The adapter protein SLP-76 mediates "outside-in" integrin signaling and function in T cells

Mol Cell Biol. 2009 Oct;29(20):5578-89. doi: 10.1128/MCB.00283-09. Epub 2009 Aug 10.

Abstract

The adapter protein SH2 domain-containing leukocyte protein of 76 kDa (SLP-76) is an essential mediator of signaling from the T-cell antigen receptor (TCR). We report here that SLP-76 also mediates signaling downstream of integrins in T cells and that SLP-76-deficient T cells fail to support adhesion to integrin ligands. In response to both TCR and integrin stimulation, SLP-76 relocalizes to surface microclusters that colocalize with phosphorylated signaling proteins. Disruption of SLP-76 recruitment to the protein named LAT (linker for activation of T cells) inhibits SLP-76 clustering downstream of the TCR but not downstream of integrins. Conversely, an SLP-76 mutant unable to bind ADAP (adhesion and degranulation-promoting adapter protein) forms clusters following TCR but not integrin engagement and fails to support T-cell adhesion to integrin ligands. These findings demonstrate that SLP-76 relocalizes to integrin-initiated signaling complexes by a mechanism different from that employed during TCR signaling and that SLP-76 relocalization corresponds to SLP-76-dependent integrin function in T cells.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Cell Adhesion / physiology
  • Cell Line, Tumor
  • Cell Membrane / metabolism
  • Cell Movement / physiology
  • Humans
  • Integrins / metabolism*
  • Lymphocyte Function-Associated Antigen-1 / metabolism
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Receptors, Antigen, T-Cell / metabolism*
  • Signal Transduction / physiology
  • T-Lymphocytes / metabolism*
  • rap1 GTP-Binding Proteins / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • FYB1 protein, human
  • Integrins
  • LAT protein, human
  • Lymphocyte Function-Associated Antigen-1
  • Membrane Proteins
  • Phosphoproteins
  • Receptors, Antigen, T-Cell
  • SLP-76 signal Transducing adaptor proteins
  • Receptor Protein-Tyrosine Kinases
  • rap1 GTP-Binding Proteins