The human novel gene pp5644 (GeneBank Accession No. AF289559) coding for 124 amino acids was recently cloned. Overexpression of pp5644 in Hela cells significantly inhibited the growth and colony formation. The pp5644-interacting protein FAPP1 (phosphatidylinositol-four-phosphate adaptor protein1) associated protein-1, called FASP1, was obtained by using yeast two-hybrid system. The interaction between pp5644 and FASP1 was experimentally confirmed by GST pull-down assay in vitro and co-immunoprecipitation assay in vivo. Co-localization of pp5644 and FASP1 in cytoplasm in Hela cells could further support the interaction. Based on the experimental results, it is suggested that pp5644 physically bind to FASP1 and the biological significance of this kind of interaction in vivo is discussed.