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Characterizing F-actin Disassembly Induced by the Semaphorin-Signaling Component MICAL

Jimok Yoon1, Ruei-Jiun Hung1,2, Jonathan R Terman3

  • 1Departments of Neuroscience and Pharmacology and Neuroscience Graduate Program, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.

Methods in Molecular Biology (Clifton, N.J.)
|October 28, 2016
PubMed

Insights

The MICAL proteins regulate cell behavior by directly modifying actin filaments (F-actin). These redox enzymes oxidize actin, controlling its dynamics and disassembly.

Area of Science:

  • Cell Biology
  • Protein Biochemistry
  • Cytoskeletal Dynamics

Background:

  • MICALs are conserved cytoplasmic proteins involved in semaphorin-plexin signaling.
  • They function as actin regulatory proteins, influencing cellular behaviors.
  • Their precise mechanism of actin regulation was not fully understood.

Purpose of the Study:

  • To characterize the MICALs' function as actin regulatory proteins.
  • To elucidate the mechanism of MICAL-mediated F-actin disassembly.
  • To establish in vitro methods for studying MICAL-actin interactions.

Main Methods:

  • Purification of MICAL proteins and actin.
  • In vitro biochemical assays to assess F-actin dynamics.
  • Characterization of MICAL enzymatic activity on actin substrates.

Main Results:

  • MICALs directly interact with and oxidize actin filaments (F-actin).
  • Specific methionine residues (Met44 and Met47) in actin are stereospecifically oxidized by MICALs.
  • This oxidation leads to the destabilization and disassembly of F-actin.
  • A conserved N-terminal flavoprotein monooxygenase domain is responsible for the redox activity on F-actin.

Conclusions:

  • MICALs are unique redox enzymes that directly regulate F-actin dynamics through oxidation.
  • The characterized in vitro methods allow for detailed study of MICAL-mediated actin disassembly.
  • Understanding this mechanism provides insights into cellular processes regulated by MICALs and actin dynamics.
Keywords:
Actin sedimentationF-actin disassemblyMICALsOxidoreductasePlexinPyrene-actin

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