A. Representative immunoblot of Zip7 and total ERK expression in cellular homogenates (5μg) harvested from non-treated control and CbCln6nclf mutant cells. B. Densitometry analysis of immunoblots (N=3 biological replicates), normalized to expression of total ERK protein was performed using ImageJ. Values are mean + SEM. ** p<0.01 by Student’s t-test. C–F Total cellular zinc (C), copper (D), iron (E) and calcium (F) concentrations were analysed using ICP-MS. Metal concentrations are normalized to total cellular protein content, as measured by BCA assay, and are expressed as mean + SEM.