Band3 contributed to S1P efflux from K562 cells.

<p>The effects of the overexpression or the knockdown of Band3 on S1P excretion from K562 cells were investigated. (A–C) Band3 plasmid or GFP plasmid was transfected into K562 cells and 48 hours later, a C₁₇S1P formation assay was performed with or without 0.1 mM H₂DIDS. (A) Western blots of Band3 with membranous protein. The whole cell lysate of RBCs (2 μg) was placed as a positive control. Pan-cadherin was utilized as an internal control (n = 3/group). (B, C) C₁₇S1P levels in the supernatants (B) and in the K562 cells (C) (n = 5/group). *<i>P</i> < 0.05 vs. GFP alone and GFP with H₂DIDS. †<i>P</i> < 0.05 vs. GFP with H₂DIDS. (D–F) The knockdown of Band3 was performed using siRNA. Forty-eight hours later, a C₁₇S1P formation assay was performed. (D) Western blot of Band3 with membranous protein. Pan-cadherin was utilized as an internal control (n = 3/group). (E, F) the C₁₇S1P levels in the medium (E) and in the K562 cells (F) (n = 5/group). Error bars indicate SEM.