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Updated: May 25, 2026

Examination of Thymic Positive and Negative Selection by Flow Cytometry
14:29

Examination of Thymic Positive and Negative Selection by Flow Cytometry

Published on: October 8, 2012

Ca-dependent Ras/Erk signaling mediates negative selection of autoreactive B cells

Andre Limnander1, Arthur Weiss

  • 1Department of Medicine; Howard Hughes Medical Institute; Rosalind Russell Medical Research Center for Arthritis; University of California at San Francisco; San Francisco, CA USA.

Small Gtpases
|February 1, 2012
PubMed

Insights

Ras/Erk pathway signaling is crucial for B cell development and function. New findings reveal distinct pathway activation mechanisms controlling B cell apoptosis and selection during development.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • The Ras/Erk pathway is vital for lymphocyte development and function.
  • Mechanisms controlling distinct Ras/Erk pathway outputs in different cell types are not well understood.

Purpose of the Study:

  • To investigate the role of Ras/Erk signaling in B cell apoptosis and selection.
  • To elucidate the distinct mechanisms of Ras/Erk pathway activation in B cells.

Main Methods:

  • Analysis of Ras/Erk pathway activation in B cells.
  • Investigation of the role of cytosolic Ca(2+) and diacylglycerol (DAG) in pathway activation.
  • Examination of developmental regulation of upstream mediators.

Main Results:

  • Ras/Erk signaling unexpectedly sensitizes B cells to apoptosis for autoreactive cell elimination.
  • Cytosolic Ca(2+) increases are necessary and sufficient for a distinct Ras/Erk activation pathway.
  • Biochemical events differ between Ca(2+)- and DAG-mediated Ras/Erk activation.
  • Developmental regulation of upstream mediators dictates pathway activation at different B cell stages.

Conclusions:

  • Antigen stimulation activates distinct Ras/Erk pathways at different developmental stages, controlling B cell selection, development, and activation.
  • Specific molecular mechanisms conferring functional specificity to Ras/Erk signaling modules require further investigation.

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