Changes in annexin (lipocortin) content in human amnion and chorion at parturition.
Changes in annexin (lipocortin) content in human amnion and chorion at parturition.
复制标题
分娩时人羊膜和绒毛膜中膜联蛋白（脂皮质素）含量的变化。
DOI：
10.1002/jcb.240500405
复制
发表时间：
1992
影响因子：
4
通讯作者：
Everson,WV
中科院分区：
文献类型：
--
作者：
Myatt,L;Hirth,J;Everson,WV
在分娩时，花生四烯酸从胎膜磷脂中被动员，导致催产素的产生增加，这可能启动或维持子宫肌收缩。磷脂的动员需要激活磷脂酶a2或C，两者都需要钙来激活。膜联蛋白（脂皮素）是一个与钙和磷脂结合的超家族蛋白，因此可以通过两种机制改变磷脂酶的活性：调节细胞内游离Ca2+浓度或调节磷脂对水解酶的可及性。采用单特异性多克隆抗体的免疫印迹技术，在产程和非产程患者的羊膜和绒毛膜/蜕膜中鉴定出膜联蛋白I-VI。每个膜联蛋白存在于两个不同的池中：一个池仅在钙存在时与膜结合（钙依赖池），另一个池在钙螯合剂存在时保持膜结合。膜联蛋白I以两种形式存在，分别在36kda和68kda分解。羊膜和绒毛膜/蜕膜中膜联蛋白I总浓度随产程显著降低，绒毛膜中膜联蛋白V总浓度随产程显著升高。单个膜联蛋白库的大小也随分娩而改变：羊膜和绒毛膜中钙依赖性膜联蛋白库I和II显著减少；钙依赖性膜联蛋白V库在绒毛膜中增加；羊膜中的膜蛋白I和绒毛膜中的膜蛋白I、II和V随着分娩而显著减少。产程羊膜中膜联蛋白I总浓度的下降反映了以不依赖钙的方式与膜紧密结合的池中膜联蛋白I浓度的大幅下降（80-90%）。这一惊人的变化使膜联蛋白1成为一种潜在的候选抑制剂，在分娩时被下调，可能导致磷脂酶接触底物磷脂的途径增加，并在分娩时增加前列腺素的产生。©1992 Wiley‐Liss, Inc。
Arachidonic acid is mobilized from fetal membrane phospholipids at paturition leading to increased production of oxytocic prostaglandins which may initiate or maintain myometiral contractions. Phospholipid mobilization requires activation of phospholipase A2or C both of which require calcium for activity. The annexins (lipocortins) are a superfamily of proteins which bind to calcium and phospholipids thereby may alter phospholipase activity through two mechanism: modulation of intracellular free Ca2+concentration or regulation of the accessibility of phospholipids to hydrolyzing enzymes. Using Western immunoblotting with monospecific polyclonal antibodies, annexins I–VI were identfied in human amnion and chorion/decidua at term in tissues obtained from patients in labor or not in labor. Each annexin was present in two distinct pool: a pool which only associated with the membrane in the presence of calcium (calcium‐dependent pool) and a calcium‐independent pool that remained membrane bound in the presence of calicium chelators. Annexin I was present as two species, resolving at 36 kDa and 68 kDa. The total concentration of annexin I in both amnion and chorion/decidua was significantly decreased with labor, while the total concentration of annexin V in chorion significantly increased with labor. The size of individual pools of annexins also changed with labor: the calcium‐dependent pool of annexins I and II in both amnion and chorion significantly decreased; the calcium‐dependent pool of annexin V increased in chorion; and calcium‐independent pools of annexin I in amnion and annexins I, II, and V in chorion significantly decreased with labor. The decrease in totoal annexin I concentration with labor in amnion reflects a substantial decrease (80–90%) in the pool tightly bound to the membrane in a calcium‐independent manner. The striking change distinguishes annexin I as a potential candiate inhibitor which is specially downgregulated a parturition, potentially leading to increased access of phospholipases to substrate phospholipids and increased prostglandins production at labor. © 1992 Wiley‐Liss, Inc.