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 (PI 4 P) 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 PI 4 P in the plasma membrane and Golgi, but the C. albicans plasma membrane pool of PI 4 P could be selectively eliminated by deleting the STT4 kinase, which creates PI 4 P. Interestingly, stt4 Δ mutants were strongly defective in disseminated candidiasis in mice but were not defective in an oral infection. This suggested that abnormal exposure of β-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 PI 4 P and reinforce the need to test the virulence of C. albicans mutants at different host sites.