Clusters of glycolipid and glycosylphosphatidylinositol-anchored proteins in lymphoid cells: accumulation of actin regulated by local tyrosine phosphorylation

Eur J Immunol. 1999 Feb;29(2):556-62. doi: 10.1002/(SICI)1521-4141(199902)29:02<556::AID-IMMU556>3.0.CO;2-2.


Lateral cross-linking of glycosylphosphatidylinositol (GPI)-anchored proteins and glycosphingolipids can trigger a signaling cascade which leads to activation of lymphoid cells. A possible explanation how the signal is transduced through the plasma membrane has arisen from the concept of raft sphingolipid-cholesterol microdomains in cell membranes. Cross-linking of GPI-anchored proteins, glycolipids and other raft components leads to the formation of stabilized membrane patches in the plasma membrane which enrich members of the Src-tyrosine kinase family. We have studied cellular responses to raft patch formation in the Jurkat T cell line and in particular changes in the actin cytoskeleton. We found that raft patches formed by GPI-anchored CD59 protein and the ganglioside GM1 accumulate filamentous actin. Most interestingly, we observed a strong accumulation of tyrosine-phosphorylated proteins in raft patches, strongly supporting the view that they can function as centers of signal transduction. Using a Lck kinase-deficient variant of Jurkat cells and a specific Lck and Fyn tyrosine kinase inhibitor we found that enrichment of actin in raft patches is dependent on phosphotyrosine accumulation in the patches. These observations show a link between raft-mediated signaling and the interaction of actin cytoskeleton with raft membrane domains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / immunology*
  • Cell Membrane / immunology
  • Cell Membrane / metabolism
  • Cross-Linking Reagents
  • Glycosphingolipids / immunology*
  • Glycosphingolipids / metabolism
  • Glycosylphosphatidylinositols
  • Humans
  • Jurkat Cells
  • Lymphocyte Activation
  • Membrane Glycoproteins / immunology*
  • Signal Transduction / immunology*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism


  • Actins
  • Cross-Linking Reagents
  • Glycosphingolipids
  • Glycosylphosphatidylinositols
  • Membrane Glycoproteins