Cyclins are essential components of the cell cycle regulatory machinery, which act by activating cyclin-dependent kinases. At the beginning of prophase the mitotic kinase, cyclinB1-cdc2, translocates from the cytoplasm to the nucleus. This translocation is probably controlled by phosphorylation in the amino-terminus of cyclin B1 and may be one of the first events in the initiation of mitosis. The aim of this project is to gain better understanding of the initiation of mitosis through: 1) The identification of the mitosis-specific phosphowlation site(s) in cyclin B1.
2) The analysis of the role of phosphorylation in triggering the translocation of cyclin B1 .
3) The purification of the protein kinase responsible for phosphorylation of cyclin B1 at the initiation of mitosis.
An elucidation of the regulation of the cyclin B1-cdc2 complexes is fundamental to our understanding of the controle of mitosis, and is likely to have a bearing on the deregulation of the cell cycle in cancer cells.