Mitosis persists in the absence of Cdk1 activity when proteolysis or protein phosphatase activity is suppressed

Skoufias, Dimitrios A.; Indorato, Rose-Laure; Lacroix, Françoise B.; Panopoulos, Andreas; Margolis, Robert L.

doi:10.1083/jcb.200704117

Cited by 93 publications

(101 citation statements)

References 68 publications

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“…We checked the exit of mitosis by the localization of markers differently distributed in mitosis and interphase (data not shown). Exit from mitosis of LMB-treated cells was confirmed by the absence of MPM2 mitosis-specific phosphoproteins in the nuclei 34,35 and by the absence of cyclin B1 in early G 1 nuclei as expected after destruction in metaphase. 36 We verified that mitotic phosphorylation of B23/NPM on Thr199, 37 is released in LMB-treated cells.…”

Section: Resultssupporting

confidence: 53%

The traffic of proteins between nucleolar organizer regions and prenucleolar bodies governs the assembly of the nucleolus at exit of mitosis

Muro¹,

Gébrane-Younès²,

Jobart-Malfait³

et al. 2010

Nucleus

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is also a plurifunctional domain involved in assembly of RNPs and a target for viral proteins and viral RNAs. [8][9][10][11] The assembly of the nucleolus starts during telophase by activation of rDNA transcription of several nucleolar organizer regions (NORs) and by progressive recruitment of early and late processing proteins on rRNA transcripts. In parallel, prenucleolar bodies (PNBs) are assembled. [12][13][14][15][16] The PNBs contain nucleolar processing proteins, pre-rRNAs and snoRNAs. 17 Even though PNBs are formed in all animal and plant cells, their role in the dynamics of DFC and GC assembly is still unknown.It is possible to observe and measure the motion of proteins or RNP complexes in living cells. Using these approaches it was demonstrated that macromolecules within the nucleus are highly mobile by a combination of passive diffusion and highaffinity binding sites. [18][19][20] It was also established that the assembly of nuclear bodies after mitosis is strictly ordered. 14,[21][22][23][24] It is now important to characterize the dynamics of the complexes during the building of the functional domains integrated in the nuclear network. We examined the role of the PNB step in the kinetics of DFC and GC assembly. Using photoactivation, 25 weThe building of nuclear bodies after mitosis is a coordinated event crucial for nuclear organization and function. The nucleolus is assembled during early G 1 phase. Here, two periods (early G1a and early G1b) have been defined. During these periods, the nucleolar compartments (DFC, GC) corresponding to different steps of ribosome biogenesis are progressively assembled. In telophase, rDNA transcription is first activated and PNBs (reservoirs of nucleolar processing proteins) are formed. The traffic of the processing proteins between incipient nucleoli and PNBs was analyzed using photoactivation. We demonstrate that the DFC protein fibrillarin passes from one incipient nucleolus to other nucleoli but not to PNBs, and that the GC proteins, B23/NPM and Nop52, shuttle between PNBs and incipient nucleoli. This difference in traffic suggests a way of regulating assembly first of DFC and then of GC. The time of residency of GC proteins is high in incipient nucleoli compared to interphase nuclei, it decreases in LMB-treated early G1a cells impairing the assembly of GC. Because the assembly of the nucleolus and that of the Cajal body at the exit from mitosis are both sensitive to CRM1 activity, we discuss the fact that assembly of GC and/or its interaction with DFC in early G1a depends on shuttling between PNBs and NORs in a manner dependent on Cajal body assembly.www.landesbioscience.comNucleus 203 RESEARCH PAPER decreases as expected of proteins trafficking between nucleolus and nucleoplasm. Surprisingly, activated PAGFP-B23/NPM is detected in PNBs 5-10 seconds after activation (Fig. 1D). The uptake of B23/NPM in PNBs is observed in all PNBs containing mDsRed-Nop52 visible in the focal plane. This indicates that feedback of activated molecules occurs between incipient nuc...

