Stress related proteases in Caulobacter crescentus

描述(由申请人提供)：细菌使用能量依赖的蛋白酶来响应压力条件。这些蛋白水解酶有双重作用：破坏异常的、潜在的有毒物质， 受损的蛋白质，并通过调节因子的降解产生胁迫响应信号。细胞经常因应激而阻止复制，但目前尚不清楚受调控的蛋白质分解如何导致细菌的细胞周期停止。这项建议阐述了应激相关的蛋白酶如何使用生化、遗传和蛋白质组学方法相结合的方法来靶向复制因子，特别是侧重于模式细菌新月弯杆菌的蛋白酶和复制因子。目标1和2决定了在蛋白毒性应激过程中产生的错误折叠的蛋白质如何直接刺激Lon蛋白酶破坏复制启动子DNAA，并在应激过程中导致生长停滞。目标3和4侧重于ClpXP蛋白酶如何部分处理夹紧加载子亚单位DNAX对于DNA损伤过程中的复制应激耐受至关重要。由于这些蛋白酶和复制因子在所有细菌中都是高度保守的，这些结果将影响我们对复制、蛋白分解和应激耐受性的一般理解。这些因素的关键作用 细菌毒力和致病性中的蛋白酶，以及细菌应激反应中对这些酶的普遍要求，表明它们是开发新的抗生素策略的极佳靶点，这些策略对人类健康的迫切需要。

DESCRIPTION (provided by applicant): Bacteria use energy dependent proteases to respond to stressful conditions. These proteases serve a dual role: destroying aberrant, potentially toxic, damaged proteins and generating stress responsive signals through degradation of regulatory factors. Cells often arrest replication in response to stress, but how regulated proteolysis contributes to cell cycle arrest in bacteria is currently poorly understood. This proposal addresses how stress related proteases target replication factors using a combination of biochemical, genetic and proteomic approaches, specifically focusing on proteases and replication factors from the model bacteria Caulobacter crescentus. Aims 1 and 2 determine how misfolded proteins generated during proteotoxic stress directly stimulate the Lon protease to destroy the replication initiator DnaA and cause growth arrest during stress. Aims 3 and 4 focus on how partial processing of the clamp loader subunit DnaX by the ClpXP protease is critical for replication stress tolerance during DNA damage. Because these proteases and replication factors are highly conserved throughout all bacteria, these results will impact our general understanding of replication, proteolysis, and stress tolerance. The critical role of these proteases in bacterial virulence and pathogenicity, together with the universal requirement for these proteases in bacterial stress responses, suggests that they are excellent targets for development of new antibiotic strategies that are of immediate human health need.