Phospholipase Cgamma2 provides survival signals via Bcl2 and A1 in different subpopulations of B cells

J Biol Chem. 2003 Oct 31;278(44):43654-62. doi: 10.1074/jbc.M307318200. Epub 2003 Aug 19.

Abstract

PLCgamma2 plays a critical role in B cell receptor (BCR) signaling and its targeted deletion results in defective B cell development and function. Here, we show that PLCgamma2 deficiency specifically blocks B cell maturation at the transitional type 2 (T2) to follicular (FO) B cell transition and the PLCgamma2 pathway regulates survival of B cells. BCR-induced apoptosis is dramatically enhanced in all subsets of splenic PLCgamma2-deficient B cells, especially in T2 and FO B cell subpopulations. We also find that all splenic PLCgamma2-deficient B cell subpopulations express abnormally low levels of Bcl-2 protein. In addition, PLCgamma2 deficiency disrupts BCR-mediated induction of A1 expression. Enforced expression of Bcl-2 prevents BCR-induced apoptosis in all splenic PLCgamma2-deficient B cell subpopulations and partially restores the numbers of PLCgamma2-deficient FO B cells. In contrast to Bcl-2, enforced expression of A1 preferentially prevents BCR-induced apoptosis in PLCgamma2-deficient FO B cells and partially restores the numbers of these B cells. Therefore, the PLCgamma2 pathway provides a survival signal via regulation of Bcl-2 in all splenic B cell subpopulations and via additional induction of A1 in mature FO B cells.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis
  • B-Lymphocytes / metabolism
  • Blotting, Western
  • Bone Marrow Transplantation
  • Cell Separation
  • Cell Survival
  • Cells, Cultured
  • DNA-Binding Proteins / metabolism*
  • Flow Cytometry
  • Humans
  • In Situ Nick-End Labeling
  • Mice
  • Phospholipase C gamma
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Rats
  • Replication Protein C
  • Retroviridae
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction*
  • Spleen / metabolism
  • Time Factors
  • Type C Phospholipases / metabolism*

Substances

  • DNA-Binding Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Type C Phospholipases
  • Phospholipase C gamma
  • Replication Protein C