Figure 4

Kinetics of hZIP4 and truncated hZIP4 zinc transport. (A) Zn²⁺ uptake in HEK293 cells expressed full-length hZIP4 (▲), truncated hZIP4 (●), or empty vector (□) as a function of time. (B) full-length hZIP4 and truncated hZIP4 expression level on the plasma membrane of HEK293 determined by biotinylation assay. Full-length imaging is shown in Supplement Fig. S1. (C) Zn²⁺ uptake in HEK293 cells expressed full-length hZIP4 (▲), truncated hZIP4 (●), or empty vector (□) at various Zn²⁺ concentrations, and the transport parameters, K_m and V_max of full-length hZIP4 were calculated as 3.14 ± 0.2 µM and 0.24 ± 0.01, respectively. K_m and V_max of truncated hZIP4 are 3.46 ± 0.3 µM and 0.23 ± 0.01, respectively.