Ubiquitin plays an atypical role in GPCR-induced p38 MAP kinase activation on endosomes.
Ubiquitin plays an atypical role in GPCR-induced p38 MAP kinase activation on endosomes.
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DOI：
10.1083/jcb.201504007
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发表时间：
2015-09-28
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影响因子：
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通讯作者：
Trejo J
中科院分区：
文献类型：
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作者：
Grimsey NJ;Aguilar B;Smith TH;Le P;Soohoo AL;Puthenveedu MA;Nizet V;Trejo J
NEDD4-2 E3泛素连接酶介导的K63连接的GPCRs泛素化调节TAB1-TAB2复合体在内体上的募集，并通过非规范途径刺激p38MAPK，这对内皮屏障的破坏至关重要。蛋白水解酶激活受体1(PAR1)是凝血酶的G蛋白偶联受体，通过包括p38丝裂原活化蛋白激酶信号在内的多条途径促进炎症反应。调控PAR1诱导的p38激活的机制尚不清楚。在这里，我们定义了一种非典型的泛素依赖的p38激活途径，PAR1使用该途径来调节内皮屏障的通透性。活化的PAR1K63连接的泛素化是由NEDD4-2E3泛素连接酶介导的，并启动了转化生长因子β激活的蛋白激酶1结合蛋白2(TAB2)的募集。TAB2的泛素结合区对于募集到含有PAR1的内涵体是必不可少的。TAB2与TAB1相关，诱导不依赖于MKK3和MKK6的p38激活。通过NEDD4-2介导的泛素化和TAB1-TAB2，P2Y1嘌呤能GPCR也能刺激p38的激活。在体外，TAB1-TAB2依赖的p38激活是PAR1促进内皮屏障通透性的关键，而在体内，PAR1诱导的血管渗漏需要p38信号。这些研究确定了一种非典型的泛素介导的信号通路，GPCRs的子集使用该通路来调节内体p38信号和内皮屏障的破坏。
K63-linked ubiquitination of GPCRs mediated by the NEDD4-2 E3 ubiquitin ligase regulates recruitment of a TAB1–TAB2 complex on endosomes and stimulates p38 MAPK through a noncanonical pathway, which is critical for endothelial barrier disruption. Protease-activated receptor 1 (PAR1) is a G protein–coupled receptor (GPCR) for thrombin and promotes inflammatory responses through multiple pathways including p38 mitogen-activated protein kinase signaling. The mechanisms that govern PAR1-induced p38 activation remain unclear. Here, we define an atypical ubiquitin-dependent pathway for p38 activation used by PAR1 that regulates endothelial barrier permeability. Activated PAR1 K63-linked ubiquitination is mediated by the NEDD4-2 E3 ubiquitin ligase and initiated recruitment of transforming growth factor-β–activated protein kinase-1 binding protein-2 (TAB2). The ubiquitin-binding domain of TAB2 was essential for recruitment to PAR1-containing endosomes. TAB2 associated with TAB1, which induced p38 activation independent of MKK3 and MKK6. The P2Y1 purinergic GPCR also stimulated p38 activation via NEDD4-2–mediated ubiquitination and TAB1–TAB2. TAB1–TAB2-dependent p38 activation was critical for PAR1-promoted endothelial barrier permeability in vitro, and p38 signaling was required for PAR1-induced vascular leakage in vivo. These studies define an atypical ubiquitin-mediated signaling pathway used by a subset of GPCRs that regulates endosomal p38 signaling and endothelial barrier disruption.