Mutation of Arginine 54 (R54) to Alanine disrupts the Golgi localization of the mutant proteins (AAAA and APWS) in T24 cells, indicating that RPWS motif also serves as the Golgi retention signal for UBIAD1 in bladder carcinoma T24 cells. This evidence concerns the gene UBIAD1 and urinary bladder carcinoma.