Nuclear organisation of NIPP1, a regulatory subunit of protein phosphatase 1 that associates with pre-mRNA splicing factors.
Protein phosphatase-1 (PP1) is complexed to many proteins that target it to particular subcellular locations and regulate its activity. Here, we show that 'nuclear inhibitor of PP1' (NIPP1), a major nuclear PP1-binding protein, shows a speckled nucleoplasmic distribution where it is colocalised with pre-mRNA splicing factors. One of these factors (Sm) is also shown to be complexed to NIPP1 in nuclear extracts. Immunodepletion of NIPP1 from nuclear extracts, or addition of a 'dominant negative' mutant lacking a functional PP1 binding site, greatly reduces pre-mRNA splicing activity in vitro. These findings implicate the NIPP1-PP1 complex in the control of pre-mRNA splicing.
Trinkle-Mulcahy
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L
Department of Biochemistry, The University, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, Scotland, UK. l.trinklemulcahy@dundee.ac.uk
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Prescott
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Claverie-Martin
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Cohen
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S
Lamond
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Cohen
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D002352:Carrier Proteins; D002467:Cell Nucleus / Q000378:metabolism; D004722:Endoribonucleases; D004791:Enzyme Inhibitors / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D016297:Mutagenesis, Site-Directed; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D054645:Protein Phosphatase 1; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017381:Spliceosomes / Q000378:metabolism
D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C021042:protein phosphatase inhibitor-1; D004722:Endoribonucleases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; C097081:PPP1R8 protein, human