A cDNA encoding a putative ion channel protein was isolated from a rat hippocampus library. This gene, termed phosphohippolin (Php), contains 318 bp open reading frame encoding a single transmembrane protein with a 5' signal peptide region. The deduced amino acid sequence shares 48.1% homology with phospholemman (Plm). Expression sequence tag database (dEST) search identified a mouse (AA521976) and human (AA209241) Php gene homologues. The tissue distribution studies of Php mRNA showed its abundant expression in rat brain and kidney, and in the brain, high expression was observed in hippocampus and cerebellum.