The role of the chlamydial effector CPAF in the induction of genomic instability.
The role of the chlamydial effector CPAF in the induction of genomic instability.
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衣原体效应器 CPAF 在诱导基因组不稳定中的作用。
DOI：
10.1111/2049-632x.12207
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发表时间：
2014
影响因子：
3.3
通讯作者：
Grieshaber,NicoleA
中科院分区：
文献类型：
--
作者：
Grieshaber,ScottS;Grieshaber,NicoleA
CPAF在衣原体毒力中的作用无疑是一个混乱的问题。CPAF是一种能够切割许多蛋白质的有效且混杂的半胱氨酸蛋白酶（Zhong，2011）。自Guaming Zohng的实验室中CPAF的最初表征（Zhong等人，2001）衣原体研究人员提供了一长串鉴定的衣原体和宿主来源的CPAF可裂解靶蛋白（A Conrad et al.，2013年）。然而，Tan和Sutterlin小组的仔细研究令人信服地证明，感染细胞中的大部分CPAF活性实际上被隔离在衣原体包涵体中，并且在许多情况下依赖于细胞均质化的生物化学测定释放隔离的CPAF，允许在生物条件下不与CPAF相互作用的“靶标”降解（Chen et al.，2012年）。因此，问题不是CPAF切割什么样的宿主蛋白，而是CPAF可以接触什么样的宿主蛋白以及它何时获得这种接触。来自对由艾米丽（Emily）在瓦尔迪维亚实验室分离的两种无CPAF活性的衣原体突变株的生长和毒力表型的研究的新数据增加了关键的观察结果，这些观察结果已经发展了我们对CPAF在发病机制中的作用的理解（Snavely等人，2014年）。Valdivia实验室观察到，与同基因CPAF阳性衣原体菌株相比，CPAF无效菌株遵循相同的发育周期并产生正常外观的包涵体（Snavely等人，2014年）。然而，CPAF突变体产生的后代感染性约低三倍。尚不清楚该缺陷处于发育的哪个阶段（Snavely等人，2014年）。我们先前已经证明，沙眼衣原体感染通过诱导中心体的过度复制、导致过早的有丝分裂退出和限制中心体/微管网络的重组而引起基因组不稳定性（诺尔顿等人，2011; Brown等人，2012年）。这些表型导致染色体分离错误，导致胞质分裂失败和多核化（Brown等人，2012年）。我们证明了细胞周期蛋白B1和securin（两种参与有丝分裂检查点控制的蛋白质）都可以被CPAF降解，并且理论上CPAF参与基因组不稳定性的诱导（Brown等人，2012年）。然而，来自Tan实验室的公开结果表明，大多数检测到的细胞周期蛋白B1裂解是由于样品处理期间的包涵体裂解（Chen等人，2012年）。我们验证了这一结果，并且还发现securin降解也仅在样品处理期间观察到。随着Valdivia实验室慷慨共享的等基因CPAF突变分离株的可用性，我们直接测试了CPAF在基因组不稳定性中的作用。我们的研究发表在6月版的PlosOne上，表明CPAF无效菌株在诱导中心体扩增和早期有丝分裂退出方面有缺陷，这两种关键表型涉及引起基因组不稳定性（Brown et al.，2014）。结果，这些菌株引起显著较少的多核化（Brown等人，2014年）。通过研究GspE衣原体突变体中的基因组不稳定性[由Valdivia实验室分离和描述（Nguyen & Valdivia，2012）]，我们进一步证明了通过II型分泌系统的分泌是中心体扩增和早期有丝分裂退出的CPAF依赖性表型所需的（Brown等人，2014).虽然我们已经证明了一个明确的表型依赖于CPAF生产和分泌衣原体，关键问题仍然存在。我们还没有确定相关目标...
