[Identification of new substrates of cyclin-activated kinases in breast cancers].
Mitogenic and growth-inhibitory signals influence cell-cycle progression through their action on a family of cyclin-dependent kinases (cdks). The activity of cdk complexes is regulated in part by the association of a cyclin partner that acts as a positive effector. These cyclin/CDK complexes promote cell cycle progression by the phosphorylation of key substrates. Cyclin D1 and E are frequently overexpressed in breast cancers and cyclin E overexpression has been correlated with a poor prognostic outcome. The in vivo substrates of cyclin E/CDK2 are, however, not well defined. We screened for cyclin E/CDK2 substrates in nuclear extracts of breast cancer cells as well as using a spotted-array protein library with purified active cyclin E/CDK2 complexes that were expressed in and purified from insect cells. Using this technique several potential cyclin E/CDK2 substrates were isolated. Further work is presently underway to identify these substrates and verify their authenticity as in vivo substrates of cyclin E/CDK2. These potential new substrates will help to unravel the highly complex mechanisms of cell cycle control and perhaps offer new targets for the diagnosis and/or treatment of breast cancer patients.
Lilischkis
R
R
Institute für Pathologie, Medizinische Hochschule Hannover.
Barczak
E
E
Marwedel
M
M
Mehraein
Y
Y
Lauterlein
M
M
Lüscher
B
B
Kreipe
H
H
D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D042846:CDC2-CDC28 Kinases; D019927:Cyclin E / Q000235:genetics; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D005260:Female; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D013379:Substrate Specificity
D019927:Cyclin E; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases