Phospholipase D activity facilitates Ca2+-induced aggregation and fusion of complex liposomes
Phospholipase D activity facilitates Ca2+-induced aggregation and fusion of complex liposomes
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DOI：
10.1152/ajpcell.1997.272.4.c1279
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发表时间：
1997-04-01
影响因子：
5.5
通讯作者：
French, S
中科院分区：
文献类型：
--
作者：
Blackwood, RA;Smolen, JE;French, S
磷脂酶D（PLD）在受刺激的中性粒细胞中的激活导致膜磷脂酰胆碱（PC）转化为磷脂酸（PA）。膜磷脂组成的这种变化对脱粒有两个潜在的积极影响。它1）用促融合磷脂取代非促融合磷脂，2）增加膜和膜联蛋白之间相互作用的可能性。模拟中性粒细胞脱颗粒，我们研究了PLD（链霉菌chromofuscus）水解对脂质体在膜联蛋白I存在和不存在下的聚集和融合的影响。我们发现PLD介导的PC向PA的转化降低了融合所需的[Ca 2 +]。膜联蛋白I增加了PA存在下的融合率，但它没有降低阈值[Ca 2 +]，这仍然高于生理范围。然而，PLD水解后，膜联蛋白I降低了聚集所需的[Ca 2 +]近三个数量级，接近生理浓度。这些研究表明PLD的激活和PA的产生可能在膜联蛋白介导的膜-膜沉积中起作用。
Phospholipase D (PLD) activation in stimulated neutrophils results in the conversion of membrane phosphatidylcholine (PC) to phosphatidic acid (PA). This change in membrane phospholipid composition has two potentially positive effects on degranulation. It 1) replaces a nonfusogenic phospholipid with a fusogenic one and 2) increases the potential for interactions between membranes and the annexins. Modeling neutrophil degranulation, we examined the effect of PLD (Streptomyces chromofuscus) hydrolysis on the aggregation and fusion of liposomes in the presence and absence of annexin I. We found that PLD-mediated conversion of PC to PA lowered the [Ca2+] required for fusion. Annexin I increased the rate of fusion in the presence of PA, although it did not lower threshold [Ca2+], which remained above the physiological range. However, after hydrolysis by PLD, annexin I lowered the [Ca2+] required for aggregation by almost three orders of magnitude, to near physiological concentrations. These studies indicate that the activation of PLD and the production of PA may play a role in annexin-mediated membrane-membrane apposition.