Premium
Human cyclin B3
Author(s) -
Tschöp Katrin,
Müller Gerd A.,
Grosche Jens,
Engeland Kurt
Publication year - 2006
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05184.x
Subject(s) - cyclin a2 , cyclin a , cyclin d , cyclin , cyclin e , microbiology and biotechnology , cyclin b , biology , cyclin d1 , cyclin dependent kinase complex , cyclin dependent kinase , cell cycle , biochemistry , cell
Cyclins form complexes with cyclin‐dependent kinases. By controlling activity of the enzymes, cyclins regulate progression through the cell cycle. A‐ and B‐type cyclins were discovered due to their distinct appearance in S and G 2 phases and their rapid proteolytic destruction during mitosis. Transition from G 2 to mitosis is basically controlled by B‐type cyclins. In mammals, two cyclin B proteins are well characterized, cyclin B1 and cyclin B2. Recently, a human cyclin B3 gene was described. In contrast to the expression pattern of other B‐type cyclins, we find cyclin B3 mRNA expressed not only in S and G 2 /M cells but also in G 0 and G 1 . Human cyclin B3 is expressed in different variants. We show that one isoform remains in the cytoplasm, whereas the other variant is translocated to the nucleus. Transport to the nucleus is dependent on three autonomous nonclassical nuclear localization signals that where previously not implicated in nuclear translocation. It had been shown that cyclin B3 coimmunoprecipitates with cdk2; but this complex does not exhibit any kinase activity. Furthermore, a degradation‐resistant version of cyclin B3 can arrest cells in G 1 and G 2 . Taken together with the finding that cyclin B3 mRNA is not only expressed in G 2 /M but is also detected in significant amounts in resting cells and in G 1 cells. This may suggest a dominant‐negative function of human cyclin B3 in competition with activating cyclins in G 0 and the G 1 phase of the cell cycle.