title: Damage resistance protein (Dap) contributes to azole resistance in a sterol-regulatory-element-binding protein SrbA-dependent way.
abstract: The targeting of stress-response regulators has emerged as a powerful strategy to enhance azole drug efficacy and to abrogate azole drug resistance. Previously, we reported that a damage resistance protein (Dap) family, composed of DapA, DapB, and DapC, could respond to azole stress stimuli in Aspergillus fumigatus, although the exact response mechanisms remain unknown. In this study, RNA-seq analysis found that a total of 180 genes are induced by azole in a dapA-dependent manner. These genes are involved in oxidation-reduction, metabolic processes, and transmembrane transport. Following azole stress stimuli, DapA and DapC consistently show a stable endoplasmic reticulum (ER)-localization pattern. In comparison, the sterol-regulatory element-binding protein SrbA is capable of nuclear translocation from the ER after azole-stress stimuli, suggesting that SrbA, but not Daps, can directly sense azole stress. Moreover, we found that SrbA is required for the normal expression of DapA and DapC but not of DapB. In addition, in the absence of SrbA, the enhanced expression of DapA induced by azole-itraconazole is blocked, indicating that SrbA is required for the DapA response to azole stress. Double mutants together with overexpression experiments suggest that DapA might act downstream of SrbA to respond to azole stress stimuli. Compared with the ΔsrbA strain, no additional increase in sensitivity was observed in the double mutants ΔsrbAΔdapB and ΔsrbAΔdapC, indicating that DapA might be of central importance in the response to azole drugs. Thus, our findings demonstrate that Dap proteins indirectly sense azole stress and link the function of the azole stress-regulator SrbA with the role of Daps in azole susceptibility.
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, Nanjing Normal University, Nanjing, 210023, China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Song
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, Nanjing Normal University, Nanjing, 210023, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Zhai
authors.affiliation: College of Life Sciences, Nanjing Normal University, No. 1 Wen Yuan Rd, Qi Xia District, Nanjing, 210023, China. linglu@njnu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Lu
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001232:Aspergillus fumigatus / Q000187:drug effects* / Q000235:genetics*; D001393:Azoles / Q000494:pharmacology*; D001692:Biological Transport; D004252:DNA Mutational Analysis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D008658:Inactivation, Metabolic; D053858:Metabolic Networks and Pathways; D051779:Sterol Regulatory Element Binding Proteins / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D001393:Azoles; D005656:Fungal Proteins; D051779:Sterol Regulatory Element Binding Proteins
keywords: Aspergillus fumigatus; Azole; Dap family; SrbA