Fig 3. Histoplasma Ctr3 enables copper import.

Copper (A) and iron (B) acquisition of Ctr3-expressing (CTR3, black) and Ctr3-deficient (ctr3, red) yeasts. Total cellular metal levels were measured by ICP-MS of yeasts in exponential growth in HMM (which contains 10 nM CuSO₄ and 3 μM FeSO₄) before and after metal depletion (treatment of yeasts for 24 hours with 2 mM BCS (A) or 16 μM BPS (B)) and after 3 hours with replenishment of copper and iron in the growth medium. Data represent the average level of copper or iron per 10⁸ yeasts ± standard deviations among biological replicates (n = 3). Asterisks represent significant differences in metal levels between Ctr3-expressing and Ctr3-deficient yeasts (* P < 0.05, *** P < 0.001, ns P > 0.05) as determined by two-tailed Student’s t-test.