Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
Ubiquitin Signalling Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.
Nat Commun. 2021 Dec 2;12(1):7047. doi: 10.1038/s41467-021-27343-z.
Eph receptor tyrosine kinases play a key role in cell-cell communication. Lack of structural information on the entire multi-domain intracellular region of any Eph receptor has hindered understanding of their signaling mechanisms. Here, we use integrative structural biology to investigate the structure and dynamics of the EphA2 intracellular region. EphA2 promotes cancer malignancy through a poorly understood non-canonical form of signaling involving serine/threonine phosphorylation of the linker connecting its kinase and SAM domains. We show that accumulation of multiple linker negative charges, mimicking phosphorylation, induces cooperative changes in the EphA2 intracellular region from more closed to more extended conformations and perturbs the EphA2 juxtamembrane segment and kinase domain. In cells, linker negative charges promote EphA2 oligomerization. We also identify multiple kinases catalyzing linker phosphorylation. Our findings suggest multiple effects of linker phosphorylation on EphA2 signaling and imply that coordination of different kinases is necessary to promote EphA2 non-canonical signaling.
Eph 受体酪氨酸激酶在细胞间通讯中发挥着关键作用。由于缺乏任何 Eph 受体的完整多结构域细胞内区域的结构信息，因此阻碍了对其信号转导机制的理解。在这里，我们使用综合结构生物学来研究 EphA2 细胞内区域的结构和动态。EphA2 通过一种尚未完全了解的非典型信号通路促进癌症恶性，该通路涉及激酶和 SAM 结构域之间连接肽的丝氨酸/苏氨酸磷酸化。我们表明，类似磷酸化的多个连接肽负电荷的积累会诱导 EphA2 细胞内区域从更封闭到更扩展构象的协同变化，并扰乱 EphA2 跨膜片段和激酶结构域。在细胞中，连接肽负电荷会促进 EphA2 寡聚化。我们还鉴定了多个催化连接肽磷酸化的激酶。我们的研究结果表明，连接肽磷酸化对 EphA2 信号转导有多种影响，并暗示不同激酶的协调对于促进 EphA2 非典型信号转导是必要的。
