scholarly journals Role of arginine residues in the stimulation of the smooth-muscle plasma-membrane Ca2+ pump by negatively charged phospholipids

1989 ◽  
Vol 264 (2) ◽  
pp. 609-612 ◽  
Author(s):  
L Missiaen ◽  
L Raeymaekers ◽  
G Droogmans ◽  
F Wuytack ◽  
R Casteels

Negatively charged phospholipids strongly stimulate the purified plasma membrane Ca2+ pump of erythrocytes [Enyedi, Flura, Sarkadi, Gardos & Carafoli (1987) J. Biol. Chem. 262, 6425-6430] and of smooth muscle [Missiaen, Raeymaekers, Wuytack, Vrolix, De Smedt & Casteels, (1989) Biochem. J. 263, 687-694]. We have investigated the role of arginine residues in the interaction of these acidic phospholipids with the smooth-muscle Ca2+ transport ATPase. The arginine-modifying reagent phenylglyoxal inhiibited the ATPase activity in a time-dependent fashion by decreasing the Vmax. of the Ca2(+)-activation curve. Low concentrations of PtdIns, PtdIns4P, PtdIns(4,5) P2, phosphatidylserine and phosphatidic acid partially prevented this inactivation. This protective effect was however not apparent at higher concentrations of PtdIns4P, PtdIns(4,5) P2 and phosphatidic acid, which may be related to the previously observed inhibition of the enzyme at higher concentrations of these phospholipids. These findings indicate that the functionally important interaction of the acidic lipids with the protein occurs at least partially via arginine residue(s).

2003 ◽  
Vol 14 (12) ◽  
pp. 4885-4895 ◽  
Author(s):  
Maria Jose Lopez-Andreo ◽  
Juan C. Gomez-Fernandez ◽  
Senena Corbalan-Garcia

To evaluate the role of the C2 domain in protein kinase Cϵ (PKCϵ) localization and activation after stimulation of the IgE receptor in RBL-2H3 cells, we used a series of mutants located in the phospholipid binding region of the enzyme. The results obtained suggest that the interaction of the C2 domain with the phospholipids in the plasma membrane is essential for anchoring the enzyme in this cellular compartment. Furthermore, the use of specific inhibitors of the different pathways that generate both diacylglycerol and phosphatidic acid has shown that the phosphatidic acid generated via phospholipase D (PLD)-dependent pathway, in addition to the diacylglycerol generated via phosphoinosite-phospholipase C (PLC), are involved in the localization of PKCϵ in the plasma membrane. Direct stimulation of RBL-2H3 cells with very low concentrations of permeable phosphatidic acid and diacylglycerol exerted a synergistic effect on the plasma membrane localization of PKCϵ. Moreover, the in vitro kinase assays showed that both phosphatidic acid and diacylglycerol are essential for enzyme activation. Together, these results demonstrate that phosphatidic acid is an important and essential activator of PKCϵ through the C2 domain and locate this isoenzyme in a new scenario where it acts as a downstream target of PLD.


1989 ◽  
Vol 263 (3) ◽  
pp. 687-694 ◽  
Author(s):  
L Missiaen ◽  
L Raeymaekers ◽  
F Wuytack ◽  
M Vrolix ◽  
H de Smedt ◽  
...  

