The F-Actin-Binding MPRIP Forms Phase-Separated Condensates and Associates with PI(4,5)P2 and Active RNA Polymerase

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Can Balaban1, Martin Sztacho1, Michaela Blažíková2

  • 1Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Czech Academy of Sciences, v.v.i., 142 20 Prague, Czech Republic.

Cells
|April 30, 2021
PubMed

Insights

Myosin phosphatase rho-interacting protein (MPRIP) is found in the cell nucleus, binding to nuclear actin and regulating transcription. This discovery sheds light on nuclear actin dynamics and gene expression control.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Myosin phosphatase rho-interacting protein (MPRIP) is an F-actin-binding protein.
  • Nuclear actin dynamics play a role in gene regulation.

Purpose of the Study:

  • To investigate the presence and function of MPRIP in the cell nucleus.
  • To elucidate the role of MPRIP in nuclear processes, particularly transcription.

Main Methods:

  • Immunofluorescence microscopy to detect MPRIP localization.
  • Biochemical assays to identify MPRIP complex components.
  • In vitro studies to analyze MPRIP phase separation and actin binding.

Main Results:

  • MPRIP localizes to nuclear speckles and lipid islets, sites involved in transcription.
  • MPRIP is a component of the RNA Polymerase II/Nuclear Myosin 1 complex.
  • MPRIP forms liquid-like phase-separated condensates that bind nuclear F-actin.

Conclusions:

  • MPRIP's nuclear localization and interaction with actin suggest a role in regulating transcription.
  • PIP2/MPRIP association and phase separation may control RNAPII transcription via nuclear actin polymerization.
Keywords:
MPRIPPIP2actinnucleusphase separation

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