Functional analysis of novel gene products, citrin and aralar

SLC 25 A13是一个新的基因，通过纯合性定位和定位克隆，被确定为负责成人发病的II型瓜氨酸血症（CTLN 2）。Citrin的整体结构与arcadine非常相似，由基因SLC 25 A12编码。本课题研究了Citrin和Arrhythmia在CTLN 2危象机制、诊断和治疗中的作用。Citrin主要分布于肝、肾、心脏和新生儿小肠。在膈肌、骨骼肌、心脏、脑和肾脏中表达Arabidine，但在肝脏中不表达。重要的是，对于肝脏特异性的Citrin缺乏症CTLN 2，注意到肝脏是唯一大量表达Citrin的器官，但它不表达arrhythmia。Citrin和arrhythmia定位于线粒体内膜，是线粒体天冬氨酸谷氨酸载体（AGC）的亚型，其C-半结构域具有活跃的AGC活性，N-端具有EF-手形Ca结合 ...更多信息 dpmains。AGC是苹果酸-天冬氨酸（NADH）穿梭的重要组成部分。穿梭的主要功能是将NADH（还原当量）从细胞质运输到线粒体。AGC对于氨合成尿素也很重要，因为线粒体中氨通过谷氨酸形成的天冬氨酸应该通过AGC进入细胞质，并为乙酰氨基琥珀酸合成酶提供。这些结果表明，上述两种作用中的一种或两种都可能导致CTLN 2的症状。为了鉴定与柠檬酸结合的蛋白，我们利用酵母双杂交系统从人肝cDNA文库中筛选了柠檬酸结合蛋白。经测序分析，我们鉴定出两个蛋白质，一个是调节蛋白激酶C钙效应的蛋白质，另一个是氧化还原相关蛋白。柠檬酸和这些蛋白质之间的相互作用的精确表征需要进行评估。突变的citrin和GFP融合蛋白的表达，其中大部分跨膜结构域被保留，显示出与线粒体选择性染料MitoTracker Red CMXRos共定位的点状分布模式。需要进一步的研究来确定这种线粒体标点是否诱导细胞死亡过程，即凋亡。少

A novel gene, SLC25A13, was identified by homozygosity mapping and positional cloning as the responsible for adult-onset type II citrullinemia (CTLN2). The overall structure of citrin is very similar to that of aralar, encoded by the gene SLC25A12. In this project we have studied the function of citrin and aralar for use in elucidation of crisis mechanism, diagnosis and treatment of CTLN2.Citrin was distributed mainly in the liver, kidney, heart and newborn small intestine. Aralar was expressed in diaphragm, skeletal muscle, heart, brain, and kidney, but not in the liver. It is important for the liver-specific disorder of citrin deficiency, CTLN2, to note that the liver is the only organ expressing citrin in large amounts, but that it dose not express aralar. Citrin and aralar localized to mitochondrial inner membrane were found to be isoforms of mitochondrial aspartate glutamate carriers (AGC) with active AGC activity in their C-half domains and EF-hand Ca binding in their N-terminal … More dpmains. The AGC is an essential component of malate aspartate (NADH) shuttle. The main function of the shuttle is the transport of NADH )reducing equivalent) from cytosol to mitochondria. The AGC is also important for urea synthesis from ammonia, because aspartate formed from ammonia via glutamate in the mitochondria should go out to cytosol through AGC and be supplied for argininosuccinate synthetase. These result suggest that either or both of these effects could lead to the symptoms of CTLN2.In order to identify the protein that interact with citrin, we screened cDNA library derived from human liver by using yeast two hybrid system. After sequencing analysis, we have identified two proteins, one is a protein which regulats Ca effect of protein kinase C, and the other is a redox related protein. The precise characterization of interaction between citrin and these protein needs to be assessed. Expression of mutated citrin and GFP fusion proteins, in which most oftransmembrane domain is retained, showed a punctuate pattern of distribution that colocalized with mitochondria selective dye, MitoTracker Red CMXRos. Further study is required to determine whether this mitochondrial punctuation induces cell death process, apoptosis. Less