Phosphorylation of CDC25A on SER283 in late S/G2 by CDK/cyclin complexes accelerates mitotic entry Laurent Mazzolini Anaïs Broban Carine Froment Odile Burlet-Schiltz Arnaud Besson Stéphane Manenti Christine Dozier 10.6084/m9.figshare.3573591.v2 https://tandf.figshare.com/articles/dataset/Phosphorylation_of_CDC25A_on_SER283_in_Late_S_G2_by_CDK_Cyclin_complexes_accelerates_mitotic_entry/3573591 <p>The Cdc25A phosphatase is an essential activator of CDK-cyclin complexes at all steps of the eukaryotic cell cycle. The activity of Cdc25A is itself regulated in part by positive and negative feedback regulatory loops performed by its CDK-cyclin substrates that occur in G1 as well as during the G1/S and G2/M transitions. However, the regulation of Cdc25A during G2 phase progression before mitotic entry has not been intensively characterized. Here, we identify by mass spectrometry analysis a new phosphorylation event of Cdc25A on Serine283. Phospho-specific antibodies revealed that the phosphorylation of this residue appears in late S/G2 phase of an unperturbed cell cycle and is performed by CDK-cyclin complexes. Overexpression studies of wild-type and non-phosphorylatable mutant forms of Cdc25A indicated that Ser283 phosphorylation increases the G2/M-promoting activity of the phosphatase without impacting its stability or subcellular localization. Our results therefore identify a new positive regulatory loop between Cdc25A and its CDK-cyclin substrates which contributes to accelerate entry into mitosis through the regulation of Cdc25A activity in G2.</p> 2016-08-31 19:54:10 activating phosphorylation Cdc25A CDK-cyclin cell cycle G2/M transition