Time-lapse imaging reveals dynamic relocalization of PP1gamma throughout the mammalian cell cycle.
Protein phosphatase 1 (PP1) is a ubiquitous serine/threonine phosphatase that regulates many cellular processes, including cell division. When transiently expressed as fluorescent protein (FP) fusions, the three PP1 isoforms, alpha, beta/delta, and gamma1, are active phosphatases with distinct localization patterns. We report here the establishment and characterization of HeLa cell lines stably expressing either FP-PP1gamma or FP alone. Time-lapse imaging reveals dynamic targeting of FP-PP1gamma to specific sites throughout the cell cycle, contrasting with the diffuse pattern observed for FP alone. FP-PP1gamma shows a nucleolar accumulation during interphase. On entry into mitosis, it localizes initially at kinetochores, where it exchanges rapidly with the diffuse cytoplasmic pool. A dramatic relocalization of PP1 to the chromosome-containing regions occurs at the transition from early to late anaphase, and by telophase FP-PP1gamma also accumulates at the cleavage furrow and midbody. The changing spatio-temporal distribution of PP1gamma revealed using the stable PP1 cell lines implicates it in multiple processes, including nucleolar function, the regulation of chromosome segregation and cytokinesis.
Trinkle-Mulcahy
Laura
L
Wellcome Trust Biocentre, University of Dundee, Dundee DD1 5EH, United Kingdom. l.trinklemulcahy@dundee.ac.uk
Andrews
Paul D
PD
Wickramasinghe
Sasala
S
Sleeman
Judith
J
Prescott
Alan
A
Lam
Yun Wah
YW
Lyon
Carol
C
Swedlow
Jason R
JR
Lamond
Angus I
AI
D002453:Cell Cycle / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002466:Cell Nucleolus / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D054645:Protein Phosphatase 1; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D011993:Recombinant Fusion Proteins; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1