MCF-7 whole cell and membrane extracts (30 μg) were separated by 7.5% SDS-PAGE, and the membrane was blotted with ATP6V0A4 antibody [N1N3-2] (GTX111243) diluted at 1:3000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.