Non-canonical phosphorylation of Bmf by p38 MAPK promotes its apoptotic activity in anoikis
Non-canonical phosphorylation of Bmf by p38 MAPK promotes its apoptotic activity in anoikis
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p38 MAPK 对 Bmf 的非经典磷酸化促进失巢凋亡中的凋亡活性
DOI：
10.1038/s41418-021-00855-3
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发表时间：
2021-08-30
影响因子：
12.4
通讯作者：
Shao, Yongping
中科院分区：
文献类型：
--
作者：
Zhi, Zhe;Ouyang, Zhenlin;Shao, Yongping
当细胞失去对细胞外基质的附着时，Bmf通过从细胞骨架转移到线粒体，从而促进了anoikis的发生。然而，Bmf细胞骨架系住的结构细节和失去锚定时Bmf释放的控制仍不清楚。本研究表明，细胞脱离诱导乳腺上皮细胞系中p38 MAPK的快速和持续激活。p38信号的抑制或Bmf的敲低挽救了anoikis。活化的p38 MAPK可以直接磷酸化Bmf的多个位点，包括非脯氨酸定向位点苏氨酸72 （T72）。晶体学研究表明Bmf T72直接参与DLC2结合，其磷酸化会通过位阻阻断Bmf/DLC2相互作用。最后，我们在体外和敲入小鼠模型中发现T72的拟磷突变增强了Bmf的凋亡活性。这项工作揭示了一种新的动物骨髓瘤活性调控机制，为动物骨髓瘤细胞骨架系结和解离提供了结构基础。
Bmf contributes to the onset of anoikis by translocating from cytoskeleton to mitochondria when cells lose attachment to the extracellular matrix. However, the structural details of Bmf cytoskeleton tethering and the control of Bmf release upon loss of anchorage remained unknown. Here we showed that cell detachment induced rapid and sustained activation of p38 MAPK in mammary epithelial cell lines. Inhibition of p38 signaling or Bmf knockdown rescued anoikis. Activated p38 MAPK could directly phosphorylate Bmf at multiple sites including a non-proline-directed site threonine 72 (T72). Crystallographic studies revealed that Bmf T72 directly participated in DLC2 binding and its phosphorylation would block Bmf/DLC2 interaction through steric hindrance. Finally, we showed that phosphomimetic mutation of T72 enhanced Bmf apoptotic activity in vitro and in a knock-in mouse model. This work unraveled a novel regulatory mechanism of Bmf activity during anoikis and provided structural basis for Bmf cytoskeleton tethering and dissociation.