Molecular control of irreversible bistability during trypanosome developmental commitment.
Molecular control of irreversible bistability during trypanosome developmental commitment.
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DOI：
10.1083/jcb.201506114
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发表时间：
2015-10-26
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影响因子：
--
通讯作者：
Matthews KR
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作者：
Domingo-Sananes MR;Szöőr B;Ferguson MA;Urbaniak MD;Matthews KR
对锥虫发育过程的磷酸化蛋白质组学和功能分析表明，这种转变表现出双稳态，分化需要新的蛋白质合成，蛋白激酶NRK是一个关键调节因子。布氏锥虫的生命周期涉及允许这些寄生虫存活、增殖和传播的发育转变。其中之一，在哺乳动物血液中的生长停滞的短形分化成昆虫阶段的前环形式，可以诱导在体外与顺乌头酸同步。在这里，我们表明，这种转变是一个不可逆的开关，我们映射点的承诺分化后，暴露于顺乌头酸。这种不可逆性意味着正反馈机制的运作允许承诺（即，建立暴露于分化信号的“记忆”）。使用可逆的翻译抑制剂放线菌酮，我们表明，这种信号记忆需要新的蛋白质合成。我们进一步进行了稳定同位素标记的氨基酸在细胞培养中分析同步寄生虫种群，建立蛋白质和磷酸化的寄生虫前和后承诺，从而定义了“承诺蛋白质组。”该数据集的功能询问确定了Nek相关激酶作为第一个发现的蛋白激酶，其控制分化为前环形式的起始。
Phosphoproteomic and functional analysis of the developmental progression of Trypanosomes demonstrates that this transition shows bistability, with commitment to differentiation requiring new protein synthesis, and that the protein kinase NRK is a key regulator. The life cycle of Trypanosoma brucei involves developmental transitions that allow survival, proliferation, and transmission of these parasites. One of these, the differentiation of growth-arrested stumpy forms in the mammalian blood into insect-stage procyclic forms, can be induced synchronously in vitro with cis-aconitate. Here, we show that this transition is an irreversible bistable switch, and we map the point of commitment to differentiation after exposure to cis-aconitate. This irreversibility implies that positive feedback mechanisms operate to allow commitment (i.e., the establishment of “memory” of exposure to the differentiation signal). Using the reversible translational inhibitor cycloheximide, we show that this signal memory requires new protein synthesis. We further performed stable isotope labeling by amino acids in cell culture to analyze synchronized parasite populations, establishing the protein and phosphorylation profile of parasites pre- and postcommitment, thereby defining the “commitment proteome.” Functional interrogation of this data set identified Nek-related kinase as the first-discovered protein kinase controlling the initiation of differentiation to procyclic forms.