Molecular cloning, characterization, and dynamics of rat formiminotransferase cyclodeaminase, a Golgi-associated 58-kDa protein
Molecular cloning, characterization, and dynamics of rat formiminotransferase cyclodeaminase, a Golgi-associated 58-kDa protein
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DOI：
10.1074/jbc.273.50.33825
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发表时间：
1998-12-11
影响因子：
4.8
通讯作者：
Sztul, E
中科院分区：
文献类型：
--
作者：
Gao, YS;Alvarez, C;Sztul, E
先前已经描述了功能未知的外周相关的58-kDa高尔基体蛋白（58 K）（Bloom，G.美国，Brashear，T. A.（1989）J，Biol，Chem，264，16083-16092）。为了对58 K进行分子表征，我们使用抗58 K单克隆抗体（单克隆抗体58 K-9）筛选大鼠肝脏cDNA表达文库。阳性克隆被分离、表征并部分测序。所获得的序列显示出与猪甲亚胺基转移酶环脱氨酶（FTCD）的序列的高水平的同一性，表明58 K是大鼠FTCD。大鼠FTCD：在结构上与猪FTCD相似，是一种参与组氨酸转化为谷氨酸的代谢酶，存在于二聚体、四聚体和八聚体复合物中，对蛋白水解具有抗性。为了定义FTCD与高尔基体相关的参数，在特定条件下检查其与各种高尔基体和ER-高尔基体中间室标记蛋白的行为的比较。结果表明，FTCD的提取参数与紧密结合的高尔基体基质蛋白GM 130相似，FTCD是高尔基体的动态组分，部分FTCD分子在高尔基体和分泌途径的前区室之间循环。FTCD仍然与高尔基体片段在微管破坏，并没有释放到胞质溶胶在布雷菲德菌素A治疗。相反，FTCD从高尔基体搬迁，但其重新分配的时间过程是不同的甘露糖苷酶II搬迁。当甘露糖苷酶II仍然主要定位于高尔基体结构时，FTCD已经分散成小的点状结构。在源自高尔基体并含有甘露糖苷酶II的小管中未观察到FTCD。相反，它似乎重新分布在小泡排列在一个线性的“珍珠串”模式。这些结果表明，FTCD搬迁是时间和空间上不同的甘露糖苷酶II搬迁，FTCD提供了一个新的标记，研究高尔基体动态。
A peripherally associated 58-kDa Golgi protein (58K) of unknown function has been previously described (Bloom, G. S., and Brashear, T. A. (1989) J, Biol, Chem, 264, 16083-16092). To molecularly characterize 58K, we used a monoclonal anti-58K antibody (monoclonal antibody 58K-9) to screen a rat liver cDNA expression library. Positive clones were isolated, characterized, and partially sequenced. The obtained sequences show a high level of identity with sequences of porcine formiminotransferase cyclodeaminase (FTCD), suggesting that 58K is rat FTCD. Rat FTCD :is structurally similar to porcine FTCD, a metabolic enzyme involved in conversion of histidine to glutamic acid, and exists in dimeric, tetrameric, and octameric complexes resistant to proteolysis. To define parameters of FTCD association with the Golgi, comparison of its behavior with various Golgi and ER-to-Golgi intermediate compartment marker proteins was examined under specific conditions. The results show that extraction parameters of FTCD are similar to those of GM130, a tightly associated Golgi matrix protein, FTCD appears to be a dynamic component of the Golgi, and a proportion of FTCD molecules cycle between the Golgi and earlier compartments of the secretory pathway. FTCD remains associated with Golgi fragments during microtubule disruption and is not released into cytosol during brefeldin A treatment. Instead, FTCD relocates from the Golgi, but the time course of its redistribution is distinct from that of mannosidase II relocation. FTCD is already dispersed into small punctate structures at a time when mannosidase II is still largely localized to Golgi structures. FTCD is not observed in tubules originating from the Golgi and containing mannosidase II. Instead, it appears to redistribute in small vesicles arranged in a linear "pearls on a string" pattern. These results suggest that FTCD relocation is temporally and spatially distinct from mannosidase II relocation and that; FTCD provides a novel marker to study Golgi dynamics.