Protein phosphatase that associates with over 200 regulatory proteins to form highly specific holoenzymes which dephosphorylate hundreds of biological targets. Protein phosphatase 1 (PP1) is essential for cell division, and participates in the regulation of glycogen metabolism, muscle contractility and protein synthesis. Dephosphorylates RPS6KB1. Involved in regulation of ionic conductances and long-term synaptic plasticity. May play an important role in dephosphorylating substrates such as the postsynaptic density-associated Ca(2+)/calmodulin dependent protein kinase II. Component of the PTW/PP1 phosphatase complex, which plays a role in the control of chromatin structure and cell cycle progression during the transition from mitosis into interphase. In balance with CSNK1D and CSNK1E, determines the circadian period length, through the regulation of the speed and rhythmicity of PER1 and PER2 phosphorylation. May dephosphorylate CSNK1D and CSNK1E. Dephosphorylates the 'Ser-418' residue of FOXP3 in regulatory T-cells (Treg) from patients with rheumatoid arthritis, thereby inactivating FOXP3 and rendering Treg cells functionally defective .
Subcellular locations: Cytoplasm, Nucleus, Nucleus, Nucleolus, Nucleus, Nucleoplasm, Nucleus speckle, Chromosome, Centromere, Kinetochore, Cleavage furrow, Midbody, Mitochondrion, Cytoplasm, Cytoskeleton, Microtubule organizing center
Colocalizes with SPZ1 in the nucleus (By similarity). Colocalizes with URI1 at mitochondrion . Rapidly exchanges between the nucleolar, nucleoplasmic and cytoplasmic compartments . Highly mobile in cells and can be relocalized through interaction with targeting subunits . In the presence of PPP1R8 relocalizes from the nucleolus to nuclear speckles . Shows a dynamic targeting to specific sites throughout the cell cycle . Highly concentrated in nucleoli of interphase cells and localizes at kinetochores early in mitosis . Relocalization to chromosome-containing regions occurs at the transition from early to late anaphase . Also accumulates at the cleavage furrow and midbody by telophase . Colocalizes with DYNLT4 in the microtubule organizing center (MTOC).