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Initial activation of cyclin‐B1–cdc2 kinase requires phosphorylation of cyclin B1
Author(s) -
Peter Marion,
Le Peuch Christian,
Labbé JeanClaude,
Meyer April N,
Donoghue Daniel J,
Dorée Marcel
Publication year - 2002
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kvf111
Subject(s) - cyclin b1 , cyclin dependent kinase 1 , cyclin dependent kinase complex , cyclin a , cyclin b , cyclin d , microbiology and biotechnology , cyclin a2 , cyclin , biology , phosphorylation , chemistry , cell cycle , biochemistry , cyclin dependent kinase 2 , protein kinase a , cell
At the G 2 /M transition of the cell cycle, the cdc25c phosphatase dephosphorylates inhibitory residues of cdc2, and cyclin‐B–cdc2 kinase (MPF) is activated. Phosphorylation of cyclin B1 induces its nuclear accumulation, and, since cdc25c is also believed to accumulate and activate shortly before G 2 /M in the nucleus, it has been proposed that this induces cyclin‐B1–cdc2 kinase activation. We demonstrate that cyclin B1 phosphorylation has another essential function in vivo : it is required for cdc25c and MPF activation, which does not require nuclear accumulation of cyclin B1, and occurs in the cytoplasm.