Anti-Protein A antibodies enable researchers to detect and measure the Protein A antigen in biological samples. This target is a reported synonym of the CALHM3 gene, which encodes calcium homeostasis modulator 3. This protein is reported to be a pore-forming subunit of a voltage-gated ion channel, also permeable to larger molecules including ATP. The human version of Protein A has a canonical amino acid length of 344 residues and a protein mass of 38.5 kilodaltons. It is reported to be localized in the cell membrane of cells. Protein A is a member of the CALHM protein family.