The most widespread desmosomal cadherin, desmoglein 2, is a novel target of caspase 3-mediated apoptotic machinery
The most widespread desmosomal cadherin, desmoglein 2, is a novel target of caspase 3-mediated apoptotic machinery
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DOI：
10.1002/jcb.21431
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发表时间：
2008-02-01
影响因子：
4
通讯作者：
Lanza, Alessandro
中科院分区：
文献类型：
--
作者：
Cirillo, Nicola;Lanza, Michele;Lanza, Alessandro
已知凋亡细胞通过半胱天冬酶活性调节细胞间接触的有序分解。尽管桥粒芯糖蛋白（Dsg）2在上皮细胞-细胞粘附中的重要作用，但这种广泛存在的桥粒钙粘蛋白在凋亡过程中的命运仍知之甚少。在这里，通过药理学的方法，我们调查是否Dsg 2的目标是在HaCaT和HT-29细胞系进行星形孢菌素（STS）诱导的凋亡的半胱天冬酶。结果显示，STS诱导角质形成细胞（HaCaT）和肠上皮细胞（HT-29）中的半胱天冬酶依赖性形式的细胞死亡，这与细胞裂解物中Dsg 2的进行性消耗相关。全长Dsg 2的蛋白水解加工导致70 kDa片段的出现，该片段被释放到胞质溶胶中。一致的，免疫荧光研究表明，Dsg 2染色从细胞表面被取消，而Dsg 2的胞质区域定位于细胞内。斑珠蛋白（Pg）也经历切割并从Dsg 2上脱离。细胞凋亡变化与细胞间粘附强度的进行性丧失平行。所有这些生物化学、形态学和功能变化均受caspase 3调控。事实上，在存在半胱天冬酶3抑制剂z-DEVD-favor的情况下，全长Dsg 2蛋白水平得以保留，而70-kDa片段的量维持在对照水平。此外，用z-DEVD-fetamine预处理的细胞保留Dsg 2的膜标记。综上所述，我们的数据表明，Dsg 2的凋亡过程中介导的caspase 3在上皮细胞。
Apoptotic cells are known to regulate the ordered dismantling of intercellular contacts through caspase activity. Despite the important role of desmoglein (Dsg) 2 in epithelial cell-cell adhesion, the fate of this widespread desmosomal cadherin during apoptosis is yet poorly understood. Here, by means of pharmacological approaches, we investigated whether Dsg2 was targeted by caspases in HaCaT and HT-29 cell lines undergoing staurosporine (STS) induced apoptosis. Results showed that STS induced a caspase-dependent form of cell-death in both keratinocytes (HaCaT) and enterocytes (HT-29), that associated with progressive depletion of Dsg2 from cell lysates. The proteolytic processing of full-length Dsg2 resulted in the appearance of a 70-kDa fragment which was released into the cytosol. Consistently, immunofluorescence studies revealed that Dsg2 staining was abolished from cell surface whereas the cytoplasmic region of Dsg2 did localize intracellularly. Plakoglobin (Pg) also underwent cleavage and detached from Dsg2. Apoptotic changes paralleled with progressive loss of intercellular adhesion strength. All these biochemical, morphological, and functional changes were regulated by caspase 3. Indeed, in the presence of the caspase 3-inhibitor z-DEVD-fmk, full-length Dsg2 protein levels were preserved, whereas the amount of the 70-kDa fragment was maintained on control levels. Furthermore, cells pretreated with z-DEVD-fmk retained the membrane labeling of Dsg2. Taken together, our data demonstrate that the apoptotic processing of Dsg2 is mediated by caspase 3 in epithelial cells.