Repo-Man recruits PP1γ to chromatin and is essential for cell viability

Laura Trinkle-Mulcahy, Jens Andersen, Wah Lam Yun, Greg Moorhead, Matthias Mann, Angus I. Lamond

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213 Citations (Scopus)


Protein phosphatase 1 (PP1) is a ubiquitous serine/threonine phosphatase regulating many cellular processes. PP1α and -γ are closely related isoforms with distinct localization patterns, shown here by time-lapse microscopy of stably expressed fluorescent protein fusions. A pool of PP1γ is selectively loaded onto chromatin at anaphase. Using stable isotope labeling and proteomics, we identified a novel PP1 binding protein, Repo-Man, which selectively recruits PP1γ onto mitotic chromatin at anaphase and into the following interphase. This approach revealed both novel and known PP1 binding proteins, quantitating their relative distribution between PP1α and -γ in vivo. When overexpressed, Repo-Man can also recruit PP1́ to chromatin. Mutating Repo-Man's PP1 binding domain does not disrupt chromatin binding but abolishes recruitment of PP1 onto chromatin. RNA interference-induced knockdown of Repo-Man caused large-scale cell death by apoptosis, as did overexpression of this dominant-negative mutant. The data indicate that Repo-Man forms an essential complex with PP1γ and is required for the recruitment of PP1 to chromatin.
Original languageEnglish
Pages (from-to)679-692
Number of pages14
JournalJournal of Cell Biology
Issue number5
Early online date21 Feb 2006
Publication statusPublished - 27 Feb 2006
Externally publishedYes

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