title: Determinants of the nucleolar targeting of protein phosphatase-1.
abstract: The ubiquitously expressed protein Ser/Thr phosphatase-1 isoforms PP1alpha, PP1beta and PP1gamma1 are dynamically targeted to distinct, but overlapping cellular compartments by associated proteins. Within the nucleus of HeLa cells, EGFP-tagged PP1gamma1 and PP1beta were predominantly targeted to the nucleoli, while PP1alpha showed a more diffuse distribution. Using PP1 chimaeras and point mutants we show here that a single N-terminal residue, i.e., Gln20 for PP1alpha, Arg19 for PP1beta and Arg20 for PP1gamma1 accounts for their distinct subnuclear distribution. Our data also suggest that the N-terminus of PP1beta and PP1gamma1 harbours an interaction site for one or more nucleolar interactors.
authors.affiliation: Division of Biochemistry, Department of Molecular Cell Biology, Faculty of Medicine, Campus Gasthuisberg, KULeuven, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Lesage
authors.forename: Monique
authors.initials: M
authors.lastname: Beullens
authors.forename: Hugo
authors.initials: H
authors.lastname: Ceulemans
authors.forename: Bernard
authors.initials: B
authors.lastname: Himpens
authors.forename: Mathieu
authors.initials: M
authors.lastname: Bollen
mesh_terms: D000595:Amino Acid Sequence; D002466:Cell Nucleolus / Q000201:enzymology*; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D007527:Isoenzymes / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D011487:Protein Conformation; D054645:Protein Phosphatase 1; D021381:Protein Transport / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1