Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2000-9-7
pubmed:abstractText
Cyclins and cyclin-dependent kinases (CDKs) are key regulators of the human cell cycle. Here we have directly measured the concentrations of the G(1) and G(2) cyclins and their CDK partners in highly synchronized human cervical carcinoma cells (HeLa). To determine the exact concentrations of cyclins and CDKs in the cell extracts, we developed a relatively simple method that combined the use of (35)S-labeled standards produced in rabbit reticulocyte lysates and immunoblotting with specific antibodies. Using this approach, we formally demonstrated that CDC2 and CDK2 are in excess of their cyclin partners. We found that the concentrations of cyclin A2 and cyclin B1 (at their peak levels in the G(2) phase) were about 30-fold less than that of their partner CDC2. The peak levels of cyclin A2 and cyclin E1, at the G(2) phase and G(1) phase, respectively, were only about 8-fold less than that of their partner CDK2. These ratios are in good agreement with size fractionation analysis of the relative amount of monomeric and complexed forms of CDC2 and CDK2 in the cell. All the cyclin A2 and cyclin E1 are in complexes with CDC2 and CDK2, but there are some indications that a significant portion of cyclin B1 may not be in complex with CDC2. Furthermore, we also demonstrated that the concentration of the CDK inhibitor p21(CIP1/WAF1) induced after DNA damage is sufficient to overcome the cyclin-CDK2 complexes in MCF-7 cells. These direct quantitations formally confirmed the long-held presumption that CDKs are in excess of the cyclins in the cell. Moreover, similar approaches can be used to measure the concentration of any protein in cell-free extracts.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/CDC2 Protein Kinase, http://linkedlifedata.com/resource/pubmed/chemical/CDC2-CDC28 Kinases, http://linkedlifedata.com/resource/pubmed/chemical/CDK2 protein, human, http://linkedlifedata.com/resource/pubmed/chemical/CDKN1A protein, human, http://linkedlifedata.com/resource/pubmed/chemical/Cyclin-Dependent Kinase 2, http://linkedlifedata.com/resource/pubmed/chemical/Cyclin-Dependent Kinase Inhibitor..., http://linkedlifedata.com/resource/pubmed/chemical/Cyclin-Dependent Kinases, http://linkedlifedata.com/resource/pubmed/chemical/Cyclins, http://linkedlifedata.com/resource/pubmed/chemical/Doxorubicin, http://linkedlifedata.com/resource/pubmed/chemical/Enzyme Inhibitors, http://linkedlifedata.com/resource/pubmed/chemical/Protein-Serine-Threonine Kinases
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9494-501
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:10924145-Adenocarcinoma, pubmed-meshheading:10924145-Animals, pubmed-meshheading:10924145-CDC2 Protein Kinase, pubmed-meshheading:10924145-CDC2-CDC28 Kinases, pubmed-meshheading:10924145-Cell Cycle, pubmed-meshheading:10924145-Cell Line, pubmed-meshheading:10924145-Cell-Free System, pubmed-meshheading:10924145-Cyclin-Dependent Kinase 2, pubmed-meshheading:10924145-Cyclin-Dependent Kinase Inhibitor p21, pubmed-meshheading:10924145-Cyclin-Dependent Kinases, pubmed-meshheading:10924145-Cyclins, pubmed-meshheading:10924145-DNA Damage, pubmed-meshheading:10924145-Doxorubicin, pubmed-meshheading:10924145-Enzyme Inhibitors, pubmed-meshheading:10924145-Female, pubmed-meshheading:10924145-HeLa Cells, pubmed-meshheading:10924145-Humans, pubmed-meshheading:10924145-Mammary Neoplasms, Animal, pubmed-meshheading:10924145-Protein-Serine-Threonine Kinases, pubmed-meshheading:10924145-Tumor Cells, Cultured
pubmed:year
2000
pubmed:articleTitle
On the concentrations of cyclins and cyclin-dependent kinases in extracts of cultured human cells.
pubmed:affiliation
Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't