The role of CPAF in chlamydial virulence is justifiably a tangle of confusion. CPAF is a potent and promiscuous cysteine protease capable of cleaving many proteins (Zhong, 2011). Over the 13 years since the original characterization of CPAF in the laboratory of Guaming Zohng (Zhong et al., 2001) chlamydial researchers have contributed a long list of identified CPAF cleavable target proteins of both chlamydial and host origin (A Conrad et al., 2013). However, careful studies by the Tan and Sutterlin group convincingly demonstrated that the majority of CPAF activity in infected cells is actually sequestered in the chlamydial inclusion and that biochemical assays relying on cell homogenization in many cases released the sequestered CPAF allowing degradation of ‘targets’ that would not interact with CPAF under biological conditions (Chen et al., 2012). Thus, the question becomes not what host proteins does CPAF cleave but what host proteins does CPAF have access to and when does it gain this access. New data from the investigation of growth and virulence phenotypes of two mutant strains of chlamydia null for CPAF activity isolated by Emily Snavely in the Valdivia laboratory have added critical observations that have evolved our understanding of the role of CPAF in pathogenesis (Snavely et al., 2014). The Valdivia laboratory observed that CPAF null strains follow the same developmental cycle and produce normal appearing inclusions when compared to isogenic CPAF positive chlamydial strains (Snavely et al., 2014). The CPAF mutants, however, produce approximately threefold less infectious progeny. It is not yet clear at what stage in development this defect lies (Snavely et al., 2014). We had previously demonstrated that Chlamydia trachomatis infection causes genomic instability by inducing the over duplication of centrosomes, causing premature mitotic exit and restricting reorganization of the centrosome/microtubule network (Knowlton et al., 2011; Brown et al., 2012). These phenotypes contribute to chromosome segregation errors leading to cytokinesis failure and multinucleation (Brown et al., 2012). We demonstrated biochemically that both cyclin B1 and securin (two proteins involved in mitotic check point control) could be degraded by CPAF and theorized CPAF to be involved in the induction of genomic instability (Brown et al., 2012). However, the published results from the Tan laboratory demonstrated that the majority of detected cyclin B1 cleavage was due to inclusion lysis during sample handling (Chen et al., 2012). We verified this result, and additionally found that securin degradation was also only observed during sample handling. With the availability of the isogenic CPAF mutant isolates generously shared by the Valdivia laboratory, we directly tested the role of CPAF in genomic instability. Our studies published in the June edition of PlosOne showed that CPAF null strains were deficient in inducing centrosome amplification and early mitotic exit, two critical phenotypes involved in causing genomic instability (Brown et al., 2014). As a result, these strains caused dramatically less multinucleation (Brown et al., 2014). By investigating genomic instability in the GspE chlamydial mutant [isolated and described by the Valdivia laboratory (Nguyen & Valdivia, 2012)] we further demonstrated that secretion through the type II secretion system is required for the CPAF-dependent phenotypes of centrosome amplification and early mitotic exit (Brown et al., 2014).Although we have demonstrated a clear phenotype dependent on CPAF production and secretion from chlamydia, critical questions remain. We have not yet identified the relevant targets of …
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沙眼衣原体的定位假设蛋白CT311在宿主细胞细胞质中的定位。
影响因子：
3.8
作者：
Lei L;Qi M;Budrys N;Schenken R;Zhong G
通讯作者：
Zhong G
影响因子：
5.8
作者：
A Conrad T;Yang Z;Ojcius D;Zhong G
通讯作者：
Zhong G
DOI：
10.1016/j.str.2013.06.027
发表时间：
2013-09-03
期刊：
Structure (London, England : 1993)
影响因子：
--
作者：
Lu C;Turley S;Marionni ST;Park YJ;Lee KK;Patrick M;Shah R;Sandkvist M;Bush MF;Hol WG
通讯作者：
Hol WG
影响因子：
3.3
作者：
Snavely EA;Kokes M;Dunn JD;Saka HA;Nguyen BD;Bastidas RJ;McCafferty DG;Valdivia RH
通讯作者：
Valdivia RH