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Lamellipodin promotes actin assembly by clustering Ena/VASP proteins and tethering them to actin filaments

Scott D Hansen1, R Dyche Mullins1

  • 1Department of Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, United States.

Elife
|August 22, 2015
PubMed

Insights

Lamellipodin (Lpd) binds actin filaments, enhancing VASP protein activity and promoting actin assembly. This discovery reveals a positive feedback mechanism controlling actin network formation and protein localization.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Molecular Biology

Background:

  • Enabled/Vasodilator (Ena/VASP) proteins are crucial for actin filament assembly at cell membranes, focal adhesions, and pathogen surfaces.
  • The mig-10/Lamellipodin/RIAM (MRL) protein family acts as key regulators of Ena/VASP, influencing lamellipod formation and neuronal development.

Purpose of the Study:

  • To investigate the interaction between Lamellipodin (Lpd), actin, and VASP.
  • To elucidate the mechanism by which MRL proteins promote actin network formation.

Main Methods:

  • In vivo and in vitro biochemical assays.
  • Analysis of protein-protein interactions and protein activity.

Main Results:

  • Lamellipodin (Lpd) directly binds to actin filaments.
  • Lpd binding regulates Lpd's subcellular localization and enhances VASP polymerase activity.
  • Lpd delivers Ena/VASP proteins to growing actin filament barbed ends, increasing their assembly activity.

Conclusions:

  • Lpd acts as an adaptor, tethering Ena/VASP proteins to actin filaments.
  • This interaction creates a positive feedback loop, enhancing actin filament assembly and regulating protein localization and activity.
Keywords:
E. coliTIRF microscropyactinbiochemistrycell biologycytoskeletonhumanmembranemousesingle moleculexenopus

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