| Sp1 phosphorylation by cyclin-dependent kinase 1/cyclin B1 represses its DNA-binding activity during mitosis in cancer cells. | |
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MedLine Citation:
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PMID: 22266860 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Sp1 is important for the transcription of many genes. Our previous studies have shown that Sp1 is degraded in normal cell, but it is preserved in cancer cells during mitosis and exists a priori in the daughter cells, ready to engage in gene transcription and thereby contributes to the proliferation and survival of cancer cells. The mechanism by which Sp1 is preserved in cancer cells during mitosis remains unknown. In this study, we observed that Sp1 strongly colocalized with cyclin-dependent kinase 1 (CDK1)/cyclin B1 during mitosis. Moreover, we showed that Sp1 is a novel mitotic substrate of CDK1/cyclin B1 and is phosphorylated by it at Thr 739 before the onset of mitosis. Phospho-Sp1 reduced its DNA-binding ability and facilitated the chromatin condensation process during mitosis. Mutation of Thr739 to alanine resulted in Sp1 remaining in the chromosomes, delayed cell-cycle progression, and eventually led to apoptosis. Screening of Sp1-associated proteins during mitosis by using liquid chromatography/mass spectrometry indicated the tethering of Sp1 to myosin/F-actin. Furthermore, phospho-Sp1 and myosin/F-actin appeared to exist as a congregated ring at the periphery of the chromosome. However, at the end of mitosis and the beginning of interphase, Sp1 was dephosphorylated by PP2A and returned to the chromatin. These results indicate that cancer cells use CDK1 and PP2A to regulate the movement of Sp1 in and out of the chromosomes during cell-cycle progression, which may benefit cancer-cell proliferation.Oncogene advance online publication, 23 January 2012; doi:10.1038/onc.2011.649. |
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Authors:
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J-Y Chuang; S-A Wang; W-B Yang; H-C Yang; C-Y Hung; T-P Su; W-C Chang; J-J Hung |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-23 |
Journal Detail:
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Title: Oncogene Volume: - ISSN: 1476-5594 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-23 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8711562 Medline TA: Oncogene Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, Tainan, Taiwan. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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