在致死和非致死情况下,半胱天冬酶在人类蛋白质组中切割超过1,500个底物。然而,底物裂解的生理后果的报道是有限的。此外,在非致死性情况下,caspase仅裂解一部分底物的方式仍有待阐明。BubR1,主轴装配检查点元件,是人类的半胱天冬酶底物,其生理功能尚不清楚。这里,我们发现caspases,尤其是Drice,在N端KEN盒基序和C端激酶结构域之间切割果蝇BubR1。通过使用邻近标签,我们发现Drice,而不是Dcp-1,与BubR1接近,这表明蛋白质接近促进了底物偏好。显示出切割的碎片,改变亚细胞定位和蛋白质-蛋白质相互作用。在秋水仙碱处理后,带有抗卵裂BubR1的苍蝇显示出BubR1定位到动粒的持续时间更长。此外,这些苍蝇的寿命延长了.因此,我们认为caspase介导的BubR1裂解限制了纺锤体组装检查点和生物体寿命。我们的结果强调了体内底物个体分析对确定caspase依赖性非致死细胞过程的生物学意义的重要性。
Caspases cleave over 1500 substrates in the human proteome in both lethal and non-lethal scenarios. However, reports of the physiological consequences of substrate cleavage are limited. Additionally, the manner in which caspase cleaves only a subset of substrates in the non-lethal scenario remains to be elucidated.
BubR1, a spindle assembly checkpoint component, is a caspase substrate in humans, the physiological function of which remains unclear. Here, we found that caspases, especially Drice, cleave Drosophila
BubR1 between the N-terminal KEN box motif and C-terminal kinase domain. By using proximity labelling, we found that Drice, but not Dcp-1, is in proximity to
BubR1, suggesting that protein proximity facilitates substrate preference. The cleaved fragments displayed altered subcellular localization and protein-protein interactions. Flies that harboured cleavage-resistant
BubR1 showed longer duration of
BubR1 localization to the kinetochore upon colchicine treatment. Furthermore, these flies showed extended lifespan. Thus, we propose that the caspase-mediated cleavage of
BubR1 limits spindle assembly checkpoint and organismal lifespan. Our results highlight the importance of the individual analysis of substrates in vivo to determine the biological significance of caspase-dependent non-lethal cellular processes.