Figure 1.

Acquisition and distribution of copper in fungi. ❶. Dedicated high-affinity copper transporters at the plasma membrane facilitate the unidirectional import of copper (purple spheres) to the cytoplasm. ❷ Once internalized, copper is bound by copper chaperones or other buffering components that facilitate the delivery of copper to ❸ cytoplasmic and mitochondrial enzymes for copper-dependent activation or ❹ subcellular compartments for storage or loading into secretory copper-dependent enzymes. However, if copper accumulates beyond homeostatic capacities, fungi employ copper detoxification mechanisms such as ➎copper sequestration or efflux. ➏ Under conditions of extracellular copper deficiency cells mobilize vacuolar copper stores. ➐ In fungi, many of these processes are controlled at the level of transcription by copper-responsive transcription factors that regulate the expression of these components in response to intracellular copper status.