The Alzheimer’s disease-linked amyloid-bprecursor pro-tein (APP) belongs to a superfamily of proteins, which also comprises the amyloid-b precursor-like proteins, APLP1 and APLP2. Whereas APP has been identified in both lower and higher vertebrates, thus far, APLP1 and 2 have been characterized only in human and rodents. Here we identify the first nonmammalian APLP2 protein in the South African claw-toed frogXenopus identity between the Xenopusand mammalian APLP2 proteins is 75%, with the highest degree of conservation in a number of amino-terminal regions, the transmembrane domain and the cytoplasmic tail
