The present invention relates to a polypeptide having an activity for targeting a heterogeneous polypeptide to a surface of cytoplasmic membrane, a nucleic acid encoding the polypeptide, a construct for introducing into a cell, comprising the nucleic acid, a transformant harboring a carrier for introducing into a cell, a method for localizing a polypeptide on a cell surface, a method for detecting the polypeptide or nucleic acid and a kit therefor, and a method for detecting a ligand or receptor for the polypeptide.