The aim of the present work was to investigate the stimulation of the plasma-membrane Ca2+-transporting ATPase by negatively charged phospholipids. The Ca2+-transporting ATPase was purified from pig stomach smooth muscle and from pig erythrocytes, and was reactivated with phosphatidylcholine (PC) in the presence and absence of negatively charged phospholipids. The substitution of phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP), phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidic acid (PA) or phosphatidylserine (PS) for PC induced profound changes in the Vmax, the K0.5 and the Hill coefficient of the Ca2+-activation curves for both ATPases. Low concentrations of each of the negatively charged phospholipids increased the Vmax., but high ratios of PIP, PIP2 or PA to PC decreased this parameter. PI, PA and PS increased the Vmax. of the erythrocyte enzyme to a larger extent than that of the smooth-muscle enzyme. This difference was less pronounced for PIP and absent for PIP2. PI (greater than 20% PC substituted), PIP, PIP2, PA and PS all increased the affinity of the two Ca2+-transporting ATPases for Ca2+ in the following order of potency: PIP2 greater than PIP greater than PI approximately PS approximately PA. PI, PA and PS increased the Ca2+ affinity of the smooth-muscle enzyme more than that of the erythrocyte enzyme; this difference was less pronounced for PIP and absent for PIP2. Even in the presence of calmodulin, all of the negatively charged phospholipids were still able to increase the Vmax. of the erythrocyte enzyme, whereas only PIP and PIP2 increased the affinity for Ca2+. The effect of PI at low concentrations (less than 20%) on the erythrocyte enzyme was peculiar in that it caused a decrease in the Ca2+ affinity instead of an increase. This effect was not observed for the smooth-muscle enzyme. All of the negatively charged phospholipids slightly increased the Hill coefficient for Ca2+ of both ATPases, and this effect was additive to that of calmodulin. The stimulation of the erythrocyte enzyme exhibited positive co-operativity towards PI and PIP, whereas that of the smooth-muscle enzyme did not. It is concluded (1) that there is a correlation between the number of negative charges on the phospholipids (PIP2 greater than PIP greater than PA approximately PI approximately PS) and the magnitude of their effect on the Vmax. and the K0.5 for Ca2+, and (2) that the action of the lipids on the smooth-muscle enzyme differs from that on the erythrocyte enzyme, indicating that these two Ca2+-transporting ATPases are not the same.


1978 ◽  
Vol 56 (6) ◽  
pp. 921-925
Author(s):  
L. Spero

A technique is described which has enabled us to measure changes in 22Na+ efflux from smooth muscle plasma membrane vesicles. The resting 22Na+ efflux from these sealed vesicles showed a concentration-dependent increase in response to acetylcholine and other muscarinic agonists, in similar concentrations to those which increased 42K+ efflux in whole muscle. The kinetics of this efflux were complex and could not be described by less than three exponential processes. The response to agonists has, therefore, been characterized by measurement of the half-life of 22Na+ efflux (t1/2). The acetylcholine effect was inhibited by atropine, but unlike the situation in the whole muscle, this inhibition was noncompetitive. Tubocuraine (a nicotinic antagonist) had no effect on this acetylcholine response. Atropine has no effect by itself on the resting 22Na+ efflux, neither did tetrodotoxin or ouabain. 22Na+ efflux from erythrocyte ghosts and liposomes, prepared from lipid extracts of the smooth muscle plasma membrane, was not modified by acetylcholine or atropine.


1985 ◽  
Vol 248 (5) ◽  
pp. C449-C456 ◽  
Author(s):  
A. K. Grover ◽  
C. Y. Kwan ◽  
P. J. Oakes

The plasma membrane-enriched fraction from dog antrum smooth muscle is enriched in ATP-dependent azide-insensitive Ca2+ uptake (0.3-0.4 microM Ca2+ required for half-maximal activity), a high-affinity Ca2+-ATPase (Km of 0.3-0.8 microM for Ca2+), a low-affinity Ca2+-ATPase (Km for 250-400 microM for Ca2+), and a Mg2+-ATPase. Studies using membranes washed with EDTA and assay media treated with Chelex 100 showed that the high-affinity Ca2+-ATPase did not depend on contaminating Mg2+. Thus, whereas the ATP-dependent Ca2+ uptake had an absolute requirement for Mg2+, the Ca2+-ATPases did not. Studies using gamma-irradiation showed that the protein responsible for the ATP-dependent Ca2+ uptake was inactivated at significantly lower doses of radiation than the three ATPases. The Ca2+ uptake and the high-affinity Ca2+-ATPase also differed in their inhibition by calmodulin antagonists and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. Thus it is unlikely that the high-affinity Ca2+-ATPase by itself is responsible for the ATP-dependent Ca2+ uptake.


