Transcriptional and post transcriptional roles of calcineurin in cationic stress and glycerol biosynthesis in Cryptococcus neoformans

Stress management is a major adaptive advantage for survival in adverse environment. Pathogens face this challenge during host colonization, requiring accurate stress response to establish infection. The fungal pathogens Cryptococcus neoformans often undergo thermal, oxidative and osmotic stresses in its natural environment and in the animal host. Different signaling systems controlled by Ras1, Hog1 and calcineurin respond to high temperature growth and osmotic stress. Cationic stress induced by Na+, K+ and Li+ can be overcome with glycerol, the preferred compatible solute in fungi. Deletion of glycerol phosphate phosphatase gene (GPP2) renders cells unable to accumulate glycerol due to a block in the last step of this biosynthetic pathway. In this work we also showed the transcriptional profile of glycerol deficient mutants and established the osmotic stress response mediated by calcineurin in C. neoformans; to our knowledge this is the first time this transcriptional profile is described. This knowledge has implications to pathogen adaptability during stress.