Chromosome repositioning requires energy. The relocation of human chromosomes 10 and 18 after incubation in low serum is energy dependent. The nuclear location of human chromosomes 10, 18, and X in were determined in normal human proliferating cell nuclei treated with ouabain (ATPase inhibitor) (a), AG10 (GTPase inhibitor) (b), or a combination of both (c) before and during incubation in low serum for 15 minutes. Normal control analysis data without any treatment is displayed in (d). The error bars show the standard error of the mean. The stars indicate a significant difference (P < 0.05) from cells treated only with the inhibitor.