Potentiation of ATP‐induced currents due to the activation of P2X receptors by ubiquitin carboxy‐terminal hydrolase L1
Potentiation of ATP‐induced currents due to the activation of P2X receptors by ubiquitin carboxy‐terminal hydrolase L1
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DOI：
10.1111/j.1471-4159.2004.02963.x
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发表时间：
2005-03
影响因子：
4.7
通讯作者：
Yoshimasa Manago;Yoshiko Kanahori;Aki Shimada;Ayumi Sato;Taiju Amano;Yae Sato-Sano;Rieko Setsuie;Mikako Sakurai;S. Aoki;Yu-Lai Wang;H. Osaka;K. Wada;M. Noda
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文献类型：
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作者：
Yoshimasa Manago;Yoshiko Kanahori;Aki Shimada;Ayumi Sato;Taiju Amano;Yae Sato-Sano;Rieko Setsuie;Mikako Sakurai;S. Aoki;Yu-Lai Wang;H. Osaka;K. Wada;M. Noda
哺乳动物神经元细胞大量表达去泛素化同工酶，泛素羧基末端水解酶L1（UCH L1）。UCH L1功能的丧失会导致退行性轴突变性。然而，UCH L1在神经元细胞中的功能仍然是难以捉摸的。在这里，我们表明UCH L1的过表达增强了ATP诱导的电流，这是由于P2 X受体的激活，P2 X受体广泛分布在大脑中，并参与各种生物活动，包括神经分泌。在常规全细胞膜片钳配置下，在模拟、野生型或突变型（C90 S）-UCH L1-转染的PC 12细胞中测量ATP诱导的内向电流。ATP诱导电流的幅度在野生型和C90 S UCH L1转染的细胞中均显著更大，表明水解酶活性不参与，但单泛素水平的增加可能起重要作用。电流增加依赖于cAMP依赖性蛋白激酶（PKA）和Ca 2+和钙调蛋白依赖性蛋白激酶（CaMKII），但不依赖于蛋白激酶C。此外，ATP诱导的电流可能通过多巴胺和环AMP调节的磷蛋白（DARPP-32）进行修饰，DARPP-32由PKA和磷酸酶调节。我们的发现首次证明了UCH L1与神经递质受体之间的关系，提示UCH L1可能在突触活动中起重要作用。
Mammalian neuronal cells abundantly express a de‐ubiquitinating isozyme, ubiquitin carboxy‐terminal hydrolase L1 (UCH L1). Loss of UCH L1 function causes dying‐back type of axonal degeneration. However, the function of UCH L1 in neuronal cells remains elusive. Here we show that overexpression of UCH L1 potentiated ATP‐induced currents due to the activation of P2X receptors that are widely distributed in the brain and involved in various biological activities including neurosecretion. ATP‐induced inward currents were measured in mock‐, wild‐type or mutant (C90S)‐UCH L1‐transfected PC12 cells under the conventional whole‐cell patch clamp configuration. The amplitude of ATP‐induced currents was significantly greater in both wild‐type and C90S UCH L1‐transfected cells, suggesting that hydrolase activity was not involved but increased level of mono‐ubiquitin might play an important role. The increased currents were dependent on cAMP‐dependent protein kinase (PKA) and Ca2+ and calmodulin‐dependent protein kinase (CaMKII) but not protein kinase C. In addition, ATP‐induced currents were likely to be modified via dopamine and cyclic AMP‐regulated phosphoprotein (DARPP‐32) that is regulated by PKA and phosphatases. Our finding shows the first evidence that there is a relationship between UCH L1 and neurotransmitter receptor, suggesting that UCH L1 may play an important role in synaptic activity.