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Rapid redistribution of CD20 to a low density detergent-insoluble membrane compartment

J P Deans1, S M Robbins, M J Polyak

  • 1Immunology Research Group, Department of Medical Biochemistry, The University of Calgary, Calgary, Alberta T2N 4N1, Canada. jdeans@acs.ucalgary.ca

The Journal of Biological Chemistry
|February 7, 1998
PubMed

Insights

Monoclonal anti-CD20 antibodies rapidly move CD20 into detergent-insoluble membrane domains in B cells. This redistribution to lipid-rich areas suggests a mechanism for CD20-mediated signal transduction.

Area of Science:

  • Immunology
  • Cell Biology
  • Biochemistry

Background:

  • CD20 is a B cell surface protein crucial for B lymphocyte signaling upon antibody engagement.
  • Anti-CD20 antibodies are used therapeutically, but the precise signaling mechanism remains incompletely understood.

Purpose of the Study:

  • To investigate the dynamic membrane redistribution of CD20 following antibody binding.
  • To elucidate the role of membrane microdomains in CD20-mediated signal transduction.

Main Methods:

  • Treatment of human B lymphocytes with anti-CD20 monoclonal antibodies.
  • Analysis of CD20 localization using detergent solubility assays.
  • Fractionation of cell membranes via sucrose density gradients.

Main Results:

  • Anti-CD20 antibody treatment rapidly induced CD20 redistribution into detergent-insoluble membrane compartments within seconds.
  • Up to 95% of CD20 molecules were found in these insoluble fractions, depending on the antibody.
  • Detergent-insoluble CD20 localized to low-density sucrose gradient fractions, indicating association with glycolipid-rich membrane domains.
  • Co-localization with Src family tyrosine kinases in these domains suggests a role in signal initiation.

Conclusions:

  • CD20 rapidly translocates to detergent-insoluble, glycolipid-rich membrane microdomains upon antibody engagement.
  • This redistribution is a key early event in CD20-mediated signal transduction.
  • Intracellular signaling partners of CD20 are likely located within these Triton-insoluble membrane fractions.

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