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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During cell division, chromosomes condense so that the replicated chromatids can be segregated by the mitotic spindle. While condensation is governed by cyclin-dependent kinase 1 (Cdk1) during mitotic entry and early mitosis, it is still poorly understood how condensation is maintained during anaphase after Cdk1 inactivation, and how decondensation is triggered in telophase. Here, we review recent reports that point to a novel role of Aurora B kinase in maintaining condensation and preventing premature nuclear envelope formation during exit from mitosis. Timely decondensation and nuclear envelope formation at the end of mitosis may then be triggered by two mechanisms. One is removing Aurora B phosphorylation marks from chromatin by specific phosphatases. The other is removing and inactivating Aurora B kinase itself by the ubiquitin system. We have recently provided evidence that the AAA ATPase Cdc48/p97 plays a central role in the inactivation of Aurora B, as it extracts ubiquitinated Aurora B from chromosomes and thus reduces chromatinassociated Aurora B activity.
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PMID:A role for Cdc48/p97 and Aurora B in controlling chromatin condensation during exit from mitosis. 2013 Jun 76

The cell cycle-regulated expression of core histone genes is required for DNA replication and proper cell cycle progression in eukaryotic cells. Although some factors involved in histone gene transcription are known, the molecular mechanisms that ensure proper induction of histone gene expression during S phase remain enigmatic. Here we demonstrate that S-phase transcription of the model histone gene HTA1 in yeast is regulated by a novel attach-release mechanism involving phosphorylation of the conserved chromatin boundary protein Yta7 by both cyclin-dependent kinase 1 (Cdk1) and casein kinase 2 (CK2). Outside S phase, integrity of the AAA-ATPase domain is required for Yta7 boundary function, as defined by correct positioning of the histone chaperone Rtt106 and the chromatin remodeling complex RSC. Conversely, in S phase, Yta7 is hyperphosphorylated, causing its release from HTA1 chromatin and productive transcription. Most importantly, abrogation of Yta7 phosphorylation results in constitutive attachment of Yta7 to HTA1 chromatin, preventing efficient transcription post-recruitment of RNA polymerase II (RNAPII). Our study identified the chromatin boundary protein Yta7 as a key regulator that links S-phase kinases with RNAPII function at cell cycle-regulated histone gene promoters.
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PMID:Restriction of histone gene transcription to S phase by phosphorylation of a chromatin boundary protein. 2215 9

In cell culture, many adherent mammalian cells undergo substantial actin cytoskeleton rearrangement prior to mitosis as they detach from the extracellular matrix and become spherical. At the end of mitosis, the actin cytoskeleton is required for cytokinesis and the reassembly of interphase structures as cells spread and reattach to substrate. To understand the processes regulating mitotic cytoskeletal remodeling, we studied how mitotic phosphorylation regulates filamin A (FLNa). FLNa is an actin-crosslinking protein that was previously identified as a cyclin-dependent kinase 1 (Cdk1) binding partner and substrate in vitro. Using quantitative label-based mass spectrometry, we find that FLNa serines 1084, 1459 and 1533 are phosphorylated in mitotic HeLa cells and all three sites match the phosphorylation consensus sequence of Cdk1. To investigate the functional role of mitotic FLNa phosphorylation, we mutated serines 1084, 1459 and 1533 to nonphosphorylatable alanine residues and expressed GFP-tagged FLNa(S1084A,S1459A,S1533A) (FLNa-AAA GFP) in a FLNa-deficient human melanoma cell line called M2. M2 cells expressing FLNa-AAA GFP have enhanced FLNa-AAA GFP and actin localization at sites of contact between daughter cells, impaired post-mitotic daughter cell separation and defects in cell migration. Therefore, mitotic phosphorylation of FLNa is important for successful cell division and interphase cell behavior.
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PMID:Phosphorylation of filamin A by Cdk1 regulates filamin A localization and daughter cell separation. 2544 90