Parkinson's disease-associated mutations in α-synuclein and UCH-L1 inhibit the unconventional secretion of UCH-L1
Parkinson's disease-associated mutations in α-synuclein and UCH-L1 inhibit the unconventional secretion of UCH-L1
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DOI：
10.1016/j.neuint.2011.05.012
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发表时间：
2011-08-01
影响因子：
4.2
通讯作者：
Kabuta, Tomohiro
中科院分区：
文献类型：
--
作者：
Konya, Chiho;Hatanaka, Yusuke;Kabuta, Tomohiro
泛素羧基末端水解酶L1（UCH-L1）是一种在神经元中大量表达的细胞内蛋白，在家族性帕金森病中发现了UCH-L1的突变。在人类脑脊液中检测到UCH-L1，提高了UCH-L1从神经元分泌的可能性。在本研究中，我们发现，UCH-L1的一部分是从培养的细胞分泌。与野生型UCH-L1相比，缺乏泛素结合活性的D30 K UCH-L1的分泌减少，而缺乏水解酶活性的C90 S UCH-L1的分泌没有减少。用Brefeldin A（一种从内质网到高尔基体的囊泡运输抑制剂）处理，没有阻断UCH-L1的分泌，表明UCH-L1是通过非常规途径分泌的。从Leu-32到Leu-39的UCH-L1序列与enrailed 2的非常规分泌信号序列相似，并且该区域内的亮氨酸取代（L32 S/L32 A/L34 S/L34 A/L39 S/L39 A）减少了UCH-L1的分泌。我们发现UCH-L1中的帕金森病相关突变I93 M减少了I93 M UCH-L1的分泌。此外，帕金森病相关的α-突触核蛋白突变体减少了内源性UCH-L1的分泌。我们的研究结果表明，水解酶活性不是UCH-L1的非常规分泌所必需的，并且暗示泛素结合活性和Leu-32和Leu-39之间的序列参与了UCH-L1的分泌。此外，UCH-L1的分泌可能参与了帕金森病的病理过程。(C)2011 Elsevier B. V.保留所有权利。
Ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) is an intracellular protein abundantly expressed in neurons, and a mutation in UCH-L1 has been identified in familial Parkinson's disease. UCH-L1 has been detected in human cerebrospinal fluid, raising the possibility that UCH-L1 is secreted from neurons. In the present study, we showed that a portion of UCH-L1 is secreted from cultured cells. The secretion of D30K UCH-L1, which lacks ubiquitin binding activity, was decreased compared with that of wild-type UCH-L1, while the secretion of C90S UCH-L1, which lacks hydrolase activity, was not. Treatment with Brefeldin A, an inhibitor of vesicle transport from the endoplasmic reticulum to the Golgi, did not block the secretion of UCH-L1, indicating that UCH-L1 is secreted by an unconventional pathway. The UCH-L1 sequence from Leu-32 to Leu-39 is similar to the unconventional secretory signal sequence of engrailed 2, and substitution of the leucines within this region (L32S/L32A/L34S/L34A/L39S/L39A) reduced the secretion of UCH-L1. We found that the Parkinson's disease-associated mutation I93M in UCH-L1 decreased the secretion of I93M UCH-L1. In addition, Parkinson's disease-linked alpha-synuclein mutants reduced the secretion of endogenous UCH-L1. Our results indicate that the hydrolase activity is not necessary for the unconventional secretion of UCH-L1, and suggest that the ubiquitin binding activity and the sequence between Leu-32 and Leu-39 are involved in the secretion. Moreover, the secretion of UCH-L1 could be involved in the pathology of Parkinson's disease. (C) 2011 Elsevier B.V. All rights reserved.