FIGURE 6: Signaling capacity and zinc uptake activity in a zrt1Δ strain expressing different Zrt1 alleles containing a mutated aspartate or glutamate residue.

(A) Schematic overview of Zrt1 with the location in or close to TMDs indicated of the aspartate and glutamate residues that were mutagenized to asparagine or glutamine, respectively.

(B, C) Activity of trehalase as a function of time after addition of 100 μM ZnCl₂ to cells of a zrt1Δ strain harboring the wild type ZRT1 gene on plasmid YCplac33-Zrt1, the empty plasmid YCplac33 or different point mutant alleles of ZRT1 on plasmid YCplac33. All experiments were performed 3-5 times; representative results are shown. (B) Wild type ZRT1 (closed circles), zrt1Δ (open circles), ZRT1^D144N (closed squares), ZRT1^E226Q (closed triangles) and ZRT1^E261Q (open squares). (C) Wild type ZRT1 (closed circles), zrt1Δ (open circles), ZRT1^E273Q (closed squares), ZRT1^D322N (open squares), ZRT1^E336Q (open triangles) and ZRT1^E354Q (closed triangles).

(D) Uptake of either 10 μM (black bars) or 100 μM (white bars) Zn⁶⁵Cl₂ in the same strains as used in B, C, n = 2.