RGS Molecule Expression in Murine B Lymphocytes and Ability to Down-Regulate Chemotaxis to Lymphoid Chemokines

Abstract

Ag-mediated changes in B lymphocyte migration are important for normal immune function, yet the mechanisms by which these changes occur are poorly defined. Because chemokines direct many lymphocyte movements, molecules that regulate signaling by G protein-coupled chemokine receptors are likely to participate in Ag receptor-induced changes in cell migration. In this study, we have investigated the expression pattern and activity in murine B cells of members of the regulators of G protein signaling (RGS) family of molecules. We present the sequence of mouse RGS1 and describe a novel short isoform of RGS3 that we term RGS3s. Following in vivo activation by Ag, B cells rapidly up-regulate expression of RGS1 and RGS2 while simultaneously decreasing expression of RGS3 and RGS14. Anergic hen egg lysozyme autoantigen-binding B cells are also shown to have slightly elevated RGS1 and RGS2 expression. CD40 signaling, by contrast, fails to cause rapid up-regulation of RGS1 or RGS2. Using a transient transfection approach in a mature B cell line, 2PK3, we demonstrate that RGS1 and RGS3s are effective inhibitors of chemotaxis toward the lymphoid tissue chemokines stromal cell-derived factor-1, B lymphocyte chemoattractant, and EBV-induced molecule 1 ligand chemokine, whereas RGS2 has a minimal effect on migration to these chemokines. Together these findings support the conclusion that Ag-mediated changes in RGS molecule expression are part of the mechanism by which Ag receptor signaling regulates B cell migration within lymphoid tissues. The findings also suggest important roles for additional G protein-mediated events in B cell activation and tolerance.

The Rap GTPases Regulate B Cell Migration Toward the Chemokine Stromal Cell-Derived Factor-1 (CXCL12): Potential Role for Rap2 in Promoting B Cell Migration

“…As an initial test of this hypothesis, we asked whether treating B cells with the chemokine SDF-1 induced the activation of Rap1 or Rap2. We tested this in three different B cell lines that had been reported to migrate in response to SDF-1, the 2PK3 and WEHI-231 murine B cell lines (36) and the DT40 chicken B cell line (11). To assess Rap activation we used a GSTRalGDS fusion protein to selectively precipitate the active GTPbound forms of Rap1 and Rap2, which could then be detected by immunoblotting.…”

“…Migration assays were performed in 24-well plates using 5-m polycarbonate Transwell inserts (Costar, Cambridge, MA) as described by Reif and Cyster (36). SDF-1 was diluted in chemotaxis medium (RPMI 1640/10 mM HEPES/0.5% BSA) and added to the lower chamber while 5 ϫ 10 5 cells in 0.1 ml chemotaxis medium were added to the upper chamber.…”

Activation of a TGF-β-Specific Multistep Gene Expression Program in Mature Macrophages Requires Glucocorticoid-Mediated Surface Expression of TGF-β Receptor II

“…ID3 has complex function in the immune and vascular systems including support of B cell immunity, dendritic cell differentiation, and angiogenesis (43,44). RGS1 has been described as a negative regulator of G protein signaling in mononuclear cells (45). The functions of RGS1 in M2 macrophages are not known.…”

Prostaglandin F2α inhibits adipocyte differentiation via a Gαq‐Calcium‐Calcineurin‐Dependent signaling pathway

“…pMSCV-GFP-RGS2 was generated by introducing the GFP-RGS2 fusion sequence from pEGFP-C1-mRGS2 [Reif and Cyster, 2000] into pMSCV-H2K. pMSCV-CD8-bARK was constructed by inserting the CD8-bARK fusion sequence from the pcDNAIII T8 bARK [Crespo et al, 1995] into pMSCV-GFP.…”