Time-lapse imaging reveals dynamic relocalization of PP1gamma throughout the mammalian cell cycle.
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Trinkle-Mulcahy L, Andrews PD, Wickramasinghe S, Sleeman J, Prescott A, Lam YW, Lyon C, Swedlow JR, Lamond AI
Time-lapse imaging reveals dynamic relocalization of PP1gamma throughout the mammalian cell cycle.
Mol Biol Cell. 2003 Jan;14(1):107-17.
- PubMed ID
- 12529430 [ View in PubMed]
- Abstract
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.