Zinc-associated proteome of Cryptococcus neoformans

Fungal diseases are critical burdens on the global healthcare system, infecting over 25% of the world’s population. For the opportunistic fungal pathogen, Cryptococcus neoformans, infection leads to cryptococcosis; a disease enabled by elaboration of sophisticated virulence factors, including polysaccharide capsule, melanin, thermotolerance, and extracellular enzymes in the presence of the host. Conversely, the host protects itself from fungal invasion by regulating and sequestering transition metals (e.g., iron, zinc, copper) important for microbial growth and survival. Building upon knowledge of zinc transport regulation at the transcriptional level, here, we explore the intricate relationship between zinc availability and fungal virulence via mass spectrometry-based quantitative proteomics. We observe distinct protein-level responses to zinc-limited and -excess conditions through a shift of the proteome profile towards stress response and metal acquisition, including the upregulation of the zinc transporter, ZIP1. In addition, we reveal a novel connection among zinc availability, protein folding, capsule production, and virulence through the detection of a Wos2-like ortholog in the secretome under replete conditions. Overall, we provide new biological insight into cellular remodeling at the protein level of C. neoformans under regulated zinc conditions and uncover a novel connection between zinc availability and fungal virulence. These findings support the development of new antifungal strategies focused on the enhancement of nutritional immunity within the host.