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Section: Resultssupporting

confidence: 53%

The traffic of proteins between nucleolar organizer regions and prenucleolar bodies governs the assembly of the nucleolus at exit of mitosis

Muro¹,

Gébrane-Younès²,

Jobart-Malfait³

et al. 2010

Nucleus

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“…To determine whether CDK1 also phosphorylates S83, HeLa cells were arrested in G1 by L-mimosine treatment or in mitosis by nocodazole treatment and then treated with CDK1 active site inhibitor RO-3306, supplemented with MG132 proteasome inhibitor to prevent mitotic slippage (28,29). CDK1 inhibition by RO-3306 abolished S83 phosphorylation and δ-4E-BP1 formation, in addition to reducing phosphorylation at the other phosphorylation sites (Fig.…”

Section: δ-4e-bp1 Hyperphosphorylation Is a Feature Of Mitosis Acrossmentioning

confidence: 97%

Mitotic protein kinase CDK1 phosphorylation of mRNA translation regulator 4E-BP1 Ser83 may contribute to cell transformation

Velásquez

Cheng

Shuda

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Mammalian target of rapamycin (mTOR)-directed eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) phosphorylation promotes cap-dependent translation and tumorigenesis. During mitosis, cyclin-dependent kinase 1 (CDK1) substitutes for mTOR and fully phosphorylates 4E-BP1 at canonical sites (T37, T46, S65, and T70) and the noncanonical S83 site, resulting in a mitosis-specific hyperphosphorylated δ isoform. Colocalization studies with a phospho-S83 specific antibody indicate that 4E-BP1 S83 phosphorylation accumulates at centrosomes during prophase, peaks at metaphase, and decreases through telophase. Although S83 phosphorylation of 4E-BP1 does not affect general cap-dependent translation, expression of an alanine substitution mutant 4E-BP1.S83A partially reverses rodent cell transformation induced by Merkel cell polyomavirus small T antigen viral oncoprotein. In contrast to inhibitory mTOR 4E-BP1 phosphorylation, these findings suggest that mitotic CDK1-directed phosphorylation of δ-4E-BP1 may yield a gain of function, distinct from translation regulation, that may be important in tumorigenesis and mitotic centrosome function.

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“…For purvalanol A or staurosporine exposure, mitotic HeLa cells arrested with 0.3 M nocodazole were collected by the mechanical shake-off procedure. After removal of nocodazole, mitotic cells were replated and incubated with medium containing 25 M purvalanol A or 10 M staurosporine for 2 h in the presence of 10 M MG132 (23).…”

Section: Methodsmentioning

confidence: 99%

“…Immunoprecipitation and Immunoblotting-Immunoprecipitation and immunoblot analyses were performed as described previously (23).…”

Section: Methodsmentioning

confidence: 99%

Furry Protein Promotes Aurora A-mediated Polo-like Kinase 1 Activation

Ikeda

Chiba

Ohashi

et al. 2012

Journal of Biological Chemistry

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Background:The protein kinase Plk1 plays a crucial role in mitotic spindle pole integrity. Results: Furry binds to Plk1 and Aurora A and promotes Aurora A-mediated Plk1 activation. Conclusion: Furry specifies the spatiotemporal regulation of Plk1 at centrosomes in early mitosis. Significance: Our data indicate a new mechanism of the regulation of Plk1 activity and bipolar spindle organization during mitosis.

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Mitosis persists in the absence of Cdk1 activity when proteolysis or protein phosphatase activity is suppressed

Cited by 93 publications

References 68 publications

The traffic of proteins between nucleolar organizer regions and prenucleolar bodies governs the assembly of the nucleolus at exit of mitosis

The traffic of proteins between nucleolar organizer regions and prenucleolar bodies governs the assembly of the nucleolus at exit of mitosis

Mitotic protein kinase CDK1 phosphorylation of mRNA translation regulator 4E-BP1 Ser83 may contribute to cell transformation

Furry Protein Promotes Aurora A-mediated Polo-like Kinase 1 Activation

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