Sac1 links phosphoinositide turnover to cryptococcal virulence

Area of Science:

• Mycology
• Infectious Diseases
• Cell Biology

Background:

• Cryptococcus neoformans causes over 140,000 deaths annually, with infection initiated by lung deposition and interaction with phagocytic cells.
• The outcome of C. neoformans-phagocyte interaction dictates infection termination or dissemination, yet factors influencing this are poorly understood.

Approach:

• Genome-wide screening of ~4,700 C. neoformans gene deletion mutants identified those with altered uptake by human and mouse phagocytes.
• Further screening assessed capsule thickness, leading to the identification of 45 key mutants, including a sac1 deletion mutant.

Key Points:

• Sac1 is implicated in both host cell uptake and capsule production in C. neoformans.
• sac1 mutants display lipid trafficking defects, reduced secretory function, and altered capsule size/composition.
• These Sac1-dependent changes are often specific to host-like tissue culture conditions, highlighting its role in virulence.

Conclusions:

• Genome-scale screening effectively identifies factors crucial for C. neoformans biology and virulence.
• Sac1 plays a significant role in C. neoformans' interaction with host cells and its protective capsule, impacting infection outcomes.