Generation of mitochondrial reactive oxygen species through a histidine kinase, HysA in Aspergillus nidulans

[摘要] The His-Asp phosphorelay signal transduction fromhistidine kinase (HK) to the response regulator (RR)is an important mechanism for adaptation to environmental changes. Aspergillus nidulans expresses15 different HKs, which may be involved in differenttypes of adaptations. As reactive oxygen species(ROS) are a key signal of environmental changes,some HKs might be involved in ROS generationthrough transcriptional regulation. Previously, weidentified 3 HK (NikA, FphA, and HysA) deletionstrains that showed increased ROS productionduring growth. We also showed that the phosphorylation function of HysA is involved in ROS generation. Here, we investigated the role of HysA in ROSproduction in A. nidulans cells. HysA protein wasdetected in both the cytosol and mitochondria bybiological fractionation of the vegetative cell lysateof A. nidulans. The subcellular localization analysisby expressing the the HysA-GFP fusion proteinalong with MitoTracker Red staining did not clearlyreveal mitochondrial localization of HysA at theconidiophore during asexual development. However,mitochondrial ROS in hysA mutant strains weredetected by MitoSOX Red staining, and their excesslevels possibly caused morphological changes duringasexual development.

[学科分类] 微生物学和免疫学

[关键词] Aspergillus nidulans;histidine kinase;His-Asp phosphorelay signal transduction;ROS(reactive oxygen species)