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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Cell Nucleolus / enzymology*
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Green Fluorescent Proteins / analysis
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Green Fluorescent Proteins / genetics
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HeLa Cells
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Humans
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Isoenzymes / analysis
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Isoenzymes / genetics
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Isoenzymes / metabolism
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Molecular Sequence Data
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Phosphoprotein Phosphatases / chemistry*
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Phosphoprotein Phosphatases / genetics
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Phosphoprotein Phosphatases / metabolism*
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Point Mutation
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Protein Conformation
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Protein Phosphatase 1
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Protein Transport / genetics
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
Substances
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Isoenzymes
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Recombinant Fusion Proteins
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enhanced green fluorescent protein
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Green Fluorescent Proteins
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Phosphoprotein Phosphatases
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Protein Phosphatase 1