An activity-based probe reveals dynamic protein-protein interactions mediating IGF-1R transactivation by the GABAB receptor
An activity-based probe reveals dynamic protein-protein interactions mediating IGF-1R transactivation by the GABAB receptor
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DOI：
10.1042/bj20120188
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发表时间：
2012-05-01
影响因子：
4.1
通讯作者：
Liu, Jianfeng
中科院分区：
文献类型：
--
作者：
Lin, Xin;Li, Xin;Liu, Jianfeng
许多 GPCR（G 蛋白偶联受体）可以在没有 RTK 配体的情况下激活 RTK（受体酪氨酸激酶），这种现象称为反式激活。然而，潜在的分子机制仍不清楚。在本研究中，我们研究了原代神经元中 GABA(B)（γ-氨基丁酸 B）受体介导的 IGF-1R（胰岛素样生长因子 I 型受体）反式激活的分子基础。我们采用化学生物学方法，开发了一种针对 GABA(B) 受体的基于活性的探针。该探针使我们能够首先将 GABA(B) 受体锁定在非活性状态，然后用正变构调节剂激活它，从而可以监测与 IGF-1R 反式激活相关的蛋白质复合物的动态。我们发现 GABA(B) 受体的激活会诱导蛋白质复合物的动态组装和分解，包括受体及其下游效应子。 FAK（粘着斑激酶）是一种非 RTK，在协调这一动态过程中发挥着关键作用。重要的是，GABA(B) 受体相关复合物的这种动态对于反式激活和反式激活依赖性神经元存活至关重要。本研究已经确定了 RTK 的 GPCR 反式激活的重要机制，该机制是通过一种普遍适用于剖析 GPCR 信号传导的新化学生物学工具实现的。
Many GPCRs (G-protein-coupled receptors) can activate RTKs (receptor tyrosine kinases) in the absence of RTK ligands, a phenomenon called transactivation. However, the underlying molecular mechanisms remain undefined. In the present study we investigate the molecular basis of GABA(B) (gamma-aminobutyric acid B) receptor-mediated transactivation of IGF-1R (insulin-like growth factor type I receptor) in primary neurons. We take a chemical biology approach by developing an activity-based probe targeting the GABA(B) receptor. This probe enables us first to lock the GABA(B) receptor in an inactive state and then activate it with a positive allosteric modulator, thereby permitting monitoring of the dynamic of the protein complex associated with IGF-1R transactivation. We find that activation of the GABA(B) receptor induces a dynamic assembly and disassembly of a protein complex, including both receptors and their downstream effectors. FAK (focal adhesion kinase), a non-RTK, plays a key role in co-ordinating this dynamic process. Importantly, this dynamic of the GABA(B) receptor-associated complex is critical for transactivation and transactivation-dependent neuronal survival. The present study has identified an important mechanism underlying GPCR transactivation of RTKs, which was enabled by a new chemical biology tool generally applicable for dissecting GPCR signalling.