Shisa Homolog 5 (SHISA5)

The induced 1.85-kb transcript encodes a deduced 235-amino acid protein. The deduced 240-amino acid human protein shares 70% identity with mouse Scotin. Both the human and the mouse proteins contain an N-terminal signal sequence, a central transmembrane domain composed of 18 hydrophobic amino acids, and a proline/tyrosine domain, and both show an apparent molecular mass of 25 kD by Western blot analysis. Immunolocalization of exogenously expressed Scotin revealed colocalization with endoplasmic reticulum (ER) markers. Scotin mRNA was induced coincident with apoptosis and was expressed only in spleen and thymus of irradiated wildtype mice and not in the spleen or thymus of irradiated p53 null mice. The deduced 170-amino acid protein contains an MYB DNA-binding domain repeat signature.