1989 ◽  
Vol 3 (11) ◽  
pp. 2298-2301 ◽  
Author(s):  
Richard J. Paul ◽  
Christopher D. Hardin ◽  
Luc Raeymaekers ◽  
Frank Wuytack ◽  
Rik Casteels

1996 ◽  
Vol 317 (3) ◽  
pp. 933-938 ◽  
Author(s):  
Meylin SUJU ◽  
Marbelly DAVILA ◽  
German POLEO ◽  
Roberto DOCAMPO ◽  
Gustavo BENAIM

Phosphatidylethanol is formed by ‘transphosphatidylation’ of phospholipids with ethanol catalysed by phospholipase D and can be accumulated in the plasma membrane of mammalian cells after treatment of animals with ethanol. In the present work we show that phosphatidylalcohols, such as phosphatidylethanol and phosphatidylbutanol, produced a twofold stimulation of the Ca2+-ATPase activity of human erythrocytes. This stimulation occurs with the purified, solubilized enzyme as well as with ghost preparations, where the enzyme is in its natural lipidic environment and is different to that obtained with other acidic phospholipids such as phosphatidylserine. Addition of either phosphatidylserine, phosphatidylethanol or phosphatidylbutanol to the purified Ca2+-ATPase, or to ghosts preparations, increased the affinity of the enzyme for Ca2+ and the maximal velocity of the reaction as compared with controls in the absence of acidic phospholipids. However, in contrast with what occurs with phosphatidylserine, simultaneous addition of phosphatidylalcohols and calmodulin increased the affinity of the enzyme for Ca2+ to a greater extent than each added separately. When ethanol was added to either the purified erythrocyte Ca2+-ATPase or to erythrocyte-ghost preparations in the presence of acidic phospholipids, an additive effect was observed. There was an increase in the affinity for Ca2+ and in the maximal velocity of the reaction, well above the values obtained with ethanol or with the acidic phospholipids tested separately. These findings could have pharmacological importance. It is conceivable that the decrease in the intracellular Ca2+ concentration that has been reported in erythrocytes as a result of ethanol intoxication could be due to the stimulation of the Ca2+-ATPase by the accumulated phosphatidylethanol, to a direct effect of ethanol on the enzyme or to an additive combination of both.


1995 ◽  
Vol 108 (4) ◽  
pp. 1597-1603
Author(s):  
R. Schaloske ◽  
C. Sordano ◽  
S. Bozzaro ◽  
D. Malchow

Platelet activating factor (PAF) induces Ca2+ influx in Dictyostelium discoideum. In this investigation we used this activity to analyze the mechanism of PAF action. We found that PAF activity was confined to the period of spike-shaped oscillations and suggest that the role of PAF is to augment cAMP relay. PAF seems to act only a few times during this time period of two hours, since Ca2+ entry adapted to a subsequent stimulus for about 30 minutes. PAF showed a reduced response in the G protein beta- strain LW14 and was unable to induce Ca2+ influx in the G alpha 2- strains HC85 and JM1. The latter expresses the cAMP receptors cAR1 constitutively, and exhibits cAMP-induced Ca2+ influx, albeit at a reduced level. In order to decide whether the inability of PAF to elicit a Ca2+ response in JM1 cells was due to the lack of differentiation and/or the lack of G alpha 2, we inhibited the IP3-dependent pathway with compound U73122 and found that Ca2+ entry was blocked, whereas a closely related inactive compound, U73343, did not alter the response. In agreement with this, NBD-Cl, an inhibitor of Ca2+ uptake into the IP3-sensitive store in Dictyostelium, also abolished PAF activity. The latter was not inhibited by the plasma membrane antagonists BN-52021 or WEB 2170. Therefore PAF seems to operate intracellularly via the IP3-signalling pathway at or upstream of the IP3-sensitive store.


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