P24A, a type I transmembrane protein, controls ARF1-dependent resensitization of protease-activated receptor-2 by influence on receptor trafficking
P24A, a type I transmembrane protein, controls ARF1-dependent resensitization of protease-activated receptor-2 by influence on receptor trafficking
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DOI：
10.1074/jbc.m703205200
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发表时间：
2007-10-12
影响因子：
4.8
通讯作者：
Reiser, Georg
中科院分区：
文献类型：
--
作者：
Luo, Weibo;Wang, Yingfei;Reiser, Georg
蛋白水解酶激活受体-2(PAR-2)是G蛋白偶联的PAR家族中的第二个成员，被胰酶或胰蛋白酶不可逆地激活，然后靶向溶酶体进行降解。在胰酶刺激后，储存在高尔基体的细胞内合成前受体重新填充细胞表面，从而导致对胰酶信号的快速再敏感。然而，PAR-2从高尔基体胞外转运到质膜的分子机制仍很不清楚。在这里，我们展示了p24A，一种I型跨膜蛋白，它是高尔基体的重要组成部分，在高尔基体中与PAR-2结合。蛋白质的相互作用发生在p24A的N-末端区域(残基1-105；p24A-GL(带有小接头的金域))和PAR-2的第二胞外环之间。受体激活后，PAR-2与p24A解离。重要的是，我们发现ADP-核糖化因子1调节解离过程，并启动PAR-2向质膜的转运。相反，p24A-GL片段的过表达，而不是其他含有p24A功能卷曲结构域的突变体，在高尔基体阻止了PAR-2，并抑制了受体向质膜的转运，从而阻止了PAR-2的再增敏。这些发现确定了p24A作为调节PAR-2生命周期的信号依赖转运的新功能，从而揭示了PAR-2再增敏的新的分子机制。
Protease-activated receptor-2 (PAR- 2), the second member of the G protein-coupled PAR family, is irreversibly activated by trypsin or tryptase and then targeted to lysosomes for degradation. Intracellular presynthesized receptors stored at the Golgi apparatus repopulate the cell surface after trypsin stimulation, thereby leading to rapid resensitization to trypsin signaling. However, the molecular mechanisms of the exocytic trafficking of PAR- 2 from the Golgi apparatus to the plasma membrane remain largely unclear. Here we show that p24A, a type I transmembrane protein, which is a crucial constituent of the Golgi apparatus, associates with PAR- 2 at the Golgi apparatus. The protein interaction occurs between the N-terminal region of p24A (residues 1-105; p24A-GL (GOLD domain with a small linker)) and the second extracellular loop of PAR-2. After receptor activation, PAR- 2 dissociates from p24A. Importantly, we found that ADP-ribosylation factor 1 regulated the dissociation process and initiated PAR- 2 trafficking to the plasma membrane. Conversely, overexpression of the fragment p24A-GL, but not other mutants containing the functional coiled-coil domain of p24A, arrested PAR- 2 at the Golgi apparatus and inhibited receptor trafficking to the plasma membrane, which consequently prevented resensitization of PAR-2. These findings identify a new function of p24A as a regulator of signal-dependent trafficking that regulates the life cycle of PAR- 2, Thus, we reveal a new molecular mechanism underlying resensitization of PAR-2.