A composition-dependent molecular clutch between T cell signaling condensates and actin

Elife. 2019 Jul 3;8:e42695. doi: 10.7554/eLife.42695.

Abstract

During T cell activation, biomolecular condensates form at the immunological synapse (IS) through multivalency-driven phase separation of LAT, Grb2, Sos1, SLP-76, Nck, and WASP. These condensates move radially at the IS, traversing successive radially-oriented and concentric actin networks. To understand this movement, we biochemically reconstituted LAT condensates with actomyosin filaments. We found that basic regions of Nck and N-WASP/WASP promote association and co-movement of LAT condensates with actin, indicating conversion of weak individual affinities to high collective affinity upon phase separation. Condensates lacking these components were propelled differently, without strong actin adhesion. In cells, LAT condensates lost Nck as radial actin transitioned to the concentric network, and engineered condensates constitutively binding actin moved aberrantly. Our data show that Nck and WASP form a clutch between LAT condensates and actin in vitro and suggest that compositional changes may enable condensate movement by distinct actin networks in different regions of the IS.

Keywords: LAT microclusters; T cell signaling; actin cytoskeleton; biochemical reconstitution; biochemistry; biomolecular condensate; cell biology; chemical biology; compositional control; human.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Adaptor Proteins, Signal Transducing / metabolism
  • Humans
  • Lymphocyte Activation*
  • Membrane Proteins / metabolism
  • Oncogene Proteins / metabolism
  • Protein Binding
  • Protein Multimerization*
  • Protein Transport
  • Signal Transduction*
  • T-Lymphocytes / metabolism*
  • Wiskott-Aldrich Syndrome Protein / metabolism

Substances

  • Actins
  • Adaptor Proteins, Signal Transducing
  • LAT protein, human
  • Membrane Proteins
  • Nck protein
  • Oncogene Proteins
  • WAS protein, human
  • Wiskott-Aldrich Syndrome Protein