DT40 cells lacking the Ca2+-binding protein annexin 5 are resistant to Ca2+-dependent apoptosis
DT40 cells lacking the Ca2+-binding protein annexin 5 are resistant to Ca2+-dependent apoptosis
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DOI：
10.1073/pnas.132598099
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发表时间：
2002-06-11
影响因子：
11.1
通讯作者：
Moss, SE
中科院分区：
文献类型：
--
作者：
Hawkins, TE;Das, D;Moss, SE
膜联蛋白是一种广泛表达的钙离子依赖性磷脂结合蛋白，其生理作用知之甚少。提出的功能包括Ca 2+通道活性和囊泡运输，但都没有在体内得到证实。在这里，我们使用有针对性的基因破坏，以产生B淋巴细胞缺乏膜联蛋白5（Anx 5）的表达，并表明，这导致在一系列的细胞凋亡刺激的易感性降低。通过比较，缺乏膜联蛋白2（Anx 2）的B淋巴细胞没有显示出这种抗性，提供了这种效应对于Anx 5的丧失是特异性的证据。ANX 5（-/-）细胞中的缺陷发生在细胞凋亡程序的早期，在核浓缩、半胱天冬酶3激活和细胞收缩之前，但在初始Ca 2+内流的下游。只有UVA/B照射诱导野生型和ANX 5（-/-）细胞凋亡水平相似。出乎意料的是，体外透化的ANX 5（-/-）细胞也未能释放线粒体细胞色素C，这表明其抗凋亡的可能机制。这些发现表明Anx 5在决定B淋巴细胞对凋亡的易感性中的作用。
Annexins are widely expressed Ca2+-dependent phospholipid-binding proteins with poorly understood physiological roles. Proposed functions include Ca2+ channel activity and vesicle trafficking, but neither have been proven in vivo. Here we used targeted gene disruption to generate B-lymphocytes lacking annexin 5 (Anx5) expression and show that this results in reduced susceptibility to a range of apoptotic stimuli. By comparison B-lymphocytes lacking annexin 2 (Anx2) showed no such resistance, providing evidence that this effect is specific to loss of Anx5. The defect in the ANX5(-/-) cells occurs early in the apoptotic program before nuclear condensation, caspase 3 activation, and cell shrinkage, but downstream of an initial Ca2+ influx. Only UVA/B irradiation induced similar levels of apoptosis in wild-type and ANX5(-/-) cells. Unexpectedly, ANX5(-/-) cells permeabilized in vitro also failed to release mitochondrial cytochrome C, suggesting a possible mechanism for their resistance to apoptosis. These findings demonstrate a role for Anx5 in determining the susceptibility of B-lymphocytes to apoptosis.