Receptor-mediated endocytosis is not required for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis
Receptor-mediated endocytosis is not required for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis
复制标题
DOI：
10.1074/jbc.m700438200
复制
发表时间：
2007-04-27
影响因子：
4.8
通讯作者：
Cohen, Gerald M.
中科院分区：
文献类型：
--
作者：
Kohlhaas, Susan L.;Craxton, Andrew;Cohen, Gerald M.
肿瘤坏死因子相关凋亡诱导配体（tumor necrosis factor related apoptosis inducing ligand，TRAIL）对肿瘤细胞具有选择性毒性。死亡配体的TNF家族的其他成员（TNF、CD 95 L）与其各自的受体（TNF-R1和CD 95）接合，导致受体和配体的内化以及衔接蛋白向称为死亡诱导信号复合物（DISC）的胱天蛋白酶活化平台的募集。最近，TNF-R1和CD 95已显示诱导细胞凋亡，在DISC的形成中绝对需要其相应受体的内化。我们发现，TRAIL及其受体被迅速内吞的时间和浓度依赖性的方式。阻断受体内化与高渗蔗糖没有抑制TRAIL诱导的细胞凋亡，而是放大了凋亡信号的TRAIL。血小板结合和可溶性TRAIL诱导相似水平的细胞凋亡。总之，这些结果表明，无论是配体或受体内化是必需的TRAIL诱导的细胞凋亡。TRAIL的内化主要由网格蛋白依赖性内吞作用介导，也由网格蛋白非依赖性途径介导。抑制网格蛋白依赖性内化的过表达显性负形式的发动蛋白或AP 180没有抑制TRAIL诱导的细胞凋亡。与TRAIL或其受体的内化对于其凋亡信号的传递都不是必需的这一发现一致，FADD（Fas相关死亡结构域）和半胱氨酸天冬氨酸蛋白酶原-8的募集形成TRAIL相关的DISC发生在4 ℃，独立于胞吞作用。我们的研究结果表明，TRAIL和TRAIL受体1/2，不像TNF-TNF-R1或CD 95 L-CD 95，不需要内化的DISC的形成，半胱天冬酶-8的激活，或在BJAB I型细胞的凋亡信号的传输。
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is selectively toxic to tumor compared with normal cells. Other members of the TNF family of death ligands (TNF, CD95L) engage their respective receptors (TNF-R1 and CD95), resulting in internalization of receptor and ligand and recruitment of adaptor proteins to the caspase activation platform known as the death-inducing signaling complex (DISC). Recently, TNF-R1 and CD95 have been shown to induce apoptosis with an absolute requirement for internalization of their corresponding receptors in the formation of a DISC. We show that TRAIL and its receptors are rapidly endocytosed in a time- and concentration-dependent manner. Blockade of receptor internalization with hyperosmotic sucrose did not inhibit TRAIL-induced apoptosis but, rather, amplified the apoptotic signaling of TRAIL. Plate-bound and soluble TRAIL induced similar levels of apoptosis. Together these results suggest that neither ligand nor receptor internalization is required for TRAIL-induced apoptosis. Internalization of TRAIL is mediated primarily by clathrin-dependent endocytosis and also by clathrin-independent pathways. Inhibition of clathrin-dependent internalization by overexpression of dominant negative forms of dynamin or AP180 did not inhibit TRAIL-induced apoptosis. Consistent with the finding that neither internalization of TRAIL nor its receptors is required for transmission of its apoptotic signal, recruitment of FADD (Fas-associated death domain) and procaspase-8 to form the TRAIL-associated DISC occurred at 4 degrees C, independent of endocytosis. Our findings demonstrate that TRAIL and TRAIL receptor 1/2, unlike TNF-TNF-R1 or CD95L-CD95, do not require internalization for formation of the DISC, activation of caspase-8, or transmission of an apoptotic signal in BJAB type I cells.