Mérino Delphine, Lalaoui Najoua, Morizot Alexandre, Schneider Pascal, Solary Eric, Micheau Olivier
INSERM, U517, Univ. Bourgogne, Dijon F-21000, France.
Mol Cell Biol. 2006 Oct;26(19):7046-55. doi: 10.1128/MCB.00520-06.
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family that induces cancer cell death by apoptosis with some selectivity. TRAIL-induced apoptosis is mediated by the transmembrane receptors death receptor 4 (DR4) (also known as TRAIL-R1) and DR5 (TRAIL-R2). TRAIL can also bind decoy receptor 1 (DcR1) (TRAIL-R3) and DcR2 (TRAIL-R4) that fail to induce apoptosis since they lack and have a truncated cytoplasmic death domain, respectively. In addition, DcR1 and DcR2 inhibit DR4- and DR5-mediated, TRAIL-induced apoptosis and we demonstrate here that this occurs through distinct mechanisms. While DcR1 prevents the assembly of the death-inducing signaling complex (DISC) by titrating TRAIL within lipid rafts, DcR2 is corecruited with DR5 within the DISC, where it inhibits initiator caspase activation. In addition, DcR2 prevents DR4 recruitment within the DR5 DISC. The specificity of DcR1- and DcR2-mediated TRAIL inhibition reveals an additional level of complexity for the regulation of TRAIL signaling.
肿瘤坏死因子(TNF)相关凋亡诱导配体(TRAIL)是TNF家族的一员,它能以一定的选择性通过凋亡诱导癌细胞死亡。TRAIL诱导的凋亡由跨膜受体死亡受体4(DR4)(也称为TRAIL-R1)和DR5(TRAIL-R2)介导。TRAIL还可与诱饵受体1(DcR1)(TRAIL-R3)和DcR2(TRAIL-R4)结合,由于它们分别缺乏和具有截短的细胞质死亡结构域,因此无法诱导凋亡。此外,DcR1和DcR2抑制DR4和DR5介导的TRAIL诱导的凋亡,我们在此证明这是通过不同机制发生的。虽然DcR1通过在脂筏内滴定TRAIL来阻止死亡诱导信号复合物(DISC)的组装,但DcR2与DR5在DISC内共募集,在那里它抑制起始半胱天冬酶的激活。此外,DcR2阻止DR4在DR5 DISC内的募集。DcR1和DcR2介导的TRAIL抑制的特异性揭示了TRAIL信号调节的另一个复杂层面。