The 14-3-3 proteins of Trypanosoma brucei function in motility, cytokinesis, and cell cycle
The 14-3-3 proteins of Trypanosoma brucei function in motility, cytokinesis, and cell cycle
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DOI：
10.1074/jbc.m412336200
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发表时间：
2005-04-08
影响因子：
4.8
通讯作者：
Fukuma, T
中科院分区：
文献类型：
--
作者：
Inoue, M;Nakamura, Y;Fukuma, T
已在布氏锥虫中克隆了14-3-3蛋白的两种同种型（I和II）的cDNA并进行了功能表征。同种型I和II的氨基酸序列分别与人tau同种型具有47%和50%的同一性，具有重要的保守特征，包括用于结合含磷酸丝氨酸/磷酸苏氨酸的基序的潜在两亲性凹槽和核输出信号样结构域。两种亚型均以大致相等的水平（1-2 × 10（6）分子/细胞）大量表达，并主要定位于细胞质中。通过诱导血流和前循环形式中亚型I和/或II的双链RNA的敲低首先导致细胞运动性降低，然后细胞生长速率和形态学变化显著降低;这些变化包括细胞器数量异常和形状和大小异常，模拟各种胞质分裂抑制剂产生的表型。细胞周期的形态学和荧光激活细胞分选分析表明，亚型I和II可能在核（G（2）-M转换）和细胞（M-G（1）转换）分裂中起重要作用。这些发现表明14-3-3蛋白在细胞运动、胞质分裂和细胞周期中起重要作用。
The cDNAs for two isoforms (I and II) of the 14-3-3 proteins have been cloned and functionally characterized in Trypanosoma brucei. The amino acid sequences of isoforms I and II have 47 and 50% identity to the human tau isoform, respectively, with important conserved features including a potential amphipathic groove for the binding of phosphoserine/phosphothreonine-containing motifs and a nuclear export signal-like domain. Both isoforms are abundantly expressed at approximately equal levels (1-2 x 10(6) molecules/cell) and localized mainly in the cytoplasm. Knockdown by induction of double-stranded RNA of isoform I and/or II in both bloodstream and procyclic forms resulted first in a reduction of cell motility and then significant reduction in cell growth rates and morphological changes; the changes include aberrant numbers of organelles and abnormal shapes and sizes that mimic phenotypes produced by various cytokinesis inhibitors. Morphological and fluorescence-activated cell sorting analysis of the cell cycle suggested that isoforms I and II might play important roles in nuclear (G(2)-M transition) and cell (M-G(1) transition) division. These findings indicate that the 14-3-3 proteins play important roles in cell motility, cytokinesis, and the cell cycle.