Metal Acquisition and Homeostasis in Fungi

Transition metals, particularly iron, zinc and copper, have multiple biological roles and are essential elements in biological processes. Among other micronutrients, these metals are frequently available to cells in only limited amounts, thus organisms have evolved highly regulated mechanisms to cope and to compete with their scarcity. The homeostasis of such metals within the animal hosts requires the integration of multiple signals producing depleted environments that restrict the growth of microorganisms, acting as a barrier to infection. As the hosts sequester the necessary transition metals from invading pathogens, some, as is the case of fungi, have evolved elaborate mechanisms to allow their survival and development to establish infection. Metalloregulatory factors allow fungal cells to sense and to adapt to the scarce metal availability in the environment, such as in host tissues. Here we review recent advances in the identification and function of molecules that drive the acquisition and homeostasis of iron, copper and zinc in pathogenic fungi.