Department of Neuroscience, Genentech, Inc., South San Francisco, CA, USA.
Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., South San Francisco, CA, USA.
EMBO J. 2022 Jul 18;41(14):e110155. doi: 10.15252/embj.2021110155. Epub 2022 May 25.
Mitogen-activated protein kinases (MAPKs) drive key signaling cascades during neuronal survival and degeneration. The localization of kinases to specific subcellular compartments is a critical mechanism to locally control signaling activity and specificity upon stimulation. However, how MAPK signaling components tightly control their localization remains largely unknown. Here, we systematically analyzed the phosphorylation and membrane localization of all MAPKs expressed in dorsal root ganglia (DRG) neurons, under control and stress conditions. We found that MAP3K12/dual leucine zipper kinase (DLK) becomes phosphorylated and palmitoylated, and it is recruited to sphingomyelin-rich vesicles upon stress. Stress-induced DLK vesicle recruitment is essential for kinase activation; blocking DLK-membrane interaction inhibits downstream signaling, while DLK recruitment to ectopic subcellular structures is sufficient to induce kinase activation. We show that the localization of DLK to newly formed vesicles is essential for local signaling. Inhibition of membrane internalization blocks DLK activation and protects against neurodegeneration in DRG neurons. These data establish vesicular assemblies as dynamically regulated platforms for DLK signaling during neuronal stress responses.
丝裂原活化蛋白激酶（MAPKs）在神经元存活和退化过程中驱动关键的信号级联反应。激酶定位于特定的亚细胞隔室是一种在受到刺激时局部控制信号活性和特异性的关键机制。然而，MAPK 信号成分如何严格控制其定位在很大程度上仍然未知。在这里，我们系统地分析了在正常和应激条件下，背根神经节（DRG）神经元中表达的所有 MAPKs 的磷酸化和膜定位。我们发现，MAP3K12/双亮氨酸拉链激酶（DLK）发生磷酸化和棕榈酰化，并且在应激时被募集到富含神经鞘磷脂的小泡中。应激诱导的 DLK 小泡募集对于激酶激活是必需的；阻断 DLK-膜相互作用抑制下游信号，而 DLK 募集到异位亚细胞结构足以诱导激酶激活。我们表明，DLK 向新形成的小泡的定位对于局部信号传递是必需的。抑制膜内化可阻断 DLK 激活并防止 DRG 神经元的神经变性。这些数据确立了囊泡组装作为神经元应激反应中 DLK 信号的动态调节平台。
