Thermoregulation network governing virulence of a critical human fungal pathogen

Cryptococcus neoformans is an environmental fungal pathogen that causes meningoencephalitis in humans, requiring thermal adaptation to human body temperature. We employed several orthogonal complementary approaches to elucidate molecular mechanisms of calcineurin signaling, which is essential for thermotolerance of many fungal species, and in doing so, delineated a thermoregulatory network. First, genetic suppressors for loss of calcineurin activity identified a kinase, Yak1, as the primary suppressor of calcineurin. Second, the development and utilization of the proximity labeling tool TurboID identified novel subcellular interactions of calcineurin during thermal stress. Further investigation employing phosphoproteome, RNA-sequencing, and Ribo-sequencing revealed a major role for calcineurin in controlling translation initiation machinery during thermal stress adaptation. Third, truncation alleles revealed domain-specific roles of the catalytic A subunit in thermotolerance, meiosis, and virulence. Combined, this study presents a comprehensive analysis of thermotolerance-governing networks and mechanisms in a fungal pathogen of global impact.