Shadow Of Prion Protein Homolog (SPRN)

SPRN expression in human, rat, and mouse brain. The deduced human protein contains 151 amino acids. The mammalian proteins share 81 to 95% sequence identity. Alignment of all fish and mammalian Sho proteins showed that all have an N-terminal peptide sequence with an endoplasmic reticulum targeting signal for extracellular transport, a basic RG-rich region, a hydrophobic stretch in the middle of the protein that contains the same unusual composition of small aliphatic residues (GAV) as PrP and PrP-like proteins, and a C-terminal region with a putative N-glycosylation site and a possible GPI anchor site (Premzl et al., 2003, 2004). Database searches revealed that SPRN is expressed in mouse and rat embryo, brain, and retina, in human hippocampus, and in zebrafish embryo and retina.