Determinants of the nucleolar targeting of protein phosphatase-1.
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.
Lesage
Bart
B
Division of Biochemistry, Department of Molecular Cell Biology, Faculty of Medicine, Campus Gasthuisberg, KULeuven, Belgium.
Beullens
Monique
M
Ceulemans
Hugo
H
Himpens
Bernard
B
Bollen
Mathieu
M
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
D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1