Stoichiometry controls activity of phase-separated clusters of actin signaling proteins

Lindsay B. Case, Xu Zhang, Jonathon A. Ditlev, Michael K Rosen

Research output: Contribution to journalArticle

21 Scopus citations


Biomolecular condensates concentrate macromolecules into foci without a surrounding membrane. Many condensates appear to form through multivalent interactions that drive liquid-liquid phase separation (LLPS). LLPS increases the specific activity of actin regulatory proteins toward actin assembly by the Arp2/3 complex. We show that this increase occurs because LLPS of the Nephrin-Nck-N-WASP signaling pathway on lipid bilayers increases membrane dwell time of N-WASP and Arp2/3 complex, consequently increasing actin assembly. Dwell time varies with relative stoichiometry of the signaling proteins in the phase-separated clusters, rendering N-WASP and Arp2/3 activity stoichiometry dependent. This mechanism of controlling protein activity is enabled by the stoichiometrically undefined nature of biomolecular condensates. Such regulation should be a general feature of signaling systems that assemble through multivalent interactions and drive nonequilibrium outputs.

Original languageEnglish (US)
Pages (from-to)1093-1097
Number of pages5
JournalScience (New York, N.Y.)
Issue number6431
Publication statusPublished - Mar 8 2019


ASJC Scopus subject areas

  • General

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