Related Experiment Video

Updated: Apr 19, 2026

Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes
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Co-immunoprecipitation Assay for Studying Functional Interactions Between Receptors and Enzymes

Published on: September 28, 2018

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CD20 tails interact with the 14-3-3/GEF-H1 complex and microtubule network upon PKCδ phosphorylation

Kathrin Kläsener1,2,3, Cindy Eunhee Lee4,5, Julian Bender6

  • 1Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany. kathrin.klaesener@bioss.uni-freiburg.de.

The EMBO Journal
|April 17, 2026
PubMed

Insights

CD20 protein anchors the B-cell antigen receptor nanocluster, maintaining resting B-lymphocytes. Anti-CD20 antibodies disrupt this, altering B-cell signaling and potentially impacting therapeutic outcomes.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • CD20 is a B-cell specific transmembrane protein and a key target for therapeutic antibodies.
  • CD20 localizes to IgD-BCR nanoclusters, regulating naïve B-lymphocyte resting state.
  • The precise mechanism of CD20's gatekeeper function in B-cells remains unclear.

Purpose of the Study:

  • To elucidate the molecular mechanism by which CD20 maintains the resting state of B-lymphocytes.
  • To investigate the role of CD20 phosphorylation and its interaction with downstream signaling molecules.
  • To understand how anti-CD20 antibodies affect CD20 localization and B-cell function.

Main Methods:

  • Utilized Ramos cells and human peripheral blood B-cells.
  • Investigated constitutive phosphorylation of CD20 by PKCδ.
  • Examined binding interactions between CD20, 14-3-3 proteins, GEF-H1, and the microtubule network.
  • Analyzed changes in protein complexes upon anti-CD20 antibody binding, including RhoA-GTP/ROCK1.

Main Results:

  • PKCδ constitutively phosphorylates CD20 on serine residues in its cytosolic tails.
  • Phosphorylated CD20 binds 14-3-3 proteins, linking to GEF-H1 and the microtubule network, stabilizing the IgD-BCR nanocluster.
  • Anti-CD20 antibodies induce microtubule dissociation and formation of a RhoA-GTP/ROCK1/CD20 complex, promoting actomyosin contractility.
  • CD20 anchors microtubules to maintain B-cell quiescence and mediates a microtubule-actin switch upon activation.

Conclusions:

  • CD20 acts as a gatekeeper for resting B-lymphocytes by anchoring the microtubule network and stabilizing IgD-BCR nanoclusters.
  • CD20 orchestrates a signaling switch from microtubule-based to actin-based regulation during B-cell activation.
  • These findings offer insights into CD20 function and may inform anti-CD20 antibody therapy optimization.

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