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- Title
RSK promotes G2/M transition through activating phosphorylation of Cdc25A and Cdc25B.
- Authors
Wu, C F; Liu, S; Lee, Y-C; Wang, R; Sun, S; Yin, F; Bornmann, W G; Yu-Lee, L-Y; Gallick, G E; Zhang, W; Lin, S-H; Kuang, J
- Abstract
Activation of the mitogen-activated protein kinase (MAPK) cascade in mammalian cell lines positively regulates the G2/M transition. The molecular mechanism underlying this biological phenomenon remains poorly understood. Ribosomal S6 kinase (RSK) is a key downstream element of the MAPK cascade. Our previous studies established roles of RSK2 in Cdc25C activation during progesterone-induced meiotic maturation of Xenopus oocytes. In this study we demonstrate that both recombinant RSK and endogenous RSK in Xenopus egg extracts phosphorylate all three isoforms of human Cdc25 at a conserved motif near the catalytic domain. In human HEK293 and PC-3mm2 cell lines, RSK preferentially phosphorylates Cdc25A and Cdc25B in mitotic cells. Phosphorylation of the RSK sites in these Cdc25 isoforms increases their M-phase-inducing activities. Inhibition of RSK-mediated phosphorylation of Cdc25 inhibits G2/M transition. Moreover, RSK is likely to be more active in mitotic cells than in interphase cells, as evidenced by the phosphorylation status of T359/S363 in RSK. Together, these findings indicate that RSK promotes G2/M transition in mammalian cells through activating phosphorylation of Cdc25A and Cdc25B.
- Subjects
MITOGEN-activated protein kinases; CELL division; RIBOSOMES; PHOSPHORYLATION; PROGESTERONE; CATALYTIC domains; MITOSIS
- Publication
Oncogene, 2014, Vol 33, Issue 18, p2385
- ISSN
0950-9232
- Publication type
Article
- DOI
10.1038/onc.2013.182