Cryptococcus neoformans

The production of a polysaccharide capsule is a critical virulence factor for the AIDS-associated fungal pathogen Cryptococcus neoformans. Capsule formation is responsive to a variety of host signals, such as glucose, iron, and CO2 levels, which are sensed in part via by the G-protein-coupled receptor, Gpr4, and the cyclic AMP/protein kinase A (cAMP/PKA) pathway. This pathway coordinates capsule production by multiple mechanisms, including regulation of the activity of downstream transcription factors (TFs) such as Rim101 and Nrg1.