Fig. 3.

In vitro liposome assay indicates that purified ZnT8A and ZnT8B transport zinc. (A) A cartoon model representing the principle of the assay. (B) An electron micrograph of negatively-stained ZnT8 proteoliposomes; white bar denotes 200 nm. (C) Zinc transport with an internal liposome pH of 6.0 and an external buffer pH of 7.5. (D) Transport of Zn²⁺ by reconstituted ZnT8 with both liposomal and external pH of 7.5, (E) Transport of Zn²⁺ with an internal liposome pH of 7.5 and an external buffer pH of 6.0. Changes in fluozin-1 fluorescence upon Zn²⁺ and subsequent β-octyl glucoside (OG) addition (arrows), using either ZnT8A (blue trace) or ZnT8B proteoliposomes (red trace), or protein-free liposomes (grey trace). ΔF/ΔFmax is the relative change in fluorescence normalized to the maximum fluorescence following proteoliposome dissolution by OG. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)