The yeast is the most prevalent opportunistic fungal pathogen in humans. Drug resistance among isolates poses a common challenge， and overcoming this resistance represents an unmet need in managing this common pathogen. Here， we investigated ， encoding thymidylate kinase (TMPK)， as a potential drug target for the management of infections. We found that the region spanning amino acids 106-123， namely the Ca-loop of TMPK (CaTMPK)， contributes to the hyperactivity of this enzyme compared with the human enzyme (hTMPK) and to the utilization of deoxyuridine monophosphate (dUMP)/deoxy-5-fluorouridine monophosphate (5-FdUMP) as a substrate. Notably， expression of CaTMPK， but not of hTMPK， produce... More
The yeast is the most prevalent opportunistic fungal pathogen in humans. Drug resistance among isolates poses a common challenge， and overcoming this resistance represents an unmet need in managing this common pathogen. Here， we investigated ， encoding thymidylate kinase (TMPK)， as a potential drug target for the management of infections. We found that the region spanning amino acids 106-123， namely the Ca-loop of TMPK (CaTMPK)， contributes to the hyperactivity of this enzyme compared with the human enzyme (hTMPK) and to the utilization of deoxyuridine monophosphate (dUMP)/deoxy-5-fluorouridine monophosphate (5-FdUMP) as a substrate. Notably， expression of CaTMPK， but not of hTMPK， produced dUTP/5-FdUTP-mediated DNA toxicity in budding yeast (). CRISPR-mediated deletion of this Ca-loop in revealed that the Ca-loop is critical for fungal growth and susceptibility to 5-fluorouridine (5-FUrd). Of note， pathogenic and drug-resistant clones were similarly sensitive to 5-FUrd， and we also found that CaTMPK is essential for the growth of In conclusion， these findings not only identified a target site for the development of CaTMPK-selective drugs， but also revealed that 5-FUrd may have potential utility as drug for managing infections.
