Mouse CD24 as a signaling molecule for integrin-mediated cell binding: functional and physical association with src-kinases

Biochem Biophys Res Commun. 1997 May 19;234(2):330-4. doi: 10.1006/bbrc.1997.6639.


CD24 is a differentiation antigen expressed by murine hematopoietic and neural cells which is linked to the membrane via a glycosylphosphatidylinositol (GPI) anchor. In monocytic ESb-MP cells the molecule serves as a ligand for P-selectin and triggering with CD24 specific antibodies can activate VLA-5/L1-mediated cell adhesion in these cells. We report here that the aggregation is specific for CD24 and not seen with antibodies to the GPI-anchored molecule Thy-1. The Tyr-kinase inhibitor herbimycin can block the aggregation. We studied CD24 associated molecules that might be involved in signal transduction. Antibodymediated crosslinking of CD24 induced a rapid Tyr-phosphorylation of several cellular proteins in ESb-MP cells which correlated with an elevated activity of p56lck but not p60fyn or MAP-1 kinase. Several phosphorylated proteins were co-immunoprecipitated with CD24. Re-immunoprecipitation allowed the detection of p56lck, p56hck, and p54lyn but not p60fyn, PI-3k, or PLCgamma as a compenent of the CD24 detergent resistant complex. It is suggested that the CD24-associated kinases are involved in the activation of cell aggregation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies
  • Antigens, CD / chemistry
  • Antigens, CD / metabolism*
  • CD24 Antigen
  • Cell Aggregation
  • Cell Line
  • Cross-Linking Reagents
  • Enzyme Activation
  • Integrins / metabolism*
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
  • Membrane Glycoproteins*
  • Mice
  • Molecular Structure
  • Molecular Weight
  • Monocytes / cytology
  • Monocytes / immunology
  • Monocytes / metabolism
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Signal Transduction
  • Tyrosine / chemistry
  • Tyrosine / metabolism
  • src-Family Kinases / metabolism*


  • Antibodies
  • Antigens, CD
  • CD24 Antigen
  • Cd24a protein, mouse
  • Cross-Linking Reagents
  • Integrins
  • Membrane Glycoproteins
  • Phosphoproteins
  • Tyrosine
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
  • src-Family Kinases