Figure 11.

Working model for copper homeostasis in S. aureus. The CsoR transcriptional regulator binds intracellular copper, leading to derepression of the copAZ and copBL operons. CopA and CopB are transmembrane copper exporters. CopZ is a chaperon protein that binds copper and acts as a cytosolic buffer. CopL is a membrane-bound, surface-exposed, and copper-binding lipoprotein. CopL likely functions in preventing copper uptake by binding extracellular Cu to prevent it from entering or re-entering the cell after export by CopB or CopA.