Staphylococcus aureus HrtA is an ATPase required for protection against heme toxicity and prevention of a transcriptional heme stress response.

During systemic infection, Staphylococcus aureus acquires nutrient iron from heme, the cofactor of vertebrate myoglobin and hemoglobin. Upon exposure to heme, S. aureus up-regulates the expression of the heme-regulated transporter, HrtAB.