Identification of the mitochondrial ATP-Mg/Pi transporter -: Bacterial expression, reconstitution, functional characterization, and tissue distribution
Identification of the mitochondrial ATP-Mg/Pi transporter -: Bacterial expression, reconstitution, functional characterization, and tissue distribution
复制标题
DOI：
10.1074/jbc.m400445200
复制
发表时间：
2004-07-16
影响因子：
4.8
通讯作者：
Palmieri, F
中科院分区：
文献类型：
--
作者：
Fiermonte, G;De Leonardis, F;Palmieri, F
线粒体载体是转运蛋白家族，除少数例外，存在于线粒体内膜中。它们穿梭代谢物、核苷酸和辅因子通过该膜，从而连接和/或调节细胞质和基质功能。ATP-Mg被转运以交换磷酸盐，但没有蛋白质与这种活性相关。我们已经分离出三个人的cDNA，编码的蛋白质的458，468，和489个氨基酸的66-75%的相似性和线粒体载体家族的特征在其C-末端结构域和三个EF-手钙离子结合基序在其N-末端结构域。这些蛋白质在大肠杆菌中过表达，并重组成磷脂囊泡。它们的转运性质和它们对线粒体的靶向证明它们是过去在整个线粒体中描述的ATP-Mg/P-i载体的同种型。三种亚型的组织特异性表明，至少有一种亚型存在于所有研究的组织中。因为磷酸盐通过线粒体中的磷酸盐载体循环，所以ATP-Mg/P-i载体的三种同种型最有可能负责腺嘌呤核苷酸净摄取或流出线粒体，因此负责基质腺嘌呤核苷酸含量的变化，已经发现基质腺嘌呤核苷酸含量在许多生理病理学情况下发生变化。
The mitochondrial carriers are a family of transport proteins that, with a few exceptions, are found in the inner membranes of mitochondria. They shuttle metabolites, nucleotides, and cofactors through this membrane and thereby connect and/or regulate cytoplasm and matrix functions. ATP-Mg is transported in exchange for phosphate, but no protein has ever been associated with this activity. We have isolated three human cDNAs that encode proteins of 458, 468, and 489 amino acids with 66-75% similarity and with the characteristic features of the mitochondrial carrier family in their C-terminal domains and three EF-hand Ca2+-binding motifs in their N-terminal domains. These proteins have been overexpressed in Escherichia coli and reconstituted into phospholipid vesicles. Their transport properties and their targeting to mitochondria demonstrate that they are isoforms of the ATP-Mg/P-i carrier described in the past in whole mitochondria. The tissue specificity of the three isoforms shows that at least one isoform was present in all of the tissues investigated. Because phosphate recycles via the phosphate carrier in mitochondria, the three isoforms of the ATP-Mg/P-i carrier are most likely responsible for the net uptake or efflux of adenine nucleotides into or from the mitochondria and hence for the variation in the matrix adenine nucleotide content, which has been found to change in many physiopathological situations.