title: Identification and Functional Ascertainment of the Pneumocystis jirovecii Potential Drug Targets Gsc1 and Kre6 Involved in Glucan Synthesis.
abstract: The most efficient drug against the human pathogenic fungus Pneumocystis jirovecii is cotrimoxazole targeting the folate biosynthesis. However, resistance toward it is emerging and adverse effects occur in some patients. Studies in rodent models suggested that echinocandins could be useful to treat Pneumocystis pneumonia. Echinocandins inhibit the catalytic subunit Gsc1 of the enzymatic complex ensuring the synthesis of 1,3-β glucan, an essential constituent of cell walls of most fungi. Besides, inhibitors of the enzyme Kre6 involved in the synthesis of 1,6-β glucan, another essential component of fungal walls, were recently described. We identified and functionally characterized these two potential drug targets in the human pathogen P. jirovecii by rescue of the null allele of the orthologous gene in Saccharomyces cerevisiae. The P. jirovecii proteins Gsc1 and Kre6 identified using those of the relative Pneumocystis carinii as the query sequence showed high sequence identity to the putative fungal orthologs (53-97% in conserved functional domains). The expression of their encoding genes on plasmid rescued the increased sensitivity to, respectively, caspofungin or calcofluor white of the corresponding S. cerevisiae null allele. The uniqueness and likely essentiality of these proteins suggest that they are potential good drug targets.
authors.affiliation: Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, 1011, Switzerland.
authors.forename: Amanda
authors.initials: A
authors.lastname: Luraschi
authors.affiliation: Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, 1011, Switzerland.|Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, 1015, Switzerland.
authors.forename: Ousmane H
authors.initials: OH
authors.lastname: Cissé
authors.affiliation: Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, 1015, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Pagni
authors.affiliation: Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, 1011, Switzerland.
authors.forename: Philippe M
authors.initials: PM
authors.lastname: Hauser
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002473:Cell Wall / Q000378:metabolism; D003001:Cloning, Molecular; D054714:Echinocandins / Q000494:pharmacology* / Q000627:therapeutic use; D005656:Fungal Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005816:Genetic Complementation Test; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors* / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D045363:Pneumocystis carinii / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D011020:Pneumonia, Pneumocystis / Q000188:drug therapy / Q000382:microbiology; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D000935:Antifungal Agents; D054714:Echinocandins; D005656:Fungal Proteins; D008565:Membrane Proteins; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase
keywords: Cell wall; Saccharomyces cerevisiae heterologous complementation; echinocandins; human pathogen; pathogenic fungus