| Live-cell imaging RNAi screen identifies PP2A-B55alpha and importin-beta1 as key mitotic exit regulators in human cells. | |
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MedLine Citation:
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PMID: 20711181 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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When vertebrate cells exit mitosis various cellular structures are re-organized to build functional interphase cells. This depends on Cdk1 (cyclin dependent kinase 1) inactivation and subsequent dephosphorylation of its substrates. Members of the protein phosphatase 1 and 2A (PP1 and PP2A) families can dephosphorylate Cdk1 substrates in biochemical extracts during mitotic exit, but how this relates to postmitotic reassembly of interphase structures in intact cells is not known. Here, we use a live-cell imaging assay and RNAi knockdown to screen a genome-wide library of protein phosphatases for mitotic exit functions in human cells. We identify a trimeric PP2A-B55alpha complex as a key factor in mitotic spindle breakdown and postmitotic reassembly of the nuclear envelope, Golgi apparatus and decondensed chromatin. Using a chemically induced mitotic exit assay, we find that PP2A-B55alpha functions downstream of Cdk1 inactivation. PP2A-B55alpha isolated from mitotic cells had reduced phosphatase activity towards the Cdk1 substrate, histone H1, and was hyper-phosphorylated on all subunits. Mitotic PP2A complexes co-purified with the nuclear transport factor importin-beta1, and RNAi depletion of importin-beta1 delayed mitotic exit synergistically with PP2A-B55alpha. This demonstrates that PP2A-B55alpha and importin-beta1 cooperate in the regulation of postmitotic assembly mechanisms in human cells. |
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Authors:
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Michael H A Schmitz; Michael Held; Veerle Janssens; James R A Hutchins; Otto Hudecz; Elitsa Ivanova; Jozef Goris; Laura Trinkle-Mulcahy; Angus I Lamond; Ina Poser; Anthony A Hyman; Karl Mechtler; Jan-Michael Peters; Daniel W Gerlich |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-08-15 |
Journal Detail:
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Title: Nature cell biology Volume: 12 ISSN: 1476-4679 ISO Abbreviation: Nat. Cell Biol. Publication Date: 2010 Sep |
Date Detail:
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Created Date: 2010-09-02 Completed Date: 2010-10-22 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100890575 Medline TA: Nat Cell Biol Country: England |
Other Details:
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Languages: eng Pagination: 886-93 Citation Subset: IM |
Affiliation:
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Institute of Biochemistry, Swiss Federal Institute of Technology Zurich (ETHZ), Schafmattstrasse 18, CH-8093 Zurich, Switzerland. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Cell Nucleus Division
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drug effects,
physiology Chromosomes / metabolism Cyclin-Dependent Kinases / antagonists & inhibitors, metabolism Flavonoids / pharmacology Golgi Apparatus / metabolism Hela Cells Histones / metabolism Humans Image Processing, Computer-Assisted / methods Interphase / physiology Leupeptins / pharmacology Microscopy, Confocal / methods Microscopy, Fluorescence / methods Mitosis / drug effects, physiology* Mitotic Spindle Apparatus / metabolism Models, Biological Phosphorylation / physiology Piperidines / pharmacology Protein Binding / physiology Protein Phosphatase 2 / genetics, metabolism* RNA Interference* RNA, Small Interfering / genetics Transfection beta Karyopherins / genetics, metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Flavonoids; 0/Histones; 0/KPNB1 protein, human; 0/Leupeptins; 0/PPP2R1A protein, human; 0/PPP2R2A protein, human; 0/Piperidines; 0/RNA, Small Interfering; 0/beta Karyopherins; 133407-82-6/benzyloxycarbonylleucyl-leucyl-leucine aldehyde; 146426-40-6/flavopiridol; EC 2.7.11.22/Cyclin-Dependent Kinases; EC 3.1.3.16/PPP2CA protein, human; EC 3.1.3.16/Protein Phosphatase 2 |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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