Identification and characterization of a neuron-specific isoform of protrudin
Identification and characterization of a neuron-specific isoform of protrudin
复制标题
DOI：
10.1111/gtc.12109
复制
发表时间：
2014-02-01
期刊：
影响因子：
2.1
通讯作者：
Nakayama, Keiichi I.
中科院分区：
文献类型：
--
作者：
Ohnishi, Takafumi;Shirane, Michiko;Nakayama, Keiichi I.
突起蛋白是一种调节极化囊泡运输的膜蛋白。现在，我们已经鉴定出一种新的凸出蛋白异构体（凸出蛋白-L），由于微外显子（外显子L）的选择性剪接，与传统异构体（凸出蛋白- s）相比，它在FFAT基序和卷曲结构域之间含有额外的7个氨基酸。在小鼠的中枢神经系统中发现了突起蛋白- l mRNA，而在所有组织中都检测到突起蛋白- s mRNA。通过使用剪接报告基因，该基因以依赖于突起蛋白转录物剪接模式的方式产生两种不同的荧光蛋白，我们发现大多数神经元表达突起蛋白l，而星形胶质细胞表达突起蛋白异构体，而少突胶质细胞只表达突起蛋白s。与凸蛋白s相比，凸蛋白l与囊泡相关膜蛋白相关蛋白（VAP）的关联程度更大。在突起蛋白缺失小鼠海马神经元中，突起蛋白l的表达比突起蛋白s更有效地促进了神经突的生长。我们的研究结果表明，突起蛋白l是一种神经元特异性突起蛋白异构体，可促进轴突伸长并有助于神经元极性的建立。
Protrudin is a membrane protein that regulates polarized vesicular transport. Now, we have identified a novel isoform of protrudin (protrudin-L) that contains an additional seven amino acids between the FFAT motif and the coiled-coil domain compared with the conventional isoform (protrudin-S) as a result of alternative splicing of a microexon (exon L). Protrudin-L mRNA was found to be mostly restricted to the central nervous system in mice, whereas protrudin-S mRNA was detected in all tissues examined. With the use of a splicing reporter minigene that produces two distinct fluorescent proteins in a manner dependent on the splicing pattern of protrudin transcripts, we found that most neurons express protrudin-L, whereas astrocytes express both protrudin isoforms and oligodendrocytes express only protrudin-S. Protrudin-L associated to a greater extent with vesicle-associated membrane protein-associated protein (VAP) than protrudin-S. Expression of protrudin-L in hippocampal neurons of protrudin-deficient mice also promoted neurite outgrowth more efficiently than protrudin-S. Our results suggest that protrudin-L is a neuron-specific protrudin isoform that promotes axonal elongation and contributes to the establishment of neuronal polarity.