CXCR4 is located in lipid rafts in physiologic hypoxia and reoxygenation changes lipid rafts. (A) Treatment of hypoxic OCI-AML3 cells with MβCD results in a dose-dependent decrease of CXCR4 expression. (B) OCI-AML3 stained with FITC-labeled β-subunit cholera toxin show a statistically significant loss of GM1-Ganglioside upon reoxygenation. (C) Reoxygenation leads to loss of cholesterol in lipid raft fractions 1 to 3 in OCI-AML3 cells after sucrose density centrifugation, mimicking MβCD treatment. Cells kept at 21% O2 show the lowest cholesterol per protein content. (D) Western blots of fractions after sucrose density centrifugation: Lck shows redistribution in reoxygenated cells; CXCR4 is lost from lipid rafts during reoxygenation, while Ras is unaltered. Cells kept at 21% are shown as control. Graphs show mean and SD.
