SLC39A9 and Zinc deficiency: Besides, when STAT3 phosphorylation is inhibited by H89, KN93, BAPTA-AM, both the mRNA (Supplementary Figures 2B–D) and protein (Figures 6A–C) expression of ZIP9 are decreased, further confirming that ER Ca2+ leak and CaMKII activation act as upstream signals respond to zinc deficiency to activate STAT3 and promote zip9 expression.