Cruz MC, Cavallo LM, Cardenas ME, Heitman J; Interscience Conference on Antimicrobial Agents and Chemotherapy.
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 1998 Sep 24-27; 38: 497 (abstract no. J-156).
Duke University Medical Center, Durham, NC.
Cryptococccus neoformans is an opportunistic fungal pathogen that causes systemic mycosis in AIDS and other immunocompromised patients. Current therapies are limited by toxicity and resistance. Previous studies in our laboratory had demonstrated that Cryptococcus neoformans is susceptible to a natural compound called rapamycin. In the yeast Saccharomyces cerevisiae, rapamycin arrests the cell cycle in G1 phase through the formation of protein (FKBP12)-drug complexes that act as active intracellular agents. The TOR kinases involved in cell cycle progression have been identified as targets of the FKBP12-rapamycin complex. Here we report the isolation of the FRR1 gene that encodes the 108 amino acid C. neoformans FKBP12 homolog through a novel two hybrid screen. We also report the characterization of the C. neoformans TOR kinase homolog. We have disrupted the FRR1 gene by homologous recombination and characterized frr1 mutants as resistant to rapamycin and to a second FKBP12 binding drug, FK506. Furthermore, we have identified amino acid substitutions in the conserved FKBP12-rapamycin binding domain of TOR as well as in the drug binding pocket of FKBP12 (W60-R), which render cells resistant to rapamycin and prevent FKBP12-rapamycin-TOR interactions. We conclude that rapamycin antifungal action in Cryptococcus neoformans is mediated via conserved complexes with FKBP12 and TOR kinase homologs.
Publication Types:
Keywords:
- Antifungal Agents
- Antigens, Fungal
- Cryptococcus neoformans
- Humans
- Miconazole
- Phosphotransferases
- Saccharomyces cerevisiae
- Saccharomyces cerevisiae Proteins
- Sirolimus
- Tacrolimus
- Tacrolimus Binding Protein 1A
- Tacrolimus Binding Proteins
- Yeasts
- immunology
Other ID:
UI: 102188540
From Meeting Abstracts