The budding yeast PP2ACdc55 protein phosphatase prevents the onset of anaphase in response to morphogenetic defects.
Faithful chromosome transmission requires establishment of sister chromatid cohesion during S phase, followed by its removal at anaphase onset. Sister chromatids are tethered together by cohesin, which is displaced from chromosomes through cleavage of its Mcd1 subunit by the separase protease. Separase is in turn inhibited, up to this moment, by securin. Budding yeast cells respond to morphogenetic defects by a transient arrest in G2 with high securin levels and unseparated chromatids. We show that neither securin elimination nor forced cohesin cleavage is sufficient for anaphase in these conditions, suggesting that other factors contribute to cohesion maintainance in G2. We find that the protein phosphatase PP2A bound to its regulatory subunit Cdc55 plays a key role in this process, uncovering a new function for PP2A(Cdc55) in controlling a noncanonical pathway of chromatid cohesion removal.
Chiroli
Elena
E
Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano-Bicocca, Milano, Italy.
Rossio
Valentina
V
Lucchini
Giovanna
G
Piatti
Simonetta
S
D000705:Anaphase / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000502:physiology*; D002842:Chromatids / Q000201:enzymology / Q000502:physiology; D009687:Nuclear Proteins / Q000502:physiology; D010749:Phosphoprotein Phosphatases / Q000502:physiology*; D054648:Protein Phosphatase 2; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D064249:Securin
C071246:CDC55 protein, S cerevisiae; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C578004:PDS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2