Noncatalytic requirement for cyclin A-cdk2 in p27 turnover Journal Article
| Authors: | Zhu, X. H.; Nguyen, H.; Halicka, H. D.; Traganos, F.; Koff, A. |
| Article Title: | Noncatalytic requirement for cyclin A-cdk2 in p27 turnover |
| Abstract: | Ubiquitin-dependent proteolysis makes a major contribution to decreasing the levels of p27. Ubiquitin-dependent proteolysis of p27kip1 is growth and cell cycle regulated in two ways: first, skp2, a component of the E3-ubiquitin ligase, is growth regulated, and second, a kinase must phosphorylate the threonine-187 position on p27 so that it can be recognized by skp2. In vitro, p27 is phosphorylated by cyclin E- and cyclin A-associated cdk2 as well as by cyclin B1-cdk1. Having analyzed the effect of different cyclin-cyclin-dependent kinase complexes on ubiquitination of p27 in a reconstitution assay system, we now report a noncatalytic requirement for cyclin A-cdk2. Multiparameter flow cytometric analysis also indicates that p27 turnover correlates best with the onset of S phase, once the levels of cyclin A become nearly maximal. Finally, increasing the amount of both cyclin E-cdk2 and skp2 was less efficient at promoting p27 ubiquitination than was increasing the amount of cyclin A-cdk2 alone in extracts prepared from cultures of >93%-purified G1 cells. Together these lines of evidence suggest that cyclin A-cdk2 plays an ancillary noncatalytic role in the ubiquitination of p27 by the SCFskp2 complex. |
| Keywords: | protein phosphorylation; unclassified drug; human cell; mutation; flow cytometry; ubiquitin; cell cycle proteins; cell cycle s phase; complex formation; ubiquitin protein ligase; protein degradation; enzyme activity; hela cells; ubiquitination; cell culture; molecular recognition; protein p27; cyclin-dependent kinase inhibitor p27; tumor suppressor proteins; cell isolation; threonine; ubiquitin protein ligase e3; cyclin a; cell cycle g1 phase; g1 phase; s phase; reaction analysis; cyclin e; s phase kinase associated protein 2; s-phase kinase-associated proteins; cyclin dependent kinase 2; cyclin-dependent kinase 2; cell extract; enzyme reconstitution; cdc2-cdc28 kinases; humans; human; priority journal; article; staphylococcus phage 187 |
| Journal Title: | Molecular and Cellular Biology |
| Volume: | 24 |
| Issue: | 13 |
| ISSN: | 0270-7306 |
| Publisher: | American Society for Microbiology |
| Date Published: | 2004-07-01 |
| Start Page: | 6058 |
| End Page: | 6066 |
| Language: | English |
| DOI: | 10.1128/mcb.24.13.6058-6066.2004 |
| PROVIDER: | scopus |
| PMCID: | PMC480915 |
| PUBMED: | 15199159 |
| DOI/URL: | |
| Notes: | Mol. Cell. Biol. -- Cited By (since 1996):28 -- Export Date: 16 June 2014 -- CODEN: MCEBD -- Source: Scopus |
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