Zap1 is required for Candida glabrata response to fluconazole

• Autor(a) principal: Afonso, Gonçalo dos Santos
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/144824
• topic: Zap1; fluconazole; drug efflux; Cdr1; Pdr1; zinc; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Invasive fungal infections are a major healthcare problem. In these diseases, the fungus enters the bloodstream and can affect any organ, causing serious hard-to-treat infections that are associated with high mortality rates. The first line of treatment for many invasive fungal infections is fluconazole, the most prescribed antifungal drug in the world. However, the fungistatic, rather than fungicidal, nature of this drug has fostered the emergence of resistant clinical isolates. To overcome this problem, great efforts have been made to fully understand the fungal response to fluconazole. In this work, we show that in Candida glabrata, one of the most prevalent fungal species causing nosocomial invasive infections, the transcription factor Zap1 is important for yeast growth under zinc-limited conditions. We also demonstrate that Zap1 down-regulates biofilm formation. Moreover, in line with our group’s previous work, showing that deletion of ZAP1 renders cells more sensitive to fluconazole, we found that the mutant CgΔzap1 accumulates higher levels of fluconazole, which correlates well with its lower levels of ergosterol. Surprisingly, we observed that Zap1 is a negative regulator of the drug efflux transporter gene CDR1 and of its regulator, PDR1. The apparent paradox of drug accumulation in cells where genes encoding transporters relevant for drug extrusion are being overexpressed, led us to test if their activity could be impaired. Our results indicate that Zap1-depleted cells present, in addition to decreased ergosterol levels, altered composition of membrane phospholipids, which together should impact membrane function and therefore prevent fluconazole detoxification. Overall, this study brings to light the multifaceted transcription factor Zap1 as an important hub in Candida glabrata response to zinc deficiency, biofilm formation and fluconazole detoxification.