The actin cytoskeleton is required for the trafficking of the B cell antigen receptor to the late endosomes

Traffic. 2001 Jun;2(6):414-27. doi: 10.1034/j.1600-0854.2001.002006414.x.


The B cell antigen receptor (BCR) plays two central roles in B cell activation: to internalize antigens for processing and presentation, and to initiate signal transduction cascades that both promote B cells to enter the cell cycle and facilitate antigen processing by accelerating antigen transport. An early event in B cell activation is the association of BCR with the actin cytoskeleton, and an increase in cellular F-actin. Current evidence indicates that the organization of actin filaments changes in response to BCR-signaling, making actin filaments good candidates for regulation of BCR-antigen targeting. Here, we have analyzed the role of actin filaments in BCR-mediated antigen transport, using actin filament-disrupting reagents, cytochalasin D and latrunculin B, and an actin filament-stabilizing reagent, jasplakinolide. Perturbing actin filaments, either by disrupting or stabilizing them, blocked the movement of BCR from the plasma membrane to late endosomes/lysosomes. Cytochalasin D-treatment dramatically reduced the rate of internalization of BCR, and blocked the movement of the BCR from early endosomes to late endosomes/lysosomes, without affecting BCR-signaling. Thus, BCR-trafficking requires functional actin filaments for both internalization and movement to late endosomes/lysosomes, defining critical control points in BCR-antigen targeting.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / metabolism
  • Actins / physiology*
  • Animals
  • Antineoplastic Agents / pharmacology
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology
  • Cell Line
  • Cell Membrane / metabolism
  • Cross-Linking Reagents / pharmacology
  • Cytochalasin D / pharmacology
  • Cytoskeleton / metabolism*
  • Depsipeptides*
  • Dose-Response Relationship, Drug
  • Endosomes / metabolism*
  • Humans
  • Hybridomas / metabolism
  • Lymphocyte Activation
  • Lysosomes / metabolism
  • Mice
  • Microscopy, Electron
  • Microscopy, Fluorescence
  • Nucleic Acid Synthesis Inhibitors / pharmacology
  • Peptides, Cyclic / pharmacology
  • Phosphorylation
  • Protein Transport
  • Rats
  • Receptors, Antigen, B-Cell / metabolism*
  • Signal Transduction
  • Thiazoles / pharmacology
  • Thiazolidines
  • Time Factors
  • Tyrosine / metabolism


  • Actins
  • Antineoplastic Agents
  • Bridged Bicyclo Compounds, Heterocyclic
  • Cross-Linking Reagents
  • Depsipeptides
  • Nucleic Acid Synthesis Inhibitors
  • Peptides, Cyclic
  • Receptors, Antigen, B-Cell
  • Thiazoles
  • Thiazolidines
  • jasplakinolide
  • Cytochalasin D
  • Tyrosine
  • latrunculin B