title: Evolutionary features and intracellular behavior of the PRTB protein.
abstract: Human PRTB encodes a proline-rich protein of 168 amino acids (PRTB). We analyzed the evolutionary patterns of PRTB from various vertebrate species. Maximum likelihood analyses indicated that while mammalian PRTB has been very well conserved and underwent a significantly slower rate of evolution, only the branch leading to fish PRTB has undergone adaptive evolution. We generated several mutant PRTBs fused to the GFP variant, Venus, and found that the degradation of PRTB was enhanced by the transfection of an E2, UbcH5. Since mutation of the K153 site in PRTB was refractory to its degradation, proteolysis was suggested to be mediated by ubiquitination of K153. The subcellular localization of PRTB was also investigated, which showed that mutation of the K4 site completely prevented the nuclear localization of this protein. Together, these results suggest that Lys residues might play important roles in regulating the intracellular dynamics of the PRTB protein.
authors.affiliation: Department of Molecular Pathobiochemistry, Gifu University Graduate School of Medicine, Yanagido, Gifu, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Matsunami
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Tokiko
authors.initials: T
authors.lastname: Minoura
authors.forename: Yukio
authors.initials: Y
authors.lastname: Okano
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Muto
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism
chemical_list: C498224:DAZAP2 protein, human; D016601:RNA-Binding Proteins; D025801:Ubiquitin; D049452:Green Fluorescent Proteins