module: dmel_ptw_pp1_complexes
title: PTW/PP1 phosphatase complexes in Drosophila melanogaster
label: PTW/PP1 phosphatase complexes
module_type: PROTEIN_COMPLEX
description: >-
  The PTW/PP1 complex is a nuclear phosphatase complex made of the PP1-targeting
  subunit PNUTS, the DNA-binding HMG-box protein Tox4, the WD40 protein Wdr82 and a
  protein phosphatase 1 catalytic subunit. In other animals it binds chromatin,
  dephosphorylates RNA polymerase II and transcription elongation factors near the
  ends of genes and in promoter-proximal regions, and is needed for chromatin
  reorganization at mitotic exit. Drosophila has four PP1 catalytic subunits
  (Pp1-87B, Pp1alpha-96A, Pp1-13C and Flapwing, Flw), and FlyBase defines a PTW
  complex for each.
summary: >-
  PNUTS-Tox4-Wdr82 targeting module with one of four PP1 catalytic subunits.
concepts:
  - {id: GO:0072357, label: PTW/PP1 phosphatase complex}
parts:
  - id: ptw_targeting_module
    label: PNUTS-Tox4-Wdr82 targeting module
    role: PP1 targeting and chromatin binding
    genes: [PNUTS, Tox4, Wdr82]
    complex_label: PNUTS-Tox4-Wdr82
  - id: pp1_catalytic_subunit
    label: PP1 catalytic subunit
    role: phosphatase catalytic subunit
    variant_sets:
      - id: pp1_catalytic_variants
        label: PP1 paralog
        selection: EXACTLY_ONE
        variants:
          - {id: pp1_87b, label: Pp1-87B, genes: [Pp1-87B], function: {id: GO:0004722, label: protein serine/threonine phosphatase activity}}
          - {id: pp1alpha_96a, label: Pp1alpha-96A, genes: [Pp1alpha-96A], function: {id: GO:0004722, label: protein serine/threonine phosphatase activity}}
          - {id: pp1_13c, label: Pp1-13C, genes: [Pp1-13C], function: {id: GO:0004722, label: protein serine/threonine phosphatase activity}}
          - {id: flw, label: Flapwing, genes: [flw], function: {id: GO:0004722, label: protein serine/threonine phosphatase activity}}
connections:
  - source: ptw_targeting_module
    target: pp1_catalytic_subunit
    connection_type: POSITIVELY_REGULATES
    description: PNUTS binds and targets the PP1 catalytic subunit to chromatin.
notes: >-
  The four FlyBase PTW-PP1 variants share PNUTS, Tox4 and Wdr82 and differ in the
  catalytic subunit; they are modelled as one targeting part plus an EXACTLY_ONE
  catalytic choice. Whether all four PP1 paralogs bind PNUTS in vivo in Drosophila is
  not established here. Wdr82 is also a subunit of the Set1/COMPASS complex.
group: PTWP