(A–B) Immunoblots for ATP7A, known COG-dependent protein GPP130, COG seven and actin were performed in wild type HEK293 cells (6A, lane 1) and cells null for COG subunit 1 (6A, lane 2, COG1Δ/Δ) or COG subunit 8 (6A, lane 3, COG8Δ/Δ). (C) Surface biotinylation of the same cell types was performed with (6C, even lanes) and without (6C, odd lanes) the addition of 200 μM CuCl2 for two hours. Total protein extracts (6C, lanes 1–4) and surface biotinylated proteins precipitated by streptavidin beads (6C, lanes 5–8) were probed for ATP7A and CTR1, along with streptavidin-peroxidase to compare biotinylation efficiency. (D–F) ATP7A and CTR1 quantitations to measure the ratio of surface to total ATP7A (D), total surface ATP7A with and without copper (E), and total surface CTR1 with and without copper (F). D to F surface signals were corrected by the efficiency of biotinylation that was 1.84 ± 0.7 higher in COG1Δ/Δ cells (average ± SEM). Surface levels of ATP7A and CTR1 for each experimental condition were compared using non parametric Kriskal Wallis test followed by pairwise Mann-Whitney U test comparisons, n = 7.