Plasma Membrane Phosphatidylinositol 4-Phosphate Is Necessary for Virulence of Candida albicans

Phosphatidylinositol lipids regulate key processes, including vesicle trafficking and cell polarity. A recent study identified novel roles for phosphatidylinositol 4-phosphate (PI4P) in the plasma membrane of the fungal pathogen Candida albicans, including polarized hyphal growth and cell wall organization. Studies in other organisms were not able to separate the roles of PI4P in the plasma membrane and Golgi, but the C. albicans plasma membrane pool of PI4P could be selectively eliminated by deleting the STT4 kinase, which creates PI4P. Interestingly, stt4 Delta mutants were strongly defective in disseminated candidiasis in mice but were not defective in an oral infection. This suggested that abnormal exposure of beta-glucan in the mutant cell walls increased recruitment of innate immune cells during disseminated infection, which is not expected to impact oral infection. These results highlight novel roles of PI4P and reinforce the need to test the virulence of C. albicans mutants at different host sites.