PDF(Pubmed)
Abstract：
Fungal pathogens are a major cause of death, especially among immunocompromised patients. Therapies against invasive fungal infections are restricted to a few antifungals; therefore, novel therapies are necessary. Nutritional signaling and regulation are important for pathogen establishment in the host. In Cryptococcus neoformans, the causal agent of fungal meningitis, amino acid uptake and biosynthesis are major aspects of nutritional adaptation. Disruptions in these pathways lead to virulence attenuation in an animal model of infection, especially for sulfur uptake and sulfur amino acid biosynthesis. Deletion of Cys3, the main transcription factor that controls these pathways, is the most deleterious gene knockout in vitro and in vivo, making it an important target for further application. Previously, we demonstrated that Cys3 is part of a protein complex, including calcineurin, which is necessary to maintain high Cys3 protein levels during sulfur uptake and sulfur amino acid biosynthesis. In the current study, other aspects of Cys3 regulation are explored. Two lines of evidence suggest that C. neoformans Cys3 does not interact with the F-box WD40 protein annotated as Met30, indicating another protein mediates Cys3 ubiquitin degradation. However, we found another level of Cys3 regulation, which involves protein interactions between Cys3 and ATP sulfurylase (MET3 gene). We show that an atypical leucine zipper at the N-terminus of ATP sulfurylase is essential for physical interaction with Cys3 and calcineurin. Our data suggests that Cys3 and ATP sulfurylase interact to regulate Cys3 transcriptional activity. This work evidences the complexity involved in the regulation of a transcription factor essential for the sulfur metabolism, which is a biological process important to nutritional adaptation, oxidative stress response, nucleic acid stability, and methylation. This information may be useful in designing novel therapies against fungal infections.
摘要：
真菌病原体是死亡的主要原因，尤其是在免疫功能低下的患者中。针对侵袭性真菌感染的治疗仅限于一些抗真菌药物；因此，新疗法是必要的。营养信号和调节对于宿主中病原体的建立是重要的。在新生隐球菌中，真菌性脑膜炎的病因，氨基酸摄取和生物合成是营养适应的主要方面。这些途径的破坏导致感染动物模型的毒力减弱，特别是硫吸收和硫氨基酸的生物合成。Cys3是控制这些途径的主要转录因子，是体内和体外最有害的基因敲除，使其成为进一步应用的重要目标。以前,我们证明Cys3是蛋白质复合物的一部分，包括钙调磷酸酶,这对于在硫吸收和硫氨基酸生物合成过程中保持高Cys3蛋白水平是必需的。在目前的研究中,探讨了Cys3调节的其他方面。两行证据表明，新型梭状芽胞杆菌Cys3不与注释为Met30的F-boxWD40蛋白相互作用，表明另一种蛋白介导Cys3泛素降解。然而,我们发现了Cys3调节的另一个层次，其中涉及Cys3和ATP硫酸化酶（MET3基因）之间的蛋白质相互作用。我们表明，ATP硫酸化酶N末端的非典型亮氨酸拉链对于与Cys3和钙调磷酸酶的物理相互作用至关重要。我们的数据表明Cys3和ATP硫酸化酶相互作用以调节Cys3转录活性。这项工作证明了硫代谢必不可少的转录因子的调节所涉及的复杂性，这是一个对营养适应很重要的生物过程，氧化应激反应，核酸稳定性，和甲基化。这些信息可能有助于设计针对真菌感染的新疗法。
