First published online February 7, 2007
Journal of Cell Science 120, 405e (2007)
© The Company of Biologists Limited
Cyclin different places
In yeast, the mitotic cyclin Clb2 plays a fundamental role in anaphase initiation and in the maintenance of cell shape throughout G1 phase of the cell cycle. The mechanisms by which Clb2 regulates these processes remain unclear. On p. 702, Raïssa Eluère and others demonstrate that subcellular localisation of Clb2 is a key determinant of its biological function. To investigate the relevance of Clb2 compartmentalisation the authors generated mutant versions of Clb2 that exhibit impaired nuclear import or export and analysed two Clb2-dependent processes: G2-M phase progression and the switch from apical to isotropic growth. They show that nuclear Clb2 is required for timely entry into anaphase whereas the cytoplasmic pool is required for bud morphogenesis. Furthermore, they demonstrate that degradation of Clb2 is also regulated by its localisation, the cytoplasmic form being stabilised during anaphase but not during mitotic exit. The authors propose a model whereby the switch from polarised to isotropic growth occurs when the cytoplasmic pool of Clb2 reaches an appropriate level and this is independent of cell cycle progression.
Related articles in JCS:
- Compartmentalization of the functions and regulation of the mitotic cyclin Clb2 in S. cerevisiae
- Raïssa Eluère, Nicolas Offner, Isabelle Varlet, Olivia Motteux, Laurence Signon, André Picard, Eric Bailly, and Marie-Noëlle Simon
JCS 2007 120: 702-711.
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