A, western blot of HEK cells heterologously expressing Hv1‐HA or Hv1, probed with a C‐terminal anti‐Hv1 or an anti‐HA antibody. B, western blot of HEK cells expressing Hv1 and of human sperm, probed with a C‐terminal anti‐Hv1 antibody; in sperm, the antibody recognizes an additional protein of ∼25 kDa (termed Hv1Sper). C, cartoon of Hv1 showing the proteotypic peptides detected by MS (green) and the epitope of the anti‐Hv1 antibody (AB). D, western blot of human monocyte cell line THP‐1 and human lung epithelial cell lysate, probed with the C‐terminal anti‐Hv1 antibody.