulation of 32p incorporation into the polyphosphoinositides by GTP[S] could be due to a direct activation of Ptdlns and PtdIns (4) [32P]PtdIns (4) (4,5)P2. The activity of phosphomonoesterases is influenced by magnesium [29]. Therefore the stimulation of [32P]polyphosphoinositide synthesis by GTP[S] could be due to competition for magnesium.…”

Section: Resultsmentioning

confidence: 99%

Effect of guanine nucleotides on polyphosphoinositide synthesis in rat liver plasma membranes

Bénistant

Thomas

Rubin

1990

Biochemical Journal

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The effect of guanosine 5'-[gamma-thio]triphosphate (GTP[S]) on PtdIns and PtdIns(4)P kinase activities was measured in rat liver plasma membranes. The addition of [32P]ATP resulted in the rapid incorporation of 32P into PtdIns(4)P and PtdIns(4,5)P2, with maximal levels reached within 30 s. GTP[S] (25-500 microM) increased the rate and magnitude of [32P]PtdIns(4)P and [32P]PtdIns(4,5)P2 formation by 50 and 120% respectively. Similar stimulatory effects were induced by guanosine 5'-[beta gamma-imido]triphosphate, GTP, GDP and guanosine 5'-[beta-thio]diphosphate. The stimulation of PtdIns phosphorylation by GTP[S] occurred in the presence of 2 mM-EGTA, a condition which fully inhibited phosphoinositide-specific phospholipase C. GTP[S] did not stimulate phosphomonoesterase activity, and its action was not due to the binding of magnesium. However, the overall ATP-hydrolysing activity of the membrane preparation was inhibited by GTP[S] and the other guanine nucleotides. There was a direct correlation between the extent of this inhibition and the stimulation of polyphosphoinositide formation. The results indicate that stimulation of polyphosphoinositide formation by guanine nucleotides in rat liver plasma membranes can be accounted for by an inhibition of ATP hydrolysis. These data are inconsistent with a specific GTP-binding protein (G-protein)-mediated stimulation of PtdIns or PtdIns(4)P kinase.

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“…Fourthly, a binding of PFK to PtdIns4P present in cell membranes should influence the size of the accessible PtdIns4P pool, its interaction with other enzymes such as PtdIns4P kinase, phospholipase C and PtdIns4P phosphomonoesterase, and thus its functional dynamics and turnover. The concentration of PtdIns4P in plasma membranes has been shown to be sufficient by far to allow for such an interaction with PFK [51,52]. From these findings, some degree of coupling between the glycolytic activity, the phosphoinositide metabolism and the cytoplasmic Ca2l (see also [45]) may be expected.…”

Section: Discussionmentioning

confidence: 89%

Inositol 1,4-bisphosphate is an allosteric activator of muscle-type 6-phosphofructo-1-kinase

Mayr

1989

Biochemical Journal

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The allosteric effects of various inositol biphosphate (InsP2) isomers and other inositol phosphates, of glycerophosphoinositol phosphates (GroPInsPx) and of phosphoinositides (PtdInsPx) on muscle-type 6-phosphofructo-1-kinase (PFK) were investigated. The binding of these substances to PFK was indirectly estimated by their ability to stabilize the tetrameric enzyme. At near-physiological concentrations of other allosteric effectors, muscle PFK was activated AMP-dependently by Ins(1,4)P2 (Ka = 43 microM), Ins(2,4)P2 (Ka = 70 microM) and GroPIns4P (Ka = 20 microM). These compounds activated PFK by a mechanism similar to that established for activating hexose bisphosphates. Indirect binding experiments indicated minimal Kd,app. values of about 5 microM for the binding of Ins(1,4)P2 in the presence of 0.1 mM-AMP at pH 7.4. This apparent affinity was comparable with that of fructose 1,6-bisphosphate and glucose 1,6-bisphosphate at identical conditions. The enzyme was also found to interact specifically with PtdIns4P (Kd,app. = 37 microM), the inositol phospholipid carrying Ins(1,4)P2 as its head group. The regulatory behaviour of muscle-type PFK in vitro and the concentrations of Ins(1,4)P2 in vivo (between 4 and greater than 50 nmol/g wet wt. of tissue) are consistent with the hypothesis that there is a functional interaction in vivo. Furthermore, a role of PtdIns4P in membrane compartmentation of PFK is suggested. Comparative experiments with liver PFK indicate that these regulatory properties may be relatively specific for the muscle isoform. Unlike muscle PFK, the liver isoform was slightly activated by sub-micromolar concentrations of Ins(1,4,5)P3.

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Influence of Ca2+ and Mg2+ on the turnover of the phosphomonoester group of phosphatidylinositol 4-phosphate in human erythrocyte membranes

Cited by 14 publications

References 34 publications

Characterization of structural and functional phosphoinositide domains in human erythrocyte membranes

Characterization of structural and functional phosphoinositide domains in human erythrocyte membranes

Effect of guanine nucleotides on polyphosphoinositide synthesis in rat liver plasma membranes

Inositol 1,4-bisphosphate is an allosteric activator of muscle-type 6-phosphofructo-1-kinase

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