PP2A-B55 phosphatase counteracts Ki-67-dependent chromosome individualization during mitosis.
Cell Rep
; 43(7): 114494, 2024 Jul 23.
Article
in En
| MEDLINE
| ID: mdl-39003739
ABSTRACT
Cell cycle progression is regulated by the orderly balance between kinase and phosphatase activities. PP2A phosphatase holoenzymes containing the B55 family of regulatory B subunits function as major CDK1-counteracting phosphatases during mitotic exit in mammals. However, the identification of the specific mitotic roles of these PP2A-B55 complexes has been hindered by the existence of multiple B55 isoforms. Here, through the generation of loss-of-function genetic mouse models for the two ubiquitous B55 isoforms (B55α and B55δ), we report that PP2A-B55α and PP2A-B55δ complexes display overlapping roles in controlling the dynamics of proper chromosome individualization and clustering during mitosis. In the absence of PP2A-B55 activity, mitotic cells display increased chromosome individualization in the presence of enhanced phosphorylation and perichromosomal loading of Ki-67. These data provide experimental evidence for a regulatory mechanism by which the balance between kinase and PP2A-B55 phosphatase activity controls the Ki-67-mediated spatial organization of the mass of chromosomes during mitosis.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ki-67 Antigen
/
Protein Phosphatase 2
/
Mitosis
Limits:
Animals
Language:
En
Journal:
Cell Rep
Year:
2024
Document type:
Article
Affiliation country:
Spain
Country of publication:
United States