Fungal Adenylyl Cyclase Acts As a Signal Sensor and Integrator and Plays a Central Role in Interaction with Bacteria

Soon after birth, the human body establishes an intimate association with trillions of microbial cells belonging to numerous bacterial and fungal species [1]. These organisms coinhabit diverse microbial communities on cutaneous and mucosal surfaces such as the skin, the gastrointestinal tract, and the vaginal cavity [2]. Fungal and bacterial cells can interact in many ways, such as direct physical contact, secretion of toxins and signalling molecules, sharing or competing for metabolites and nutrients, and alteration of the environment [3]. These interactions can be antagonistic as well as mutually beneficial. Both bacteria and fungi have evolved sophisticated mechanisms to sense and respond to the presence and activity of other species nearby. In hospitals, fungi and bacteria are frequently isolated from the same site of infection. This raises the important question of whether fungi and bacteria interact in the process of infection, and whether the interaction dictates disease development and outcome, and if so, how they do so. This review summarizes recent discoveries in the study of signal sensing in the fungal pathogen Candida albicans. New findings support a model that adenylyl cyclases act as a hub of signal sensing and integration and may play a central role in bacterial sensing during fungal infection.