INHIBITION OF CALCIUM-INDEPENDENT PHOSPHOLIPASE A(2) PREVENTS ARACHIDONIC-ACID INCORPORATION AND PHOSPHOLIPID REMODELING IN P388D(1) MACROPHAGES
INHIBITION OF CALCIUM-INDEPENDENT PHOSPHOLIPASE A(2) PREVENTS ARACHIDONIC-ACID INCORPORATION AND PHOSPHOLIPID REMODELING IN P388D(1) MACROPHAGES
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DOI：
10.1073/pnas.92.18.8527
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发表时间：
1995-08-29
影响因子：
11.1
通讯作者：
DENNIS, EA
中科院分区：
文献类型：
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作者：
BALSINDE, J;BIANCO, ID;DENNIS, EA
游离花生四烯酸（AA）的细胞水平由脱酰/再酰化循环控制，其中脂肪酸由磷脂酶释放并由酰基转移酶重新掺入。我们发现AA酯化成膜磷脂是一个不依赖Ca ~（2+）的过程，并且它被溴烯醇内酯（BEL）阻断高达60-70%，所述溴烯醇内酯是巨噬细胞中新发现的不依赖Ca ~（2+）的磷脂酶A（2）（PLA（2））的选择性抑制剂。观察到的抑制作用与溶血磷脂稳态水平降低以及这些细胞中钙非依赖性PLA（2）活性抑制相关。这种抑制作用对Ca 2+非依赖性PLA（2）具有特异性，因为EEL处理既不影响IV组PLA（2）、II组PLA（2）、花生四烯酸-CoA合成酶、溶血磷脂：花生四烯酸-CoA酰基转移酶，也不影响CoA非依赖性转酰酶。此外，两种EEL类似物，不是钙离子非依赖性PL（A2）的抑制剂-即溴甲基酮和甲基-BEG-不抑制AA掺入磷脂。棕榈酸的酯化作用仅受EEL轻微影响，表明从头合成途径不受EEL抑制。总的来说，这些数据表明，P388 D（1）巨噬细胞中的Ca 2+非依赖性PLA（2）通过提供酰化反应中使用的溶血磷脂受体，在调节AA掺入膜磷脂中起主要作用。
Cellular levels of free arachidonic acid (AA) are controlled by a deacylation/reacylation cycle whereby the fatty acid is liberated by phospholipases and reincorporated by acyltransferases. We have found that the esterification of AA into membrane phospholipids is a Ca2+-independent process and that it is blocked up to 60-70% by a bromoenol-lactone (BEL) that is a selective inhibitor of a newly discovered Ca2+-independent phospholipase A(2) (PLA(2)) in macrophages. The observed inhibition correlates with a decreased steady-state level of lysophospholipids as well as with the inhibition of the Ca2+-independent PLA(2) activity in these cells. This inhibition is specific for the Ca2+-independent PLA(2) in that neither group IV PLA(2), group II PLA(2), arachidonoyl-CoA synthetase, lysophospholipid:arachidonoyl-CoA acyltransferase, nor CoA-independent transacylase is affected by treatment with EEL. Moreover, two EEL analogs that are not inhibitors of the Ca2+-independent PL(A2)-namely a bromo-methyl ketone and methyl-BEG-do not inhibit AA incorporation into phospholipids. Esterification of palmitic acid is only slightly affected by EEL, indicating that de novo synthetic pathways are not inhibited by EEL. Collectively, the data suggest that the Ca2+-independent PLA(2) in P388D(1) macrophages plays a major role in regulating the incorporation of AA into membrane phospholipids by providing the lysophospholipid acceptor employed in the acylation reaction.